From patchwork Fri Aug 21 05:38:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253149 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1EF4C433E1 for ; Fri, 21 Aug 2020 06:03:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4692F21775 for ; Fri, 21 Aug 2020 06:03:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="R7Z/0sSE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728004AbgHUGDW (ORCPT ); Fri, 21 Aug 2020 02:03:22 -0400 Received: from mo4-p04-ob.smtp.rzone.de ([85.215.255.122]:27503 "EHLO mo4-p04-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727822AbgHUGDT (ORCPT ); Fri, 21 Aug 2020 02:03:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1597989764; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=nY4BxNQOFda9XwFeVTl1N0PjBehJP85AOcrN7aq3NG4=; b=R7Z/0sSEeOUhtxkERCAA+MEoH9XNJ7NO9eEsUllz6V0Npp8zUlhZy3Rq+flIZaKj1J d2Gr6QvNUWIgKBhotdJS3zUwpAHgBQbeegv5gBlwBVntHanwntGe1DrX99l64Tz47OHi L/n/zDBt0+VqFTQo7Mlmm9oDTZzzKaOXSYhfANSV20UeVZ0pA9ONh6MziVFyXunu8+dt rqv5Iazvyc9/nTIahvwwlOqkdsEbGmdX+udUrapJUHg00hygsigYV9x9q2ENVJm4pIP+ zqKE0Dugv+jXm9jSFNk//VTHf1OZDINM1rJv25n3QbpBabZlKZL3Oh6rbfzDMhxJZz9c Ud7A== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xm0dNS3IdRAZAL+p6A==" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw7L61IGLF (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 21 Aug 2020 08:01:18 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter Subject: [PATCH v33 01/12] Linux Random Number Generator Date: Fri, 21 Aug 2020 07:38:37 +0200 Message-ID: <7836152.NyiUUSuA9g@positron.chronox.de> In-Reply-To: <5532247.MhkbZ0Pkbq@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> MIME-Version: 1.0 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org In an effort to provide a flexible implementation for a random number generator that also delivers entropy during early boot time, allows replacement of the deterministic random number generation mechanism, implement the various components in separate code for easier maintenance, and provide compliance to SP800-90[A|B|C], introduce the Linux Random Number Generator (LRNG) framework. The general design is as follows. Additional implementation details are given in [1]. The LRNG consists of the following components: 1. The LRNG implements a DRNG. The DRNG always generates the requested amount of output. When using the SP800-90A terminology it operates without prediction resistance. The secondary DRNG maintains a counter of how many bytes were generated since last re-seed and a timer of the elapsed time since last re-seed. If either the counter or the timer reaches a threshold, the secondary DRNG is seeded from the entropy pool. In case the Linux kernel detects a NUMA system, one secondary DRNG instance per NUMA node is maintained. 2. The DRNG is seeded by concatenating the data from the following sources: (a) the output of the entropy pool, (b) the Jitter RNG if available and enabled, and (c) the CPU-based noise source such as Intel RDRAND if available and enabled. The entropy estimate of the data of all noise sources are added to form the entropy estimate of the data used to seed the DRNG with. The LRNG ensures, however, that the DRNG after seeding is at maximum the security strength of the DRNG. The LRNG is designed such that none of these noise sources can dominate the other noise sources to provide seed data to the DRNG during due to the following: (a) During boot time, the amount of received interrupts are the trigger points to (re)seed the DRNG. (b) At runtime, the available entropy from the slow noise source is concatenated with a pre-defined amount of data from the fast noise sources. In addition, each DRNG reseed operation triggers external noise source providers to deliver one block of data. 3. The entropy pool accumulates entropy obtained from certain events, which will henceforth be collectively called "slow noise sources". The entropy pool collects noise data from slow noise sources. Any data received by the LRNG from the slow noise sources is inserted into the entropy pool using an LFSR with a primitive and irreducible polynomial. The following sources of entropy are used: (a) When an interrupt occurs, the high-resolution time stamp is mixed into the LFSR. This time stamp is credited with heuristically implied entropy. (b) HID event data like the key stroke or the mouse coordinates are mixed into the LFSR. This data is not credited with entropy by the LRNG. (c) Device drivers may provide data that is mixed into the LFSR. This data is not credited with entropy by the LRNG. (d) After the entropy pool is ``read'' by the DRNG, the data used to seed the DRNG is mixed back into the entropy pool to stir the pool. This data is not credited with entropy by the LRNG. Any data provided from user space by either writing to /dev/random, /dev/urandom or the IOCTL of RNDADDENTROPY on both device files are always injected into the entropy pool. In addition, when a hardware random number generator covered by the Linux kernel HW generator framework wants to deliver random numbers, it is injected into the entropy pool as well. HW generator noise source is handled separately from the other noise source due to the fact that the HW generator framework may decide by itself when to deliver data whereas the other noise sources always requested for data driven by the LRNG operation. Similarly any user space provided data is inserted into the entropy pool. When the DRNG requires data from the entropy pool, the entire entropy pool is processed with an SP800-90A section 10.3.1 compliant hash_df function to generate random numbers. To speed up the interrupt handling code of the LRNG, the time stamp collected for an interrupt event is truncated to the 8 least significant bits. 64 truncated time stamps are concatenated and then jointly inserted into the LFSR. During boot time, until the fully seeded stage is reached, each time stamp with its 32 least significant bits is inserted into the LFSR at the time of arrival. The LRNG allows the DRNG mechanism to be changed at runtime. Per default, a ChaCha20-based DRNG is used. The ChaCha20-DRNG implemented for the LRNG is also provided as a stand-alone user space deterministic random number generator. The LRNG also offers an SP800-90A DRBG based on the Linux kernel crypto API DRBG implementation. The processing of entropic data from the noise source before injecting them into the DRNG is performed with the following mathematical operations: 1. LFSR: The 8 least significant bits of the time stamp data received from the interrupts are processed with an LFSR. That LFSR is implemented identically to the LSFR used in the existing /dev/random implementation except that it is capable of processing an entire word and that a different polynomial is used. The reason for the different polynomial is performance in a performance sensitive code section, the interrupt handler. The chosen polynomials have 4 taps. Also, this LFSR-approach is used in the OpenBSD /dev/random equivalent. 2. Concatenation: The temporary seed buffer used to seed the DRNG is a concatenation of parts of the entropy pool data, and the CPU noise source output. The DRNG always tries to seed itself with 256 bits of entropy, except during boot. In any case, if the noise sources cannot deliver that amount, the available entropy is used and the DRNG keeps track on how much entropy it was seeded with. The entropy implied by the LRNG available in the entropy pool may be too conservative. To ensure that during boot time all available entropy from the entropy pool is transferred to the DRNG, the hash_df function always generates 256 data bits during boot to seed the DRNG. During boot, the DRNG is seeded as follows: 1. The DRNG is reseeded from the entropy pool and potentially the fast noise sources if the entropy pool has collected at least 32 bits of entropy from the interrupt noise source. The goal of this step is to ensure that the DRNG receives some initial entropy as early as possible. In addition it receives the entropy available from the fast noise sources. 2. The DRNG is reseeded from the entropy pool and potentially the fast noise sources if all noise sources collectively can provide at least 128 bits of entropy. 3. The DRNG is reseeded from the entropy pool and potentially the fast noise sources if all noise sources collectivel can provide at least 256 bits. At the time of the reseeding steps, the DRNG requests as much entropy as is available in order to skip certain steps and reach the seeding level of 256 bits. This may imply that one or more of the aforementioned steps are skipped. In all listed steps, the DRNG is (re)seeded with a number of random bytes from the entropy pool that is at most the amount of entropy present in the entropy pool. This means that when the entropy pool contains 128 or 256 bits of entropy, the DRNG is seeded with that amount of entropy as well. Before the DRNG is seeded with 256 bits of entropy in step 3, requests of random data from /dev/random are not processed. The hash_df operation providing random data from the entropy pool will always require that all entropy sources collectively can deliver at least 129 entropy bits as configured with (128 bits of entropy for seeding plus one bit of entropy that is lost with the post processing as defined in SP800-90B). The DRNG operates as deterministic random number generator with the following properties: * The maximum number of random bytes that can be generated with one DRNG generate operation is limited to 4096 bytes. When longer random numbers are requested, multiple DRNG generate operations are performed. The ChaCha20 DRNG as well as the SP800-90A DRBGs implement an update of their state after completing a generate request for backtracking resistance. * The secondary DRNG is reseeded with whatever entropy is available – in the worst case where no additional entropy can be provided by the noise sources, the DRNG is not re-seeded and continues its operation to try to reseed again after again the expiry of one of these thresholds: - If the last reseeding of the secondary DRNG is more than 600 seconds ago, or - 2^20 DRNG generate operations are performed, whatever comes first, or - the secondary DRNG is forced to reseed before the next generation of random numbers if data has been injected into the LRNG by writing data into /dev/random or /dev/urandom. The chosen values prevent high-volume requests from user space to cause frequent reseeding operations which drag down the performance of the DRNG. With the automatic reseeding after 600 seconds, the LRNG is triggered to reseed itself before the first request after a suspend that put the hardware to sleep for longer than 600 seconds. The LRNG uses the following runtime memory using the currently smallest configuration: * 576 bytes (512 bytes for the entropy pool and 64 for the entropy pool meta data) for the entropy pool management * 64 bytes per CPU for the time stamp array To support smaller devices including IoT environments, this patch allows reducing the runtime memory footprint of the LRNG at compile time by selecting smaller entropy pool sizes. The entropy pool has support for sizes of 256, 128 and 64 bytes supported by primitive and irreducible polynomials. The time stamp array is reduced to one atomic_t variable per CPU, i.e. 4 bytes when CONFIG_BASE_SMALL is selected during kernel configuration. This implies that after the receipt of 4 interrupts on one CPU, the data is injected into the LFSR. Depending on the behavior of the CPU caches, this may imply that the average interrupt handler execution time increases a bit, since instead of injecting 8 atomic_t values at one given time into the LFSR, only one is processed which may incur cache misses. When selecting the compilation of a kernel for a small environment, prevent the allocation of a buffer up to 4096 bytes to serve user space requests. In this case, the stack variable of 64 bytes is used to serve all user space requests. The LRNG has the following properties: * internal noise source: interrupts timing with fast boot time seeding * high performance of interrupt handling code: The LRNG impact on the interrupt handling has been reduced to a minimum. On one example system, the LRNG interrupt handling code executes within an average of 65 cycles whereas the existing /dev/random on the same device takes about 97 cycles when measuring the execution time of add_interrupt_randomness(). * lockless LFSR to collect raw entropy supporing concurrency-free use of massive parallel systems * use of standalone ChaCha20 based RNG with the option to use a different DRNG selectable at compile time * "atomic" seeding of secondary DRBG to ensure full entropy transport * instantiate one DRNG per NUMA node * support for runtime switchable output DRNGs * use of only well-defined entropy-preserving operations to collect, compress and forward entropy: concatenation, LFSR, SP800-90A hash_df function * compile-time selectable entropy pool size: the choice also uses the applicable LFSR polynomial to maintain the entropy pool size * support of small systems by allowing the reduction of the runtime memory needs Further details including the rationale for the design choices and properties of the LRNG together with testing is provided at [1]. In addition, the documentation explains the conducted regression tests to verify that the LRNG is API and ABI compatible with the existing /dev/random implementation. [1] https://www.chronox.de/lrng.html CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Mathematical aspects Reviewed-by: "Peter, Matthias" Reviewed-by: Marcelo Henrique Cerri Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- MAINTAINERS | 7 + drivers/char/Kconfig | 2 + drivers/char/Makefile | 9 +- drivers/char/lrng/Kconfig | 68 +++ drivers/char/lrng/Makefile | 9 + drivers/char/lrng/lrng_archrandom.c | 93 ++++ drivers/char/lrng/lrng_aux.c | 136 ++++++ drivers/char/lrng/lrng_chacha20.c | 320 ++++++++++++++ drivers/char/lrng/lrng_chacha20.h | 29 ++ drivers/char/lrng/lrng_drng.c | 409 ++++++++++++++++++ drivers/char/lrng/lrng_interfaces.c | 649 ++++++++++++++++++++++++++++ drivers/char/lrng/lrng_internal.h | 336 ++++++++++++++ drivers/char/lrng/lrng_lfsr.h | 152 +++++++ drivers/char/lrng/lrng_pool.c | 589 +++++++++++++++++++++++++ drivers/char/lrng/lrng_sw_noise.c | 155 +++++++ drivers/char/lrng/lrng_sw_noise.h | 57 +++ include/linux/lrng.h | 63 +++ 17 files changed, 3082 insertions(+), 1 deletion(-) create mode 100644 drivers/char/lrng/Kconfig create mode 100644 drivers/char/lrng/Makefile create mode 100644 drivers/char/lrng/lrng_archrandom.c create mode 100644 drivers/char/lrng/lrng_aux.c create mode 100644 drivers/char/lrng/lrng_chacha20.c create mode 100644 drivers/char/lrng/lrng_chacha20.h create mode 100644 drivers/char/lrng/lrng_drng.c create mode 100644 drivers/char/lrng/lrng_interfaces.c create mode 100644 drivers/char/lrng/lrng_internal.h create mode 100644 drivers/char/lrng/lrng_lfsr.h create mode 100644 drivers/char/lrng/lrng_pool.c create mode 100644 drivers/char/lrng/lrng_sw_noise.c create mode 100644 drivers/char/lrng/lrng_sw_noise.h create mode 100644 include/linux/lrng.h diff --git a/MAINTAINERS b/MAINTAINERS index deaafb617361..74f6fd1ba1ec 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -10084,6 +10084,13 @@ F: Documentation/litmus-tests/ F: Documentation/memory-barriers.txt F: tools/memory-model/ +LINUX RANDOM NUMBER GENERATOR (LRNG) DRIVER +M: Stephan Mueller +S: Maintained +W: https://www.chronox.de/lrng.html +F: drivers/char/lrng/* +F: include/linux/lrng.h + LIS3LV02D ACCELEROMETER DRIVER M: Eric Piel S: Maintained diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index b1bd336761b1..8a5b8a2db2c7 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -470,6 +470,8 @@ config ADI and SSM (Silicon Secured Memory). Intended consumers of this driver include crash and makedumpfile. +source "drivers/char/lrng/Kconfig" + endmenu config RANDOM_TRUST_CPU diff --git a/drivers/char/Makefile b/drivers/char/Makefile index ffce287ef415..2110d3e28cf2 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -3,7 +3,14 @@ # Makefile for the kernel character device drivers. # -obj-y += mem.o random.o +obj-y += mem.o + +ifeq ($(CONFIG_LRNG),y) + obj-y += lrng/ +else + obj-y += random.o +endif + obj-$(CONFIG_TTY_PRINTK) += ttyprintk.o obj-y += misc.o obj-$(CONFIG_ATARI_DSP56K) += dsp56k.o diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig new file mode 100644 index 000000000000..059b21d9728c --- /dev/null +++ b/drivers/char/lrng/Kconfig @@ -0,0 +1,68 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Linux Random Number Generator configuration +# + +menuconfig LRNG + bool "Linux Random Number Generator" + select CRYPTO_LIB_SHA256 if CRYPTO + help + The Linux Random Number Generator (LRNG) is the replacement + of the existing /dev/random provided with drivers/char/random.c. + It generates entropy from different noise sources and + delivers significant entropy during boot. + +if LRNG + +choice + prompt "LRNG Entropy Pool Size" + default LRNG_POOL_SIZE_4096 + help + Select the size of the LRNG entropy pool. The size of the + entropy pool is relevant for the amount of entropy that + the LRNG can maintain as a maximum. The larger the size + of the entropy pool is the more entropy can be maintained + but the less often older entropic values are overwritten + with new entropy. + + config LRNG_POOL_SIZE_512 + bool "512 bits" + + config LRNG_POOL_SIZE_1024 + bool "1024 bits" + + config LRNG_POOL_SIZE_2048 + bool "2048 bits" + + config LRNG_POOL_SIZE_4096 + bool "4096 bits (default)" + + config LRNG_POOL_SIZE_8192 + bool "8192 bits" + + config LRNG_POOL_SIZE_16384 + bool "16384 bits" + + config LRNG_POOL_SIZE_32768 + bool "32768 bits" + + config LRNG_POOL_SIZE_65536 + bool "65536 bits" + + config LRNG_POOL_SIZE_131072 + bool "131072 bits" +endchoice + +config LRNG_POOL_SIZE + int + default 0 if LRNG_POOL_SIZE_512 + default 1 if LRNG_POOL_SIZE_1024 + default 2 if LRNG_POOL_SIZE_2048 + default 3 if LRNG_POOL_SIZE_4096 + default 4 if LRNG_POOL_SIZE_8192 + default 5 if LRNG_POOL_SIZE_16384 + default 6 if LRNG_POOL_SIZE_32768 + default 7 if LRNG_POOL_SIZE_65536 + default 8 if LRNG_POOL_SIZE_131072 + +endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile new file mode 100644 index 000000000000..1d2a0211973d --- /dev/null +++ b/drivers/char/lrng/Makefile @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the Linux Random Number Generator. +# + +obj-y += lrng_pool.o lrng_aux.o \ + lrng_sw_noise.o lrng_archrandom.o \ + lrng_drng.o lrng_chacha20.o \ + lrng_interfaces.o \ diff --git a/drivers/char/lrng/lrng_archrandom.c b/drivers/char/lrng/lrng_archrandom.c new file mode 100644 index 000000000000..5e81c4e856d5 --- /dev/null +++ b/drivers/char/lrng/lrng_archrandom.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG Fast Noise Source: CPU-based noise source + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include + +#include "lrng_internal.h" + +/* + * Estimated entropy of data is a 32th of LRNG_DRNG_SECURITY_STRENGTH_BITS. + * As we have no ability to review the implementation of those noise sources, + * it is prudent to have a conservative estimate here. + */ +#define LRNG_ARCHRANDOM_DEFAULT_STRENGTH (LRNG_DRNG_SECURITY_STRENGTH_BITS>>5) +#define LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH LRNG_DRNG_SECURITY_STRENGTH_BITS +#ifdef CONFIG_RANDOM_TRUST_CPU +static u32 archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH; +#else +static u32 archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH; +#endif +module_param(archrandom, uint, 0644); +MODULE_PARM_DESC(archrandom, "Entropy in bits of 256 data bits from CPU noise source (e.g. RDRAND)"); + +static int __init lrng_parse_trust_cpu(char *arg) +{ + int ret; + bool trust_cpu = false; + + ret = kstrtobool(arg, &trust_cpu); + if (ret) + return ret; + + if (trust_cpu) + archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH; + else + archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH; + + return 0; +} +early_param("random.trust_cpu", lrng_parse_trust_cpu); + +/** + * lrng_get_arch() - Get CPU noise source entropy + * + * @outbuf: buffer to store entropy of size LRNG_DRNG_SECURITY_STRENGTH_BYTES + * + * Return: + * * > 0 on success where value provides the added entropy in bits + * * 0 if no fast source was available + */ +u32 lrng_get_arch(u8 *outbuf) +{ + u32 i, ent_bits = archrandom; + + /* operate on full blocks */ + BUILD_BUG_ON(LRNG_DRNG_SECURITY_STRENGTH_BYTES % sizeof(unsigned long)); + /* ensure we have aligned buffers */ + BUILD_BUG_ON(LRNG_KCAPI_ALIGN % sizeof(unsigned long)); + + if (!ent_bits) + return 0; + + for (i = 0; i < LRNG_DRNG_SECURITY_STRENGTH_BYTES; + i += sizeof(unsigned long)) { + if (!arch_get_random_seed_long((unsigned long *)(outbuf + i)) && + !arch_get_random_long((unsigned long *)(outbuf + i))) { + archrandom = 0; + return 0; + } + } + + /* Obtain entropy statement -- cap entropy to buffer size in bits */ + ent_bits = min_t(u32, ent_bits, LRNG_DRNG_SECURITY_STRENGTH_BITS); + pr_debug("obtained %u bits of entropy from CPU RNG noise source\n", + ent_bits); + return ent_bits; +} + +u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits) +{ + u32 arch_ent_bits = min_t(u32, archrandom, + LRNG_DRNG_SECURITY_STRENGTH_BITS); + u32 fast_noise_entropy = arch_ent_bits + lrng_jent_entropylevel(); + + if (fast_noise_entropy > required_entropy_bits) + return 0; + return (required_entropy_bits - fast_noise_entropy); +} diff --git a/drivers/char/lrng/lrng_aux.c b/drivers/char/lrng/lrng_aux.c new file mode 100644 index 000000000000..9f46c5707517 --- /dev/null +++ b/drivers/char/lrng/lrng_aux.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG auxiliary interfaces + * + * Copyright (C) 2019 Stephan Mueller + * Copyright (C) 2017 Jason A. Donenfeld . All + * Rights Reserved. + * Copyright (C) 2016 Jason Cooper + */ + +#include +#include + +#include "lrng_internal.h" + +struct batched_entropy { + union { + u64 entropy_u64[LRNG_DRNG_BLOCKSIZE / sizeof(u64)]; + u32 entropy_u32[LRNG_DRNG_BLOCKSIZE / sizeof(u32)]; + }; + unsigned int position; + spinlock_t batch_lock; +}; + +/* + * Get a random word for internal kernel use only. The quality of the random + * number is as good as /dev/urandom, but there is no backtrack protection, + * with the goal of being quite fast and not depleting entropy. + */ +static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64) = { + .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock), +}; + +u64 get_random_u64(void) +{ + u64 ret; + unsigned long flags; + struct batched_entropy *batch; + + lrng_debug_report_seedlevel("get_random_u64"); + + batch = raw_cpu_ptr(&batched_entropy_u64); + spin_lock_irqsave(&batch->batch_lock, flags); + if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) { + lrng_drng_get_atomic((u8 *)batch->entropy_u64, + LRNG_DRNG_BLOCKSIZE); + batch->position = 0; + } + ret = batch->entropy_u64[batch->position++]; + spin_unlock_irqrestore(&batch->batch_lock, flags); + return ret; +} +EXPORT_SYMBOL(get_random_u64); + +static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32) = { + .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock), +}; + +u32 get_random_u32(void) +{ + u32 ret; + unsigned long flags; + struct batched_entropy *batch; + + lrng_debug_report_seedlevel("get_random_u32"); + + batch = raw_cpu_ptr(&batched_entropy_u32); + spin_lock_irqsave(&batch->batch_lock, flags); + if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) { + lrng_drng_get_atomic((u8 *)batch->entropy_u32, + LRNG_DRNG_BLOCKSIZE); + batch->position = 0; + } + ret = batch->entropy_u32[batch->position++]; + spin_unlock_irqrestore(&batch->batch_lock, flags); + return ret; +} +EXPORT_SYMBOL(get_random_u32); + +/* + * It's important to invalidate all potential batched entropy that might + * be stored before the crng is initialized, which we can do lazily by + * simply resetting the counter to zero so that it's re-extracted on the + * next usage. + */ +void invalidate_batched_entropy(void) +{ + int cpu; + unsigned long flags; + + for_each_possible_cpu(cpu) { + struct batched_entropy *batched_entropy; + + batched_entropy = per_cpu_ptr(&batched_entropy_u32, cpu); + spin_lock_irqsave(&batched_entropy->batch_lock, flags); + batched_entropy->position = 0; + spin_unlock(&batched_entropy->batch_lock); + + batched_entropy = per_cpu_ptr(&batched_entropy_u64, cpu); + spin_lock(&batched_entropy->batch_lock); + batched_entropy->position = 0; + spin_unlock_irqrestore(&batched_entropy->batch_lock, flags); + } +} + +/** + * randomize_page - Generate a random, page aligned address + * @start: The smallest acceptable address the caller will take. + * @range: The size of the area, starting at @start, within which the + * random address must fall. + * + * If @start + @range would overflow, @range is capped. + * + * NOTE: Historical use of randomize_range, which this replaces, presumed that + * @start was already page aligned. We now align it regardless. + * + * Return: A page aligned address within [start, start + range). On error, + * @start is returned. + */ +unsigned long randomize_page(unsigned long start, unsigned long range) +{ + if (!PAGE_ALIGNED(start)) { + range -= PAGE_ALIGN(start) - start; + start = PAGE_ALIGN(start); + } + + if (start > ULONG_MAX - range) + range = ULONG_MAX - start; + + range >>= PAGE_SHIFT; + + if (range == 0) + return start; + + return start + (get_random_long() % range << PAGE_SHIFT); +} diff --git a/drivers/char/lrng/lrng_chacha20.c b/drivers/char/lrng/lrng_chacha20.c new file mode 100644 index 000000000000..9da139d89959 --- /dev/null +++ b/drivers/char/lrng/lrng_chacha20.c @@ -0,0 +1,320 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * Backend for the LRNG providing the cryptographic primitives using + * ChaCha20 cipher implementations. + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +#include "lrng_chacha20.h" +#include "lrng_internal.h" + +/******************************* ChaCha20 DRNG *******************************/ + +#define CHACHA_BLOCK_WORDS (CHACHA_BLOCK_SIZE / sizeof(u32)) + +struct chacha20_state { + struct chacha20_block block; +}; + +/* + * Have a static memory blocks for the ChaCha20 DRNG instance to avoid calling + * kmalloc too early in the boot cycle. For subsequent allocation requests, + * such as per-NUMA-node DRNG instances, kmalloc will be used. + */ +struct chacha20_state chacha20; + +/** + * Update of the ChaCha20 state by either using an unused buffer part or by + * generating one ChaCha20 block which is half of the state of the ChaCha20. + * The block is XORed into the key part of the state. This shall ensure + * backtracking resistance as well as a proper mix of the ChaCha20 state once + * the key is injected. + */ +static void lrng_chacha20_update(struct chacha20_state *chacha20_state, + u32 *buf, u32 used_words) +{ + struct chacha20_block *chacha20 = &chacha20_state->block; + u32 i, tmp[CHACHA_BLOCK_WORDS]; + + BUILD_BUG_ON(sizeof(struct chacha20_block) != CHACHA_BLOCK_SIZE); + BUILD_BUG_ON(CHACHA_BLOCK_SIZE != 2 * CHACHA_KEY_SIZE); + + if (used_words > CHACHA_KEY_SIZE_WORDS) { + chacha20_block(&chacha20->constants[0], (u8 *)tmp); + for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) + chacha20->key.u[i] ^= le32_to_cpu(tmp[i]); + memzero_explicit(tmp, sizeof(tmp)); + } else { + for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) + chacha20->key.u[i] ^= le32_to_cpu(buf[i + used_words]); + } + + /* Deterministic increment of nonce as required in RFC 7539 chapter 4 */ + chacha20->nonce[0]++; + if (chacha20->nonce[0] == 0) + chacha20->nonce[1]++; + if (chacha20->nonce[1] == 0) + chacha20->nonce[2]++; + + /* Leave counter untouched as it is start value is undefined in RFC */ +} + +/* + * Seed the ChaCha20 DRNG by injecting the input data into the key part of + * the ChaCha20 state. If the input data is longer than the ChaCha20 key size, + * perform a ChaCha20 operation after processing of key size input data. + * This operation shall spread out the entropy into the ChaCha20 state before + * new entropy is injected into the key part. + */ +static int lrng_cc20_drng_seed_helper(void *drng, const u8 *inbuf, u32 inbuflen) +{ + struct chacha20_state *chacha20_state = (struct chacha20_state *)drng; + struct chacha20_block *chacha20 = &chacha20_state->block; + + while (inbuflen) { + u32 i, todo = min_t(u32, inbuflen, CHACHA_KEY_SIZE); + + for (i = 0; i < todo; i++) + chacha20->key.b[i] ^= inbuf[i]; + + /* Break potential dependencies between the inbuf key blocks */ + lrng_chacha20_update(chacha20_state, NULL, + CHACHA_BLOCK_WORDS); + inbuf += todo; + inbuflen -= todo; + } + + return 0; +} + +/* + * Chacha20 DRNG generation of random numbers: the stream output of ChaCha20 + * is the random number. After the completion of the generation of the + * stream, the entire ChaCha20 state is updated. + * + * Note, as the ChaCha20 implements a 32 bit counter, we must ensure + * that this function is only invoked for at most 2^32 - 1 ChaCha20 blocks + * before a reseed or an update happens. This is ensured by the variable + * outbuflen which is a 32 bit integer defining the number of bytes to be + * generated by the ChaCha20 DRNG. At the end of this function, an update + * operation is invoked which implies that the 32 bit counter will never be + * overflown in this implementation. + */ +static int lrng_cc20_drng_generate_helper(void *drng, u8 *outbuf, u32 outbuflen) +{ + struct chacha20_state *chacha20_state = (struct chacha20_state *)drng; + struct chacha20_block *chacha20 = &chacha20_state->block; + u32 aligned_buf[CHACHA_BLOCK_WORDS], ret = outbuflen, + used = CHACHA_BLOCK_WORDS; + int zeroize_buf = 0; + + while (outbuflen >= CHACHA_BLOCK_SIZE) { + chacha20_block(&chacha20->constants[0], outbuf); + outbuf += CHACHA_BLOCK_SIZE; + outbuflen -= CHACHA_BLOCK_SIZE; + } + + if (outbuflen) { + chacha20_block(&chacha20->constants[0], (u8 *)aligned_buf); + memcpy(outbuf, aligned_buf, outbuflen); + used = ((outbuflen + sizeof(aligned_buf[0]) - 1) / + sizeof(aligned_buf[0])); + zeroize_buf = 1; + } + + lrng_chacha20_update(chacha20_state, aligned_buf, used); + + if (zeroize_buf) + memzero_explicit(aligned_buf, sizeof(aligned_buf)); + + return ret; +} + +void lrng_cc20_init_state(struct chacha20_state *state) +{ + struct chacha20_block *chacha20 = &state->block; + unsigned long v; + u32 i; + + lrng_cc20_init_rfc7539(chacha20); + + for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) { + chacha20->key.u[i] ^= jiffies; + chacha20->key.u[i] ^= random_get_entropy(); + if (arch_get_random_seed_long(&v) || arch_get_random_long(&v)) + chacha20->key.u[i] ^= v; + } + + for (i = 0; i < 3; i++) { + chacha20->nonce[i] ^= jiffies; + chacha20->nonce[i] ^= random_get_entropy(); + if (arch_get_random_seed_long(&v) || arch_get_random_long(&v)) + chacha20->nonce[i] ^= v; + } + + lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS); + pr_info("ChaCha20 core initialized\n"); +} + +void __init lrng_cc20_init_state_boot(struct chacha20_state *state) +{ + struct chacha20_block *chacha20 = &state->block; + unsigned long v; + u32 i; + + for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) { + if (arch_get_random_seed_long_early(&v) || + arch_get_random_long_early(&v)) + chacha20->key.u[i] ^= v; + } + + for (i = 0; i < 3; i++) { + if (arch_get_random_seed_long_early(&v) || + arch_get_random_long_early(&v)) + chacha20->nonce[i] ^= v; + } + + lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS); +} + +/* + * Allocation of the DRNG state + */ +static void *lrng_cc20_drng_alloc(u32 sec_strength) +{ + struct chacha20_state *state = NULL; + + if (sec_strength > CHACHA_KEY_SIZE) { + pr_err("Security strength of ChaCha20 DRNG (%u bits) lower than requested by LRNG (%u bits)\n", + CHACHA_KEY_SIZE * 8, sec_strength * 8); + return ERR_PTR(-EINVAL); + } + if (sec_strength < CHACHA_KEY_SIZE) + pr_warn("Security strength of ChaCha20 DRNG (%u bits) higher than requested by LRNG (%u bits)\n", + CHACHA_KEY_SIZE * 8, sec_strength * 8); + + state = kmalloc(sizeof(struct chacha20_state), GFP_KERNEL); + if (!state) + return ERR_PTR(-ENOMEM); + pr_debug("memory for ChaCha20 core allocated\n"); + + lrng_cc20_init_state(state); + + return state; +} + +static void lrng_cc20_drng_dealloc(void *drng) +{ + struct chacha20_state *chacha20_state = (struct chacha20_state *)drng; + + if (drng == &chacha20) { + memzero_explicit(chacha20_state, sizeof(*chacha20_state)); + pr_debug("static ChaCha20 core zeroized\n"); + return; + } + + pr_debug("ChaCha20 core zeroized and freed\n"); + kzfree(chacha20_state); +} + +/******************************* Hash Operation *******************************/ + +#ifdef CONFIG_CRYPTO_LIB_SHA256 + +static u32 lrng_cc20_hash_digestsize(void *hash) +{ + return SHA256_DIGEST_SIZE; +} + +static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen, + u8 *digest) +{ + struct sha256_state sctx; + + sha256_init(&sctx); + sha256_update(&sctx, inbuf, inbuflen); + sha256_final(&sctx, digest); + + /* Zeroization of sctx is performed by sha256_final */ + + return 0; +} + +static const char *lrng_cc20_hash_name(void) +{ + const char *cc20_hash_name = "SHA-256"; + return cc20_hash_name; +} + +#else /* CONFIG_CRYPTO_LIB_SHA256 */ + +/* + * If the SHA-256 support is not compiled, we fall back to SHA-1 that is always + * compiled and present in the kernel. + */ +static u32 lrng_cc20_hash_digestsize(void *hash) +{ + return (SHA1_DIGEST_WORDS * sizeof(u32)); +} + +static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen, + u8 *digest) +{ + u32 i; + u32 workspace[SHA1_WORKSPACE_WORDS]; + + WARN_ON(inbuflen % (SHA1_WORKSPACE_WORDS * sizeof(u32))); + + sha1_init((u32 *)digest); + for (i = 0; i < inbuflen; i += (SHA1_WORKSPACE_WORDS * sizeof(u32))) + sha1_transform((u32 *)digest, (inbuf + i), workspace); + memzero_explicit(workspace, sizeof(workspace)); + + return 0; +} + +static const char *lrng_cc20_hash_name(void) +{ + const char *cc20_hash_name = "SHA-1"; + return cc20_hash_name; +} + +#endif /* CONFIG_CRYPTO_LIB_SHA256 */ + +static void *lrng_cc20_hash_alloc(const u8 *key, u32 keylen) +{ + pr_info("Hash %s allocated\n", lrng_cc20_hash_name()); + return NULL; +} + +static void lrng_cc20_hash_dealloc(void *hash) +{ +} + +static const char *lrng_cc20_drng_name(void) +{ + const char *cc20_drng_name = "ChaCha20 DRNG"; + return cc20_drng_name; +} + +const struct lrng_crypto_cb lrng_cc20_crypto_cb = { + .lrng_drng_name = lrng_cc20_drng_name, + .lrng_hash_name = lrng_cc20_hash_name, + .lrng_drng_alloc = lrng_cc20_drng_alloc, + .lrng_drng_dealloc = lrng_cc20_drng_dealloc, + .lrng_drng_seed_helper = lrng_cc20_drng_seed_helper, + .lrng_drng_generate_helper = lrng_cc20_drng_generate_helper, + .lrng_hash_alloc = lrng_cc20_hash_alloc, + .lrng_hash_dealloc = lrng_cc20_hash_dealloc, + .lrng_hash_digestsize = lrng_cc20_hash_digestsize, + .lrng_hash_buffer = lrng_cc20_hash_buffer, +}; diff --git a/drivers/char/lrng/lrng_chacha20.h b/drivers/char/lrng/lrng_chacha20.h new file mode 100644 index 000000000000..1533b2490964 --- /dev/null +++ b/drivers/char/lrng/lrng_chacha20.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */ +/* + * LRNG ChaCha20 definitions + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#include + +/* State according to RFC 7539 section 2.3 */ +struct chacha20_block { + u32 constants[4]; + union { +#define CHACHA_KEY_SIZE_WORDS (CHACHA_KEY_SIZE / sizeof(u32)) + u32 u[CHACHA_KEY_SIZE_WORDS]; + u8 b[CHACHA_KEY_SIZE]; + } key __latent_entropy; + u32 counter; + u32 nonce[3] __latent_entropy; +}; + +static inline void lrng_cc20_init_rfc7539(struct chacha20_block *chacha20) +{ + /* String "expand 32-byte k" */ + chacha20->constants[0] = 0x61707865; + chacha20->constants[1] = 0x3320646e; + chacha20->constants[2] = 0x79622d32; + chacha20->constants[3] = 0x6b206574; +} diff --git a/drivers/char/lrng/lrng_drng.c b/drivers/char/lrng/lrng_drng.c new file mode 100644 index 000000000000..ac6e40794cfe --- /dev/null +++ b/drivers/char/lrng/lrng_drng.c @@ -0,0 +1,409 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG DRNG processing + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include + +#include "lrng_internal.h" + +/* + * Maximum number of seconds between DRNG reseed intervals of the DRNG. Note, + * this is enforced with the next request of random numbers from the + * DRNG. Setting this value to zero implies a reseeding attempt before every + * generated random number. + */ +int lrng_drng_reseed_max_time = 600; + +static atomic_t lrng_avail = ATOMIC_INIT(0); + +DEFINE_MUTEX(lrng_crypto_cb_update); + +/* DRNG for /dev/urandom, getrandom(2), get_random_bytes */ +static struct lrng_drng lrng_drng_init = { + .drng = &chacha20, + .crypto_cb = &lrng_cc20_crypto_cb, + .lock = __MUTEX_INITIALIZER(lrng_drng_init.lock), + .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_init.spin_lock) +}; + +/* + * DRNG for get_random_bytes when called in atomic context. This + * DRNG will always use the ChaCha20 DRNG. It will never benefit from a + * DRNG switch like the "regular" DRNG. If there was no DRNG switch, the atomic + * DRNG is identical to the "regular" DRNG. + * + * The reason for having this is due to the fact that DRNGs other than + * the ChaCha20 DRNG may sleep. + */ +static struct lrng_drng lrng_drng_atomic = { + .drng = &chacha20, + .crypto_cb = &lrng_cc20_crypto_cb, + .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_atomic.spin_lock) +}; + +/********************************** Helper ************************************/ + +bool lrng_get_available(void) +{ + return likely(atomic_read(&lrng_avail)); +} + +void lrng_set_available(void) +{ + atomic_set(&lrng_avail, 1); +} + +struct lrng_drng *lrng_drng_init_instance(void) +{ + return &lrng_drng_init; +} + +struct lrng_drng *lrng_drng_atomic_instance(void) +{ + return &lrng_drng_atomic; +} + +void lrng_drng_reset(struct lrng_drng *drng) +{ + atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH); + drng->last_seeded = jiffies; + drng->fully_seeded = false; + drng->force_reseed = true; + pr_debug("reset DRNG\n"); +} + +/* Initialize the default DRNG during boot */ +static void lrng_drngs_init_cc20(void) +{ + unsigned long flags = 0; + + if (lrng_get_available()) + return; + + lrng_drng_lock(&lrng_drng_init, &flags); + if (lrng_get_available()) { + lrng_drng_unlock(&lrng_drng_init, &flags); + return; + } + + lrng_drng_reset(&lrng_drng_init); + lrng_cc20_init_state(&chacha20); + lrng_state_init_seed_work(); + lrng_drng_unlock(&lrng_drng_init, &flags); + + lrng_drng_lock(&lrng_drng_atomic, &flags); + lrng_drng_reset(&lrng_drng_atomic); + /* + * We do not initialize the state of the atomic DRNG as it is identical + * to the DRNG at this point. + */ + lrng_drng_unlock(&lrng_drng_atomic, &flags); + + lrng_set_available(); +} + +/************************* Random Number Generation ***************************/ + +/* Inject a data buffer into the DRNG */ +static void lrng_drng_inject(struct lrng_drng *drng, + const u8 *inbuf, u32 inbuflen) +{ + const char *drng_type = unlikely(drng == &lrng_drng_atomic) ? + "atomic" : "regular"; + unsigned long flags = 0; + + BUILD_BUG_ON(LRNG_DRNG_RESEED_THRESH > INT_MAX); + pr_debug("seeding %s DRNG with %u bytes\n", drng_type, inbuflen); + lrng_drng_lock(drng, &flags); + if (drng->crypto_cb->lrng_drng_seed_helper(drng->drng, + inbuf, inbuflen) < 0) { + pr_warn("seeding of %s DRNG failed\n", drng_type); + atomic_set(&drng->requests, 1); + } else { + pr_debug("%s DRNG stats since last seeding: %lu secs; generate calls: %d\n", + drng_type, + (time_after(jiffies, drng->last_seeded) ? + (jiffies - drng->last_seeded) : 0) / HZ, + (LRNG_DRNG_RESEED_THRESH - + atomic_read(&drng->requests))); + drng->last_seeded = jiffies; + atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH); + drng->force_reseed = false; + + if (drng->drng == lrng_drng_atomic.drng) { + lrng_drng_atomic.last_seeded = jiffies; + atomic_set(&lrng_drng_atomic.requests, + LRNG_DRNG_RESEED_THRESH); + lrng_drng_atomic.force_reseed = false; + } + } + lrng_drng_unlock(drng, &flags); +} + +/* + * Perform the seeding of the DRNG with data from noise source + */ +static inline int _lrng_drng_seed(struct lrng_drng *drng) +{ + struct entropy_buf seedbuf __aligned(LRNG_KCAPI_ALIGN); + unsigned long flags = 0; + u32 total_entropy_bits; + int ret; + + lrng_drng_lock(drng, &flags); + total_entropy_bits = lrng_fill_seed_buffer(drng->crypto_cb, drng->hash, + &seedbuf, 0); + lrng_drng_unlock(drng, &flags); + + /* Allow the seeding operation to be called again */ + lrng_pool_unlock(); + lrng_init_ops(total_entropy_bits); + ret = total_entropy_bits >> 3; + + lrng_drng_inject(drng, (u8 *)&seedbuf, sizeof(seedbuf)); + memzero_explicit(&seedbuf, sizeof(seedbuf)); + + return ret; +} + +static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen); +static void lrng_drng_seed(struct lrng_drng *drng) +{ + int ret = _lrng_drng_seed(drng); + + if (ret >= LRNG_DRNG_SECURITY_STRENGTH_BYTES) + drng->fully_seeded = true; + + BUILD_BUG_ON(LRNG_MIN_SEED_ENTROPY_BITS > + LRNG_DRNG_SECURITY_STRENGTH_BITS); + + /* + * Reseed atomic DRNG from current DRNG, + * + * We can obtain random numbers from DRNG as the lock type + * chosen by lrng_drng_get is usable with the current caller. + */ + if ((drng->drng != lrng_drng_atomic.drng) && + (lrng_drng_atomic.force_reseed || + atomic_read(&lrng_drng_atomic.requests) <= 0 || + time_after(jiffies, lrng_drng_atomic.last_seeded + + lrng_drng_reseed_max_time * HZ))) { + u8 seedbuf[LRNG_DRNG_SECURITY_STRENGTH_BYTES] + __aligned(LRNG_KCAPI_ALIGN); + + ret = lrng_drng_get(drng, seedbuf, sizeof(seedbuf)); + + if (ret < 0) { + pr_warn("Error generating random numbers for atomic DRNG: %d\n", + ret); + } else { + lrng_drng_inject(&lrng_drng_atomic, seedbuf, ret); + } + memzero_explicit(&seedbuf, sizeof(seedbuf)); + } +} + +static inline void _lrng_drng_seed_work(struct lrng_drng *drng, u32 node) +{ + pr_debug("reseed triggered by interrupt noise source for DRNG on NUMA node %d\n", + node); + lrng_drng_seed(drng); + if (drng->fully_seeded) { + /* Prevent reseed storm */ + drng->last_seeded += node * 100 * HZ; + /* Prevent draining of pool on idle systems */ + lrng_drng_reseed_max_time += 100; + } +} + +/* + * DRNG reseed trigger: Kernel thread handler triggered by the schedule_work() + */ +void lrng_drng_seed_work(struct work_struct *dummy) +{ + struct lrng_drng **lrng_drng = lrng_drng_instances(); + u32 node; + + if (lrng_drng) { + for_each_online_node(node) { + struct lrng_drng *drng = lrng_drng[node]; + + if (drng && !drng->fully_seeded) { + _lrng_drng_seed_work(drng, node); + goto out; + } + } + lrng_pool_all_numa_nodes_seeded(); + } else { + if (!lrng_drng_init.fully_seeded) + _lrng_drng_seed_work(&lrng_drng_init, 0); + } + +out: + /* Allow the seeding operation to be called again */ + lrng_pool_unlock(); +} + +/* Force all DRNGs to reseed before next generation */ +void lrng_drng_force_reseed(void) +{ + struct lrng_drng **lrng_drng = lrng_drng_instances(); + u32 node; + + if (!lrng_drng) { + lrng_drng_init.force_reseed = true; + pr_debug("force reseed of initial DRNG\n"); + return; + } + for_each_online_node(node) { + struct lrng_drng *drng = lrng_drng[node]; + + if (!drng) + continue; + + drng->force_reseed = true; + pr_debug("force reseed of DRNG on node %u\n", node); + } + lrng_drng_atomic.force_reseed = true; +} + +/** + * lrng_drng_get() - Get random data out of the DRNG which is reseeded + * frequently. + * + * @outbuf: buffer for storing random data + * @outbuflen: length of outbuf + * + * Return: + * * < 0 in error case (DRNG generation or update failed) + * * >=0 returning the returned number of bytes + */ +static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen) +{ + unsigned long flags = 0; + u32 processed = 0; + + if (!outbuf || !outbuflen) + return 0; + + outbuflen = min_t(size_t, outbuflen, INT_MAX); + + lrng_drngs_init_cc20(); + + while (outbuflen) { + u32 todo = min_t(u32, outbuflen, LRNG_DRNG_MAX_REQSIZE); + int ret; + + /* All but the atomic DRNG are seeded during generation */ + if (atomic_dec_and_test(&drng->requests) || + drng->force_reseed || + time_after(jiffies, drng->last_seeded + + lrng_drng_reseed_max_time * HZ)) { + if (likely(drng != &lrng_drng_atomic)) { + if (lrng_pool_trylock()) + atomic_set(&drng->requests, 1); + else + lrng_drng_seed(drng); + } + } + + lrng_drng_lock(drng, &flags); + ret = drng->crypto_cb->lrng_drng_generate_helper( + drng->drng, outbuf + processed, todo); + lrng_drng_unlock(drng, &flags); + if (ret <= 0) { + pr_warn("getting random data from DRNG failed (%d)\n", + ret); + return -EFAULT; + } + processed += ret; + outbuflen -= ret; + } + + return processed; +} + +int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen) +{ + return lrng_drng_get(&lrng_drng_atomic, outbuf, outbuflen); +} + +int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen) +{ + struct lrng_drng **lrng_drng = lrng_drng_instances(); + struct lrng_drng *drng = &lrng_drng_init; + int node = numa_node_id(); + + might_sleep(); + + if (lrng_drng && lrng_drng[node] && lrng_drng[node]->fully_seeded) + drng = lrng_drng[node]; + + return lrng_drng_get(drng, outbuf, outbuflen); +} + +/* Reset LRNG such that all existing entropy is gone */ +static void _lrng_reset(struct work_struct *work) +{ + struct lrng_drng **lrng_drng = lrng_drng_instances(); + unsigned long flags = 0; + + if (!lrng_drng) { + lrng_drng_lock(&lrng_drng_init, &flags); + lrng_drng_reset(&lrng_drng_init); + lrng_drng_unlock(&lrng_drng_init, &flags); + } else { + u32 node; + + for_each_online_node(node) { + struct lrng_drng *drng = lrng_drng[node]; + + if (!drng) + continue; + lrng_drng_lock(drng, &flags); + lrng_drng_reset(drng); + lrng_drng_unlock(drng, &flags); + } + } + lrng_set_entropy_thresh(LRNG_INIT_ENTROPY_BITS + + LRNG_CONDITIONING_ENTROPY_LOSS); + + lrng_reset_state(); +} + +static DECLARE_WORK(lrng_reset_work, _lrng_reset); + +void lrng_reset(void) +{ + schedule_work(&lrng_reset_work); +} + +/***************************** Initialize LRNG *******************************/ + +void __init lrng_drng_init_early(void) +{ + unsigned long flags = 0; + + lrng_drng_lock(&lrng_drng_init, &flags); + lrng_cc20_init_state_boot(&chacha20); + lrng_drng_unlock(&lrng_drng_init, &flags); +} + +static int __init lrng_init(void) +{ + lrng_drngs_init_cc20(); + + lrng_drngs_numa_alloc(); + return 0; +} + +late_initcall(lrng_init); + +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Stephan Mueller "); +MODULE_DESCRIPTION("Linux Random Number Generator"); diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c new file mode 100644 index 000000000000..d9c68679136d --- /dev/null +++ b/drivers/char/lrng/lrng_interfaces.c @@ -0,0 +1,649 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG User and kernel space interfaces + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "lrng_internal.h" + +/* + * If the entropy count falls under this number of bits, then we + * should wake up processes which are selecting or polling on write + * access to /dev/random. + */ +u32 lrng_write_wakeup_bits = LRNG_WRITE_WAKEUP_ENTROPY; + +static LIST_HEAD(lrng_ready_list); +static DEFINE_SPINLOCK(lrng_ready_list_lock); + +static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait); +static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait); +static struct fasync_struct *fasync; + +struct ctl_table random_table[]; +/********************************** Helper ***********************************/ + +/* Is the DRNG seed level too low? */ +static inline bool lrng_need_entropy(void) +{ + return (lrng_avail_entropy() < lrng_write_wakeup_bits); +} + +void lrng_writer_wakeup(void) +{ + if (lrng_need_entropy() && wq_has_sleeper(&lrng_write_wait)) { + wake_up_interruptible(&lrng_write_wait); + kill_fasync(&fasync, SIGIO, POLL_OUT); + } +} + +void lrng_init_wakeup(void) +{ + wake_up_all(&lrng_init_wait); + kill_fasync(&fasync, SIGIO, POLL_IN); +} + +/** + * lrng_process_ready_list() - Ping all kernel internal callers waiting until + * the DRNG is at least minimally seeded to inform that the DRNG reached that + * seed level. + * + * When the SP800-90B testing is enabled, the ping only happens if the SP800-90B + * startup health tests are completed. This implies that kernel internal + * callers always have an SP800-90B compliant noise source when being + * pinged. + */ +void lrng_process_ready_list(void) +{ + unsigned long flags; + struct random_ready_callback *rdy, *tmp; + + if (!lrng_sp80090b_startup_complete()) + return; + + spin_lock_irqsave(&lrng_ready_list_lock, flags); + list_for_each_entry_safe(rdy, tmp, &lrng_ready_list, list) { + struct module *owner = rdy->owner; + + list_del_init(&rdy->list); + rdy->func(rdy); + module_put(owner); + } + spin_unlock_irqrestore(&lrng_ready_list_lock, flags); +} + +void lrng_debug_report_seedlevel(const char *name) +{ +#ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM + static void *previous = NULL; + void *caller = (void *) _RET_IP_; + + if (READ_ONCE(previous) == caller) + return; + + if (!lrng_state_min_seeded()) + pr_notice("%pS %s called without reaching mimimally seeded level (available entropy %u)\n", + caller, name, lrng_avail_entropy()); + + WRITE_ONCE(previous, caller); +#endif +} + +/************************ LRNG kernel input interfaces ************************/ + +/** + * add_hwgenerator_randomness() - Interface for in-kernel drivers of true + * hardware RNGs. + * + * Those devices may produce endless random bits and will be throttled + * when our pool is full. + * + * @buffer: buffer holding the entropic data from HW noise sources to be used to + * insert into entropy pool. + * @count: length of buffer + * @entropy_bits: amount of entropy in buffer (value is in bits) + */ +void add_hwgenerator_randomness(const char *buffer, size_t count, + size_t entropy_bits) +{ + /* + * Suspend writing if we are fully loaded with entropy. + * We'll be woken up again once below lrng_write_wakeup_thresh, + * or when the calling thread is about to terminate. + */ + wait_event_interruptible(lrng_write_wait, + lrng_need_entropy() || + lrng_state_exseed_allow(lrng_noise_source_hw) || + kthread_should_stop()); + lrng_state_exseed_set(lrng_noise_source_hw, false); + lrng_pool_lfsr_nonaligned(buffer, count); + lrng_pool_add_entropy(entropy_bits); +} +EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); + +/** + * add_bootloader_randomness() - Handle random seed passed by bootloader. + * + * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise + * it would be regarded as device data. + * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER. + * + * @buf: buffer holding the entropic data from HW noise sources to be used to + * insert into entropy pool. + * @size: length of buffer + */ +void add_bootloader_randomness(const void *buf, unsigned int size) +{ + if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER)) + add_hwgenerator_randomness(buf, size, size * 8); + else + add_device_randomness(buf, size); +} +EXPORT_SYMBOL_GPL(add_bootloader_randomness); + +/* + * Callback for HID layer -- use the HID event values to stir the entropy pool + */ +void add_input_randomness(unsigned int type, unsigned int code, + unsigned int value) +{ + static unsigned char last_value; + + /* ignore autorepeat and the like */ + if (value == last_value) + return; + + last_value = value; + + lrng_pool_lfsr_u32((type << 4) ^ code ^ (code >> 4) ^ value); +} +EXPORT_SYMBOL_GPL(add_input_randomness); + +/** + * add_device_randomness() - Add device- or boot-specific data to the entropy + * pool to help initialize it. + * + * None of this adds any entropy; it is meant to avoid the problem of + * the entropy pool having similar initial state across largely + * identical devices. + * + * @buf: buffer holding the entropic data from HW noise sources to be used to + * insert into entropy pool. + * @size: length of buffer + */ +void add_device_randomness(const void *buf, unsigned int size) +{ + lrng_pool_lfsr_nonaligned((u8 *)buf, size); + lrng_pool_lfsr_u32(random_get_entropy()); + lrng_pool_lfsr_u32(jiffies); +} +EXPORT_SYMBOL(add_device_randomness); + +#ifdef CONFIG_BLOCK +void rand_initialize_disk(struct gendisk *disk) { } +void add_disk_randomness(struct gendisk *disk) { } +EXPORT_SYMBOL(add_disk_randomness); +#endif + +/** + * del_random_ready_callback() - Delete a previously registered readiness + * callback function. + * + * @rdy: callback definition that was registered initially + */ +void del_random_ready_callback(struct random_ready_callback *rdy) +{ + unsigned long flags; + struct module *owner = NULL; + + spin_lock_irqsave(&lrng_ready_list_lock, flags); + if (!list_empty(&rdy->list)) { + list_del_init(&rdy->list); + owner = rdy->owner; + } + spin_unlock_irqrestore(&lrng_ready_list_lock, flags); + + module_put(owner); +} +EXPORT_SYMBOL(del_random_ready_callback); + +/** + * add_random_ready_callback() - Add a callback function that will be invoked + * when the DRNG is mimimally seeded. + * + * @rdy: callback definition to be invoked when the LRNG is seeded + * + * Return: + * * 0 if callback is successfully added + * * -EALREADY if pool is already initialised (callback not called) + * * -ENOENT if module for callback is not alive + */ +int add_random_ready_callback(struct random_ready_callback *rdy) +{ + struct module *owner; + unsigned long flags; + int err = -EALREADY; + + if (likely(lrng_state_min_seeded())) + return err; + + owner = rdy->owner; + if (!try_module_get(owner)) + return -ENOENT; + + spin_lock_irqsave(&lrng_ready_list_lock, flags); + if (lrng_state_min_seeded()) + goto out; + + owner = NULL; + + list_add(&rdy->list, &lrng_ready_list); + err = 0; + +out: + spin_unlock_irqrestore(&lrng_ready_list_lock, flags); + + module_put(owner); + + return err; +} +EXPORT_SYMBOL(add_random_ready_callback); + +/*********************** LRNG kernel output interfaces ************************/ + +/** + * get_random_bytes() - Provider of cryptographic strong random numbers for + * kernel-internal usage. + * + * This function is appropriate for all in-kernel use cases. However, + * it will always use the ChaCha20 DRNG. + * + * @buf: buffer to store the random bytes + * @nbytes: size of the buffer + */ +void get_random_bytes(void *buf, int nbytes) +{ + lrng_drng_get_atomic((u8 *)buf, (u32)nbytes); + lrng_debug_report_seedlevel("get_random_bytes"); +} +EXPORT_SYMBOL(get_random_bytes); + +/** + * get_random_bytes_full() - Provider of cryptographic strong random numbers + * for kernel-internal usage. + * + * This function is appropriate only for non-atomic use cases as this + * function may sleep. Though, it provides access to the full functionality + * of LRNG including the switchable DRNG support, that may support other + * DRNGs such as the SP800-90A DRBG. + * + * @buf: buffer to store the random bytes + * @nbytes: size of the buffer + */ +void get_random_bytes_full(void *buf, int nbytes) +{ + lrng_drng_get_sleep((u8 *)buf, (u32)nbytes); + lrng_debug_report_seedlevel("get_random_bytes_full"); +} +EXPORT_SYMBOL(get_random_bytes_full); + +/** + * wait_for_random_bytes() - Wait for the LRNG to be seeded and thus + * guaranteed to supply cryptographically secure random numbers. + * + * This applies to: the /dev/urandom device, the get_random_bytes function, + * and the get_random_{u32,u64,int,long} family of functions. Using any of + * these functions without first calling this function forfeits the guarantee + * of security. + * + * Return: + * * 0 if the LRNG has been seeded. + * * -ERESTARTSYS if the function was interrupted by a signal. + */ +int wait_for_random_bytes(void) +{ + if (likely(lrng_state_min_seeded())) + return 0; + return wait_event_interruptible(lrng_init_wait, + lrng_state_min_seeded()); +} +EXPORT_SYMBOL(wait_for_random_bytes); + +/** + * get_random_bytes_arch() - This function will use the architecture-specific + * hardware random number generator if it is available. + * + * The arch-specific hw RNG will almost certainly be faster than what we can + * do in software, but it is impossible to verify that it is implemented + * securely (as opposed, to, say, the AES encryption of a sequence number using + * a key known by the NSA). So it's useful if we need the speed, but only if + * we're willing to trust the hardware manufacturer not to have put in a back + * door. + * + * @buf: buffer allocated by caller to store the random data in + * @nbytes: length of outbuf + * + * Return: number of bytes filled in. + */ +int __must_check get_random_bytes_arch(void *buf, int nbytes) +{ + u8 *p = buf; + + while (nbytes) { + unsigned long v; + int chunk = min_t(int, nbytes, sizeof(unsigned long)); + + if (!arch_get_random_long(&v)) + break; + + memcpy(p, &v, chunk); + p += chunk; + nbytes -= chunk; + } + + if (nbytes) + lrng_drng_get_atomic((u8 *)p, (u32)nbytes); + + return nbytes; +} +EXPORT_SYMBOL(get_random_bytes_arch); + +/* + * Returns whether or not the LRNG has been seeded. + * + * Returns: true if the urandom pool has been seeded. + * false if the urandom pool has not been seeded. + */ +bool rng_is_initialized(void) +{ + return lrng_state_operational(); +} +EXPORT_SYMBOL(rng_is_initialized); + +/************************ LRNG user output interfaces *************************/ + +static ssize_t lrng_read_common(char __user *buf, size_t nbytes) +{ + ssize_t ret = 0; + u8 tmpbuf[LRNG_DRNG_BLOCKSIZE] __aligned(LRNG_KCAPI_ALIGN); + u8 *tmp_large = NULL, *tmp = tmpbuf; + u32 tmplen = sizeof(tmpbuf); + + if (nbytes == 0) + return 0; + + /* + * Satisfy large read requests -- as the common case are smaller + * request sizes, such as 16 or 32 bytes, avoid a kmalloc overhead for + * those by using the stack variable of tmpbuf. + */ + if (!CONFIG_BASE_SMALL && (nbytes > sizeof(tmpbuf))) { + tmplen = min_t(u32, nbytes, LRNG_DRNG_MAX_REQSIZE); + tmp_large = kmalloc(tmplen + LRNG_KCAPI_ALIGN, GFP_KERNEL); + if (!tmp_large) + tmplen = sizeof(tmpbuf); + else + tmp = PTR_ALIGN(tmp_large, LRNG_KCAPI_ALIGN); + } + + while (nbytes) { + u32 todo = min_t(u32, nbytes, tmplen); + int rc = 0; + + /* Reschedule if we received a large request. */ + if ((tmp_large) && need_resched()) { + if (signal_pending(current)) { + if (ret == 0) + ret = -ERESTARTSYS; + break; + } + schedule(); + } + + rc = lrng_drng_get_sleep(tmp, todo); + if (rc <= 0) { + if (rc < 0) + ret = rc; + break; + } + if (copy_to_user(buf, tmp, rc)) { + ret = -EFAULT; + break; + } + + nbytes -= rc; + buf += rc; + ret += rc; + } + + /* Wipe data just returned from memory */ + if (tmp_large) + kzfree(tmp_large); + else + memzero_explicit(tmpbuf, sizeof(tmpbuf)); + + return ret; +} + +static ssize_t +lrng_read_common_block(int nonblock, char __user *buf, size_t nbytes) +{ + if (nbytes == 0) + return 0; + + if (unlikely(!lrng_state_operational())) { + int ret; + + if (nonblock) + return -EAGAIN; + + ret = wait_event_interruptible(lrng_init_wait, + lrng_state_operational()); + if (unlikely(ret)) + return ret; + } + + return lrng_read_common(buf, nbytes); +} + +static ssize_t lrng_drng_read_block(struct file *file, char __user *buf, + size_t nbytes, loff_t *ppos) +{ + return lrng_read_common_block(file->f_flags & O_NONBLOCK, buf, nbytes); +} + +static unsigned int lrng_random_poll(struct file *file, poll_table *wait) +{ + __poll_t mask; + + poll_wait(file, &lrng_init_wait, wait); + poll_wait(file, &lrng_write_wait, wait); + mask = 0; + if (lrng_state_operational()) + mask |= EPOLLIN | EPOLLRDNORM; + if (lrng_need_entropy() || + lrng_state_exseed_allow(lrng_noise_source_user)) + mask |= EPOLLOUT | EPOLLWRNORM; + return mask; +} + +static ssize_t lrng_drng_write_common(const char __user *buffer, size_t count, + u32 entropy_bits) +{ + ssize_t ret = 0; + u8 buf[64] __aligned(LRNG_KCAPI_ALIGN); + const char __user *p = buffer; + u32 orig_entropy_bits = entropy_bits; + + if (!lrng_get_available()) + return -EAGAIN; + + count = min_t(size_t, count, INT_MAX); + while (count > 0) { + size_t bytes = min_t(size_t, count, sizeof(buf)); + u32 ent = min_t(u32, bytes<<3, entropy_bits); + + if (copy_from_user(&buf, p, bytes)) + return -EFAULT; + /* Inject data into entropy pool */ + lrng_pool_lfsr(buf, bytes); + lrng_pool_add_entropy(ent); + + count -= bytes; + p += bytes; + ret += bytes; + entropy_bits -= ent; + + cond_resched(); + } + + /* Force reseed of DRNG during next data request. */ + if (!orig_entropy_bits) + lrng_drng_force_reseed(); + + return ret; +} + +static ssize_t lrng_drng_read(struct file *file, char __user *buf, + size_t nbytes, loff_t *ppos) +{ + if (!lrng_state_min_seeded()) + pr_notice_ratelimited("%s - use of insufficiently seeded DRNG (%zu bytes read)\n", + current->comm, nbytes); + else if (!lrng_state_operational()) + pr_debug_ratelimited("%s - use of not fully seeded DRNG (%zu bytes read)\n", + current->comm, nbytes); + + return lrng_read_common(buf, nbytes); +} + +static ssize_t lrng_drng_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + return lrng_drng_write_common(buffer, count, 0); +} + +static long lrng_ioctl(struct file *f, unsigned int cmd, unsigned long arg) +{ + int size, ent_count_bits; + int __user *p = (int __user *)arg; + + switch (cmd) { + case RNDGETENTCNT: + ent_count_bits = lrng_avail_entropy(); + if (put_user(ent_count_bits, p)) + return -EFAULT; + return 0; + case RNDADDTOENTCNT: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (get_user(ent_count_bits, p)) + return -EFAULT; + ent_count_bits = (int)lrng_avail_entropy() + ent_count_bits; + if (ent_count_bits < 0) + ent_count_bits = 0; + if (ent_count_bits > LRNG_POOL_SIZE_BITS) + ent_count_bits = LRNG_POOL_SIZE_BITS; + lrng_pool_set_entropy(ent_count_bits); + return 0; + case RNDADDENTROPY: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (get_user(ent_count_bits, p++)) + return -EFAULT; + if (ent_count_bits < 0) + return -EINVAL; + if (get_user(size, p++)) + return -EFAULT; + if (size < 0) + return -EINVAL; + lrng_state_exseed_set(lrng_noise_source_user, false); + /* there cannot be more entropy than data */ + ent_count_bits = min(ent_count_bits, size<<3); + return lrng_drng_write_common((const char __user *)p, size, + ent_count_bits); + case RNDZAPENTCNT: + case RNDCLEARPOOL: + /* Clear the entropy pool counter. */ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + lrng_pool_set_entropy(0); + return 0; + case RNDRESEEDCRNG: + /* + * We leave the capability check here since it is present + * in the upstream's RNG implementation. Yet, user space + * can trigger a reseed as easy as writing into /dev/random + * or /dev/urandom where no privilege is needed. + */ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + /* Force a reseed of all DRNGs */ + lrng_drng_force_reseed(); + return 0; + default: + return -EINVAL; + } +} + +static int lrng_fasync(int fd, struct file *filp, int on) +{ + return fasync_helper(fd, filp, on, &fasync); +} + +const struct file_operations random_fops = { + .read = lrng_drng_read_block, + .write = lrng_drng_write, + .poll = lrng_random_poll, + .unlocked_ioctl = lrng_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .fasync = lrng_fasync, + .llseek = noop_llseek, +}; + +const struct file_operations urandom_fops = { + .read = lrng_drng_read, + .write = lrng_drng_write, + .unlocked_ioctl = lrng_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .fasync = lrng_fasync, + .llseek = noop_llseek, +}; + +SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, + unsigned int, flags) +{ + if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE)) + return -EINVAL; + + /* + * Requesting insecure and blocking randomness at the same time makes + * no sense. + */ + if ((flags & + (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM)) + return -EINVAL; + + if (count > INT_MAX) + count = INT_MAX; + + if (flags & GRND_INSECURE) + return lrng_drng_read(NULL, buf, count, NULL); + + return lrng_read_common_block(flags & GRND_NONBLOCK, buf, count); +} diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h new file mode 100644 index 000000000000..53c267115721 --- /dev/null +++ b/drivers/char/lrng/lrng_internal.h @@ -0,0 +1,336 @@ +/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */ +/* + * Copyright (C) 2018 - 2020, Stephan Mueller + */ + +#ifndef _LRNG_INTERNAL_H +#define _LRNG_INTERNAL_H + +#include +#include +#include +#include + +/*************************** General LRNG parameter ***************************/ + +/* Entropy pool parameter + * + * The LRNG_POOL_SIZE cannot be smaller than 64 bytes as the SHA-1 operation + * in lrng_chacha20.c requires multiples of 64 bytes + */ +#define LRNG_POOL_SIZE (16 << CONFIG_LRNG_POOL_SIZE) +#define LRNG_POOL_WORD_BYTES (4) /* (sizeof(atomic_t)) */ +#define LRNG_POOL_SIZE_BYTES (LRNG_POOL_SIZE * LRNG_POOL_WORD_BYTES) +#define LRNG_POOL_SIZE_BITS (LRNG_POOL_SIZE_BYTES * 8) +#define LRNG_POOL_WORD_BITS (LRNG_POOL_WORD_BYTES * 8) + +/* Security strength of LRNG -- this must match DRNG security strength */ +#define LRNG_DRNG_SECURITY_STRENGTH_BYTES 32 +#define LRNG_DRNG_SECURITY_STRENGTH_BITS (LRNG_DRNG_SECURITY_STRENGTH_BYTES * 8) +#define LRNG_DRNG_BLOCKSIZE 64 /* Maximum of DRNG block sizes */ + +/* + * SP800-90A defines a maximum request size of 1<<16 bytes. The given value is + * considered a safer margin. + * + * This value is allowed to be changed. + */ +#define LRNG_DRNG_MAX_REQSIZE (1<<12) + +/* + * SP800-90A defines a maximum number of requests between reseeds of 2^48. + * The given value is considered a much safer margin, balancing requests for + * frequent reseeds with the need to conserve entropy. This value MUST NOT be + * larger than INT_MAX because it is used in an atomic_t. + * + * This value is allowed to be changed. + */ +#define LRNG_DRNG_RESEED_THRESH (1<<20) + +/* + * Number of interrupts to be recorded to assume that DRNG security strength + * bits of entropy are received. + * Note: a value below the DRNG security strength should not be defined as this + * may imply the DRNG can never be fully seeded in case other noise + * sources are unavailable. + * + * This value is allowed to be changed. + */ +#define LRNG_IRQ_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS + +/* + * Min required seed entropy is 128 bits covering the minimum entropy + * requirement of SP800-131A and the German BSI's TR02102. + * + * This value is allowed to be changed. + */ +#define LRNG_FULL_SEED_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS +#define LRNG_MIN_SEED_ENTROPY_BITS 128 +#define LRNG_INIT_ENTROPY_BITS 32 + +/* + * Amount of entropy that is lost with the conditioning functions of LFSR and + * hash_df as shown with the entropy analysis compliant to SP800-90B. + */ +#define LRNG_CONDITIONING_ENTROPY_LOSS 1 + +/* + * Wakeup value + * + * This value is allowed to be changed. + */ +#if (LRNG_POOL_SIZE_BITS <= (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2)) +# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS + \ + LRNG_CONDITIONING_ENTROPY_LOSS) +#else +# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2) +#endif + +/* + * Oversampling factor of IRQ events to obtain + * LRNG_DRNG_SECURITY_STRENGTH_BYTES. This factor is used when a + * high-resolution time stamp is not available. In this case, jiffies and + * register contents are used to fill the entropy pool. These noise sources + * are much less entropic than the high-resolution timer. The entropy content + * is the entropy content assumed with LRNG_IRQ_ENTROPY_BITS divided by + * LRNG_IRQ_OVERSAMPLING_FACTOR. + * + * This value is allowed to be changed. + */ +#define LRNG_IRQ_OVERSAMPLING_FACTOR 10 + +/* + * Alignmask which should cover all cipher implementations + * WARNING: If this is changed to a value larger than 8, manual + * alignment is necessary as older versions of GCC may not be capable + * of aligning stack variables at boundaries greater than 8. + * In this case, PTR_ALIGN must be used. + */ +#define LRNG_KCAPI_ALIGN 8 + +/************************ Default DRNG implementation *************************/ + +extern struct chacha20_state chacha20; +extern const struct lrng_crypto_cb lrng_cc20_crypto_cb; +void lrng_cc20_init_state(struct chacha20_state *state); +void lrng_cc20_init_state_boot(struct chacha20_state *state); + +/********************************** /proc *************************************/ + +static inline void lrng_pool_inc_numa_node(void) { } + +/****************************** LRNG interfaces *******************************/ + +extern u32 lrng_write_wakeup_bits; +extern int lrng_drng_reseed_max_time; + +void lrng_writer_wakeup(void); +void lrng_init_wakeup(void); +void lrng_debug_report_seedlevel(const char *name); +void lrng_process_ready_list(void); + +/* External interface to use of the switchable DRBG inside the kernel */ +void get_random_bytes_full(void *buf, int nbytes); + +/************************** Entropy pool management ***************************/ + +enum lrng_external_noise_source { + lrng_noise_source_hw, + lrng_noise_source_user +}; + +bool lrng_state_exseed_allow(enum lrng_external_noise_source source); +void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type); +void lrng_state_init_seed_work(void); +u32 lrng_avail_entropy(void); +void lrng_set_entropy_thresh(u32 new); +int lrng_pool_trylock(void); +void lrng_pool_unlock(void); +void lrng_reset_state(void); +void lrng_pool_all_numa_nodes_seeded(void); +bool lrng_state_min_seeded(void); +bool lrng_state_fully_seeded(void); +bool lrng_state_operational(void); +bool lrng_pool_highres_timer(void); +void lrng_pool_set_entropy(u32 entropy_bits); +void lrng_pool_lfsr(const u8 *buf, u32 buflen); +void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen); +void lrng_pool_lfsr_u32(u32 value); +void lrng_pool_add_irq(u32 irq_num); +void lrng_pool_add_entropy(u32 entropy_bits); + +struct entropy_buf { + u8 a[LRNG_DRNG_SECURITY_STRENGTH_BYTES]; + u8 b[LRNG_DRNG_SECURITY_STRENGTH_BYTES]; + u8 c[LRNG_DRNG_SECURITY_STRENGTH_BYTES]; + u32 now; +}; + +int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash, + struct entropy_buf *entropy_buf, u32 entropy_retain); +void lrng_init_ops(u32 seed_bits); + +/************************** Jitter RNG Noise Source ***************************/ + +#ifdef CONFIG_LRNG_JENT +u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen); +u32 lrng_jent_entropylevel(void); +#else /* CONFIG_CRYPTO_JITTERENTROPY */ +static inline u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen) {return 0; } +static inline u32 lrng_jent_entropylevel(void) { return 0; } +#endif /* CONFIG_CRYPTO_JITTERENTROPY */ + +/*************************** CPU-based Noise Source ***************************/ + +u32 lrng_get_arch(u8 *outbuf); +u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits); + +/****************************** DRNG processing *******************************/ + +/* Secondary DRNG state handle */ +struct lrng_drng { + void *drng; /* DRNG handle */ + void *hash; /* Hash handle */ + const struct lrng_crypto_cb *crypto_cb; /* Crypto callbacks */ + atomic_t requests; /* Number of DRNG requests */ + unsigned long last_seeded; /* Last time it was seeded */ + bool fully_seeded; /* Is DRNG fully seeded? */ + bool force_reseed; /* Force a reseed */ + struct mutex lock; + spinlock_t spin_lock; +}; + +extern struct mutex lrng_crypto_cb_update; + +struct lrng_drng *lrng_drng_init_instance(void); +struct lrng_drng *lrng_drng_atomic_instance(void); + +static __always_inline bool lrng_drng_is_atomic(struct lrng_drng *drng) +{ + return (drng->drng == lrng_drng_atomic_instance()->drng); +} + +/* Lock the DRNG */ +static __always_inline void lrng_drng_lock(struct lrng_drng *drng, + unsigned long *flags) +{ + /* Use spin lock in case the atomic DRNG context is used */ + if (lrng_drng_is_atomic(drng)) { + spin_lock_irqsave(&drng->spin_lock, *flags); + + /* + * In case a lock transition happened while we were spinning, + * catch this case and use the new lock type. + */ + if (!lrng_drng_is_atomic(drng)) { + spin_unlock_irqrestore(&drng->spin_lock, *flags); + mutex_lock(&drng->lock); + } + } else { + mutex_lock(&drng->lock); + } +} + +/* Unlock the DRNG */ +static __always_inline void lrng_drng_unlock(struct lrng_drng *drng, + unsigned long *flags) +{ + if (lrng_drng_is_atomic(drng)) + spin_unlock_irqrestore(&drng->spin_lock, *flags); + else + mutex_unlock(&drng->lock); +} + +void lrng_drng_init_early(void); +bool lrng_get_available(void); +void lrng_set_available(void); +void lrng_drng_reset(struct lrng_drng *drng); +int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen); +int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen); +void lrng_drng_force_reseed(void); +void lrng_drng_seed_work(struct work_struct *dummy); + +static inline struct lrng_drng **lrng_drng_instances(void) { return NULL; } +static inline void lrng_drngs_numa_alloc(void) { return; } + +/************************** Health Test linking code **************************/ + +enum lrng_health_res { + lrng_health_pass, /* Health test passes on time stamp */ + lrng_health_fail_use, /* Time stamp unhealthy, but mix in */ + lrng_health_fail_drop /* Time stamp unhealthy, drop it */ +}; + +#ifdef CONFIG_LRNG_HEALTH_TESTS +bool lrng_sp80090b_startup_complete(void); +bool lrng_sp80090b_compliant(void); + +enum lrng_health_res lrng_health_test(u32 now_time); +void lrng_health_disable(void); + +void lrng_reset(void); +#else /* CONFIG_LRNG_HEALTH_TESTS */ +static inline bool lrng_sp80090b_startup_complete(void) { return true; } +static inline bool lrng_sp80090b_compliant(void) { return false; } + +static inline enum lrng_health_res +lrng_health_test(u32 now_time) { return lrng_health_pass; } +static inline void lrng_health_disable(void) { } +#endif /* CONFIG_LRNG_HEALTH_TESTS */ + +/****************************** Helper code ***********************************/ + +static inline u32 atomic_read_u32(atomic_t *v) +{ + return (u32)atomic_read(v); +} + +/*************************** Auxiliary functions ******************************/ + +void invalidate_batched_entropy(void); + +/***************************** Testing code ***********************************/ + +#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY +bool lrng_raw_hires_entropy_store(u32 value); +#else /* CONFIG_LRNG_RAW_HIRES_ENTROPY */ +static inline bool lrng_raw_hires_entropy_store(u32 value) { return false; } +#endif /* CONFIG_LRNG_RAW_HIRES_ENTROPY */ + +#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY +bool lrng_raw_jiffies_entropy_store(u32 value); +#else /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */ +static inline bool lrng_raw_jiffies_entropy_store(u32 value) { return false; } +#endif /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */ + +#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY +bool lrng_raw_irq_entropy_store(u32 value); +#else /* CONFIG_LRNG_RAW_IRQ_ENTROPY */ +static inline bool lrng_raw_irq_entropy_store(u32 value) { return false; } +#endif /* CONFIG_LRNG_RAW_IRQ_ENTROPY */ + +#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY +bool lrng_raw_irqflags_entropy_store(u32 value); +#else /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */ +static inline bool lrng_raw_irqflags_entropy_store(u32 value) { return false; } +#endif /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */ + +#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY +bool lrng_raw_retip_entropy_store(u32 value); +#else /* CONFIG_LRNG_RAW_RETIP_ENTROPY */ +static inline bool lrng_raw_retip_entropy_store(u32 value) { return false; } +#endif /* CONFIG_LRNG_RAW_RETIP_ENTROPY */ + +#ifdef CONFIG_LRNG_RAW_ARRAY +bool lrng_raw_array_entropy_store(u32 value); +#else /* CONFIG_LRNG_RAW_ARRAY */ +static inline bool lrng_raw_array_entropy_store(u32 value) { return false; } +#endif /* CONFIG_LRNG_RAW_ARRAY */ + +#ifdef CONFIG_LRNG_IRQ_PERF +bool lrng_perf_time(u32 start); +#else /* CONFIG_LRNG_IRQ_PERF */ +static inline bool lrng_perf_time(u32 start) { return false; } +#endif /*CONFIG_LRNG_IRQ_PERF */ + +#endif /* _LRNG_INTERNAL_H */ diff --git a/drivers/char/lrng/lrng_lfsr.h b/drivers/char/lrng/lrng_lfsr.h new file mode 100644 index 000000000000..978ba97107e4 --- /dev/null +++ b/drivers/char/lrng/lrng_lfsr.h @@ -0,0 +1,152 @@ +/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */ +/* + * LRNG Linear Feedback Shift Register + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +/* Status information about IRQ noise source */ +struct lrng_irq_info { + atomic_t num_events; /* Number of healthy IRQs since last read */ + atomic_t num_events_thresh; /* Reseed threshold */ + atomic_t reseed_in_progress; /* Flag for on executing reseed */ + bool irq_highres_timer; /* Is high-resolution timer available? */ + u32 irq_entropy_bits; /* LRNG_IRQ_ENTROPY_BITS? */ +}; + +/* + * This is the entropy pool used by the slow noise source. Its size should + * be at least as large as LRNG_DRNG_SECURITY_STRENGTH_BITS. + * + * The pool array is aligned to 8 bytes to comfort the kernel crypto API cipher + * implementations of the hash functions used to read the pool: for some + * accelerated implementations, we need an alignment to avoid a realignment + * which involves memcpy(). The alignment to 8 bytes should satisfy all crypto + * implementations. + * + * LRNG_POOL_SIZE is allowed to be changed only if the taps of the polynomial + * used for the LFSR are changed as well. The size must be in powers of 2 due + * to the mask handling in lrng_pool_lfsr_u32 which uses AND instead of modulo. + */ +struct lrng_pool { + union { + struct { + /* + * hash_df implementation: counter, requested_bits and + * pool form a linear buffer that is used in the + * hash_df function specified in SP800-90A section + * 10.3.1 + */ + unsigned char counter; + __be32 requested_bits; + + /* Pool */ + atomic_t pool[LRNG_POOL_SIZE] __latent_entropy; + /* Ptr into pool for next IRQ word injection */ + atomic_t pool_ptr; + /* rotate for LFSR */ + atomic_t input_rotate; + /* All NUMA DRNGs seeded? */ + bool all_online_numa_node_seeded; + /* IRQ noise source status info */ + struct lrng_irq_info irq_info; + /* Serialize read of entropy pool */ + spinlock_t lock; + }; + /* + * Static SHA-1 implementation in lrng_cc20_hash_buffer + * processes data 64-byte-wise. Hence, ensure proper size + * of LRNG entropy pool data structure. + */ + u8 hash_input_buf[LRNG_POOL_SIZE_BYTES + 64]; + }; +}; + +/* + * Implement a (modified) twisted Generalized Feedback Shift Register. (See M. + * Matsumoto & Y. Kurita, 1992. Twisted GFSR generators. ACM Transactions on + * Modeling and Computer Simulation 2(3):179-194. Also see M. Matsumoto & Y. + * Kurita, 1994. Twisted GFSR generators II. ACM Transactions on Modeling and + * Computer Simulation 4:254-266). + */ +static u32 const lrng_twist_table[8] = { + 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, + 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 }; + +/* + * The polynomials for the LFSR are taken from the document "Table of Linear + * Feedback Shift Registers" by Roy Ward, Tim Molteno, October 26, 2007. + * The first polynomial is from "Primitive Binary Polynomials" by Wayne + * Stahnke (1973) and is primitive as well as irreducible. + * + * Note, the tap values are smaller by one compared to the documentation because + * they are used as an index into an array where the index starts by zero. + * + * All polynomials were also checked to be primitive and irreducible with magma + * which ensures that the key property of the LFSR providing a compression + * function for entropy is guaranteed. + */ +static u32 const lrng_lfsr_polynomial[][4] = { + { 15, 13, 12, 10 }, /* 16 words */ + { 31, 29, 25, 24 }, /* 32 words */ + { 63, 62, 60, 59 }, /* 64 words */ + { 127, 28, 26, 1 }, /* 128 words by Stahnke */ + { 255, 253, 250, 245 }, /* 256 words */ + { 511, 509, 506, 503 }, /* 512 words */ + { 1023, 1014, 1001, 1000 }, /* 1024 words */ + { 2047, 2034, 2033, 2028 }, /* 2048 words */ + { 4095, 4094, 4080, 4068 }, /* 4096 words */ +}; + +static inline void _lrng_pool_lfsr_u32(struct lrng_pool *pool, u32 value) +{ + /* + * Process the LFSR by altering not adjacent words but rather + * more spaced apart words. Using a prime number ensures that all words + * are processed evenly. As some the LFSR polynomials taps are close + * together, processing adjacent words with the LSFR taps may be + * inappropriate as the data just mixed-in at these taps may be not + * independent from the current data to be mixed in. + */ + u32 ptr = (u32)atomic_add_return_relaxed(67, &pool->pool_ptr) & + (LRNG_POOL_SIZE - 1); + /* + * Add 7 bits of rotation to the pool. At the beginning of the + * pool, add an extra 7 bits rotation, so that successive passes + * spread the input bits across the pool evenly. + * + * Note, there is a race between getting ptr and calculating + * input_rotate when ptr is obtained on two or more CPUs at the + * same time. This race is irrelevant as it may only come into effect + * if 3 or more CPUs race at the same time which is very unlikely. If + * the race happens, it applies to one event only. As this rolling + * supports the LFSR without being strictly needed, we accept this + * race. + */ + u32 input_rotate = (u32)atomic_add_return_relaxed((ptr ? 7 : 14), + &pool->input_rotate) & 31; + u32 word = rol32(value, input_rotate); + + BUILD_BUG_ON(LRNG_POOL_WORD_BYTES != sizeof(pool->pool[0])); + BUILD_BUG_ON(LRNG_POOL_SIZE - 1 != + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]); + word ^= atomic_read_u32(&pool->pool[ptr]); + word ^= atomic_read_u32(&pool->pool[ + (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]) & + (LRNG_POOL_SIZE - 1)]); + word ^= atomic_read_u32(&pool->pool[ + (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][1]) & + (LRNG_POOL_SIZE - 1)]); + word ^= atomic_read_u32(&pool->pool[ + (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][2]) & + (LRNG_POOL_SIZE - 1)]); + word ^= atomic_read_u32(&pool->pool[ + (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][3]) & + (LRNG_POOL_SIZE - 1)]); + + word = (word >> 3) ^ lrng_twist_table[word & 7]; + atomic_set(&pool->pool[ptr], word); +} + +u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash, + struct lrng_pool *pool, u8 *outbuf, u32 requested_bits); diff --git a/drivers/char/lrng/lrng_pool.c b/drivers/char/lrng/lrng_pool.c new file mode 100644 index 000000000000..0d4111ce7bc2 --- /dev/null +++ b/drivers/char/lrng/lrng_pool.c @@ -0,0 +1,589 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG Entropy pool management + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include + +#include "lrng_internal.h" +#include "lrng_lfsr.h" + +struct lrng_state { + bool lrng_operational; /* Is DRNG operational? */ + bool lrng_fully_seeded; /* Is DRNG fully seeded? */ + bool lrng_min_seeded; /* Is DRNG minimally seeded? */ + + /* + * To ensure that external entropy providers cannot dominate the + * internal noise sources but yet cannot be dominated by internal + * noise sources, the following booleans are intended to allow + * external to provide seed once when a DRNG reseed occurs. This + * triggering of external noise source is performed even when the + * entropy pool has sufficient entropy. + */ + bool lrng_seed_hw; /* Allow HW to provide seed */ + bool lrng_seed_user; /* Allow user space to provide seed */ + + struct work_struct lrng_seed_work; /* (re)seed work queue */ +}; + +static struct lrng_pool lrng_pool __aligned(LRNG_KCAPI_ALIGN) = { + .irq_info = { + .irq_entropy_bits = LRNG_IRQ_ENTROPY_BITS, + .num_events_thresh = ATOMIC_INIT(LRNG_INIT_ENTROPY_BITS + + LRNG_CONDITIONING_ENTROPY_LOSS), + /* Sample IRQ pointer data at least during boot */ + .irq_highres_timer = false }, + .lock = __SPIN_LOCK_UNLOCKED(lrng_pool.lock) +}; + +static struct lrng_state lrng_state = { false, false, false, true, true }; + +/********************************** Helper ***********************************/ + +/* External entropy provider is allowed to provide seed data */ +bool lrng_state_exseed_allow(enum lrng_external_noise_source source) +{ + if (source == lrng_noise_source_hw) + return lrng_state.lrng_seed_hw; + return lrng_state.lrng_seed_user; +} + +/* Enable / disable external entropy provider to furnish seed */ +void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type) +{ + if (source == lrng_noise_source_hw) + lrng_state.lrng_seed_hw = type; + else + lrng_state.lrng_seed_user = type; +} + +static inline void lrng_state_exseed_allow_all(void) +{ + lrng_state_exseed_set(lrng_noise_source_hw, true); + lrng_state_exseed_set(lrng_noise_source_user, true); +} + +void lrng_state_init_seed_work(void) +{ + INIT_WORK(&lrng_state.lrng_seed_work, lrng_drng_seed_work); +} + +static inline u32 lrng_entropy_to_data(u32 entropy_bits) +{ + return ((entropy_bits * lrng_pool.irq_info.irq_entropy_bits) / + LRNG_DRNG_SECURITY_STRENGTH_BITS); +} + +static inline u32 lrng_data_to_entropy(u32 irqnum) +{ + return ((irqnum * LRNG_DRNG_SECURITY_STRENGTH_BITS) / + lrng_pool.irq_info.irq_entropy_bits); +} + +u32 lrng_avail_entropy(void) +{ + return min_t(u32, LRNG_POOL_SIZE_BITS, lrng_data_to_entropy( + atomic_read_u32(&lrng_pool.irq_info.num_events))); +} + +void lrng_set_entropy_thresh(u32 new) +{ + atomic_set(&lrng_pool.irq_info.num_events_thresh, + lrng_entropy_to_data(new)); +} + +/* + * Reading of the LRNG pool is only allowed by one caller. The reading is + * only performed to (re)seed DRNGs. Thus, if this "lock" is already taken, + * the reseeding operation is in progress. The caller is not intended to wait + * but continue with its other operation. + */ +int lrng_pool_trylock(void) +{ + return atomic_cmpxchg(&lrng_pool.irq_info.reseed_in_progress, 0, 1); +} + +void lrng_pool_unlock(void) +{ + atomic_set(&lrng_pool.irq_info.reseed_in_progress, 0); +} + +void lrng_reset_state(void) +{ + struct lrng_irq_info *irq_info = &lrng_pool.irq_info; + + atomic_set(&irq_info->num_events, 0); + lrng_state.lrng_operational = false; + lrng_state.lrng_fully_seeded = false; + lrng_state.lrng_min_seeded = false; + lrng_pool.all_online_numa_node_seeded = false; + pr_debug("reset LRNG\n"); +} + +void lrng_pool_all_numa_nodes_seeded(void) +{ + lrng_pool.all_online_numa_node_seeded = true; +} + +bool lrng_state_min_seeded(void) +{ + return lrng_state.lrng_min_seeded; +} + +bool lrng_state_fully_seeded(void) +{ + return lrng_state.lrng_fully_seeded; +} + +bool lrng_state_operational(void) +{ + return lrng_state.lrng_operational; +} + +bool lrng_pool_highres_timer(void) +{ + return lrng_pool.irq_info.irq_highres_timer; +} + +void lrng_pool_set_entropy(u32 entropy_bits) +{ + atomic_set(&lrng_pool.irq_info.num_events, + lrng_entropy_to_data(entropy_bits)); +} + +static void lrng_pool_configure(bool highres_timer, u32 irq_entropy_bits) +{ + struct lrng_irq_info *irq_info = &lrng_pool.irq_info; + + irq_info->irq_highres_timer = highres_timer; + if (irq_info->irq_entropy_bits != irq_entropy_bits) { + irq_info->irq_entropy_bits = irq_entropy_bits; + /* Reset the threshold based on new oversampling factor. */ + lrng_set_entropy_thresh(atomic_read_u32( + &irq_info->num_events_thresh)); + } +} + +static int __init lrng_init_time_source(void) +{ + if (random_get_entropy() || random_get_entropy()) { + /* + * As the highres timer is identified here, previous interrupts + * obtained during boot time are treated like a lowres-timer + * would have been present. + */ + lrng_pool_configure(true, LRNG_IRQ_ENTROPY_BITS); + } else { + lrng_health_disable(); + lrng_pool_configure(false, LRNG_IRQ_ENTROPY_BITS * + LRNG_IRQ_OVERSAMPLING_FACTOR); + pr_warn("operating without high-resolution timer and applying IRQ oversampling factor %u\n", + LRNG_IRQ_OVERSAMPLING_FACTOR); + } + + return 0; +} + +core_initcall(lrng_init_time_source); + +/* invoke function with buffer aligned to 4 bytes */ +void lrng_pool_lfsr(const u8 *buf, u32 buflen) +{ + u32 *p_buf = (u32 *)buf; + + for (; buflen >= 4; buflen -= 4) + lrng_pool_lfsr_u32(*p_buf++); + + buf = (u8 *)p_buf; + while (buflen--) + lrng_pool_lfsr_u32(*buf++); +} + +void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen) +{ + while (buflen) { + if (!((unsigned long)buf & (sizeof(u32) - 1))) { + lrng_pool_lfsr(buf, buflen); + return; + } + + lrng_pool_lfsr_u32(*buf++); + buflen--; + } +} + +/**************************** Interrupt processing ****************************/ + +/* + * Hot code path - inject data into entropy pool using LFSR + */ +void lrng_pool_lfsr_u32(u32 value) +{ + _lrng_pool_lfsr_u32(&lrng_pool, value); +} + +/* + * Hot code path - mix data into entropy pool + */ +void lrng_pool_add_irq(u32 irq_num) +{ + struct lrng_irq_info *irq_info = &lrng_pool.irq_info; + + atomic_add(irq_num, &irq_info->num_events); + + /* + * Once all DRNGs are fully seeded, the interrupt noise + * sources will not trigger any reseeding any more. + */ + if (likely(lrng_pool.all_online_numa_node_seeded)) + return; + + /* Only try to reseed if the DRNG is alive. */ + if (!lrng_get_available()) + return; + + /* Only trigger the DRNG reseed if we have collected enough IRQs. */ + if (atomic_read_u32(&lrng_pool.irq_info.num_events) < + atomic_read_u32(&lrng_pool.irq_info.num_events_thresh)) + return; + + /* Ensure that the seeding only occurs once at any given time. */ + if (lrng_pool_trylock()) + return; + + /* Seed the DRNG with IRQ noise. */ + schedule_work(&lrng_state.lrng_seed_work); +} + +void lrng_pool_add_entropy(u32 entropy_bits) +{ + lrng_pool_add_irq(lrng_entropy_to_data(entropy_bits)); +} + +/* + * Generate a hashed output of pool using the SP800-90A section 10.3.1 hash_df + * function + */ +u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash, + struct lrng_pool *pool, u8 *outbuf, u32 requested_bits) +{ + u32 digestsize, requested_bytes = requested_bits >> 3, + generated_bytes = 0; + u8 digest[64] __aligned(LRNG_KCAPI_ALIGN); + + digestsize = crypto_cb->lrng_hash_digestsize(hash); + if (digestsize > sizeof(digest)) { + pr_err("Digest buffer too small\n"); + return 0; + } + + pool->counter = 1; + pool->requested_bits = cpu_to_be32(requested_bytes << 3); + + while (requested_bytes) { + u32 tocopy = min_t(u32, requested_bytes, digestsize); + + /* The counter must not wrap */ + if (pool->counter == 0) + goto out; + + if (crypto_cb->lrng_hash_buffer(hash, (u8 *)pool, + LRNG_POOL_SIZE_BYTES + 64, + digest)) + goto out; + + /* Copy the data out to the caller */ + memcpy(outbuf + generated_bytes, digest, tocopy); + requested_bytes -= tocopy; + generated_bytes += tocopy; + pool->counter++; + } + +out: + /* Mix read data back into pool for backtracking resistance */ + if (generated_bytes) + lrng_pool_lfsr(outbuf, generated_bytes); + memzero_explicit(digest, digestsize); + return (generated_bytes<<3); +} + +static inline u32 lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, + void *hash, u8 *outbuf, u32 requested_bits) +{ + return __lrng_pool_hash_df(crypto_cb, hash, &lrng_pool, outbuf, + requested_bits); +} + +/** + * lrng_get_pool() - Read the entropy pool out for use. + * + * This function handles the translation from the number of received interrupts + * into an entropy statement. The conversion depends on LRNG_IRQ_ENTROPY_BITS + * which defines how many interrupts must be received to obtain 256 bits of + * entropy. With this value, the function lrng_data_to_entropy converts a given + * data size (received interrupts, requested amount of data, etc.) into an + * entropy statement. lrng_entropy_to_data does the reverse. + * + * Both functions are agnostic about the type of data: when the number of + * interrupts is processed by these functions, the resulting entropy value is in + * bits as we assume the entropy of interrupts is measured in bits. When data is + * processed, the entropy value is in bytes as the data is measured in bytes. + * + * @outbuf: buffer to store data in with size LRNG_DRNG_SECURITY_STRENGTH_BYTES + * @requested_entropy_bits: requested bits of entropy -- the function will + * return at least this amount of entropy if available + * @entropy_retain: amount of entropy in bits that should be left in the pool + * + * Return: estimated entropy from the IRQs that was obtained + */ +static u32 lrng_get_pool(const struct lrng_crypto_cb *crypto_cb, void *hash, + u8 *outbuf, u32 requested_entropy_bits, + u32 entropy_retain) +{ + struct lrng_pool *pool = &lrng_pool; + struct lrng_state *state = &lrng_state; + struct lrng_irq_info *irq_info = &pool->irq_info; + unsigned long flags; + + u32 irq_num_events_used, irq_num_events, avail_entropy_bits; + + /* This get_pool operation must only be called once at a given time! */ + spin_lock_irqsave(&pool->lock, flags); + + /* How many unused interrupts are in entropy pool? */ + irq_num_events = atomic_read_u32(&irq_info->num_events); + /* Convert available interrupts into entropy statement */ + avail_entropy_bits = lrng_data_to_entropy(irq_num_events); + + /* Cap available entropy to pool size */ + avail_entropy_bits = + min_t(u32, avail_entropy_bits, LRNG_POOL_SIZE_BITS); + + /* How much entropy we need to and can we use? */ + if (unlikely(!state->lrng_fully_seeded)) { + /* + * During boot time, we read 256 bits data with + * avail_entropy_bits entropy. In case our conservative + * entropy estimate underestimates the available entropy + * we can transport as much available entropy as + * possible. The entropy pool does not operate compliant to + * the German AIS 21/31 NTG.1 yet. + */ + requested_entropy_bits = + LRNG_DRNG_SECURITY_STRENGTH_BITS; + } else { + /* Provide all entropy above retaining level */ + if (avail_entropy_bits < entropy_retain) { + requested_entropy_bits = 0; + goto out; + } + avail_entropy_bits -= entropy_retain; + requested_entropy_bits = min_t(u32, avail_entropy_bits, + requested_entropy_bits); + } + + /* Hash is a compression function: we generate entropy amount of data */ + requested_entropy_bits = round_down(requested_entropy_bits, 8); + + requested_entropy_bits = lrng_pool_hash_df(crypto_cb, hash, outbuf, + requested_entropy_bits); + + /* Boot time: After getting the full buffer adjust the entropy value. */ + requested_entropy_bits = min_t(u32, avail_entropy_bits, + requested_entropy_bits); + +out: + /* Convert used entropy into interrupt number for subtraction */ + irq_num_events_used = lrng_entropy_to_data(requested_entropy_bits); + + /* + * The hash_df operation entropy assessment shows that the output + * entropy is one bit smaller than the input entropy. Therefore we + * account for this one bit of entropy here: if we have sufficient + * entropy in the LFSR, we say we used one bit of entropy more. + * Otherwise we reduce the amount of entropy we say we generated with + * the hash_df. + */ + if (irq_num_events_used) { + if ((irq_num_events_used + LRNG_CONDITIONING_ENTROPY_LOSS) <= + lrng_entropy_to_data(avail_entropy_bits)) { + irq_num_events_used += LRNG_CONDITIONING_ENTROPY_LOSS; + } else { + if (unlikely(requested_entropy_bits < + LRNG_CONDITIONING_ENTROPY_LOSS)) + requested_entropy_bits = 0; + else + requested_entropy_bits -= + LRNG_CONDITIONING_ENTROPY_LOSS; + } + } + + /* + * New events might have arrived in the meanwhile and we don't + * want to throw them away unconditionally. On the other hand, + * these new events might have been mixed in before + * lrng_hash_df_pool() had been able to draw any entropy + * from the pool and thus, the pool capacity might have been + * exceeded at some point. Note that in theory, some events + * might get lost inbetween the atomic_read() and + * atomic_set() below. But that's fine, because it's no real + * concern while code preventing this would come at the cost of + * additional complexity. Likewise, some events which arrived + * after full or partial completion of the __lrng_hash_df_pool() + * above might get unnecessarily thrown away by the min() + * operation below; the same argument applies there. + */ + irq_num_events = atomic_read_u32(&irq_info->num_events); + irq_num_events = min_t(u32, irq_num_events, + lrng_entropy_to_data(LRNG_POOL_SIZE_BITS)); + irq_num_events -= irq_num_events_used; + atomic_set(&irq_info->num_events, irq_num_events); + + spin_unlock_irqrestore(&pool->lock, flags); + + /* Obtain entropy statement in bits from the used entropy */ + pr_debug("obtained %u bits of entropy from %u newly collected interrupts - not using %u interrupts\n", + requested_entropy_bits, irq_num_events_used, + irq_num_events); + + return requested_entropy_bits; +} + +/* Fill the seed buffer with data from the noise sources */ +int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash, + struct entropy_buf *entropy_buf, u32 entropy_retain) +{ + struct lrng_state *state = &lrng_state; + u32 total_entropy_bits = 0; + + /* Require at least 128 bits of entropy for any reseed. */ + if (state->lrng_fully_seeded && + (lrng_avail_entropy() < + lrng_slow_noise_req_entropy(LRNG_MIN_SEED_ENTROPY_BITS + + LRNG_CONDITIONING_ENTROPY_LOSS) + + entropy_retain)) + goto wakeup; + + /* + * Concatenate the output of the noise sources. This would be the + * spot to add an entropy extractor logic if desired. Note, this + * has the ability to collect entropy equal or larger than the DRNG + * strength. + */ + total_entropy_bits = lrng_get_pool(crypto_cb, hash, entropy_buf->a, + LRNG_DRNG_SECURITY_STRENGTH_BITS, + entropy_retain); + total_entropy_bits += lrng_get_arch(entropy_buf->b); + total_entropy_bits += lrng_get_jent(entropy_buf->c, + LRNG_DRNG_SECURITY_STRENGTH_BYTES); + + /* also reseed the DRNG with the current time stamp */ + entropy_buf->now = random_get_entropy(); + + /* allow external entropy provider to provide seed */ + lrng_state_exseed_allow_all(); + +wakeup: + /* + * Shall we wake up user space writers? This location covers + * ensures that the user space provider does not dominate the internal + * noise sources since in case the first call of this function finds + * sufficient entropy in the entropy pool, it will not trigger the + * wakeup. This implies that when the next /dev/urandom read happens, + * the entropy pool is drained. + */ + lrng_writer_wakeup(); + + return total_entropy_bits; +} + +/** + * lrng_init_ops() - Set seed stages of LRNG + * + * Set the slow noise source reseed trigger threshold. The initial threshold + * is set to the minimum data size that can be read from the pool: a word. Upon + * reaching this value, the next seed threshold of 128 bits is set followed + * by 256 bits. + * + * @entropy_bits: size of entropy currently injected into DRNG + */ +void lrng_init_ops(u32 seed_bits) +{ + struct lrng_state *state = &lrng_state; + + if (state->lrng_operational) + return; + + /* DRNG is seeded with full security strength */ + if (state->lrng_fully_seeded) { + state->lrng_operational = lrng_sp80090b_startup_complete(); + lrng_process_ready_list(); + lrng_init_wakeup(); + } else if (seed_bits >= LRNG_FULL_SEED_ENTROPY_BITS) { + invalidate_batched_entropy(); + state->lrng_fully_seeded = true; + state->lrng_operational = lrng_sp80090b_startup_complete(); + state->lrng_min_seeded = true; + pr_info("LRNG fully seeded with %u bits of entropy\n", + seed_bits); + lrng_set_entropy_thresh(LRNG_FULL_SEED_ENTROPY_BITS + + LRNG_CONDITIONING_ENTROPY_LOSS); + lrng_process_ready_list(); + lrng_init_wakeup(); + + } else if (!state->lrng_min_seeded) { + + /* DRNG is seeded with at least 128 bits of entropy */ + if (seed_bits >= LRNG_MIN_SEED_ENTROPY_BITS) { + invalidate_batched_entropy(); + state->lrng_min_seeded = true; + pr_info("LRNG minimally seeded with %u bits of entropy\n", + seed_bits); + lrng_set_entropy_thresh( + lrng_slow_noise_req_entropy( + LRNG_FULL_SEED_ENTROPY_BITS + + LRNG_CONDITIONING_ENTROPY_LOSS)); + lrng_process_ready_list(); + lrng_init_wakeup(); + + /* DRNG is seeded with at least LRNG_INIT_ENTROPY_BITS bits */ + } else if (seed_bits >= LRNG_INIT_ENTROPY_BITS) { + pr_info("LRNG initial entropy level %u bits of entropy\n", + seed_bits); + lrng_set_entropy_thresh( + lrng_slow_noise_req_entropy( + LRNG_MIN_SEED_ENTROPY_BITS + + LRNG_CONDITIONING_ENTROPY_LOSS)); + } + } +} + +int __init rand_initialize(void) +{ + ktime_t now_time = ktime_get_real(); + unsigned long rand; + unsigned int i; + + lrng_drng_init_early(); + + lrng_pool_lfsr_u32(now_time); + for (i = 0; i < LRNG_POOL_SIZE; i++) { + if (!arch_get_random_seed_long_early(&rand) && + !arch_get_random_long_early(&rand)) + rand = random_get_entropy(); + lrng_pool_lfsr((u8 *)&rand, sizeof(rand)); + } + lrng_pool_lfsr_nonaligned((u8 *)utsname(), sizeof(*(utsname()))); + + return 0; +} diff --git a/drivers/char/lrng/lrng_sw_noise.c b/drivers/char/lrng/lrng_sw_noise.c new file mode 100644 index 000000000000..1183d77005ac --- /dev/null +++ b/drivers/char/lrng/lrng_sw_noise.c @@ -0,0 +1,155 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG Slow Noise Source: Interrupt data collection + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#include +#include +#include + +#include "lrng_internal.h" +#include "lrng_sw_noise.h" + +/* Holder of time stamps before mixing them into the entropy pool */ +static DEFINE_PER_CPU(u32 [LRNG_TIME_ARRAY_SIZE], lrng_time); +static DEFINE_PER_CPU(u32, lrng_time_ptr) = 0; +static DEFINE_PER_CPU(u8, lrng_time_irqs) = 0; + +/* + * Batching up of entropy in per-CPU array before injecting into entropy pool. + * + * The random32_data is solely to be used for the external random32 PRNG. + */ +static inline void lrng_time_process(u32 random32_data) +{ + u32 i, ptr, now_time = random_get_entropy(); + u32 now_time_masked = now_time & LRNG_TIME_SLOTSIZE_MASK; + enum lrng_health_res health_test; + + /* Ensure sufficient space in lrng_time_irqs */ + BUILD_BUG_ON(LRNG_TIME_NUM_VALUES >= (1 << (sizeof(u8) << 3))); + BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS % LRNG_TIME_SLOTSIZE_BITS); + /* Ensure consistency of values */ + BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS != sizeof(lrng_time[0]) << 3); + + /* During boot time, we mix the full time stamp directly into LFSR */ + if (unlikely(!lrng_state_fully_seeded())) { + + /* Seed random32 PRNG with data not used by LRNG. */ + this_cpu_add(net_rand_state.s1, random32_data); + + if (lrng_raw_hires_entropy_store(now_time)) + goto out; + + health_test = lrng_health_test(now_time); + if (health_test > lrng_health_fail_use) + goto out; + + lrng_pool_lfsr_u32(now_time); + if (health_test == lrng_health_pass) + lrng_pool_add_irq(1); + goto out; + } + + /* Runtime operation */ + if (lrng_raw_hires_entropy_store(now_time_masked)) + goto out; + + /* Seed random32 PRNG with data not used by LRNG. */ + this_cpu_add(net_rand_state.s1, + (now_time & ~LRNG_TIME_SLOTSIZE_MASK) ^ random32_data); + + health_test = lrng_health_test(now_time_masked); + if (health_test > lrng_health_fail_use) + goto out; + + ptr = this_cpu_inc_return(lrng_time_ptr) & LRNG_TIME_WORD_MASK; + this_cpu_or(lrng_time[lrng_time_idx2array(ptr)], + lrng_time_slot_val(now_time_masked, + lrng_time_idx2slot(ptr))); + + /* Interrupt delivers entropy if health test passes */ + if (health_test == lrng_health_pass) + this_cpu_inc(lrng_time_irqs); + + /* Only mix the buffer of time stamps into LFSR when wrapping */ + if (ptr < LRNG_TIME_WORD_MASK) + goto out; + + for (i = 0; i < LRNG_TIME_ARRAY_SIZE; i++) { + if (lrng_raw_array_entropy_store(this_cpu_read(lrng_time[i]))) { + /* + * If we fed even a part of the array to external + * analysis, we mark that the entire array has no + * entropy. This is due to the non-IID property of + * the data as we do not fully know whether the + * existing dependencies diminish the entropy beyond + * to what we expect it has. + */ + this_cpu_write(lrng_time_irqs, 0); + } else { + lrng_pool_lfsr_u32(this_cpu_read(lrng_time[i])); + } + + this_cpu_write(lrng_time[i], 0); + } + lrng_pool_add_irq(this_cpu_read(lrng_time_irqs)); + this_cpu_write(lrng_time_irqs, 0); + +out: + lrng_perf_time(now_time); +} + +/* + * Hot code path - Callback for interrupt handler + */ +void add_interrupt_randomness(int irq, int irq_flags) +{ + if (lrng_pool_highres_timer()) { + lrng_time_process( + (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^ + (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 : + irq_flags) ^ + (lrng_raw_retip_entropy_store(_RET_IP_) ? 0 : + _RET_IP_)); + } else { + struct pt_regs *regs = get_irq_regs(); + static atomic_t reg_idx = ATOMIC_INIT(0); + u64 ip; + + if (regs) { + u32 *ptr = (u32 *)regs; + int reg_ptr = atomic_add_return_relaxed(1, ®_idx); + size_t n = (sizeof(struct pt_regs) / sizeof(u32)); + + ip = instruction_pointer(regs); + lrng_pool_lfsr_u32(*(ptr + (reg_ptr % n))); + + lrng_time_process( + lrng_raw_retip_entropy_store(_RET_IP_) ? 0 : + _RET_IP_); + } else { + ip = _RET_IP_; + + lrng_time_process(0); + } + + /* + * The XOR operation combining the different values is not + * considered to destroy entropy since the entirety of all + * processed values delivers the entropy (and not each + * value separately of the other values). + */ + lrng_pool_lfsr_u32( + (lrng_raw_jiffies_entropy_store(jiffies) ? 0 : + jiffies) ^ + (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^ + (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 : + irq_flags) ^ + (ip >> 32) ^ + (lrng_raw_retip_entropy_store(ip) ? 0 : ip)); + } +} +EXPORT_SYMBOL(add_interrupt_randomness); diff --git a/drivers/char/lrng/lrng_sw_noise.h b/drivers/char/lrng/lrng_sw_noise.h new file mode 100644 index 000000000000..919d8c368991 --- /dev/null +++ b/drivers/char/lrng/lrng_sw_noise.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */ +/* + * LRNG Slow Noise Source: Time stamp array handling + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +/* + * To limit the impact on the interrupt handling, the LRNG concatenates + * entropic LSB parts of the time stamps in a per-CPU array and only + * injects them into the entropy pool when the array is full. + */ + +/* Store multiple integers in one u32 */ +#define LRNG_TIME_SLOTSIZE_BITS (8) +#define LRNG_TIME_SLOTSIZE_MASK ((1 << LRNG_TIME_SLOTSIZE_BITS) - 1) +#define LRNG_TIME_ARRAY_MEMBER_BITS (4 << 3) /* ((sizeof(u32)) << 3) */ +#define LRNG_TIME_SLOTS_PER_UINT (LRNG_TIME_ARRAY_MEMBER_BITS / \ + LRNG_TIME_SLOTSIZE_BITS) + +/* + * Number of time values to store in the array - in small environments + * only one atomic_t variable per CPU is used. + */ +#define LRNG_TIME_NUM_VALUES (CONFIG_BASE_SMALL ? \ + LRNG_TIME_SLOTS_PER_UINT : 64) +/* Mask of LSB of time stamp to store */ +#define LRNG_TIME_WORD_MASK (LRNG_TIME_NUM_VALUES - 1) + +#define LRNG_TIME_SLOTS_MASK (LRNG_TIME_SLOTS_PER_UINT - 1) +#define LRNG_TIME_ARRAY_SIZE (LRNG_TIME_NUM_VALUES / \ + LRNG_TIME_SLOTS_PER_UINT) + +/* Starting bit index of slot */ +static inline unsigned int lrng_time_slot2bitindex(unsigned int slot) +{ + return (LRNG_TIME_SLOTSIZE_BITS * slot); +} + +/* Convert index into the array index */ +static inline unsigned int lrng_time_idx2array(unsigned int idx) +{ + return idx / LRNG_TIME_SLOTS_PER_UINT; +} + +/* Convert index into the slot of a given array index */ +static inline unsigned int lrng_time_idx2slot(unsigned int idx) +{ + return idx & LRNG_TIME_SLOTS_MASK; +} + +/* Convert value into slot value */ +static inline unsigned int lrng_time_slot_val(unsigned int val, + unsigned int slot) +{ + return val << lrng_time_slot2bitindex(slot); +} diff --git a/include/linux/lrng.h b/include/linux/lrng.h new file mode 100644 index 000000000000..2c3d2ed32a91 --- /dev/null +++ b/include/linux/lrng.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */ +/* + * Copyright (C) 2018 - 2020, Stephan Mueller + */ + +#ifndef _LRNG_H +#define _LRNG_H + +#include +#include + +/** + * struct lrng_crypto_cb - cryptographic callback functions + * @lrng_drng_name Name of DRNG + * @lrng_hash_name Name of Hash used for reading entropy pool + * @lrng_drng_alloc: Allocate DRNG -- the provided integer should be + * used for sanity checks. + * return: allocated data structure or PTR_ERR on + * error + * @lrng_drng_dealloc: Deallocate DRNG + * @lrng_drng_seed_helper: Seed the DRNG with data of arbitrary length + * drng: is pointer to data structure allocated + * with lrng_drng_alloc + * return: >= 0 on success, < 0 on error + * @lrng_drng_generate_helper: Generate random numbers from the DRNG with + * arbitrary length + * @lrng_hash_alloc: Allocate the hash for reading the entropy pool + * return: allocated data structure (NULL is + * success too) or ERR_PTR on error + * @lrng_hash_dealloc: Deallocate Hash + * @lrng_hash_digestsize: Return the digestsize for the used hash to read + * out entropy pool + * hash: is pointer to data structure allocated + * with lrng_hash_alloc + * return: size of digest of hash in bytes + * @lrng_hash_buffer: Generate hash + * hash: is pointer to data structure allocated + * with lrng_hash_alloc + * return: 0 on success, < 0 on error + */ +struct lrng_crypto_cb { + const char *(*lrng_drng_name)(void); + const char *(*lrng_hash_name)(void); + void *(*lrng_drng_alloc)(u32 sec_strength); + void (*lrng_drng_dealloc)(void *drng); + int (*lrng_drng_seed_helper)(void *drng, const u8 *inbuf, u32 inbuflen); + int (*lrng_drng_generate_helper)(void *drng, u8 *outbuf, u32 outbuflen); + void *(*lrng_hash_alloc)(const u8 *key, u32 keylen); + void (*lrng_hash_dealloc)(void *hash); + u32 (*lrng_hash_digestsize)(void *hash); + int (*lrng_hash_buffer)(void *hash, const u8 *inbuf, u32 inbuflen, + u8 *digest); +}; + +/* Register cryptographic backend */ +#ifdef CONFIG_LRNG_DRNG_SWITCH +int lrng_set_drng_cb(const struct lrng_crypto_cb *cb); +#else /* CONFIG_LRNG_DRNG_SWITCH */ +static inline int +lrng_set_drng_cb(const struct lrng_crypto_cb *cb) { return -EOPNOTSUPP; } +#endif /* CONFIG_LRNG_DRNG_SWITCH */ + +#endif /* _LRNG_H */ From patchwork Fri Aug 21 05:39:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253150 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F30FC433DF for ; Fri, 21 Aug 2020 06:03:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 72D8221741 for ; Fri, 21 Aug 2020 06:03:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="MenzR/KU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727950AbgHUGDI (ORCPT ); Fri, 21 Aug 2020 02:03:08 -0400 Received: from mo4-p04-ob.smtp.rzone.de ([81.169.146.179]:33022 "EHLO mo4-p04-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727881AbgHUGCg (ORCPT ); Fri, 21 Aug 2020 02:02:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1597989749; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=6nvWosFlFIPSHnhQOytG9NyohOjJd5sSg28RiRIWLk8=; b=MenzR/KUEobD2T1o7YFRiSXtxc7m3rECm3xVWLwPZUvRwI7+xbr8xcqQz8IWM7rmtH KjT4iznyTruXtGEN9vr3AcyqApe7sQmP1Wj6kgckDdPK0QHOKElFCJ+bo/fjvmO4MNyK kQlHhGx8yKNGRsXfrWJy+bdVeLkLTnaxD4Kd5CZSTTq2zFSUwdW/5MGGGpera2UowXs+ AmqRvLmlW5AwTARrfvut/06+yffMlXoDHRBUaOqoUBw8sOcLxr8hx0XGpd+emNRkrTTn 5Ld7xZXqewAYLPT/enqqUZbssmJCOw14CUEtYwSvuTv2R5YHoVwjLxLrBQCQfvmECqh1 TWqQ== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xm0dNS3IdRAZAL+p6A==" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw7L61EGLB (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 21 Aug 2020 08:01:14 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter Subject: [PATCH v33 02/12] LRNG - allocate one DRNG instance per NUMA node Date: Fri, 21 Aug 2020 07:39:11 +0200 Message-ID: <3244231.QJadu78ljV@positron.chronox.de> In-Reply-To: <5532247.MhkbZ0Pkbq@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> MIME-Version: 1.0 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org In order to improve NUMA-locality when serving getrandom(2) requests, allocate one DRNG instance per node. The DRNG instance that is present right from the start of the kernel is reused as the first per-NUMA-node DRNG. For all remaining online NUMA nodes a new DRNG instance is allocated. During boot time, the multiple DRNG instances are seeded sequentially. With this, the first DRNG instance (referenced as the initial DRNG in the code) is completely seeded with 256 bits of entropy before the next DRNG instance is completely seeded. When random numbers are requested, the NUMA-node-local DRNG is checked whether it has been already fully seeded. If this is not the case, the initial DRNG is used to serve the request. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Marcelo Henrique Cerri Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Makefile | 2 + drivers/char/lrng/lrng_internal.h | 5 ++ drivers/char/lrng/lrng_numa.c | 101 ++++++++++++++++++++++++++++++ 3 files changed, 108 insertions(+) create mode 100644 drivers/char/lrng/lrng_numa.c diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 1d2a0211973d..0a32f22c2c1a 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -7,3 +7,5 @@ obj-y += lrng_pool.o lrng_aux.o \ lrng_sw_noise.o lrng_archrandom.o \ lrng_drng.o lrng_chacha20.o \ lrng_interfaces.o \ + +obj-$(CONFIG_NUMA) += lrng_numa.o diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h index 53c267115721..5587be09f495 100644 --- a/drivers/char/lrng/lrng_internal.h +++ b/drivers/char/lrng/lrng_internal.h @@ -250,8 +250,13 @@ int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen); void lrng_drng_force_reseed(void); void lrng_drng_seed_work(struct work_struct *dummy); +#ifdef CONFIG_NUMA +struct lrng_drng **lrng_drng_instances(void); +void lrng_drngs_numa_alloc(void); +#else /* CONFIG_NUMA */ static inline struct lrng_drng **lrng_drng_instances(void) { return NULL; } static inline void lrng_drngs_numa_alloc(void) { return; } +#endif /* CONFIG_NUMA */ /************************** Health Test linking code **************************/ diff --git a/drivers/char/lrng/lrng_numa.c b/drivers/char/lrng/lrng_numa.c new file mode 100644 index 000000000000..947c5b3ed517 --- /dev/null +++ b/drivers/char/lrng/lrng_numa.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG NUMA support + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include + +#include "lrng_internal.h" + +static struct lrng_drng **lrng_drng __read_mostly = NULL; + +struct lrng_drng **lrng_drng_instances(void) +{ + return lrng_drng; +} + +/* Allocate the data structures for the per-NUMA node DRNGs */ +static void _lrng_drngs_numa_alloc(struct work_struct *work) +{ + struct lrng_drng **drngs; + struct lrng_drng *lrng_drng_init = lrng_drng_init_instance(); + u32 node; + bool init_drng_used = false; + + mutex_lock(&lrng_crypto_cb_update); + + /* per-NUMA-node DRNGs are already present */ + if (lrng_drng) + goto unlock; + + drngs = kcalloc(nr_node_ids, sizeof(void *), GFP_KERNEL|__GFP_NOFAIL); + for_each_online_node(node) { + struct lrng_drng *drng; + + if (!init_drng_used) { + drngs[node] = lrng_drng_init; + init_drng_used = true; + continue; + } + + drng = kmalloc_node(sizeof(struct lrng_drng), + GFP_KERNEL|__GFP_NOFAIL, node); + memset(drng, 0, sizeof(lrng_drng)); + + drng->crypto_cb = lrng_drng_init->crypto_cb; + drng->drng = drng->crypto_cb->lrng_drng_alloc( + LRNG_DRNG_SECURITY_STRENGTH_BYTES); + if (IS_ERR(drng->drng)) { + kfree(drng); + goto err; + } + + mutex_init(&drng->lock); + spin_lock_init(&drng->spin_lock); + + /* + * No reseeding of NUMA DRNGs from previous DRNGs as this + * would complicate the code. Let it simply reseed. + */ + lrng_drng_reset(drng); + drngs[node] = drng; + + lrng_pool_inc_numa_node(); + pr_info("DRNG for NUMA node %d allocated\n", node); + } + + /* Ensure that all NUMA nodes receive changed memory here. */ + mb(); + + if (!cmpxchg(&lrng_drng, NULL, drngs)) + goto unlock; + +err: + for_each_online_node(node) { + struct lrng_drng *drng = drngs[node]; + + if (drng == lrng_drng_init) + continue; + + if (drng) { + drng->crypto_cb->lrng_drng_dealloc(drng->drng); + kfree(drng); + } + } + kfree(drngs); + +unlock: + mutex_unlock(&lrng_crypto_cb_update); +} + +static DECLARE_WORK(lrng_drngs_numa_alloc_work, _lrng_drngs_numa_alloc); + +void lrng_drngs_numa_alloc(void) +{ + schedule_work(&lrng_drngs_numa_alloc_work); +} From patchwork Fri Sep 18 09:49:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 252997 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EB4CC43466 for ; Fri, 18 Sep 2020 10:13:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E44D621D7B for ; Fri, 18 Sep 2020 10:13:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="U8DIS+qO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726748AbgIRKMv (ORCPT ); Fri, 18 Sep 2020 06:12:51 -0400 Received: from mo4-p04-ob.smtp.rzone.de ([81.169.146.178]:8625 "EHLO mo4-p04-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726720AbgIRKMe (ORCPT ); Fri, 18 Sep 2020 06:12:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1600423949; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=gBbQN/OKbVVWgTcmybAPnfKONV3cgvVYwqTlbmUmgAk=; b=U8DIS+qOG+lzJ92+DAYaV3Xls+CR93YUpQblzQIWNM6HxzIbu5/2NDOVj0n7ODMcto uOkcyVbkdLczKQU/QNH13anvXYm71X7s2qEJHRCuRwIQC9pfuJNrAq4RcUl3zDkGULpC zA5zwHPgY0Ke7Nrh4Ya7dzu2uFmFsh+6r1jz3PlB+IyB/V4y/KUKpYyfIzfif7fyeWXi OLU+CMP+qM84BMQ1xfZ8UdTr0kZaN/0x8r1Tj5SXm8x1oekzBrsy1HKIHu+RFFDpLQtS wlfxA7CVdsIj8OC128TIqarVQT+oW4EJu1rnyeII3KlER0HoHOWto192g1YGz5cP3mWL om4A== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaJPScXyVH" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw8IA0J2TF (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Sep 2020 12:00:19 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr , ebiggers@kernel.org Subject: [PATCH v35 03/13] LRNG - sysctls and /proc interface Date: Fri, 18 Sep 2020 11:49:07 +0200 Message-ID: <2065317.irdbgypaU6@positron.chronox.de> In-Reply-To: <5667034.lOV4Wx5bFT@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <5667034.lOV4Wx5bFT@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org The LRNG sysctl interface provides the same controls as the existing /dev/random implementation. These sysctls behave identically and are implemented identically. The goal is to allow a possible merge of the existing /dev/random implementation with this implementation which implies that this patch tries have a very close similarity. Yet, all sysctls are documented at [1]. In addition, it provides the file lrng_type which provides details about the LRNG: - the name of the DRNG that produces the random numbers for /dev/random, /dev/urandom, getrandom(2) - the hash used to produce random numbers from the entropy pool - the number of secondary DRNG instances - indicator whether the LRNG operates SP800-90B compliant - indicator whether a high-resolution timer is identified - only with a high-resolution timer the interrupt noise source will deliver sufficient entropy - indicator whether the LRNG has been minimally seeded (i.e. is the secondary DRNG seeded with at least 128 bits of of entropy) - indicator whether the LRNG has been fully seeded (i.e. is the secondary DRNG seeded with at least 256 bits of entropy) [1] https://www.chronox.de/lrng.html CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Marcelo Henrique Cerri Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_interfaces.c | 2 - drivers/char/lrng/lrng_internal.h | 4 + drivers/char/lrng/lrng_proc.c | 181 ++++++++++++++++++++++++++++ 4 files changed, 186 insertions(+), 2 deletions(-) create mode 100644 drivers/char/lrng/lrng_proc.c diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 29724c65287d..ac97f0b11cb7 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -9,3 +9,4 @@ obj-y += lrng_pool.o lrng_aux.o \ lrng_interfaces.o obj-$(CONFIG_NUMA) += lrng_numa.o +obj-$(CONFIG_SYSCTL) += lrng_proc.o diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c index 19d01d3f7492..b55de97523ad 100644 --- a/drivers/char/lrng/lrng_interfaces.c +++ b/drivers/char/lrng/lrng_interfaces.c @@ -38,8 +38,6 @@ static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait); static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait); static struct fasync_struct *fasync; -struct ctl_table random_table[]; - /********************************** Helper ***********************************/ /* Is the DRNG seed level too low? */ diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h index c405cbf379d6..42014df47028 100644 --- a/drivers/char/lrng/lrng_internal.h +++ b/drivers/char/lrng/lrng_internal.h @@ -113,7 +113,11 @@ void lrng_cc20_init_state_boot(struct chacha20_state *state); /********************************** /proc *************************************/ +#ifdef CONFIG_SYSCTL +void lrng_pool_inc_numa_node(void); +#else static inline void lrng_pool_inc_numa_node(void) { } +#endif /****************************** LRNG interfaces *******************************/ diff --git a/drivers/char/lrng/lrng_proc.c b/drivers/char/lrng/lrng_proc.c new file mode 100644 index 000000000000..7cd1628d823f --- /dev/null +++ b/drivers/char/lrng/lrng_proc.c @@ -0,0 +1,181 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG proc and sysctl interfaces + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#include +#include +#include +#include +#include + +#include "lrng_internal.h" +#include "lrng_sw_noise.h" + +/* + * This function is used to return both the bootid UUID, and random + * UUID. The difference is in whether table->data is NULL; if it is, + * then a new UUID is generated and returned to the user. + * + * If the user accesses this via the proc interface, the UUID will be + * returned as an ASCII string in the standard UUID format; if via the + * sysctl system call, as 16 bytes of binary data. + */ +static int lrng_proc_do_uuid(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table fake_table; + unsigned char buf[64], tmp_uuid[16], *uuid; + + uuid = table->data; + if (!uuid) { + uuid = tmp_uuid; + generate_random_uuid(uuid); + } else { + static DEFINE_SPINLOCK(bootid_spinlock); + + spin_lock(&bootid_spinlock); + if (!uuid[8]) + generate_random_uuid(uuid); + spin_unlock(&bootid_spinlock); + } + + sprintf(buf, "%pU", uuid); + + fake_table.data = buf; + fake_table.maxlen = sizeof(buf); + + return proc_dostring(&fake_table, write, buffer, lenp, ppos); +} + +static int lrng_proc_do_entropy(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table fake_table; + int entropy_count; + + entropy_count = lrng_avail_entropy(); + + fake_table.data = &entropy_count; + fake_table.maxlen = sizeof(entropy_count); + + return proc_dointvec(&fake_table, write, buffer, lenp, ppos); +} + +static int lrng_proc_do_poolsize(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table fake_table; + int entropy_count; + + entropy_count = lrng_max_entropy(); + + fake_table.data = &entropy_count; + fake_table.maxlen = sizeof(entropy_count); + + return proc_dointvec(&fake_table, write, buffer, lenp, ppos); +} + +static int lrng_min_write_thresh; +static int lrng_max_write_thresh = LRNG_MAX_DIGESTSIZE; +static char lrng_sysctl_bootid[16]; +static int lrng_drng_reseed_max_min; + +struct ctl_table random_table[] = { + { + .procname = "poolsize", + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = lrng_proc_do_poolsize, + }, + { + .procname = "entropy_avail", + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = lrng_proc_do_entropy, + }, + { + .procname = "write_wakeup_threshold", + .data = &lrng_write_wakeup_bits, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &lrng_min_write_thresh, + .extra2 = &lrng_max_write_thresh, + }, + { + .procname = "boot_id", + .data = &lrng_sysctl_bootid, + .maxlen = 16, + .mode = 0444, + .proc_handler = lrng_proc_do_uuid, + }, + { + .procname = "uuid", + .maxlen = 16, + .mode = 0444, + .proc_handler = lrng_proc_do_uuid, + }, + { + .procname = "urandom_min_reseed_secs", + .data = &lrng_drng_reseed_max_time, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + .extra1 = &lrng_drng_reseed_max_min, + }, + { } +}; + +/* Number of online DRNGs */ +static u32 numa_drngs = 1; + +void lrng_pool_inc_numa_node(void) +{ + numa_drngs++; +} + +static int lrng_proc_type_show(struct seq_file *m, void *v) +{ + struct lrng_drng *lrng_drng_init = lrng_drng_init_instance(); + unsigned long flags = 0; + unsigned char buf[350]; + + lrng_drng_lock(lrng_drng_init, &flags); + snprintf(buf, sizeof(buf), + "DRNG name: %s\n" + "Hash for reading entropy pool: %s\n" + "Hash for operating aux entropy pool: %s\n" + "LRNG security strength in bits: %d\n" + "per-CPU interrupt collection size: %u\n" + "number of DRNG instances: %u\n" + "SP800-90B compliance: %s\n" + "High-resolution timer: %s\n" + "LRNG minimally seeded: %s\n" + "LRNG fully seeded: %s\n", + lrng_drng_init->crypto_cb->lrng_drng_name(), + lrng_drng_init->crypto_cb->lrng_hash_name(), + lrng_drng_init->crypto_cb->lrng_hash_name(), + lrng_security_strength(), + LRNG_DATA_NUM_VALUES, + numa_drngs, + lrng_sp80090b_compliant() ? "true" : "false", + lrng_pool_highres_timer() ? "true" : "false", + lrng_state_min_seeded() ? "true" : "false", + lrng_state_fully_seeded() ? "true" : "false"); + lrng_drng_unlock(lrng_drng_init, &flags); + + seq_write(m, buf, strlen(buf)); + + return 0; +} + +static int __init lrng_proc_type_init(void) +{ + proc_create_single("lrng_type", 0444, NULL, &lrng_proc_type_show); + return 0; +} + +module_init(lrng_proc_type_init); From patchwork Fri Sep 18 09:49:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 252999 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8475CC43463 for ; Fri, 18 Sep 2020 10:12:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DD5221D7B for ; Fri, 18 Sep 2020 10:12:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="kHUbt809" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726769AbgIRKMx (ORCPT ); Fri, 18 Sep 2020 06:12:53 -0400 Received: from mo4-p04-ob.smtp.rzone.de ([85.215.255.123]:28280 "EHLO mo4-p04-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbgIRKM2 (ORCPT ); Fri, 18 Sep 2020 06:12:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1600423944; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=v6UKI3JqDhmwQx0fWPYKmkm+kSCC1Ys+IklZuXkcT8o=; b=kHUbt809moKT5J0dcECcqSc8bhMR8u/QhmSWdEU2rvGvTxgOKa50oIDggUl5OWoacO 7NEbOe2dG9lZS1xvrvj1x5KtOs6iYqScyOHp2eD5isLXJZNlQB6XlpxhNCYRZCUypBlb iK0Ptr24AnZjun76SwRA0k1ux6Uu2ImXCmd/zpMzjx4hzpZWl7fE2b6K9cBKVzea41TZ O+UWeeMdkw1+lqFta+g1zHzqBX6FyXqLNPY7RasqP/fvraBOwnJS0rOE1d4a45cD9sut AQ89QI/S9RNojOvRVFuWWZ/MSoyVnp6dw5G+tdAYdel/7EhbzU3a1NcJDw753joPgmgO rODA== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaJPScXyVH" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw8IA0H2TD (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Sep 2020 12:00:17 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr , ebiggers@kernel.org Subject: [PATCH v35 04/13] LRNG - add switchable DRNG support Date: Fri, 18 Sep 2020 11:49:30 +0200 Message-ID: <2767509.e9J7NaK4W3@positron.chronox.de> In-Reply-To: <5667034.lOV4Wx5bFT@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <5667034.lOV4Wx5bFT@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org The DRNG switch support allows replacing the DRNG mechanism of the LRNG. The switching support rests on the interface definition of include/linux/lrng.h. A new DRNG is implemented by filling in the interface defined in this header file. In addition to the DRNG, the extension also has to provide a hash implementation that is used to hash the entropy pool for random number extraction. Note: It is permissible to implement a DRNG whose operations may sleep. However, the hash function must not sleep. The switchable DRNG support allows replacing the DRNG at runtime. However, only one DRNG extension is allowed to be loaded at any given time. Before replacing it with another DRNG implementation, the possibly existing DRNG extension must be unloaded. The switchable DRNG extension activates the new DRNG during load time. It is expected, however, that such a DRNG switch would be done only once by an administrator to load the intended DRNG implementation. It is permissible to compile DRNG extensions either as kernel modules or statically. The initialization of the DRNG extension should be performed with a late_initcall to ensure the extension is available when user space starts but after all other initialization completed. The initialization is performed by registering the function call data structure with the lrng_set_drng_cb function. In order to unload the DRNG extension, lrng_set_drng_cb must be invoked with the NULL parameter. The DRNG extension should always provide a security strength that is at least as strong as LRNG_DRNG_SECURITY_STRENGTH_BITS. The hash extension must not sleep and must not maintain a separate state. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Marcelo Henrique Cerri Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 7 ++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_switch.c | 203 ++++++++++++++++++++++++++++++++ 3 files changed, 211 insertions(+) create mode 100644 drivers/char/lrng/lrng_switch.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index fbbcf2ef43b6..e211fcf5aa8b 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -69,4 +69,11 @@ config LRNG_COLLECTION_SIZE default 512 if LRNG_COLLECTION_SIZE_512 default 1024 if LRNG_COLLECTION_SIZE_1024 +menuconfig LRNG_DRNG_SWITCH + bool "Support DRNG runtime switching" + help + The Linux RNG per default uses a ChaCha20 DRNG that is + accessible via the external interfaces. With this configuration + option other DRNGs can be selected and loaded at runtime. + endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index ac97f0b11cb7..0eb4a6849c88 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -10,3 +10,4 @@ obj-y += lrng_pool.o lrng_aux.o \ obj-$(CONFIG_NUMA) += lrng_numa.o obj-$(CONFIG_SYSCTL) += lrng_proc.o +obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o diff --git a/drivers/char/lrng/lrng_switch.c b/drivers/char/lrng/lrng_switch.c new file mode 100644 index 000000000000..cbaf5cd544aa --- /dev/null +++ b/drivers/char/lrng/lrng_switch.c @@ -0,0 +1,203 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG DRNG switching support + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include + +#include "lrng_internal.h" + +static int lrng_drng_switch(struct lrng_drng *drng_store, + const struct lrng_crypto_cb *cb, int node) +{ + const struct lrng_crypto_cb *old_cb; + unsigned long flags = 0, flags2 = 0; + int ret; + u8 seed[LRNG_DRNG_SECURITY_STRENGTH_BYTES]; + void *new_drng = cb->lrng_drng_alloc(LRNG_DRNG_SECURITY_STRENGTH_BYTES); + void *old_drng, *new_hash, *old_hash; + u32 current_security_strength; + bool sl = false, reset_drng = !lrng_get_available(); + + if (IS_ERR(new_drng)) { + pr_warn("could not allocate new DRNG for NUMA node %d (%ld)\n", + node, PTR_ERR(new_drng)); + return PTR_ERR(new_drng); + } + + new_hash = cb->lrng_hash_alloc(); + if (IS_ERR(new_hash)) { + pr_warn("could not allocate new LRNG pool hash (%ld)\n", + PTR_ERR(new_hash)); + cb->lrng_drng_dealloc(new_drng); + return PTR_ERR(new_hash); + } + + if (cb->lrng_hash_digestsize(new_hash) > LRNG_MAX_DIGESTSIZE) { + pr_warn("digest size of newly requested hash too large\n"); + cb->lrng_hash_dealloc(new_hash); + cb->lrng_drng_dealloc(new_drng); + return -EINVAL; + } + + current_security_strength = lrng_security_strength(); + lrng_drng_lock(drng_store, &flags); + + /* + * Pull from existing DRNG to seed new DRNG regardless of seed status + * of old DRNG -- the entropy state for the DRNG is left unchanged which + * implies that als the new DRNG is reseeded when deemed necessary. This + * seeding of the new DRNG shall only ensure that the new DRNG has the + * same entropy as the old DRNG. + */ + ret = drng_store->crypto_cb->lrng_drng_generate_helper( + drng_store->drng, seed, sizeof(seed)); + lrng_drng_unlock(drng_store, &flags); + + if (ret < 0) { + reset_drng = true; + pr_warn("getting random data from DRNG failed for NUMA node %d (%d)\n", + node, ret); + } else { + /* seed new DRNG with data */ + ret = cb->lrng_drng_seed_helper(new_drng, seed, ret); + if (ret < 0) { + reset_drng = true; + pr_warn("seeding of new DRNG failed for NUMA node %d (%d)\n", + node, ret); + } else { + pr_debug("seeded new DRNG of NUMA node %d instance from old DRNG instance\n", + node); + } + } + + mutex_lock(&drng_store->lock); + write_lock_irqsave(&drng_store->hash_lock, flags2); + /* + * If we switch the DRNG from the initial ChaCha20 DRNG to something + * else, there is a lock transition from spin lock to mutex (see + * lrng_drng_is_atomic and how the lock is taken in lrng_drng_lock). + * Thus, we need to take both locks during the transition phase. + */ + if (lrng_drng_is_atomic(drng_store)) { + spin_lock_irqsave(&drng_store->spin_lock, flags); + sl = true; + } else { + __acquire(&drng_store->spin_lock); + } + + if (reset_drng) + lrng_drng_reset(drng_store); + + old_drng = drng_store->drng; + old_cb = drng_store->crypto_cb; + drng_store->drng = new_drng; + drng_store->crypto_cb = cb; + + old_hash = drng_store->hash; + drng_store->hash = new_hash; + pr_info("Entropy pool read-hash allocated for DRNG for NUMA node %d\n", + node); + + lrng_set_digestsize(cb->lrng_hash_digestsize(new_hash)); + + /* Reseed if previous LRNG security strength was insufficient */ + if (current_security_strength < lrng_security_strength()) + drng_store->force_reseed = true; + + if (sl) + spin_unlock_irqrestore(&drng_store->spin_lock, flags); + else + __release(&drng_store->spin_lock); + write_unlock_irqrestore(&drng_store->hash_lock, flags2); + mutex_unlock(&drng_store->lock); + + /* ChaCha20 serves as atomic instance left untouched. */ + if (old_drng != &chacha20) { + old_cb->lrng_drng_dealloc(old_drng); + old_cb->lrng_hash_dealloc(old_hash); + } + + pr_info("DRNG of NUMA node %d switched\n", node); + + return 0; +} + +/* + * Switch the existing DRNG instances with new using the new crypto callbacks. + * The caller must hold the lrng_crypto_cb_update lock. + */ +static int lrng_drngs_switch(const struct lrng_crypto_cb *cb) +{ + struct lrng_drng **lrng_drng = lrng_drng_instances(); + struct lrng_drng *lrng_drng_init = lrng_drng_init_instance(); + int ret = 0; + + /* Update DRNG */ + if (lrng_drng) { + u32 node; + + for_each_online_node(node) { + if (lrng_drng[node]) + ret = lrng_drng_switch(lrng_drng[node], cb, + node); + } + } else { + ret = lrng_drng_switch(lrng_drng_init, cb, 0); + } + + if (!ret) + lrng_set_available(); + + return 0; +} + +/** + * lrng_set_drng_cb - Register new cryptographic callback functions for DRNG + * The registering implies that all old DRNG states are replaced with new + * DRNG states. + * + * @cb: Callback functions to be registered -- if NULL, use the default + * callbacks pointing to the ChaCha20 DRNG. + * + * Return: + * * 0 on success + * * < 0 on error + */ +int lrng_set_drng_cb(const struct lrng_crypto_cb *cb) +{ + struct lrng_drng *lrng_drng_init = lrng_drng_init_instance(); + int ret; + + if (!cb) + cb = &lrng_cc20_crypto_cb; + + mutex_lock(&lrng_crypto_cb_update); + + /* + * If a callback other than the default is set, allow it only to be + * set back to the default callback. This ensures that multiple + * different callbacks can be registered at the same time. If a + * callback different from the current callback and the default + * callback shall be set, the current callback must be deregistered + * (e.g. the kernel module providing it must be unloaded) and the new + * implementation can be registered. + */ + if ((cb != &lrng_cc20_crypto_cb) && + (lrng_drng_init->crypto_cb != &lrng_cc20_crypto_cb)) { + pr_warn("disallow setting new cipher callbacks, unload the old callbacks first!\n"); + ret = -EINVAL; + goto out; + } + + ret = lrng_drngs_switch(cb); + +out: + mutex_unlock(&lrng_crypto_cb_update); + return ret; +} +EXPORT_SYMBOL(lrng_set_drng_cb); From patchwork Fri Sep 18 09:50:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253002 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA18CC43466 for ; Fri, 18 Sep 2020 10:12:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60C7921D7B for ; Fri, 18 Sep 2020 10:12:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="kCjXhTK5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726705AbgIRKM0 (ORCPT ); Fri, 18 Sep 2020 06:12:26 -0400 Received: from mo4-p04-ob.smtp.rzone.de ([85.215.255.122]:27451 "EHLO mo4-p04-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726640AbgIRKMX (ORCPT ); Fri, 18 Sep 2020 06:12:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1600423938; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=zF0XvhOgHe9HHCKXKdk8jAsesCr99Fxl+Ol9Mz2GahA=; b=kCjXhTK5Fec1aLGhngsBrY2G6+NTi9awU35YOpRoVtNzgC68q3WRhhe9d9roAF+Ct8 LnfoHc3prAJb2tDgieXpSR/4LCfrGn6wV3JpUwCZaHO3HJhiFA9BDCqaVvS3kSpQXPAe 1l6xpbb1T41Z7vAEyXs6RXYkemOb1rzCcPbnWzzqspnmT19EMDdMIv/uOPxDDNiQ/yeR EPM6WvzL/UZn2ZcGzDrZkCDxYq9ojcbijLy1rPvmfboLikFQ8mrlqGTH1RDBU45qdz0A XIMi31dehskCubkTGfrkkef+leudwXzalv8ReWauHFOG3Rszu3Y6SvqvJHt+EPXQTSVs EcDw== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaJPScXyVH" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw8IA0D2T9 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Sep 2020 12:00:13 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr , ebiggers@kernel.org Subject: [PATCH v35 07/13] LRNG - add SP800-90A DRBG extension Date: Fri, 18 Sep 2020 11:50:41 +0200 Message-ID: <1862891.PYKUYFuaPT@positron.chronox.de> In-Reply-To: <5667034.lOV4Wx5bFT@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <5667034.lOV4Wx5bFT@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Using the LRNG switchable DRNG support, the SP800-90A DRBG extension is implemented. The DRBG uses the kernel crypto API DRBG implementation. In addition, it uses the kernel crypto API SHASH support to provide the hashing operation. The DRBG supports the choice of either a CTR DRBG using AES-256, HMAC DRBG with SHA-512 core or Hash DRBG with SHA-512 core. The used core can be selected with the module parameter lrng_drbg_type. The default is the CTR DRBG. When compiling the DRBG extension statically, the DRBG is loaded at late_initcall stage which implies that with the start of user space, the user space interfaces of getrandom(2), /dev/random and /dev/urandom provide random data produced by an SP800-90A DRBG. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 10 ++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_drbg.c | 197 ++++++++++++++++++++++++++++++++++ 3 files changed, 208 insertions(+) create mode 100644 drivers/char/lrng/lrng_drbg.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index daa2057248ac..a3c4cd153f35 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -81,6 +81,16 @@ if LRNG_DRNG_SWITCH config LRNG_KCAPI_HASH bool +config LRNG_DRBG + tristate "SP800-90A support for the LRNG" + depends on CRYPTO + select CRYPTO_DRBG_MENU + select CRYPTO_SHA512 + select LRNG_KCAPI_HASH + help + Enable the SP800-90A DRBG support for the LRNG. Once the + module is loaded, output from /dev/random, /dev/urandom, + getrandom(2), or get_random_bytes_full is provided by a DRBG. endif # LRNG_DRNG_SWITCH endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 40f8826edeeb..6ebd252db12f 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_NUMA) += lrng_numa.o obj-$(CONFIG_SYSCTL) += lrng_proc.o obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o obj-$(CONFIG_LRNG_KCAPI_HASH) += lrng_kcapi_hash.o +obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o diff --git a/drivers/char/lrng/lrng_drbg.c b/drivers/char/lrng/lrng_drbg.c new file mode 100644 index 000000000000..c428d41af64d --- /dev/null +++ b/drivers/char/lrng/lrng_drbg.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * Backend for the LRNG providing the cryptographic primitives using the + * kernel crypto API and its DRBG. + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include + +#include "lrng_kcapi_hash.h" + +/* + * Define a DRBG plus a hash / MAC used to extract data from the entropy pool. + * For LRNG_HASH_NAME you can use a hash or a MAC (HMAC or CMAC) of your choice + * (Note, you should use the suggested selections below -- using SHA-1 or MD5 + * is not wise). The idea is that the used cipher primitive can be selected to + * be the same as used for the DRBG. I.e. the LRNG only uses one cipher + * primitive using the same cipher implementation with the options offered in + * the following. This means, if the CTR DRBG is selected and AES-NI is present, + * both the CTR DRBG and the selected cmac(aes) use AES-NI. + * + * The security strengths of the DRBGs are all 256 bits according to + * SP800-57 section 5.6.1. + * + * This definition is allowed to be changed. + */ +#ifdef CONFIG_CRYPTO_DRBG_CTR +static unsigned int lrng_drbg_type = 0; +#elif defined CONFIG_CRYPTO_DRBG_HMAC +static unsigned int lrng_drbg_type = 1; +#elif defined CONFIG_CRYPTO_DRBG_HASH +static unsigned int lrng_drbg_type = 2; +#else +#error "Unknown DRBG in use" +#endif + +/* The parameter must be r/o in sysfs as otherwise races appear. */ +module_param(lrng_drbg_type, uint, 0444); +MODULE_PARM_DESC(lrng_drbg_type, "DRBG type used for LRNG (0->CTR_DRBG, 1->HMAC_DRBG, 2->Hash_DRBG)"); + +struct lrng_drbg { + const char *hash_name; + const char *drbg_core; +}; + +static const struct lrng_drbg lrng_drbg_types[] = { + { /* CTR_DRBG with AES-256 using derivation function */ + .hash_name = "sha512", + .drbg_core = "drbg_nopr_ctr_aes256", + }, { /* HMAC_DRBG with SHA-512 */ + .hash_name = "sha512", + .drbg_core = "drbg_nopr_hmac_sha512", + }, { /* Hash_DRBG with SHA-512 using derivation function */ + .hash_name = "sha512", + .drbg_core = "drbg_nopr_sha512" + } +}; + +static int lrng_drbg_drng_seed_helper(void *drng, const u8 *inbuf, u32 inbuflen) +{ + struct drbg_state *drbg = (struct drbg_state *)drng; + LIST_HEAD(seedlist); + struct drbg_string data; + int ret; + + drbg_string_fill(&data, inbuf, inbuflen); + list_add_tail(&data.list, &seedlist); + ret = drbg->d_ops->update(drbg, &seedlist, drbg->seeded); + + if (ret >= 0) + drbg->seeded = true; + + return ret; +} + +static int lrng_drbg_drng_generate_helper(void *drng, u8 *outbuf, u32 outbuflen) +{ + struct drbg_state *drbg = (struct drbg_state *)drng; + + return drbg->d_ops->generate(drbg, outbuf, outbuflen, NULL); +} + +static void *lrng_drbg_drng_alloc(u32 sec_strength) +{ + struct drbg_state *drbg; + int coreref = -1; + bool pr = false; + int ret; + + drbg_convert_tfm_core(lrng_drbg_types[lrng_drbg_type].drbg_core, + &coreref, &pr); + if (coreref < 0) + return ERR_PTR(-EFAULT); + + drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL); + if (!drbg) + return ERR_PTR(-ENOMEM); + + drbg->core = &drbg_cores[coreref]; + drbg->seeded = false; + ret = drbg_alloc_state(drbg); + if (ret) + goto err; + + if (sec_strength > drbg_sec_strength(drbg->core->flags)) { + pr_err("Security strength of DRBG (%u bits) lower than requested by LRNG (%u bits)\n", + drbg_sec_strength(drbg->core->flags) * 8, + sec_strength * 8); + goto dealloc; + } + + if (sec_strength < drbg_sec_strength(drbg->core->flags)) + pr_warn("Security strength of DRBG (%u bits) higher than requested by LRNG (%u bits)\n", + drbg_sec_strength(drbg->core->flags) * 8, + sec_strength * 8); + + pr_info("DRBG with %s core allocated\n", drbg->core->backend_cra_name); + + return drbg; + +dealloc: + if (drbg->d_ops) + drbg->d_ops->crypto_fini(drbg); + drbg_dealloc_state(drbg); +err: + kfree(drbg); + return ERR_PTR(-EINVAL); +} + +static void lrng_drbg_drng_dealloc(void *drng) +{ + struct drbg_state *drbg = (struct drbg_state *)drng; + + if (drbg && drbg->d_ops) + drbg->d_ops->crypto_fini(drbg); + drbg_dealloc_state(drbg); + kfree_sensitive(drbg); + pr_info("DRBG deallocated\n"); +} + +static void *lrng_drbg_hash_alloc(void) +{ + return lrng_kcapi_hash_alloc(lrng_drbg_types[lrng_drbg_type].hash_name); +} + +static const char *lrng_drbg_name(void) +{ + return lrng_drbg_types[lrng_drbg_type].drbg_core; +} + +static const char *lrng_hash_name(void) +{ + return lrng_drbg_types[lrng_drbg_type].hash_name; +} + +static const struct lrng_crypto_cb lrng_drbg_crypto_cb = { + .lrng_drng_name = lrng_drbg_name, + .lrng_hash_name = lrng_hash_name, + .lrng_drng_alloc = lrng_drbg_drng_alloc, + .lrng_drng_dealloc = lrng_drbg_drng_dealloc, + .lrng_drng_seed_helper = lrng_drbg_drng_seed_helper, + .lrng_drng_generate_helper = lrng_drbg_drng_generate_helper, + .lrng_hash_alloc = lrng_drbg_hash_alloc, + .lrng_hash_dealloc = lrng_kcapi_hash_dealloc, + .lrng_hash_digestsize = lrng_kcapi_hash_digestsize, + .lrng_hash_init = lrng_kcapi_hash_init, + .lrng_hash_update = lrng_kcapi_hash_update, + .lrng_hash_final = lrng_kcapi_hash_final, +}; + +static int __init lrng_drbg_init(void) +{ + if (lrng_drbg_type >= ARRAY_SIZE(lrng_drbg_types)) { + pr_err("lrng_drbg_type parameter too large (given %u - max: %lu)", + lrng_drbg_type, + (unsigned long)ARRAY_SIZE(lrng_drbg_types) - 1); + return -EAGAIN; + } + return lrng_set_drng_cb(&lrng_drbg_crypto_cb); +} + +static void __exit lrng_drbg_exit(void) +{ + lrng_set_drng_cb(NULL); +} + +late_initcall(lrng_drbg_init); +module_exit(lrng_drbg_exit); +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Stephan Mueller "); +MODULE_DESCRIPTION("Linux Random Number Generator - SP800-90A DRBG backend"); From patchwork Tue Aug 25 07:26:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253118 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EE7AC433E1 for ; Tue, 25 Aug 2020 07:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3AFE2074D for ; Tue, 25 Aug 2020 07:38:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="e4I5mqmf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729646AbgHYHiF (ORCPT ); Tue, 25 Aug 2020 03:38:05 -0400 Received: from mo4-p03-ob.smtp.rzone.de ([85.215.255.103]:36316 "EHLO mo4-p03-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729522AbgHYHge (ORCPT ); Tue, 25 Aug 2020 03:36:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1598340988; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=Es9pGKLx4z5oIgmChL28JnLmrOhua6NbH8JPKO7vMAs=; b=e4I5mqmfnm1DWjo4fHrE36LAD04vYUE4xX4LkHrZLHfClvSsvucOtEZj6tp3cKvTQ/ GHRln+OuAFHgt00Tw3o3hndnzgQ7u7d/hqpQMJlYJbF4z5BM7PhOTsNn2A4lhjZ0wzav OJ0BgY23h9RcWC1C/3ghPQJgaec3MSm/ZIPX+zz4FPiO1b2VGy3iF2YTmmuhUNCKaeP/ 2EotqecGO49cQ+5bV7akdNeK/j3to4jQIqlDzediWitLmAuPPTkamnG0Ro6KB2mO88hz mrTE5RMocK12mK+tt94GlnyYghgtTf9e1nxVv+kNqtSvkrsUPDCKr70rneJofnXnDoVc kX/Q== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaIvSXRbo=" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw7P7ZGZGO (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Tue, 25 Aug 2020 09:35:16 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr Subject: [PATCH v34 08/12] crypto: provide access to a static Jitter RNG state Date: Tue, 25 Aug 2020 09:26:04 +0200 Message-ID: <1896203.PYKUYFuaPT@positron.chronox.de> In-Reply-To: <11649613.O9o76ZdvQC@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <11649613.O9o76ZdvQC@positron.chronox.de> MIME-Version: 1.0 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org To support the LRNG operation which uses the Jitter RNG separately from the kernel crypto API, at a time where potentially the regular memory management is not yet initialized, the Jitter RNG needs to provide a state whose memory is defined at compile time. As only once instance will ever be needed by the LRNG, define once static memory block which is solely to be used by the LRNG. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- crypto/jitterentropy-kcapi.c | 3 +- crypto/jitterentropy.c | 31 ++++++++++++++++++- .../crypto/internal}/jitterentropy.h | 3 ++ 3 files changed, 34 insertions(+), 3 deletions(-) rename {crypto => include/crypto/internal}/jitterentropy.h (84%) diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c index eb7d1dd506bf..25a192f5984e 100644 --- a/crypto/jitterentropy-kcapi.c +++ b/crypto/jitterentropy-kcapi.c @@ -43,8 +43,7 @@ #include #include #include - -#include "jitterentropy.h" +#include /*************************************************************************** * Helper function diff --git a/crypto/jitterentropy.c b/crypto/jitterentropy.c index 6e147c43fc18..fa1459f09b01 100644 --- a/crypto/jitterentropy.c +++ b/crypto/jitterentropy.c @@ -117,7 +117,7 @@ struct rand_data { #define JENT_EHEALTH 9 /* Health test failed during initialization */ #define JENT_ERCT 10 /* RCT failed during initialization */ -#include "jitterentropy.h" +#include /*************************************************************************** * Adaptive Proportion Test @@ -854,3 +854,32 @@ int jent_entropy_init(void) return 0; } + +struct rand_data *jent_lrng_entropy_collector(void) +{ + static unsigned char lrng_jent_mem[JENT_MEMORY_SIZE]; + static struct rand_data lrng_jent_state = { + .data = 0, + .old_data = 0, + .prev_time = 0, + .last_delta = 0, + .last_delta2 = 0, + .osr = 1, + .mem = lrng_jent_mem, + .memlocation = 0, + .memblocks = JENT_MEMORY_BLOCKSIZE, + .memblocksize = JENT_MEMORY_BLOCKS, + .memaccessloops = JENT_MEMORY_ACCESSLOOPS, + .rct_count = 0, + .apt_observations = 0, + .apt_count = 0, + .apt_base = 0, + .apt_base_set = 0, + .health_failure = 0 + }; + + if (jent_entropy_init()) + return NULL; + + return &lrng_jent_state; +} diff --git a/crypto/jitterentropy.h b/include/crypto/internal/jitterentropy.h similarity index 84% rename from crypto/jitterentropy.h rename to include/crypto/internal/jitterentropy.h index c83fff32d130..6e07d86eac82 100644 --- a/crypto/jitterentropy.h +++ b/include/crypto/internal/jitterentropy.h @@ -15,3 +15,6 @@ extern int jent_read_entropy(struct rand_data *ec, unsigned char *data, extern struct rand_data *jent_entropy_collector_alloc(unsigned int osr, unsigned int flags); extern void jent_entropy_collector_free(struct rand_data *entropy_collector); + +/* Access to statically allocated Jitter RNG instance */ +extern struct rand_data *jent_lrng_entropy_collector(void); From patchwork Tue Aug 25 07:27:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253119 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1E14C433DF for ; Tue, 25 Aug 2020 07:38:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D51B20578 for ; Tue, 25 Aug 2020 07:38:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="QQv3vXCD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729552AbgHYHh2 (ORCPT ); Tue, 25 Aug 2020 03:37:28 -0400 Received: from mo4-p03-ob.smtp.rzone.de ([81.169.146.172]:31292 "EHLO mo4-p03-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729529AbgHYHgm (ORCPT ); Tue, 25 Aug 2020 03:36:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1598340994; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=wZ8/hbwxlEy5OIg3sgvuloCpw6JAyIs2muWXpN/DQX4=; b=QQv3vXCDJEWANPbUTlmow2bBGeZTvo6pv6lkJMOFtEe9zc4KmfjM/LtkKBl+WOHLyg oNE+jxnBASC5lQqvc/O8TgBebI5zzQM/DH771JvwVh2uOJbm4cRPrNmQmClCAIkEHs77 BH99D/k+7QiHTM77aSGVNcgV+N8uF7vyR4WH9sm5IrZS26wrtrTsQCQdDzOzK9GOmfQA GvMJCBOp5xItj3J7so9L80Tbd/9jyYPSqa/LZ4wEfFJmR/FaZE9PTX/R5U/phMMGNfZn YrL/sdPnnHfzqOlqiI+Esy+cPTsUOTobFzdanJ3NytivoKrTlfAEtOMSM1fPbn4xCiO0 1hiQ== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaIvSXRbo=" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw7P7ZDZGL (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Tue, 25 Aug 2020 09:35:13 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr Subject: [PATCH v34 10/12] LRNG - add SP800-90B compliant health tests Date: Tue, 25 Aug 2020 09:27:01 +0200 Message-ID: <3383497.iIbC2pHGDl@positron.chronox.de> In-Reply-To: <11649613.O9o76ZdvQC@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <11649613.O9o76ZdvQC@positron.chronox.de> MIME-Version: 1.0 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Implement health tests for LRNG's slow noise sources as mandated by SP-800-90B The file contains the following health tests: - stuck test: The stuck test calculates the first, second and third discrete derivative of the time stamp to be processed by the LFSR. Only if all three values are non-zero, the received time delta is considered to be non-stuck. - SP800-90B Repetition Count Test (RCT): The LRNG uses an enhanced version of the RCT specified in SP800-90B section 4.4.1. Instead of counting identical back-to-back values, the input to the RCT is the counting of the stuck values during the processing of received interrupt events. The RCT is applied with alpha=2^-30 compliant to the recommendation of FIPS 140-2 IG 9.8. During the counting operation, the LRNG always calculates the RCT cut-off value of C. If that value exceeds the allowed cut-off value, the LRNG will trigger the health test failure discussed below. An error is logged to the kernel log that such RCT failure occurred. This test is only applied and enforced in FIPS mode, i.e. when the kernel compiled with CONFIG_CONFIG_FIPS is started with fips=1. - SP800-90B Adaptive Proportion Test (APT): The LRNG implements the APT as defined in SP800-90B section 4.4.2. The applied significance level again is alpha=2^-30 compliant to the recommendation of FIPS 140-2 IG 9.8. The aforementioned health tests are applied to the first 1,024 time stamps obtained from interrupt events. In case one error is identified for either the RCT, or the APT, the collected entropy is invalidated and the SP800-90B startup health test is restarted. As long as the SP800-90B startup health test is not completed, all LRNG random number output interfaces that may block will block and not generate any data. This implies that only those potentially blocking interfaces are defined to provide random numbers that are seeded with the interrupt noise source being SP800-90B compliant. All other output interfaces will not be affected by the SP800-90B startup test and thus are not considered SP800-90B compliant. At runtime, the SP800-90B APT and RCT are applied to each time stamp generated for a received interrupt. When either the APT and RCT indicates a noise source failure, the LRNG is reset to a state it has immediately after boot: - all entropy counters are set to zero - the SP800-90B startup tests are re-performed which implies that getrandom(2) would block again until new entropy was collected To summarize, the following rules apply: • SP800-90B compliant output interfaces - /dev/random - getrandom(2) system call - get_random_bytes kernel-internal interface when being triggered by the callback registered with add_random_ready_callback • SP800-90B non-compliant output interfaces - /dev/urandom - get_random_bytes kernel-internal interface called directly - randomize_page kernel-internal interface - get_random_u32 and get_random_u64 kernel-internal interfaces - get_random_u32_wait, get_random_u64_wait, get_random_int_wait, and get_random_long_wait kernel-internal interfaces If either the RCT, or the APT health test fails irrespective whether during initialization or runtime, the following actions occur: 1. The entropy of the entire entropy pool is invalidated. 2. All DRNGs are reset which imply that they are treated as being not seeded and require a reseed during next invocation. 3. The SP800-90B startup health test are initiated with all implications of the startup tests. That implies that from that point on, new events must be observed and its entropy must be inserted into the entropy pool before random numbers are calculated from the entropy pool. Further details on the SP800-90B compliance and the availability of all test tools required to perform all tests mandated by SP800-90B are provided at [1]. The entire health testing code is compile-time configurable. The patch provides a CONFIG_BROKEN configuration of the APT / RCT cutoff values which have a high likelihood to trigger the health test failure. The BROKEN APT cutoff is set to the exact mean of the expected value if the time stamps are equally distributed (512 time stamps divided by 16 possible values due to using the 4 LSB of the time stamp). The BROKEN RCT cutoff value is set to 1 which is likely to be triggered during regular operation. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 56 +++++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_health.c | 407 ++++++++++++++++++++++++++++++++ 3 files changed, 464 insertions(+) create mode 100644 drivers/char/lrng/lrng_health.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index 377593fc1985..452ee4adb577 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -108,4 +108,60 @@ config LRNG_JENT time or at runtime with the lrng_base.jitterrng configuration variable. +config LRNG_HEALTH_TESTS + bool "Enable noise source online health tests" + help + The online health tests validate the noise source at + runtime for fatal errors. These tests include SP800-90B + compliant tests which are invoked if the system is booted + with fips=1. In case of fatal errors during active + SP800-90B tests, the issue is logged and the noise + data is discarded. These tests are required for full + compliance with SP800-90B. + + If unsure, say Y. + +config LRNG_RCT_BROKEN + bool "SP800-90B RCT with dangerous low cutoff value" + depends on LRNG_HEALTH_TESTS + depends on BROKEN + default n + help + This option enables a dangerously low SP800-90B repetitive + count test (RCT) cutoff value which makes it very likely + that the RCT is triggered to raise a self test failure. + + This option is ONLY intended for developers wanting to + test the effectiveness of the SP800-90B RCT health test. + + If unsure, say N. + +config LRNG_APT_BROKEN + bool "SP800-90B APT with dangerous low cutoff value" + depends on LRNG_HEALTH_TESTS + depends on BROKEN + default n + help + This option enables a dangerously low SP800-90B adaptive + proportion test (APT) cutoff value which makes it very + likely that the RCT is triggered to raise a self test + failure. + + This option is ONLY intended for developers wanting to + test the effectiveness of the SP800-90B APT health test. + + If unsure, say N. + +# Default taken from SP800-90B sec 4.4.1 - significance level 2^-30 +config LRNG_RCT_CUTOFF + int + default 31 if !LRNG_RCT_BROKEN + default 1 if LRNG_RCT_BROKEN + +# Default taken from SP800-90B sec 4.4.2 - significance level 2^-30 +config LRNG_APT_CUTOFF + int + default 325 if !LRNG_APT_BROKEN + default 32 if LRNG_APT_BROKEN + endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 4f5b6f38f0c4..c3008763dd14 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -14,3 +14,4 @@ obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o obj-$(CONFIG_LRNG_JENT) += lrng_jent.o +obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o diff --git a/drivers/char/lrng/lrng_health.c b/drivers/char/lrng/lrng_health.c new file mode 100644 index 000000000000..7817aa6f3357 --- /dev/null +++ b/drivers/char/lrng/lrng_health.c @@ -0,0 +1,407 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * Linux Random Number Generator (LRNG) Health Testing + * + * Copyright (C) 2019 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include + +#include "lrng_internal.h" + +/* Stuck Test */ +struct lrng_stuck_test { + u32 last_time; /* Stuck test: time of previous IRQ */ + u32 last_delta; /* Stuck test: delta of previous IRQ */ + u32 last_delta2; /* Stuck test: 2. time derivation of prev IRQ */ +}; + +/* Repetition Count Test */ +struct lrng_rct { + atomic_t rct_count; /* Number of stuck values */ +}; + +/* Adaptive Proportion Test */ +struct lrng_apt { + /* Data window size */ +#define LRNG_APT_WINDOW_SIZE 512 + /* LSB of time stamp to process */ +#define LRNG_APT_LSB 16 +#define LRNG_APT_WORD_MASK (LRNG_APT_LSB - 1) + atomic_t apt_count; /* APT counter */ + atomic_t apt_base; /* APT base reference */ + + atomic_t apt_trigger; + bool apt_base_set; /* Is APT base set? */ +}; + +/* The health test code must operate lock-less */ +struct lrng_health { + struct lrng_rct rct; + struct lrng_apt apt; + + bool health_test_enabled; + + /* SP800-90B startup health tests */ +#define LRNG_SP80090B_STARTUP_SAMPLES 1024 +#define LRNG_SP80090B_STARTUP_BLOCKS ((LRNG_SP80090B_STARTUP_SAMPLES + \ + LRNG_APT_WINDOW_SIZE - 1) / \ + LRNG_APT_WINDOW_SIZE) + bool sp80090b_startup_done; + atomic_t sp80090b_startup_blocks; +}; + +static struct lrng_health lrng_health = { + .rct.rct_count = ATOMIC_INIT(0), + + .apt.apt_count = ATOMIC_INIT(0), + .apt.apt_base = ATOMIC_INIT(-1), + .apt.apt_trigger = ATOMIC_INIT(LRNG_APT_WINDOW_SIZE), + .apt.apt_base_set = false, + + .health_test_enabled = true, + + .sp80090b_startup_blocks = ATOMIC_INIT(LRNG_SP80090B_STARTUP_BLOCKS), + .sp80090b_startup_done = false, +}; + +static DEFINE_PER_CPU(struct lrng_stuck_test, lrng_stuck_test); + +static inline bool lrng_sp80090b_health_requested(void) +{ + /* Health tests are only requested in FIPS mode */ + return fips_enabled; +} + +static inline bool lrng_sp80090b_health_enabled(void) +{ + struct lrng_health *health = &lrng_health; + + return lrng_sp80090b_health_requested() && health->health_test_enabled; +} + +/*************************************************************************** + * SP800-90B Compliance + * + * If the Linux-RNG is booted into FIPS mode, the following interfaces + * provide an SP800-90B compliant noise source: + * + * * /dev/random + * * getrandom(2) + * * get_random_bytes when using it in conjunction with + * add_random_ready_callback + * + * All other interfaces, including /dev/urandom or get_random_bytes without + * the add_random_ready_callback cannot claim to use an SP800-90B compliant + * noise source. + ***************************************************************************/ + +/* + * Perform SP800-90B startup testing + */ +static inline void lrng_sp80090b_startup(struct lrng_health *health) +{ + if (!health->sp80090b_startup_done && + atomic_dec_and_test(&health->sp80090b_startup_blocks)) { + health->sp80090b_startup_done = true; + pr_info("SP800-90B startup health tests completed\n"); + lrng_init_ops(0); + + /* + * Force a reseed of DRNGs to ensure they are seeded with + * entropy that passed the SP800-90B health tests. + * As the DRNG always will reseed before generating + * random numbers, it does not need a reseed trigger. + */ + lrng_drng_force_reseed(); + } +} + +/* + * Handle failure of SP800-90B startup testing + */ +static inline void lrng_sp80090b_startup_failure(struct lrng_health *health) +{ + /* Reset of LRNG and its entropy - NOTE: we are in atomic context */ + lrng_reset(); + + /* + * Reset the SP800-90B startup test. + * + * NOTE SP800-90B section 4.3 bullet 4 does not specify what + * exactly is to be done in case of failure! Thus, we do what + * makes sense, i.e. restarting the health test and thus gating + * the output function of /dev/random and getrandom(2). + */ + atomic_set(&health->sp80090b_startup_blocks, + LRNG_SP80090B_STARTUP_BLOCKS); +} + +/* + * Handle failure of SP800-90B runtime testing + */ +static inline void lrng_sp80090b_runtime_failure(struct lrng_health *health) +{ + lrng_sp80090b_startup_failure(health); + health->sp80090b_startup_done = false; +} + +static inline void lrng_sp80090b_failure(struct lrng_health *health) +{ + if (health->sp80090b_startup_done) { + pr_err("SP800-90B runtime health test failure - invalidating all existing entropy and initiate SP800-90B startup\n"); + lrng_sp80090b_runtime_failure(health); + } else { + pr_err("SP800-90B startup test failure - resetting\n"); + lrng_sp80090b_startup_failure(health); + } +} + +/* + * Is the SP800-90B startup testing complete? + * + * This function is called by the LRNG to determine whether to unblock + * a certain user interface. Therefore, only the potentially blocking + * user interfaces are considered SP800-90B compliant. + */ +bool lrng_sp80090b_startup_complete(void) +{ + struct lrng_health *health = &lrng_health; + + return (lrng_sp80090b_health_enabled()) ? health->sp80090b_startup_done: + true; +} + +bool lrng_sp80090b_compliant(void) +{ + struct lrng_health *health = &lrng_health; + + return lrng_sp80090b_health_enabled() && health->sp80090b_startup_done; +} + +/*************************************************************************** + * Adaptive Proportion Test + * + * This test complies with SP800-90B section 4.4.2. + ***************************************************************************/ + +/* + * Reset the APT counter + * + * @health [in] Reference to health state + */ +static inline void lrng_apt_reset(struct lrng_health *health, + unsigned int time_masked) +{ + struct lrng_apt *apt = &health->apt; + + pr_debug("APT value %d for base %d\n", + atomic_read(&apt->apt_count), atomic_read(&apt->apt_base)); + + /* Reset APT */ + atomic_set(&apt->apt_count, 0); + atomic_set(&apt->apt_base, time_masked); +} + +static inline void lrng_apt_restart(struct lrng_health *health) +{ + struct lrng_apt *apt = &health->apt; + + atomic_set(&apt->apt_trigger, LRNG_APT_WINDOW_SIZE); +} + +/* + * Insert a new entropy event into APT + * + * This function does is void as it does not decide about the fate of a time + * stamp. An APT failure can only happen at the same time of a stuck test + * failure. Thus, the stuck failure will already decide how the time stamp + * is handled. + * + * @health [in] Reference to health state + * @now_time [in] Time stamp to process + */ +static inline void lrng_apt_insert(struct lrng_health *health, + unsigned int now_time) +{ + struct lrng_apt *apt = &health->apt; + + if (!lrng_sp80090b_health_requested()) + return; + + now_time &= LRNG_APT_WORD_MASK; + + /* Initialization of APT */ + if (!apt->apt_base_set) { + atomic_set(&apt->apt_base, now_time); + apt->apt_base_set = true; + return; + } + + if (now_time == (unsigned int)atomic_read(&apt->apt_base)) { + u32 apt_val = (u32)atomic_inc_return_relaxed(&apt->apt_count); + + if (apt_val >= CONFIG_LRNG_APT_CUTOFF) + lrng_sp80090b_failure(health); + } + + if (atomic_dec_and_test(&apt->apt_trigger)) { + lrng_apt_restart(health); + lrng_apt_reset(health, now_time); + lrng_sp80090b_startup(health); + } +} + +/*************************************************************************** + * Repetition Count Test + * + * The LRNG uses an enhanced version of the Repetition Count Test + * (RCT) specified in SP800-90B section 4.4.1. Instead of counting identical + * back-to-back values, the input to the RCT is the counting of the stuck + * values while filling the entropy pool. + * + * The RCT is applied with an alpha of 2^-30 compliant to FIPS 140-2 IG 9.8. + * + * During the counting operation, the LRNG always calculates the RCT + * cut-off value of C. If that value exceeds the allowed cut-off value, + * the LRNG will invalidate all entropy for the entropy pool which implies + * that no data can be extracted from the entropy pool unless new entropy + * is received. + ***************************************************************************/ + +/* + * Hot code path - Insert data for Repetition Count Test + * + * @health: Reference to health information + * @stuck: Decision of stuck test + */ +static inline void lrng_rct(struct lrng_health *health, int stuck) +{ + struct lrng_rct *rct = &health->rct; + + if (!lrng_sp80090b_health_requested()) + return; + + if (stuck) { + u32 rct_count = atomic_add_return_relaxed(1, &rct->rct_count); + + pr_debug("RCT count: %u\n", rct_count); + + /* + * The cutoff value is based on the following consideration: + * alpha = 2^-30 as recommended in FIPS 140-2 IG 9.8. + * In addition, we imply an entropy value H of 1 bit as this + * is the minimum entropy required to provide full entropy. + * + * Note, rct_count (which equals to value B in the + * pseudo code of SP800-90B section 4.4.1) starts with zero. + * Hence we need to subtract one from the cutoff value as + * calculated following SP800-90B. + */ + if (rct_count >= CONFIG_LRNG_RCT_CUTOFF) { + atomic_set(&rct->rct_count, 0); + + /* + * APT must start anew as we consider all previously + * recorded data to contain no entropy. + */ + lrng_apt_restart(health); + + lrng_sp80090b_failure(health); + } + } else { + atomic_set(&rct->rct_count, 0); + } +} + +/*************************************************************************** + * Stuck Test + * + * Checking the: + * 1st derivative of the event occurrence (time delta) + * 2nd derivative of the event occurrence (delta of time deltas) + * 3rd derivative of the event occurrence (delta of delta of time deltas) + * + * All values must always be non-zero. The stuck test is only valid disabled if + * high-resolution time stamps are identified after initialization. + ***************************************************************************/ + +static inline u32 lrng_delta(u32 prev, u32 next) +{ + /* + * Note that this (unsigned) subtraction does yield the correct value + * in the wraparound-case, i.e. when next < prev. + */ + return (next - prev); +} + +/* + * Hot code path + * + * @health: Reference to health information + * @now: Event time + * @return: 0 event occurrence not stuck (good time stamp) + * != 0 event occurrence stuck (reject time stamp) + */ +static inline int lrng_irq_stuck(struct lrng_stuck_test *stuck, u32 now_time) +{ + u32 delta = lrng_delta(stuck->last_time, now_time); + u32 delta2 = lrng_delta(stuck->last_delta, delta); + u32 delta3 = lrng_delta(stuck->last_delta2, delta2); + + stuck->last_time = now_time; + stuck->last_delta = delta; + stuck->last_delta2 = delta2; + + if (!delta || !delta2 || !delta3) + return 1; + + return 0; +} + +/*************************************************************************** + * Health test interfaces + ***************************************************************************/ + +/* + * Disable all health tests + */ +void lrng_health_disable(void) +{ + struct lrng_health *health = &lrng_health; + + health->health_test_enabled = false; + + if (lrng_sp80090b_health_requested()) + pr_warn("SP800-90B compliance requested but the Linux RNG is NOT SP800-90B compliant\n"); +} + +/* + * Hot code path - Perform health test on time stamp received from an event + * + * @now_time Time stamp + */ +enum lrng_health_res lrng_health_test(u32 now_time) +{ + struct lrng_health *health = &lrng_health; + struct lrng_stuck_test *stuck_test = this_cpu_ptr(&lrng_stuck_test); + int stuck; + + if (!health->health_test_enabled) + return lrng_health_pass; + + lrng_apt_insert(health, now_time); + + stuck = lrng_irq_stuck(stuck_test, now_time); + lrng_rct(health, stuck); + if (stuck) { + /* SP800-90B disallows using a failing health test time stamp */ + return lrng_sp80090b_health_requested() ? + lrng_health_fail_drop : lrng_health_fail_use; + } + + return lrng_health_pass; +} From patchwork Fri Sep 18 09:52:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253001 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8DC9C43468 for ; Fri, 18 Sep 2020 10:12:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65B7C21D7B for ; Fri, 18 Sep 2020 10:12:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="Dke3g9hX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726638AbgIRKMS (ORCPT ); Fri, 18 Sep 2020 06:12:18 -0400 Received: from mo4-p03-ob.smtp.rzone.de ([85.215.255.104]:18637 "EHLO mo4-p03-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbgIRKMP (ORCPT ); Fri, 18 Sep 2020 06:12:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1600423928; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=d9icfjHkaDJSlGy4ZCjGiuL5ZjPPKb077JfkcRqcs0E=; b=Dke3g9hXrYf6zbxdn82Ah0bkl7nC7zm/Zadr5oolwzyLQmRFQUgLMT4exdKNXmaEHN r6Jcnt57Rt+o4+4zVrs9zj/cZeikZ84KOeYq6FTxzr4CVo+GhjVXWWmtM774T/Fzj8a3 UWoe9W2NpQ4l2KZjiokli0/3xXe+lWNYyzm0bgIaujl09mACQBZSy/MPwZJ1e+5BIse/ ITvpaDcY6DWGxBflx9GyJgsJe6SF7KWLj5SBCMWCZzf9pyfGqujEiq9RukYdy4gc20PD 6BMyN1/sAeFr8ATYdM8Kj7kP8jIX/uQvtA+Zs/wHh/ywffDARU8nr2yTmpa2chDj1Z64 gANQ== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaJPScXyVH" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw8IA072T1 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Sep 2020 12:00:07 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr , ebiggers@kernel.org Subject: [PATCH v35 11/13] LRNG - add SP800-90B compliant health tests Date: Fri, 18 Sep 2020 11:52:14 +0200 Message-ID: <1700589.VLH7GnMWUR@positron.chronox.de> In-Reply-To: <5667034.lOV4Wx5bFT@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <5667034.lOV4Wx5bFT@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Implement health tests for LRNG's slow noise sources as mandated by SP-800-90B The file contains the following health tests: - stuck test: The stuck test calculates the first, second and third discrete derivative of the time stamp to be processed by the hash for the per-CPU entropy pool. Only if all three values are non-zero, the received time delta is considered to be non-stuck. - SP800-90B Repetition Count Test (RCT): The LRNG uses an enhanced version of the RCT specified in SP800-90B section 4.4.1. Instead of counting identical back-to-back values, the input to the RCT is the counting of the stuck values during the processing of received interrupt events. The RCT is applied with alpha=2^-30 compliant to the recommendation of FIPS 140-2 IG 9.8. During the counting operation, the LRNG always calculates the RCT cut-off value of C. If that value exceeds the allowed cut-off value, the LRNG will trigger the health test failure discussed below. An error is logged to the kernel log that such RCT failure occurred. This test is only applied and enforced in FIPS mode, i.e. when the kernel compiled with CONFIG_CONFIG_FIPS is started with fips=1. - SP800-90B Adaptive Proportion Test (APT): The LRNG implements the APT as defined in SP800-90B section 4.4.2. The applied significance level again is alpha=2^-30 compliant to the recommendation of FIPS 140-2 IG 9.8. The aforementioned health tests are applied to the first 1,024 time stamps obtained from interrupt events. In case one error is identified for either the RCT, or the APT, the collected entropy is invalidated and the SP800-90B startup health test is restarted. As long as the SP800-90B startup health test is not completed, all LRNG random number output interfaces that may block will block and not generate any data. This implies that only those potentially blocking interfaces are defined to provide random numbers that are seeded with the interrupt noise source being SP800-90B compliant. All other output interfaces will not be affected by the SP800-90B startup test and thus are not considered SP800-90B compliant. At runtime, the SP800-90B APT and RCT are applied to each time stamp generated for a received interrupt. When either the APT and RCT indicates a noise source failure, the LRNG is reset to a state it has immediately after boot: - all entropy counters are set to zero - the SP800-90B startup tests are re-performed which implies that getrandom(2) would block again until new entropy was collected To summarize, the following rules apply: • SP800-90B compliant output interfaces - /dev/random - getrandom(2) system call - get_random_bytes kernel-internal interface when being triggered by the callback registered with add_random_ready_callback • SP800-90B non-compliant output interfaces - /dev/urandom - get_random_bytes kernel-internal interface called directly - randomize_page kernel-internal interface - get_random_u32 and get_random_u64 kernel-internal interfaces - get_random_u32_wait, get_random_u64_wait, get_random_int_wait, and get_random_long_wait kernel-internal interfaces If either the RCT, or the APT health test fails irrespective whether during initialization or runtime, the following actions occur: 1. The entropy of the entire entropy pool is invalidated. 2. All DRNGs are reset which imply that they are treated as being not seeded and require a reseed during next invocation. 3. The SP800-90B startup health test are initiated with all implications of the startup tests. That implies that from that point on, new events must be observed and its entropy must be inserted into the entropy pool before random numbers are calculated from the entropy pool. Further details on the SP800-90B compliance and the availability of all test tools required to perform all tests mandated by SP800-90B are provided at [1]. The entire health testing code is compile-time configurable. The patch provides a CONFIG_BROKEN configuration of the APT / RCT cutoff values which have a high likelihood to trigger the health test failure. The BROKEN APT cutoff is set to the exact mean of the expected value if the time stamps are equally distributed (512 time stamps divided by 16 possible values due to using the 4 LSB of the time stamp). The BROKEN RCT cutoff value is set to 1 which is likely to be triggered during regular operation. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 56 +++++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_health.c | 407 ++++++++++++++++++++++++++++++++ 3 files changed, 464 insertions(+) create mode 100644 drivers/char/lrng/lrng_health.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index 87682f57efb8..a059da0b2f5d 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -118,4 +118,60 @@ config LRNG_JENT time or at runtime with the lrng_base.jitterrng configuration variable. +config LRNG_HEALTH_TESTS + bool "Enable noise source online health tests" + help + The online health tests validate the noise source at + runtime for fatal errors. These tests include SP800-90B + compliant tests which are invoked if the system is booted + with fips=1. In case of fatal errors during active + SP800-90B tests, the issue is logged and the noise + data is discarded. These tests are required for full + compliance with SP800-90B. + + If unsure, say Y. + +config LRNG_RCT_BROKEN + bool "SP800-90B RCT with dangerous low cutoff value" + depends on LRNG_HEALTH_TESTS + depends on BROKEN + default n + help + This option enables a dangerously low SP800-90B repetitive + count test (RCT) cutoff value which makes it very likely + that the RCT is triggered to raise a self test failure. + + This option is ONLY intended for developers wanting to + test the effectiveness of the SP800-90B RCT health test. + + If unsure, say N. + +config LRNG_APT_BROKEN + bool "SP800-90B APT with dangerous low cutoff value" + depends on LRNG_HEALTH_TESTS + depends on BROKEN + default n + help + This option enables a dangerously low SP800-90B adaptive + proportion test (APT) cutoff value which makes it very + likely that the APT is triggered to raise a self test + failure. + + This option is ONLY intended for developers wanting to + test the effectiveness of the SP800-90B APT health test. + + If unsure, say N. + +# Default taken from SP800-90B sec 4.4.1 - significance level 2^-30 +config LRNG_RCT_CUTOFF + int + default 31 if !LRNG_RCT_BROKEN + default 1 if LRNG_RCT_BROKEN + +# Default taken from SP800-90B sec 4.4.2 - significance level 2^-30 +config LRNG_APT_CUTOFF + int + default 325 if !LRNG_APT_BROKEN + default 32 if LRNG_APT_BROKEN + endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 6be88156010a..3c8637befb42 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -15,3 +15,4 @@ obj-$(CONFIG_LRNG_KCAPI_HASH) += lrng_kcapi_hash.o obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o obj-$(CONFIG_LRNG_JENT) += lrng_jent.o +obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o diff --git a/drivers/char/lrng/lrng_health.c b/drivers/char/lrng/lrng_health.c new file mode 100644 index 000000000000..7817aa6f3357 --- /dev/null +++ b/drivers/char/lrng/lrng_health.c @@ -0,0 +1,407 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * Linux Random Number Generator (LRNG) Health Testing + * + * Copyright (C) 2019 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include + +#include "lrng_internal.h" + +/* Stuck Test */ +struct lrng_stuck_test { + u32 last_time; /* Stuck test: time of previous IRQ */ + u32 last_delta; /* Stuck test: delta of previous IRQ */ + u32 last_delta2; /* Stuck test: 2. time derivation of prev IRQ */ +}; + +/* Repetition Count Test */ +struct lrng_rct { + atomic_t rct_count; /* Number of stuck values */ +}; + +/* Adaptive Proportion Test */ +struct lrng_apt { + /* Data window size */ +#define LRNG_APT_WINDOW_SIZE 512 + /* LSB of time stamp to process */ +#define LRNG_APT_LSB 16 +#define LRNG_APT_WORD_MASK (LRNG_APT_LSB - 1) + atomic_t apt_count; /* APT counter */ + atomic_t apt_base; /* APT base reference */ + + atomic_t apt_trigger; + bool apt_base_set; /* Is APT base set? */ +}; + +/* The health test code must operate lock-less */ +struct lrng_health { + struct lrng_rct rct; + struct lrng_apt apt; + + bool health_test_enabled; + + /* SP800-90B startup health tests */ +#define LRNG_SP80090B_STARTUP_SAMPLES 1024 +#define LRNG_SP80090B_STARTUP_BLOCKS ((LRNG_SP80090B_STARTUP_SAMPLES + \ + LRNG_APT_WINDOW_SIZE - 1) / \ + LRNG_APT_WINDOW_SIZE) + bool sp80090b_startup_done; + atomic_t sp80090b_startup_blocks; +}; + +static struct lrng_health lrng_health = { + .rct.rct_count = ATOMIC_INIT(0), + + .apt.apt_count = ATOMIC_INIT(0), + .apt.apt_base = ATOMIC_INIT(-1), + .apt.apt_trigger = ATOMIC_INIT(LRNG_APT_WINDOW_SIZE), + .apt.apt_base_set = false, + + .health_test_enabled = true, + + .sp80090b_startup_blocks = ATOMIC_INIT(LRNG_SP80090B_STARTUP_BLOCKS), + .sp80090b_startup_done = false, +}; + +static DEFINE_PER_CPU(struct lrng_stuck_test, lrng_stuck_test); + +static inline bool lrng_sp80090b_health_requested(void) +{ + /* Health tests are only requested in FIPS mode */ + return fips_enabled; +} + +static inline bool lrng_sp80090b_health_enabled(void) +{ + struct lrng_health *health = &lrng_health; + + return lrng_sp80090b_health_requested() && health->health_test_enabled; +} + +/*************************************************************************** + * SP800-90B Compliance + * + * If the Linux-RNG is booted into FIPS mode, the following interfaces + * provide an SP800-90B compliant noise source: + * + * * /dev/random + * * getrandom(2) + * * get_random_bytes when using it in conjunction with + * add_random_ready_callback + * + * All other interfaces, including /dev/urandom or get_random_bytes without + * the add_random_ready_callback cannot claim to use an SP800-90B compliant + * noise source. + ***************************************************************************/ + +/* + * Perform SP800-90B startup testing + */ +static inline void lrng_sp80090b_startup(struct lrng_health *health) +{ + if (!health->sp80090b_startup_done && + atomic_dec_and_test(&health->sp80090b_startup_blocks)) { + health->sp80090b_startup_done = true; + pr_info("SP800-90B startup health tests completed\n"); + lrng_init_ops(0); + + /* + * Force a reseed of DRNGs to ensure they are seeded with + * entropy that passed the SP800-90B health tests. + * As the DRNG always will reseed before generating + * random numbers, it does not need a reseed trigger. + */ + lrng_drng_force_reseed(); + } +} + +/* + * Handle failure of SP800-90B startup testing + */ +static inline void lrng_sp80090b_startup_failure(struct lrng_health *health) +{ + /* Reset of LRNG and its entropy - NOTE: we are in atomic context */ + lrng_reset(); + + /* + * Reset the SP800-90B startup test. + * + * NOTE SP800-90B section 4.3 bullet 4 does not specify what + * exactly is to be done in case of failure! Thus, we do what + * makes sense, i.e. restarting the health test and thus gating + * the output function of /dev/random and getrandom(2). + */ + atomic_set(&health->sp80090b_startup_blocks, + LRNG_SP80090B_STARTUP_BLOCKS); +} + +/* + * Handle failure of SP800-90B runtime testing + */ +static inline void lrng_sp80090b_runtime_failure(struct lrng_health *health) +{ + lrng_sp80090b_startup_failure(health); + health->sp80090b_startup_done = false; +} + +static inline void lrng_sp80090b_failure(struct lrng_health *health) +{ + if (health->sp80090b_startup_done) { + pr_err("SP800-90B runtime health test failure - invalidating all existing entropy and initiate SP800-90B startup\n"); + lrng_sp80090b_runtime_failure(health); + } else { + pr_err("SP800-90B startup test failure - resetting\n"); + lrng_sp80090b_startup_failure(health); + } +} + +/* + * Is the SP800-90B startup testing complete? + * + * This function is called by the LRNG to determine whether to unblock + * a certain user interface. Therefore, only the potentially blocking + * user interfaces are considered SP800-90B compliant. + */ +bool lrng_sp80090b_startup_complete(void) +{ + struct lrng_health *health = &lrng_health; + + return (lrng_sp80090b_health_enabled()) ? health->sp80090b_startup_done: + true; +} + +bool lrng_sp80090b_compliant(void) +{ + struct lrng_health *health = &lrng_health; + + return lrng_sp80090b_health_enabled() && health->sp80090b_startup_done; +} + +/*************************************************************************** + * Adaptive Proportion Test + * + * This test complies with SP800-90B section 4.4.2. + ***************************************************************************/ + +/* + * Reset the APT counter + * + * @health [in] Reference to health state + */ +static inline void lrng_apt_reset(struct lrng_health *health, + unsigned int time_masked) +{ + struct lrng_apt *apt = &health->apt; + + pr_debug("APT value %d for base %d\n", + atomic_read(&apt->apt_count), atomic_read(&apt->apt_base)); + + /* Reset APT */ + atomic_set(&apt->apt_count, 0); + atomic_set(&apt->apt_base, time_masked); +} + +static inline void lrng_apt_restart(struct lrng_health *health) +{ + struct lrng_apt *apt = &health->apt; + + atomic_set(&apt->apt_trigger, LRNG_APT_WINDOW_SIZE); +} + +/* + * Insert a new entropy event into APT + * + * This function does is void as it does not decide about the fate of a time + * stamp. An APT failure can only happen at the same time of a stuck test + * failure. Thus, the stuck failure will already decide how the time stamp + * is handled. + * + * @health [in] Reference to health state + * @now_time [in] Time stamp to process + */ +static inline void lrng_apt_insert(struct lrng_health *health, + unsigned int now_time) +{ + struct lrng_apt *apt = &health->apt; + + if (!lrng_sp80090b_health_requested()) + return; + + now_time &= LRNG_APT_WORD_MASK; + + /* Initialization of APT */ + if (!apt->apt_base_set) { + atomic_set(&apt->apt_base, now_time); + apt->apt_base_set = true; + return; + } + + if (now_time == (unsigned int)atomic_read(&apt->apt_base)) { + u32 apt_val = (u32)atomic_inc_return_relaxed(&apt->apt_count); + + if (apt_val >= CONFIG_LRNG_APT_CUTOFF) + lrng_sp80090b_failure(health); + } + + if (atomic_dec_and_test(&apt->apt_trigger)) { + lrng_apt_restart(health); + lrng_apt_reset(health, now_time); + lrng_sp80090b_startup(health); + } +} + +/*************************************************************************** + * Repetition Count Test + * + * The LRNG uses an enhanced version of the Repetition Count Test + * (RCT) specified in SP800-90B section 4.4.1. Instead of counting identical + * back-to-back values, the input to the RCT is the counting of the stuck + * values while filling the entropy pool. + * + * The RCT is applied with an alpha of 2^-30 compliant to FIPS 140-2 IG 9.8. + * + * During the counting operation, the LRNG always calculates the RCT + * cut-off value of C. If that value exceeds the allowed cut-off value, + * the LRNG will invalidate all entropy for the entropy pool which implies + * that no data can be extracted from the entropy pool unless new entropy + * is received. + ***************************************************************************/ + +/* + * Hot code path - Insert data for Repetition Count Test + * + * @health: Reference to health information + * @stuck: Decision of stuck test + */ +static inline void lrng_rct(struct lrng_health *health, int stuck) +{ + struct lrng_rct *rct = &health->rct; + + if (!lrng_sp80090b_health_requested()) + return; + + if (stuck) { + u32 rct_count = atomic_add_return_relaxed(1, &rct->rct_count); + + pr_debug("RCT count: %u\n", rct_count); + + /* + * The cutoff value is based on the following consideration: + * alpha = 2^-30 as recommended in FIPS 140-2 IG 9.8. + * In addition, we imply an entropy value H of 1 bit as this + * is the minimum entropy required to provide full entropy. + * + * Note, rct_count (which equals to value B in the + * pseudo code of SP800-90B section 4.4.1) starts with zero. + * Hence we need to subtract one from the cutoff value as + * calculated following SP800-90B. + */ + if (rct_count >= CONFIG_LRNG_RCT_CUTOFF) { + atomic_set(&rct->rct_count, 0); + + /* + * APT must start anew as we consider all previously + * recorded data to contain no entropy. + */ + lrng_apt_restart(health); + + lrng_sp80090b_failure(health); + } + } else { + atomic_set(&rct->rct_count, 0); + } +} + +/*************************************************************************** + * Stuck Test + * + * Checking the: + * 1st derivative of the event occurrence (time delta) + * 2nd derivative of the event occurrence (delta of time deltas) + * 3rd derivative of the event occurrence (delta of delta of time deltas) + * + * All values must always be non-zero. The stuck test is only valid disabled if + * high-resolution time stamps are identified after initialization. + ***************************************************************************/ + +static inline u32 lrng_delta(u32 prev, u32 next) +{ + /* + * Note that this (unsigned) subtraction does yield the correct value + * in the wraparound-case, i.e. when next < prev. + */ + return (next - prev); +} + +/* + * Hot code path + * + * @health: Reference to health information + * @now: Event time + * @return: 0 event occurrence not stuck (good time stamp) + * != 0 event occurrence stuck (reject time stamp) + */ +static inline int lrng_irq_stuck(struct lrng_stuck_test *stuck, u32 now_time) +{ + u32 delta = lrng_delta(stuck->last_time, now_time); + u32 delta2 = lrng_delta(stuck->last_delta, delta); + u32 delta3 = lrng_delta(stuck->last_delta2, delta2); + + stuck->last_time = now_time; + stuck->last_delta = delta; + stuck->last_delta2 = delta2; + + if (!delta || !delta2 || !delta3) + return 1; + + return 0; +} + +/*************************************************************************** + * Health test interfaces + ***************************************************************************/ + +/* + * Disable all health tests + */ +void lrng_health_disable(void) +{ + struct lrng_health *health = &lrng_health; + + health->health_test_enabled = false; + + if (lrng_sp80090b_health_requested()) + pr_warn("SP800-90B compliance requested but the Linux RNG is NOT SP800-90B compliant\n"); +} + +/* + * Hot code path - Perform health test on time stamp received from an event + * + * @now_time Time stamp + */ +enum lrng_health_res lrng_health_test(u32 now_time) +{ + struct lrng_health *health = &lrng_health; + struct lrng_stuck_test *stuck_test = this_cpu_ptr(&lrng_stuck_test); + int stuck; + + if (!health->health_test_enabled) + return lrng_health_pass; + + lrng_apt_insert(health, now_time); + + stuck = lrng_irq_stuck(stuck_test, now_time); + lrng_rct(health, stuck); + if (stuck) { + /* SP800-90B disallows using a failing health test time stamp */ + return lrng_sp80090b_health_requested() ? + lrng_health_fail_drop : lrng_health_fail_use; + } + + return lrng_health_pass; +} From patchwork Fri Sep 18 09:53:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253000 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CACFBC4346A for ; Fri, 18 Sep 2020 10:12:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E90B21D7B for ; Fri, 18 Sep 2020 10:12:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="pH0NbijK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726626AbgIRKMS (ORCPT ); Fri, 18 Sep 2020 06:12:18 -0400 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.83]:30768 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726115AbgIRKMQ (ORCPT ); Fri, 18 Sep 2020 06:12:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1600423928; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=ktlzzxMQgq8TrFw2NQyRoXaxQkX267lzZ+6GaPBteMY=; b=pH0NbijK7CkykC+ZGv/QCmE4N3GNKIKgrPyOANMUBc0ARTkyl+g99oEhOBcqs4tLwU E3mf6WruHEOkdrsSNmCa6VyFM5OCgjbN5omk6fI2VmFvDDmiDHH1auynAjOL5jgCHmi3 1Dob4AhHxLybu0Sf+hUd3Pn7OwYvHSL698oPQCmUHwCqJfXsuC3KcITEp7j6EZnTN1eQ Iyhw2p/lkpaq+sOn8oM53k05K66qoKufWGHL8xTfIEp9eDE8CA02nAK31x4hpVGvAKHa PWjoPbttId50yrgqMD/45sosRa/QnU95AVNsrVUw93FJdPOoAmlNFPC6lAUhmN/yqPZf vwRA== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaJPScXyVH" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw8IA062Sy (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Sep 2020 12:00:06 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr , ebiggers@kernel.org Subject: [PATCH v35 12/13] LRNG - add interface for gathering of raw entropy Date: Fri, 18 Sep 2020 11:53:25 +0200 Message-ID: <21955344.6Emhk5qWAg@positron.chronox.de> In-Reply-To: <5667034.lOV4Wx5bFT@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <5667034.lOV4Wx5bFT@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org The test interface allows a privileged process to capture the raw unconditioned noise that is collected by the LRNG for statistical analysis. Such testing allows the analysis how much entropy the interrupt noise source provides on a given platform. Extracted noise data is not used to seed the LRNG. This is a test interface and not appropriate for production systems. Yet, the interface is considered to be sufficiently secured for production systems. Access to the data is given through the lrng_raw debugfs file. The data buffer should be multiples of sizeof(u32) to fill the entire buffer. Using the option lrng_testing.boot_test=1 the raw noise of the first 1000 entropy events since boot can be sampled. This test interface allows generating the data required for analysis whether the LRNG is in compliance with SP800-90B sections 3.1.3 and 3.1.4. In addition, the test interface allows gathering of the concatenated raw entropy data to verify that the concatenation works appropriately. This includes sampling of the following raw data: * high-resolution time stamp * Jiffies * IRQ number * IRQ flags * return instruction pointer * interrupt register state * array logic batching the high-resolution time stamp Also, a testing interface to support ACVT of the hash implementation is provided. The reason why only hash testing is supported (as opposed to also provide testing for the DRNG) is the fact that the LRNG software hash implementation contains glue code that may warrant testing in addition to the testing of the software ciphers via the kernel crypto API. Also, for testing the CTR-DRBG, the underlying AES implementation would need to be tested. However, such AES test interface cannot be provided by the LRNG as it has no means to access the AES operation. Finally, the execution duration for processing a time stamp can be obtained with the LRNG raw entropy interface. If a test interface is not compiled, its code is a noop which has no impact on the performance. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtmüller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 150 +++++++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_testing.c | 687 +++++++++++++++++++++++++++++++ 3 files changed, 838 insertions(+) create mode 100644 drivers/char/lrng/lrng_testing.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index a059da0b2f5d..bb785bc61abb 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -174,4 +174,154 @@ config LRNG_APT_CUTOFF default 325 if !LRNG_APT_BROKEN default 32 if LRNG_APT_BROKEN +menuconfig LRNG_TESTING_MENU + bool "LRNG testing interfaces" + depends on DEBUG_FS + help + Enable one or more of the following test interfaces. + + If unsure, say N. + +if LRNG_TESTING_MENU + +config LRNG_RAW_HIRES_ENTROPY + bool "Enable entropy test interface to hires timer noise source" + default y + help + The test interface allows a privileged process to capture + the raw unconditioned high resolution time stamp noise that + is collected by the LRNG for statistical analysis. Extracted + noise data is not used to seed the LRNG. + + The raw noise data can be obtained using the lrng_raw_hires + debugfs file. Using the option lrng_testing.boot_raw_hires_test=1 + the raw noise of the first 1000 entropy events since boot + can be sampled. + +config LRNG_RAW_JIFFIES_ENTROPY + bool "Enable entropy test interface to Jiffies noise source" + help + The test interface allows a privileged process to capture + the raw unconditioned Jiffies that is collected by + the LRNG for statistical analysis. This data is used for + seeding the LRNG if a high-resolution time stamp is not + available. If a high-resolution time stamp is detected, + the Jiffies value is not collected by the LRNG and no + data is provided via the test interface. Extracted noise + data is not used to seed the random number generator. + + The raw noise data can be obtained using the lrng_raw_jiffies + debugfs file. Using the option lrng_testing.boot_raw_jiffies_test=1 + the raw noise of the first 1000 entropy events since boot + can be sampled. + +config LRNG_RAW_IRQ_ENTROPY + bool "Enable entropy test interface to IRQ number noise source" + help + The test interface allows a privileged process to capture + the raw unconditioned interrupt number that is collected by + the LRNG for statistical analysis. This data is used for + seeding the random32 PRNG external to the LRNG if a + high-resolution time stamp is available or it will be used to + seed the LRNG otherwise. Extracted noise data is not used to + seed the random number generator. + + The raw noise data can be obtained using the lrng_raw_irq + debugfs file. Using the option lrng_testing.boot_raw_irq_test=1 + the raw noise of the first 1000 entropy events since boot + can be sampled. + +config LRNG_RAW_IRQFLAGS_ENTROPY + bool "Enable entropy test interface to IRQ flags noise source" + help + The test interface allows a privileged process to capture + the raw unconditioned interrupt flags that is collected by + the LRNG for statistical analysis. This data is used for + seeding the random32 PRNG external to the LRNG if a + high-resolution time stamp is available or it will be used to + seed the LRNG otherwise. Extracted noise data is not used to + seed the random number generator. + + The raw noise data can be obtained using the lrng_raw_irqflags + debugfs file. Using the option lrng_testing.boot_raw_irqflags_test=1 + the raw noise of the first 1000 entropy events since boot + can be sampled. + +config LRNG_RAW_RETIP_ENTROPY + bool "Enable entropy test interface to RETIP value noise source" + help + The test interface allows a privileged process to capture + the raw unconditioned return instruction pointer value + that is collected by the LRNG for statistical analysis. + This data is used for seeding the random32 PRNG external + to the LRNG if a high-resolution time stamp is available or + it will be used to seed the LRNG otherwise. Extracted noise + data is not used to seed the random number generator. + + The raw noise data can be obtained using the lrng_raw_retip + debugfs file. Using the option lrng_testing.boot_raw_retip_test=1 + the raw noise of the first 1000 entropy events since boot + can be sampled. + +config LRNG_RAW_REGS_ENTROPY + bool "Enable entropy test interface to IRQ register value noise source" + help + The test interface allows a privileged process to capture + the raw unconditioned interrupt register value that is + collected by the LRNG for statistical analysis. Extracted noise + data is not used to seed the random number generator. + + The raw noise data can be obtained using the lrng_raw_regs + debugfs file. Using the option lrng_testing.boot_raw_regs_test=1 + the raw noise of the first 1000 entropy events since boot + can be sampled. + +config LRNG_RAW_ARRAY + bool "Enable test interface to LRNG raw entropy storage array" + help + The test interface allows a privileged process to capture + the raw noise data that is collected by the LRNG + in the per-CPU array for statistical analysis. The purpose + of this interface is to verify that the array handling code + truly only concatenates data and provides the same entropy + rate as the raw unconditioned noise source when assessing + the collected data byte-wise. + + The data can be obtained using the lrng_raw_array debugfs + file. Using the option lrng_testing.boot_raw_array=1 + the raw noise of the first 1000 entropy events since boot + can be sampled. + +config LRNG_IRQ_PERF + bool "Enable LRNG interrupt performance monitor" + help + With this option, the performance monitor of the LRNG + interrupt handling code is enabled. The file provides + the execution time of the interrupt handler in + cycles. + + The interrupt performance data can be obtained using + the lrng_irq_perf debugfs file. Using the option + lrng_testing.boot_irq_perf=1 the performance data of + the first 1000 entropy events since boot can be sampled. + +config LRNG_ACVT_HASH + bool "Enable LRNG ACVT Hash interface" + help + With this option, the LRNG built-in hash function used for + auxiliary pool management and prior to switching the + cryptographic backends is made available for ACVT. The + interface allows writing of the data to be hashed + into the interface. The read operation triggers the hash + operation to generate message digest. + + The ACVT interface is available with the lrng_acvt_hash + debugfs file. + +config LRNG_TESTING + bool + default y if (LRNG_RAW_HIRES_ENTROPY || LRNG_RAW_JIFFIES_ENTROPY ||LRNG_RAW_IRQ_ENTROPY || LRNG_RAW_IRQFLAGS_ENTROPY || LRNG_RAW_RETIP_ENTROPY || LRNG_RAW_REGS_ENTROPY || LRNG_RAW_ARRAY || LRNG_IRQ_PERF || LRNG_ACVT_HASH) + +endif #LRNG_TESTING_MENU + endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 3c8637befb42..532501b38a00 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -16,3 +16,4 @@ obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o obj-$(CONFIG_LRNG_JENT) += lrng_jent.o obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o +obj-$(CONFIG_LRNG_TESTING) += lrng_testing.o diff --git a/drivers/char/lrng/lrng_testing.c b/drivers/char/lrng/lrng_testing.c new file mode 100644 index 000000000000..51adfda9bb38 --- /dev/null +++ b/drivers/char/lrng/lrng_testing.c @@ -0,0 +1,687 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * Linux Random Number Generator (LRNG) testing interfaces + * + * Copyright (C) 2019 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "lrng_internal.h" + +#define LRNG_TESTING_RINGBUFFER_SIZE 1024 +#define LRNG_TESTING_RINGBUFFER_MASK (LRNG_TESTING_RINGBUFFER_SIZE - 1) + +struct lrng_testing { + u32 lrng_testing_rb[LRNG_TESTING_RINGBUFFER_SIZE]; + u32 rb_reader; + u32 rb_writer; + atomic_t lrng_testing_enabled; + spinlock_t lock; + wait_queue_head_t read_wait; +}; + +/*************************** Generic Data Handling ****************************/ + +/* + * boot variable: + * 0 ==> No boot test, gathering of runtime data allowed + * 1 ==> Boot test enabled and ready for collecting data, gathering runtime + * data is disabled + * 2 ==> Boot test completed and disabled, gathering of runtime data is + * disabled + */ + +static inline void lrng_testing_reset(struct lrng_testing *data) +{ + unsigned long flags; + + spin_lock_irqsave(&data->lock, flags); + data->rb_reader = 0; + data->rb_writer = 0; + spin_unlock_irqrestore(&data->lock, flags); +} + +static inline void lrng_testing_init(struct lrng_testing *data, u32 boot) +{ + /* + * The boot time testing implies we have a running test. If the + * caller wants to clear it, he has to unset the boot_test flag + * at runtime via sysfs to enable regular runtime testing + */ + if (boot) + return; + + lrng_testing_reset(data); + atomic_set(&data->lrng_testing_enabled, 1); + pr_warn("Enabling data collection\n"); +} + +static inline void lrng_testing_fini(struct lrng_testing *data) +{ + atomic_set(&data->lrng_testing_enabled, 0); + lrng_testing_reset(data); + pr_warn("Disabling data collection\n"); +} + + +static inline bool lrng_testing_store(struct lrng_testing *data, u32 value, + u32 *boot) +{ + unsigned long flags; + + if (!atomic_read(&data->lrng_testing_enabled) && (*boot != 1)) + return false; + + spin_lock_irqsave(&data->lock, flags); + + /* + * Disable entropy testing for boot time testing after ring buffer + * is filled. + */ + if (*boot) { + if (data->rb_writer > LRNG_TESTING_RINGBUFFER_SIZE) { + *boot = 2; + pr_warn_once("One time data collection test disabled\n"); + spin_unlock_irqrestore(&data->lock, flags); + return false; + } + + if (data->rb_writer == 1) + pr_warn("One time data collection test enabled\n"); + } + + data->lrng_testing_rb[data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK] = + value; + data->rb_writer++; + + spin_unlock_irqrestore(&data->lock, flags); + + if (wq_has_sleeper(&data->read_wait)) + wake_up_interruptible(&data->read_wait); + + return true; +} + +static inline bool lrng_testing_have_data(struct lrng_testing *data) +{ + return ((data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK) != + (data->rb_reader & LRNG_TESTING_RINGBUFFER_MASK)); +} + +static inline int lrng_testing_reader(struct lrng_testing *data, u32 *boot, + u8 *outbuf, u32 outbuflen) +{ + unsigned long flags; + int collected_data = 0; + + lrng_testing_init(data, *boot); + + while (outbuflen) { + spin_lock_irqsave(&data->lock, flags); + + /* We have no data or reached the writer. */ + if (!data->rb_writer || + (data->rb_writer == data->rb_reader)) { + + spin_unlock_irqrestore(&data->lock, flags); + + /* + * Now we gathered all boot data, enable regular data + * collection. + */ + if (*boot) { + *boot = 0; + goto out; + } + + wait_event_interruptible(data->read_wait, + lrng_testing_have_data(data)); + if (signal_pending(current)) { + collected_data = -ERESTARTSYS; + goto out; + } + + continue; + } + + /* We copy out word-wise */ + if (outbuflen < sizeof(u32)) { + spin_unlock_irqrestore(&data->lock, flags); + goto out; + } + + memcpy(outbuf, &data->lrng_testing_rb[data->rb_reader], + sizeof(u32)); + data->rb_reader++; + + spin_unlock_irqrestore(&data->lock, flags); + + outbuf += sizeof(u32); + outbuflen -= sizeof(u32); + collected_data += sizeof(u32); + } + +out: + if (!lrng_testing_have_data(data)) + lrng_testing_fini(data); + return collected_data; +} + +static int lrng_testing_extract_user(struct file *file, char __user *buf, + size_t nbytes, loff_t *ppos, + int (*reader)(u8 *outbuf, u32 outbuflen)) +{ + u8 *tmp, *tmp_aligned; + int ret = 0, large_request = (nbytes > 256); + + if (!nbytes) + return 0; + + /* + * The intention of this interface is for collecting at least + * 1000 samples due to the SP800-90B requirements. So, we make no + * effort in avoiding allocating more memory that actually needed + * by the user. Hence, we allocate sufficient memory to always hold + * that amount of data. + */ + tmp = kmalloc(LRNG_TESTING_RINGBUFFER_SIZE + sizeof(u32), GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + tmp_aligned = PTR_ALIGN(tmp, sizeof(u32)); + + while (nbytes) { + int i; + + if (large_request && need_resched()) { + if (signal_pending(current)) { + if (ret == 0) + ret = -ERESTARTSYS; + break; + } + schedule(); + } + + i = min_t(int, nbytes, LRNG_TESTING_RINGBUFFER_SIZE); + i = reader(tmp_aligned, i); + if (i <= 0) { + if (i < 0) + ret = i; + break; + } + if (copy_to_user(buf, tmp_aligned, i)) { + ret = -EFAULT; + break; + } + + nbytes -= i; + buf += i; + ret += i; + } + + kfree_sensitive(tmp); + + if (ret > 0) + *ppos += ret; + + return ret; +} + +/************** Raw High-Resolution Timer Entropy Data Handling ***************/ + +#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY + +static u32 boot_raw_hires_test = 0; +module_param(boot_raw_hires_test, uint, 0644); +MODULE_PARM_DESC(boot_raw_hires_test, "Enable gathering boot time high resolution timer entropy of the first entropy events"); + +static struct lrng_testing lrng_raw_hires = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_hires.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_hires.read_wait) +}; + +bool lrng_raw_hires_entropy_store(u32 value) +{ + return lrng_testing_store(&lrng_raw_hires, value, &boot_raw_hires_test); +} + +static int lrng_raw_hires_entropy_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_raw_hires, &boot_raw_hires_test, + outbuf, outbuflen); +} + +static ssize_t lrng_raw_hires_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_raw_hires_entropy_reader); +} + +static const struct file_operations lrng_raw_hires_fops = { + .owner = THIS_MODULE, + .read = lrng_raw_hires_read, +}; + +#endif /* CONFIG_LRNG_RAW_HIRES_ENTROPY */ + +/********************* Raw Jiffies Entropy Data Handling **********************/ + +#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY + +static u32 boot_raw_jiffies_test = 0; +module_param(boot_raw_jiffies_test, uint, 0644); +MODULE_PARM_DESC(boot_raw_jiffies_test, "Enable gathering boot time high resolution timer entropy of the first entropy events"); + +static struct lrng_testing lrng_raw_jiffies = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_jiffies.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_jiffies.read_wait) +}; + +bool lrng_raw_jiffies_entropy_store(u32 value) +{ + return lrng_testing_store(&lrng_raw_jiffies, value, + &boot_raw_jiffies_test); +} + +static int lrng_raw_jiffies_entropy_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_raw_jiffies, &boot_raw_jiffies_test, + outbuf, outbuflen); +} + +static ssize_t lrng_raw_jiffies_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_raw_jiffies_entropy_reader); +} + +static const struct file_operations lrng_raw_jiffies_fops = { + .owner = THIS_MODULE, + .read = lrng_raw_jiffies_read, +}; + +#endif /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */ + +/************************** Raw IRQ Data Handling ****************************/ + +#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY + +static u32 boot_raw_irq_test = 0; +module_param(boot_raw_irq_test, uint, 0644); +MODULE_PARM_DESC(boot_raw_irq_test, "Enable gathering boot time entropy of the first IRQ entropy events"); + +static struct lrng_testing lrng_raw_irq = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_irq.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_irq.read_wait) +}; + +bool lrng_raw_irq_entropy_store(u32 value) +{ + return lrng_testing_store(&lrng_raw_irq, value, &boot_raw_irq_test); +} + +static int lrng_raw_irq_entropy_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_raw_irq, &boot_raw_irq_test, outbuf, + outbuflen); +} + +static ssize_t lrng_raw_irq_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_raw_irq_entropy_reader); +} + +static const struct file_operations lrng_raw_irq_fops = { + .owner = THIS_MODULE, + .read = lrng_raw_irq_read, +}; + +#endif /* CONFIG_LRNG_RAW_IRQ_ENTROPY */ + +/************************ Raw IRQFLAGS Data Handling **************************/ + +#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY + +static u32 boot_raw_irqflags_test = 0; +module_param(boot_raw_irqflags_test, uint, 0644); +MODULE_PARM_DESC(boot_raw_irqflags_test, "Enable gathering boot time entropy of the first IRQ flags entropy events"); + +static struct lrng_testing lrng_raw_irqflags = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_irqflags.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_irqflags.read_wait) +}; + +bool lrng_raw_irqflags_entropy_store(u32 value) +{ + return lrng_testing_store(&lrng_raw_irqflags, value, + &boot_raw_irqflags_test); +} + +static int lrng_raw_irqflags_entropy_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_raw_irqflags, &boot_raw_irqflags_test, + outbuf, outbuflen); +} + +static ssize_t lrng_raw_irqflags_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_raw_irqflags_entropy_reader); +} + +static const struct file_operations lrng_raw_irqflags_fops = { + .owner = THIS_MODULE, + .read = lrng_raw_irqflags_read, +}; + +#endif /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */ + +/************************ Raw _RET_IP_ Data Handling **************************/ + +#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY + +static u32 boot_raw_retip_test = 0; +module_param(boot_raw_retip_test, uint, 0644); +MODULE_PARM_DESC(boot_raw_retip_test, "Enable gathering boot time entropy of the first return instruction pointer entropy events"); + +static struct lrng_testing lrng_raw_retip = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_retip.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_retip.read_wait) +}; + +bool lrng_raw_retip_entropy_store(u32 value) +{ + return lrng_testing_store(&lrng_raw_retip, value, &boot_raw_retip_test); +} + +static int lrng_raw_retip_entropy_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_raw_retip, &boot_raw_retip_test, + outbuf, outbuflen); +} + +static ssize_t lrng_raw_retip_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_raw_retip_entropy_reader); +} + +static const struct file_operations lrng_raw_retip_fops = { + .owner = THIS_MODULE, + .read = lrng_raw_retip_read, +}; + +#endif /* CONFIG_LRNG_RAW_RETIP_ENTROPY */ + +/********************** Raw IRQ register Data Handling ************************/ + +#ifdef CONFIG_LRNG_RAW_REGS_ENTROPY + +static u32 boot_raw_regs_test = 0; +module_param(boot_raw_regs_test, uint, 0644); +MODULE_PARM_DESC(boot_raw_regs_test, "Enable gathering boot time entropy of the first interrupt register entropy events"); + +static struct lrng_testing lrng_raw_regs = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_regs.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_regs.read_wait) +}; + +bool lrng_raw_regs_entropy_store(u32 value) +{ + return lrng_testing_store(&lrng_raw_regs, value, &boot_raw_regs_test); +} + +static int lrng_raw_regs_entropy_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_raw_regs, &boot_raw_regs_test, + outbuf, outbuflen); +} + +static ssize_t lrng_raw_regs_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_raw_regs_entropy_reader); +} + +static const struct file_operations lrng_raw_regs_fops = { + .owner = THIS_MODULE, + .read = lrng_raw_regs_read, +}; + +#endif /* CONFIG_LRNG_RAW_REGS_ENTROPY */ + +/********************** Raw Entropy Array Data Handling ***********************/ + +#ifdef CONFIG_LRNG_RAW_ARRAY + +static u32 boot_raw_array = 0; +module_param(boot_raw_array, uint, 0644); +MODULE_PARM_DESC(boot_raw_array, "Enable gathering boot time raw noise array data of the first entropy events"); + +static struct lrng_testing lrng_raw_array = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_array.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_array.read_wait) +}; + +bool lrng_raw_array_entropy_store(u32 value) +{ + return lrng_testing_store(&lrng_raw_array, value, &boot_raw_array); +} + +static int lrng_raw_array_entropy_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_raw_array, &boot_raw_array, outbuf, + outbuflen); +} + +static ssize_t lrng_raw_array_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_raw_array_entropy_reader); +} + +static const struct file_operations lrng_raw_array_fops = { + .owner = THIS_MODULE, + .read = lrng_raw_array_read, +}; + +#endif /* CONFIG_LRNG_RAW_ARRAY */ + +/******************** Interrupt Performance Data Handling *********************/ + +#ifdef CONFIG_LRNG_IRQ_PERF + +static u32 boot_irq_perf = 0; +module_param(boot_irq_perf, uint, 0644); +MODULE_PARM_DESC(boot_irq_perf, "Enable gathering boot time interrupt performance data of the first entropy events"); + +static struct lrng_testing lrng_irq_perf = { + .rb_reader = 0, + .rb_writer = 0, + .lock = __SPIN_LOCK_UNLOCKED(lrng_irq_perf.lock), + .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_irq_perf.read_wait) +}; + +bool lrng_perf_time(u32 start) +{ + return lrng_testing_store(&lrng_irq_perf, random_get_entropy() - start, + &boot_irq_perf); +} + +static int lrng_irq_perf_reader(u8 *outbuf, u32 outbuflen) +{ + return lrng_testing_reader(&lrng_irq_perf, &boot_irq_perf, outbuf, + outbuflen); +} + +static ssize_t lrng_irq_perf_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + return lrng_testing_extract_user(file, to, count, ppos, + lrng_irq_perf_reader); +} + +static const struct file_operations lrng_irq_perf_fops = { + .owner = THIS_MODULE, + .read = lrng_irq_perf_read, +}; + +#endif /* CONFIG_LRNG_IRQ_PERF */ + +/*********************************** ACVT ************************************/ + +#ifdef CONFIG_LRNG_ACVT_HASH + +/* maximum amount of data to be hashed as defined by ACVP */ +#define LRNG_ACVT_MAX_SHA_MSG (65536 >> 3) + +/* + * As we use static variables to store the data, it is clear that the + * test interface is only able to handle single threaded testing. This is + * considered to be sufficient for testing. If multi-threaded use of the + * ACVT test interface would be performed, the caller would get garbage + * but the kernel operation is unaffected by this. + */ +static u8 lrng_acvt_hash_data[LRNG_ACVT_MAX_SHA_MSG] + __aligned(LRNG_KCAPI_ALIGN); +static atomic_t lrng_acvt_hash_data_size = ATOMIC_INIT(0); +static u8 lrng_acvt_hash_digest[LRNG_ATOMIC_DIGEST_SIZE]; + +static ssize_t lrng_acvt_hash_write(struct file *file, const char __user *buf, + size_t nbytes, loff_t *ppos) +{ + if (nbytes > LRNG_ACVT_MAX_SHA_MSG) + return -EINVAL; + + atomic_set(&lrng_acvt_hash_data_size, (int)nbytes); + + return simple_write_to_buffer(lrng_acvt_hash_data, + LRNG_ACVT_MAX_SHA_MSG, ppos, buf, nbytes); +} + +static ssize_t lrng_acvt_hash_read(struct file *file, char __user *to, + size_t count, loff_t *ppos) +{ + SHASH_DESC_ON_STACK(shash, NULL); + const struct lrng_crypto_cb *crypto_cb = &lrng_cc20_crypto_cb; + ssize_t ret; + + if (count > LRNG_ATOMIC_DIGEST_SIZE) + return -EINVAL; + + ret = crypto_cb->lrng_hash_init(shash, NULL) ?: + crypto_cb->lrng_hash_update(shash, lrng_acvt_hash_data, + atomic_read_u32(&lrng_acvt_hash_data_size)) ?: + crypto_cb->lrng_hash_final(shash, lrng_acvt_hash_digest); + if (ret) + return ret; + + return simple_read_from_buffer(to, count, ppos, lrng_acvt_hash_digest, + sizeof(lrng_acvt_hash_digest)); +} + +static const struct file_operations lrng_acvt_hash_fops = { + .owner = THIS_MODULE, + .open = simple_open, + .llseek = default_llseek, + .read = lrng_acvt_hash_read, + .write = lrng_acvt_hash_write, +}; + +#endif /* CONFIG_LRNG_ACVT_DRNG */ + +/************************************************************************** + * Debugfs interface + **************************************************************************/ + +static int __init lrng_raw_init(void) +{ + struct dentry *lrng_raw_debugfs_root; + + lrng_raw_debugfs_root = debugfs_create_dir(KBUILD_MODNAME, NULL); + +#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY + debugfs_create_file_unsafe("lrng_raw_hires", 0400, + lrng_raw_debugfs_root, NULL, + &lrng_raw_hires_fops); +#endif +#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY + debugfs_create_file_unsafe("lrng_raw_jiffies", 0400, + lrng_raw_debugfs_root, NULL, + &lrng_raw_jiffies_fops); +#endif +#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY + debugfs_create_file_unsafe("lrng_raw_irq", 0400, lrng_raw_debugfs_root, + NULL, &lrng_raw_irq_fops); +#endif +#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY + debugfs_create_file_unsafe("lrng_raw_irqflags", 0400, + lrng_raw_debugfs_root, NULL, + &lrng_raw_irqflags_fops); +#endif +#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY + debugfs_create_file_unsafe("lrng_raw_retip", 0400, + lrng_raw_debugfs_root, NULL, + &lrng_raw_retip_fops); +#endif +#ifdef CONFIG_LRNG_RAW_REGS_ENTROPY + debugfs_create_file_unsafe("lrng_raw_regs", 0400, + lrng_raw_debugfs_root, NULL, + &lrng_raw_regs_fops); +#endif +#ifdef CONFIG_LRNG_RAW_ARRAY + debugfs_create_file_unsafe("lrng_raw_array", 0400, + lrng_raw_debugfs_root, NULL, + &lrng_raw_array_fops); +#endif +#ifdef CONFIG_LRNG_IRQ_PERF + debugfs_create_file_unsafe("lrng_irq_perf", 0400, lrng_raw_debugfs_root, + NULL, &lrng_irq_perf_fops); +#endif +#ifdef CONFIG_LRNG_ACVT_HASH + debugfs_create_file_unsafe("lrng_acvt_hash", 0600, + lrng_raw_debugfs_root, NULL, + &lrng_acvt_hash_fops); +#endif + + return 0; +} + +module_init(lrng_raw_init); From patchwork Fri Sep 18 09:53:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 253003 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E62C8C43464 for ; Fri, 18 Sep 2020 10:12:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8003521D7B for ; Fri, 18 Sep 2020 10:12:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="DX72MxT3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726279AbgIRKMM (ORCPT ); Fri, 18 Sep 2020 06:12:12 -0400 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.83]:26402 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725874AbgIRKMM (ORCPT ); Fri, 18 Sep 2020 06:12:12 -0400 X-Greylist: delayed 639 seconds by postgrey-1.27 at vger.kernel.org; Fri, 18 Sep 2020 06:12:06 EDT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1600423925; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=Xxovtjs+eAxIxsl2kZwOe320WfK0hEfmL6b01D5S84U=; b=DX72MxT3jXKzYJ8evHFAajO2IrLQGsitgDO9bqSXfeBY/mYqZvChbdht9pZpds8UAs Zs2dMtZu2Fi1QmILdBc20RginMP0N1m0lhOj3pj8G0trdE/40XswgZw99VFnyYTat5vM GMNEWXG0WWqCVCHbOOD7/GNDIuyEKrT2aRu0gbBx78aZOod7ZOfTISxnEFTKIQa8mxGR +ZJjVvB44AVYsRmNTzEF9qJW17+g+tBdNs9FbMcLFrOGzMlqTgEdMfGq81j7Q1XXiyTY tM++RwRVmBn+KKh+mc8VOxWPfIOvvkNjxynTwmX6xyMV6KEAaVzzdSDc5zMasARmDRAz IlIA== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzHHXDaJPScXyVH" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw8IA032Sx (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Sep 2020 12:00:03 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr , ebiggers@kernel.org Subject: [PATCH v35 13/13] LRNG - add power-on and runtime self-tests Date: Fri, 18 Sep 2020 11:53:47 +0200 Message-ID: <4083447.ejJDZkT8p0@positron.chronox.de> In-Reply-To: <5667034.lOV4Wx5bFT@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> <5532247.MhkbZ0Pkbq@positron.chronox.de> <5667034.lOV4Wx5bFT@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Parts of the LRNG are already covered by self-tests, including: * Self-test of SP800-90A DRBG provided by the Linux kernel crypto API. * Self-test of the PRNG provided by the Linux kernel crypto API. * Raw noise source data testing including SP800-90B compliant tests when enabling CONFIG_LRNG_HEALTH_TESTS This patch adds the self-tests for the remaining critical functions of the LRNG that are essential to maintain entropy and provide cryptographic strong random numbers. The following self-tests are implemented: * Self-test of the time array maintenance. This test verifies whether the time stamp array management to store multiple values in one integer implements a concatenation of the data. * Self-test of the software hash implementation ensures that this function operates compliant to the FIPS 180-4 specification. The self-test performs a hash operation of a zeroized per-CPU data array. * Self-test of the ChaCha20 DRNG is based on the self-tests that are already present and implemented with the stand-alone user space ChaCha20 DRNG implementation available at [1]. The self-tests cover different use cases of the DRNG seeded with known seed data. The status of the LRNG self-tests is provided with the selftest_status SysFS file. If the file contains a zero, the self-tests passed. The value 0xffffffff means that the self-tests were not executed. Any other value indicates a self-test failure. The self-test may be compiled to panic the system if the self-test fails. All self-tests operate on private state data structures. This implies that none of the self-tests have any impact on the regular LRNG operations. This allows the self-tests to be repeated at runtime by writing anything into the selftest_status SysFS file. [1] https://www.chronox.de/chacha20.html CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange CC: Marcelo Henrique Cerri CC: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 26 +++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_selftest.c | 344 ++++++++++++++++++++++++++++++ 3 files changed, 371 insertions(+) create mode 100644 drivers/char/lrng/lrng_selftest.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index bb785bc61abb..6f180641a5da 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -324,4 +324,30 @@ config LRNG_TESTING endif #LRNG_TESTING_MENU +config LRNG_SELFTEST + bool "Enable power-on and on-demand self-tests" + help + The power-on self-tests are executed during boot time + covering the ChaCha20 DRNG, the hash operation used for + processing the entropy pools and the auxiliary pool, and + the time stamp management of the LRNG. + + The on-demand self-tests are triggered by writing any + value into the SysFS file selftest_status. At the same + time, when reading this file, the test status is + returned. A zero indicates that all tests were executed + successfully. + + If unsure, say Y. + +if LRNG_SELFTEST + +config LRNG_SELFTEST_PANIC + bool "Panic the kernel upon self-test failure" + help + If the option is enabled, the kernel is terminated if an + LRNG power-on self-test failure is detected. + +endif # LRNG_SELFTEST + endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 532501b38a00..a633638af991 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -17,3 +17,4 @@ obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o obj-$(CONFIG_LRNG_JENT) += lrng_jent.o obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o obj-$(CONFIG_LRNG_TESTING) += lrng_testing.o +obj-$(CONFIG_LRNG_SELFTEST) += lrng_selftest.o diff --git a/drivers/char/lrng/lrng_selftest.c b/drivers/char/lrng/lrng_selftest.c new file mode 100644 index 000000000000..4c7d124d24a4 --- /dev/null +++ b/drivers/char/lrng/lrng_selftest.c @@ -0,0 +1,344 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * LRNG power-on and on-demand self-test + * + * Copyright (C) 2016 - 2020, Stephan Mueller + */ + +/* + * In addition to the self-tests below, the following LRNG components + * are covered with self-tests during regular operation: + * + * * power-on self-test: SP800-90A DRBG provided by the Linux kernel crypto API + * * power-on self-test: PRNG provided by the Linux kernel crypto API + * * runtime test: Raw noise source data testing including SP800-90B compliant + * tests when enabling CONFIG_LRNG_HEALTH_TESTS + * + * Additional developer tests present with LRNG code: + * * SP800-90B APT and RCT test enforcement validation when enabling + * CONFIG_LRNG_APT_BROKEN or CONFIG_LRNG_RCT_BROKEN. + * * Collection of raw entropy from the interrupt noise source when enabling + * CONFIG_LRNG_TESTING and pulling the data from the kernel with the provided + * interface. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include + +#include "lrng_chacha20.h" +#include "lrng_internal.h" +#include "lrng_sw_noise.h" + +#define LRNG_SELFTEST_PASSED 0 +#define LRNG_SEFLTEST_ERROR_TIME (1 << 0) +#define LRNG_SEFLTEST_ERROR_CHACHA20 (1 << 1) +#define LRNG_SEFLTEST_ERROR_HASH (1 << 2) +#define LRNG_SELFTEST_NOT_EXECUTED 0xffffffff + +static u32 lrng_data_selftest_ptr = 0; +static u32 lrng_data_selftest[LRNG_DATA_ARRAY_SIZE]; + +static unsigned int lrng_selftest_status = LRNG_SELFTEST_NOT_EXECUTED; + +static inline void lrng_selftest_bswap32(u32 *ptr, u32 words) +{ + u32 i; + + /* Byte-swap data which is an LE representation */ + for (i = 0; i < words; i++) { + __le32 *p = (__le32 *)ptr; + + *p = cpu_to_le32(*ptr); + ptr++; + } +} + +static inline void lrng_data_process_selftest_insert(u32 time) +{ + u32 ptr = lrng_data_selftest_ptr++ & LRNG_DATA_WORD_MASK; + + lrng_data_selftest[lrng_data_idx2array(ptr)] |= + lrng_data_slot_val(time & LRNG_DATA_SLOTSIZE_MASK, + lrng_data_idx2slot(ptr)); +} + +static inline void lrng_data_process_selftest_u32(uint32_t data) +{ + uint32_t pre_ptr, ptr, mask; + + /* Increment pointer by number of slots taken for input value */ + lrng_data_selftest_ptr += LRNG_DATA_SLOTS_PER_UINT; + + /* ptr to current unit */ + ptr = lrng_data_selftest_ptr; + /* ptr to previous unit */ + pre_ptr = (lrng_data_selftest_ptr - LRNG_DATA_SLOTS_PER_UINT) & + LRNG_DATA_WORD_MASK; + ptr &= LRNG_DATA_WORD_MASK; + + /* mask to split data into the two parts for the two units */ + mask = ((1 << (pre_ptr & (LRNG_DATA_SLOTS_PER_UINT - 1)) * + LRNG_DATA_SLOTSIZE_BITS)) - 1; + + /* MSB of data go into previous unit */ + lrng_data_selftest[lrng_data_idx2array(pre_ptr)] |= data & ~mask; + + /* LSB of data go into current unit */ + lrng_data_selftest[lrng_data_idx2array(ptr)] = data & mask; +} + +static unsigned int lrng_data_process_selftest(void) +{ + u32 time; + u32 idx_zero_compare = (0 << 0) | (1 << 8) | (2 << 16) | (3 << 24); + u32 idx_one_compare = (4 << 0) | (5 << 8) | (6 << 16) | (7 << 24); + u32 idx_last_compare = + (((LRNG_DATA_NUM_VALUES - 4) & LRNG_DATA_SLOTSIZE_MASK) << 0) | + (((LRNG_DATA_NUM_VALUES - 3) & LRNG_DATA_SLOTSIZE_MASK) << 8) | + (((LRNG_DATA_NUM_VALUES - 2) & LRNG_DATA_SLOTSIZE_MASK) << 16) | + (((LRNG_DATA_NUM_VALUES - 1) & LRNG_DATA_SLOTSIZE_MASK) << 24); + + (void)idx_one_compare; + + lrng_data_process_selftest_insert(0); + /* + * Note, when using lrng_data_process_u32() on unaligned ptr, + * the first slots will go into next word, and the last slots go + * into the previous word. + */ + lrng_data_process_selftest_u32((4 << 0) | (1 << 8) | (2 << 16) | + (3 << 24)); + lrng_data_process_selftest_insert(5); + lrng_data_process_selftest_insert(6); + lrng_data_process_selftest_insert(7); + + if ((lrng_data_selftest[0] != idx_zero_compare) || + (lrng_data_selftest[1] != idx_one_compare)) + goto err; + + /* Reset for next test */ + lrng_data_selftest[0] = 0; + lrng_data_selftest[1] = 0; + lrng_data_selftest_ptr = 0; + + for (time = 0; time < LRNG_DATA_NUM_VALUES; time++) + lrng_data_process_selftest_insert(time); + + if ((lrng_data_selftest[0] != idx_zero_compare) || + (lrng_data_selftest[1] != idx_one_compare) || + (lrng_data_selftest[LRNG_DATA_ARRAY_SIZE - 1] != idx_last_compare)) + goto err; + + return LRNG_SELFTEST_PASSED; + +err: + pr_err("LRNG data array self-test FAILED\n"); + return LRNG_SEFLTEST_ERROR_TIME; +} + +/* The test vectors are taken from crypto/testmgr.h */ +static unsigned int lrng_hash_selftest(void) +{ + SHASH_DESC_ON_STACK(shash, NULL); + const struct lrng_crypto_cb *crypto_cb = &lrng_cc20_crypto_cb; + static const u8 lrng_hash_selftest_result[] = +#ifdef CONFIG_CRYPTO_LIB_SHA256 + { 0xba, 0x78, 0x16, 0xbf, 0x8f, 0x01, 0xcf, 0xea, + 0x41, 0x41, 0x40, 0xde, 0x5d, 0xae, 0x22, 0x23, + 0xb0, 0x03, 0x61, 0xa3, 0x96, 0x17, 0x7a, 0x9c, + 0xb4, 0x10, 0xff, 0x61, 0xf2, 0x00, 0x15, 0xad }; +#else /* CONFIG_CRYPTO_LIB_SHA256 */ + { 0xa9, 0x99, 0x3e, 0x36, 0x47, 0x06, 0x81, 0x6a, 0xba, 0x3e, + 0x25, 0x71, 0x78, 0x50, 0xc2, 0x6c, 0x9c, 0xd0, 0xd8, 0x9d }; +#endif /* CONFIG_CRYPTO_LIB_SHA256 */ + static const u8 hash_input[] = { 0x61, 0x62, 0x63 }; /* "abc" */ + u8 digest[sizeof(lrng_hash_selftest_result)] __aligned(sizeof(u32)); + + BUG_ON(sizeof(digest) != crypto_cb->lrng_hash_digestsize(NULL)); + + if (!crypto_cb->lrng_hash_init(shash, NULL) && + !crypto_cb->lrng_hash_update(shash, hash_input, + sizeof(hash_input)) && + !crypto_cb->lrng_hash_final(shash, digest) && + !memcmp(digest, lrng_hash_selftest_result, sizeof(digest))) + return 0; + + pr_err("LRNG %s Hash self-test FAILED\n", crypto_cb->lrng_hash_name()); + return LRNG_SEFLTEST_ERROR_HASH; +} + +/* + * The test vectors were generated using the ChaCha20 DRNG from + * https://www.chronox.de/chacha20.html + */ +static unsigned int lrng_chacha20_drng_selftest(void) +{ + const struct lrng_crypto_cb *crypto_cb = &lrng_cc20_crypto_cb; + u8 seed[CHACHA_KEY_SIZE * 2] = { + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, + 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, + 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, + 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, + 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, + 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, + 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, + 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, + }; + struct chacha20_block chacha20; + int ret; + u8 outbuf[CHACHA_KEY_SIZE * 2] __aligned(sizeof(u32)); + + /* + * Expected result when ChaCha20 DRNG state is zero: + * * constants are set to "expand 32-byte k" + * * remaining state is 0 + * and pulling one half ChaCha20 DRNG block. + */ + static const u8 expected_halfblock[CHACHA_KEY_SIZE] = { + 0x76, 0xb8, 0xe0, 0xad, 0xa0, 0xf1, 0x3d, 0x90, + 0x40, 0x5d, 0x6a, 0xe5, 0x53, 0x86, 0xbd, 0x28, + 0xbd, 0xd2, 0x19, 0xb8, 0xa0, 0x8d, 0xed, 0x1a, + 0xa8, 0x36, 0xef, 0xcc, 0x8b, 0x77, 0x0d, 0xc7 }; + + /* + * Expected result when ChaCha20 DRNG state is zero: + * * constants are set to "expand 32-byte k" + * * remaining state is 0 + * followed by a reseed with two keyblocks + * 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, + * 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, + * 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, + * 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, + * 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, + * 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, + * 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, + * 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f + * and pulling one ChaCha20 DRNG block. + */ + static const u8 expected_oneblock[CHACHA_KEY_SIZE * 2] = { + 0xf5, 0xb4, 0xb6, 0x5a, 0xec, 0xcd, 0x5a, 0x65, + 0x87, 0x56, 0xe3, 0x86, 0x51, 0x54, 0xfc, 0x90, + 0x56, 0xff, 0x5e, 0xae, 0x58, 0xf2, 0x01, 0x88, + 0xb1, 0x7e, 0xb8, 0x2e, 0x17, 0x9a, 0x27, 0xe6, + 0x86, 0xb3, 0xed, 0x33, 0xf7, 0xb9, 0x06, 0x05, + 0x8a, 0x2d, 0x1a, 0x93, 0xc9, 0x0b, 0x80, 0x04, + 0x03, 0xaa, 0x60, 0xaf, 0xd5, 0x36, 0x40, 0x11, + 0x67, 0x89, 0xb1, 0x66, 0xd5, 0x88, 0x62, 0x6d }; + + /* + * Expected result when ChaCha20 DRNG state is zero: + * * constants are set to "expand 32-byte k" + * * remaining state is 0 + * followed by a reseed with one key block plus one byte + * 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, + * 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, + * 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, + * 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, + * 0x20 + * and pulling less than one ChaCha20 DRNG block. + */ + static const u8 expected_block_nonalinged[CHACHA_KEY_SIZE + 4] = { + 0x9d, 0xdd, 0x4f, 0xbe, 0x97, 0xcd, 0x8e, 0x15, + 0xb3, 0xc4, 0x1a, 0x17, 0x49, 0x29, 0x32, 0x7c, + 0xb3, 0x84, 0xa4, 0x9b, 0xa7, 0x14, 0xb3, 0xc1, + 0x5b, 0x3b, 0xfb, 0xa1, 0xe4, 0x23, 0x42, 0x8e, + 0x08, 0x1f, 0x53, 0xa2 }; + + BUILD_BUG_ON(sizeof(seed) % sizeof(u32)); + + memset(&chacha20, 0, sizeof(chacha20)); + lrng_cc20_init_rfc7539(&chacha20); + lrng_selftest_bswap32((u32 *)seed, sizeof(seed) / sizeof(u32)); + + /* Generate with zero state */ + ret = crypto_cb->lrng_drng_generate_helper(&chacha20, outbuf, + sizeof(expected_halfblock)); + if (ret != sizeof(expected_halfblock)) + goto err; + if (memcmp(outbuf, expected_halfblock, sizeof(expected_halfblock))) + goto err; + + /* Clear state of DRNG */ + memset(&chacha20.key.u[0], 0, 48); + + /* Reseed with 2 key blocks */ + ret = crypto_cb->lrng_drng_seed_helper(&chacha20, seed, + sizeof(expected_oneblock)); + if (ret < 0) + goto err; + ret = crypto_cb->lrng_drng_generate_helper(&chacha20, outbuf, + sizeof(expected_oneblock)); + if (ret != sizeof(expected_oneblock)) + goto err; + if (memcmp(outbuf, expected_oneblock, sizeof(expected_oneblock))) + goto err; + + /* Clear state of DRNG */ + memset(&chacha20.key.u[0], 0, 48); + + /* Reseed with 1 key block and one byte */ + ret = crypto_cb->lrng_drng_seed_helper(&chacha20, seed, + sizeof(expected_block_nonalinged)); + if (ret < 0) + goto err; + ret = crypto_cb->lrng_drng_generate_helper(&chacha20, outbuf, + sizeof(expected_block_nonalinged)); + if (ret != sizeof(expected_block_nonalinged)) + goto err; + if (memcmp(outbuf, expected_block_nonalinged, + sizeof(expected_block_nonalinged))) + goto err; + + return LRNG_SELFTEST_PASSED; + +err: + pr_err("LRNG ChaCha20 DRNG self-test FAILED\n"); + return LRNG_SEFLTEST_ERROR_CHACHA20; +} + +static int lrng_selftest(void) +{ + unsigned int ret = lrng_data_process_selftest(); + + ret |= lrng_chacha20_drng_selftest(); + ret |= lrng_hash_selftest(); + + if (ret) { + if (IS_ENABLED(CONFIG_LRNG_SELFTEST_PANIC)) + panic("LRNG self-tests failed: %u\n", ret); + } else { + pr_info("LRNG self-tests passed\n"); + } + + lrng_selftest_status = ret; + + if (lrng_selftest_status) + return -EFAULT; + return 0; +} + +#ifdef CONFIG_SYSFS +/* Re-perform self-test when any value is written to the sysfs file. */ +static int lrng_selftest_sysfs_set(const char *val, + const struct kernel_param *kp) +{ + return lrng_selftest(); +} + +static const struct kernel_param_ops lrng_selftest_sysfs = { + .set = lrng_selftest_sysfs_set, + .get = param_get_uint, +}; +module_param_cb(selftest_status, &lrng_selftest_sysfs, &lrng_selftest_status, + 0644); +#endif /* CONFIG_SYSFS */ + +static int __init lrng_selftest_init(void) +{ + return lrng_selftest(); +} + +module_init(lrng_selftest_init);