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");