From patchwork Thu May 27 16:01:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 448934 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 C4778C4708D for ; Thu, 27 May 2021 16:13:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9510613C0 for ; Thu, 27 May 2021 16:13:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237189AbhE0QOd (ORCPT ); Thu, 27 May 2021 12:14:33 -0400 Received: from mo4-p04-ob.smtp.rzone.de ([81.169.146.223]:25373 "EHLO mo4-p04-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237087AbhE0QOR (ORCPT ); Thu, 27 May 2021 12:14:17 -0400 ARC-Seal: i=1; a=rsa-sha256; t=1622131887; cv=none; d=strato.com; s=strato-dkim-0002; b=bEwvwvBoBWCf9lTUMqKe58fgcarh1J8fAdavnvnOlV0BS/JLBo+vZVQWepSFrNQhCc VO/S6BTrZBCIfRSa5H/AMpkzgqfSSxCNw72HRITvE6XmMyVKss/FgzwT+F5HaeoBjij0 pAEjFNlUSXvV2phJZO+mSDuv9JJcNoSXVH7Owrtv2JYWwbX0IpQ2ifR8KjXp0JDlUGh+ 0V/Ufofa4SFAbYH/f4WUQf1VzprkV4d2pi3ZU2w/9OuIYVvu8qCfuZkwooq4vnA4bpGC EE/puAUiAncRKUP3BAmsBesfiWGz8GiPYSo684mxx+vD/NJN35H00wm/USe7x9IFU4zS D6dA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1622131887; s=strato-dkim-0002; d=strato.com; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=3pBKXIPhg6POanG6QDgGnbnoTwPPrak5Z6fegZwHEO0=; b=MKWiulWkx7wS30+a63Bil5nMDpcQYITvcRwm49Km3CHFWchtpEg9B42ESPFa3H7GbK GfaIvq/MbXj89N9qAaWxYFLDYoKgWfaj3xjcVOWQvNVmrkBaX/H3a+VFDXJ3iFdqF5Ho 67p3FcPGfi6tsQMzPzGg8e4RK01ZPG0ujriGNAFs3eBqjGxpW9CKh7nhCg3kPVzbKG9Y GCB6iDAvIaTVTxe7n4BkCkrfr6MDTtRoWkf/cAt+G23Pxk7v7XLFLkW5JSE/zkaMFa7m 6lstXbWHgf6+NH5IH17rW9hIBNTVrlAurlBKoSUvCqbDUkLxVSom1MzZrNXV/2dqxqz1 poHA== ARC-Authentication-Results: i=1; strato.com; dkim=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1622131887; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=3pBKXIPhg6POanG6QDgGnbnoTwPPrak5Z6fegZwHEO0=; b=gSj4Z2Nr3Dt8EQEfVBMAk4zJzPjdisTDqv29J0Z6ERgDtrJD/YeBQjo0EbCKfHQp2P ZiMdV3e3QwyhOeh9ocwKBZMC9TPib3OHFYKWhVmSMv7+BsGXRrrpuBsx0kk2Tdp6G238 MywTyGXHJMdDrpXwJ1npLc0nzbadFzQVvPkalhw3HUktCSQF7hvNNJgpsk03XTH80IYZ Kvk2P7qnAberJp9mwi+5e7TC3zyxVeoq3NijL2oFS/5ZmGvTpN97CNpn8rzPM6jhBaNx meupDA3teMOzmb+QQIX5tN5TkiQSJGPSofT9dFU4DHicut10BhVRdOl8Hy0mcoYMh3ys s7nQ== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPbJvSfFeK2" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 47.26.3 DYNA|AUTH) with ESMTPSA id R0123ax4RGBQ0Tm (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Thu, 27 May 2021 18:11:26 +0200 (CEST) From: Stephan =?iso-8859-1?q?M=FCller?= To: Tso Ted , linux-crypto@vger.kernel.org Cc: Willy Tarreau , Nicolai Stange , LKML , Arnd Bergmann , Greg Kroah-Hartman , "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Peter Matthias , Marcelo Henrique Cerri , Neil Horman , Randy Dunlap , Julia Lawall , Dan Carpenter , Andy Lavr , Eric Biggers , "Jason A. Donenfeld" , Petr Tesarik , John Haxby Subject: [PATCH v40 08/13] LRNG - add kernel crypto API PRNG extension Date: Thu, 27 May 2021 18:01:25 +0200 Message-ID: <26609241.FcOYrYUqip@positron.chronox.de> In-Reply-To: <18450229.rjpLZT9oXI@positron.chronox.de> References: <18450229.rjpLZT9oXI@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Add runtime-pluggable support for all PRNGs that are accessible via the kernel crypto API, including hardware PRNGs. The PRNG is selected with the module parameter drng_name where the name must be one that the kernel crypto API can resolve into an RNG. This allows using of the kernel crypto API PRNG implementations that provide an interface to hardware PRNGs. Using this extension, the LRNG uses the hardware PRNGs to generate random numbers. An example is the S390 CPACF support providing such a PRNG. The hash is provided by a kernel crypto API SHASH whose digest size complies with the seedsize of the PRNG. CC: Torsten Duwe 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: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 13 ++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_kcapi.c | 227 +++++++++++++++++++++++++++++++++ 3 files changed, 241 insertions(+) create mode 100644 drivers/char/lrng/lrng_kcapi.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index e5fe8a764059..e66e8cd1d86f 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -181,6 +181,19 @@ config LRNG_DRBG 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. + +config LRNG_KCAPI + tristate "Kernel Crypto API support for the LRNG" + depends on CRYPTO + depends on !LRNG_DRBG + select CRYPTO_RNG + select LRNG_KCAPI_HASH + help + Enable the support for generic pseudo-random number + generators offered by the kernel crypto API with the + LRNG. Once the module is loaded, output from /dev/random, + /dev/urandom, getrandom(2), or get_random_bytes is + provided by the selected kernel crypto API RNG. endif # LRNG_DRNG_SWITCH endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 6ebd252db12f..97d2b13d3227 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -13,3 +13,4 @@ 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 +obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o diff --git a/drivers/char/lrng/lrng_kcapi.c b/drivers/char/lrng/lrng_kcapi.c new file mode 100644 index 000000000000..b06449cb2365 --- /dev/null +++ b/drivers/char/lrng/lrng_kcapi.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * Backend for the LRNG providing the cryptographic primitives using the + * kernel crypto API. + * + * Copyright (C) 2018 - 2021, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +#include "lrng_kcapi_hash.h" + +static char *drng_name = NULL; +module_param(drng_name, charp, 0444); +MODULE_PARM_DESC(drng_name, "Kernel crypto API name of DRNG"); + +static char *pool_hash = "sha512"; +module_param(pool_hash, charp, 0444); +MODULE_PARM_DESC(pool_hash, + "Kernel crypto API name of hash or keyed message digest to read the entropy pool"); + +static char *seed_hash = NULL; +module_param(seed_hash, charp, 0444); +MODULE_PARM_DESC(seed_hash, + "Kernel crypto API name of hash with output size equal to seedsize of DRNG to bring seed string to the size required by the DRNG"); + +struct lrng_drng_info { + struct crypto_rng *kcapi_rng; + void *lrng_hash; +}; + +static void *lrng_kcapi_drng_hash_alloc(void) +{ + return lrng_kcapi_hash_alloc(pool_hash); +} + +static int lrng_kcapi_drng_seed_helper(void *drng, const u8 *inbuf, + u32 inbuflen) +{ + SHASH_DESC_ON_STACK(shash, NULL); + struct lrng_drng_info *lrng_drng_info = (struct lrng_drng_info *)drng; + struct crypto_rng *kcapi_rng = lrng_drng_info->kcapi_rng; + void *hash = lrng_drng_info->lrng_hash; + u32 digestsize = lrng_kcapi_hash_digestsize(hash); + u8 digest[64] __aligned(8); + int ret; + + if (!hash) + return crypto_rng_reset(kcapi_rng, inbuf, inbuflen); + + BUG_ON(digestsize > sizeof(digest)); + + ret = lrng_kcapi_hash_init(shash, hash) ?: + lrng_kcapi_hash_update(shash, inbuf, inbuflen) ?: + lrng_kcapi_hash_final(shash, digest); + lrng_kcapi_hash_zero(shash); + if (ret) + return ret; + + ret = crypto_rng_reset(kcapi_rng, digest, digestsize); + if (ret) + return ret; + + memzero_explicit(digest, digestsize); + return 0; +} + +static int lrng_kcapi_drng_generate_helper(void *drng, u8 *outbuf, + u32 outbuflen) +{ + struct lrng_drng_info *lrng_drng_info = (struct lrng_drng_info *)drng; + struct crypto_rng *kcapi_rng = lrng_drng_info->kcapi_rng; + int ret = crypto_rng_get_bytes(kcapi_rng, outbuf, outbuflen); + + if (ret < 0) + return ret; + + return outbuflen; +} + +static void *lrng_kcapi_drng_alloc(u32 sec_strength) +{ + struct lrng_drng_info *lrng_drng_info; + struct crypto_rng *kcapi_rng; + int seedsize; + void *ret = ERR_PTR(-ENOMEM); + + if (!drng_name) { + pr_err("DRNG name missing\n"); + return ERR_PTR(-EINVAL); + } + + if (!memcmp(drng_name, "drbg", 4) || + !memcmp(drng_name, "stdrng", 6) || + !memcmp(drng_name, "jitterentropy_rng", 17)) { + pr_err("Refusing to load the requested random number generator\n"); + return ERR_PTR(-EINVAL); + } + + lrng_drng_info = kmalloc(sizeof(*lrng_drng_info), GFP_KERNEL); + if (!lrng_drng_info) + return ERR_PTR(-ENOMEM); + + kcapi_rng = crypto_alloc_rng(drng_name, 0, 0); + if (IS_ERR(kcapi_rng)) { + pr_err("DRNG %s cannot be allocated\n", drng_name); + ret = ERR_CAST(kcapi_rng); + goto free; + } + lrng_drng_info->kcapi_rng = kcapi_rng; + + seedsize = crypto_rng_seedsize(kcapi_rng); + + if (sec_strength > seedsize) + pr_info("Seedsize DRNG (%u bits) lower than security strength of LRNG noise source (%u bits)\n", + crypto_rng_seedsize(kcapi_rng) * 8, sec_strength * 8); + + if (seedsize) { + void *lrng_hash; + + if (!seed_hash) { + switch (seedsize) { + case 32: + seed_hash = "sha256"; + break; + case 48: + seed_hash = "sha384"; + break; + case 64: + seed_hash = "sha512"; + break; + default: + pr_err("Seed size %d cannot be processed\n", + seedsize); + goto dealloc; + } + } + + lrng_hash = lrng_kcapi_hash_alloc(seed_hash); + if (IS_ERR(lrng_hash)) { + ret = ERR_CAST(lrng_hash); + goto dealloc; + } + + if (seedsize != lrng_kcapi_hash_digestsize(lrng_hash)) { + pr_err("Seed hash output size not equal to DRNG seed size\n"); + lrng_kcapi_hash_dealloc(lrng_hash); + ret = ERR_PTR(-EINVAL); + goto dealloc; + } + + lrng_drng_info->lrng_hash = lrng_hash; + + pr_info("Seed hash %s allocated\n", seed_hash); + } else { + lrng_drng_info->lrng_hash = NULL; + } + + pr_info("Kernel crypto API DRNG %s allocated\n", drng_name); + + return lrng_drng_info; + +dealloc: + crypto_free_rng(kcapi_rng); +free: + kfree(lrng_drng_info); + return ret; +} + +static void lrng_kcapi_drng_dealloc(void *drng) +{ + struct lrng_drng_info *lrng_drng_info = (struct lrng_drng_info *)drng; + struct crypto_rng *kcapi_rng = lrng_drng_info->kcapi_rng; + + crypto_free_rng(kcapi_rng); + if (lrng_drng_info->lrng_hash) + lrng_kcapi_hash_dealloc(lrng_drng_info->lrng_hash); + kfree(lrng_drng_info); + pr_info("DRNG %s deallocated\n", drng_name); +} + +static const char *lrng_kcapi_drng_name(void) +{ + return drng_name; +} + +static const char *lrng_kcapi_pool_hash(void) +{ + return pool_hash; +} + +static const struct lrng_crypto_cb lrng_kcapi_crypto_cb = { + .lrng_drng_name = lrng_kcapi_drng_name, + .lrng_hash_name = lrng_kcapi_pool_hash, + .lrng_drng_alloc = lrng_kcapi_drng_alloc, + .lrng_drng_dealloc = lrng_kcapi_drng_dealloc, + .lrng_drng_seed_helper = lrng_kcapi_drng_seed_helper, + .lrng_drng_generate_helper = lrng_kcapi_drng_generate_helper, + .lrng_hash_alloc = lrng_kcapi_drng_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, + .lrng_hash_desc_zero = lrng_kcapi_hash_zero, +}; + +static int __init lrng_kcapi_init(void) +{ + return lrng_set_drng_cb(&lrng_kcapi_crypto_cb); +} +static void __exit lrng_kcapi_exit(void) +{ + lrng_set_drng_cb(NULL); +} + +late_initcall(lrng_kcapi_init); +module_exit(lrng_kcapi_exit); +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Stephan Mueller "); +MODULE_DESCRIPTION("Linux Random Number Generator - kernel crypto API DRNG backend");