From mboxrd@z Thu Jan 1 00:00:00 1970 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 0F9A4C43464 for ; Fri, 18 Sep 2020 10:12:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF9F9208C3 for ; Fri, 18 Sep 2020 10:12:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="NQeltcJf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726722AbgIRKMa (ORCPT ); Fri, 18 Sep 2020 06:12:30 -0400 Received: from mo4-p04-ob.smtp.rzone.de ([85.215.255.120]:31486 "EHLO mo4-p04-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726514AbgIRKMV (ORCPT ); Fri, 18 Sep 2020 06:12:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1600423937; 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=izF07z6Mxe3cc4U56dnUzWp3gqFzbBS1w8yZJx36BTU=; b=NQeltcJfiGaeO3mvjBVsYq48AvXE79+CAcN7fUc4G5YHUNhtkV+CWoRQnjeSrjp+rh 2rsJwv6sQ9bxc/QBQv2oRLLKmUfz/fHoBoD0tqsUlO7qReFfUkBehNYoMG3YyeyIpNFi Rjm6zzNpiTHfO1t28/3R1rUD+Z/1Ksg4taOOX9E7xWwLNSiwglaAW9aoDaMWJm+aVWxI u3kHpHAumV1GxBdm989Th3RvVvN7AoVtqz5S+kwrFEfcOtoQnxAz+9JIPyWLueSiS6nU +1RAKeUXFvjeMwY1kncaPE5ouPoslMuHRudQkTzzbgNYLltUpY8a16D2O7yKj+V2ETf8 0LRQ== 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 002e9aw8IA0B2T7 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Sep 2020 12:00:11 +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 08/13] LRNG - add kernel crypto API PRNG extension Date: Fri, 18 Sep 2020 11:51:03 +0200 Message-ID: <7176488.EvYhyI6sBW@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 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" 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: "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 Drahtm=FCller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller =2D-- drivers/char/lrng/Kconfig | 13 ++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_kcapi.c | 228 +++++++++++++++++++++++++++++++++ 3 files changed, 242 insertions(+) create mode 100644 drivers/char/lrng/lrng_kcapi.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index a3c4cd153f35..af487b3391e0 100644 =2D-- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -91,6 +91,19 @@ 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 =20 endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 6ebd252db12f..97d2b13d3227 100644 =2D-- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_SYSCTL) +=3D lrng_proc.o obj-$(CONFIG_LRNG_DRNG_SWITCH) +=3D lrng_switch.o obj-$(CONFIG_LRNG_KCAPI_HASH) +=3D lrng_kcapi_hash.o obj-$(CONFIG_LRNG_DRBG) +=3D lrng_drbg.o +obj-$(CONFIG_LRNG_KCAPI) +=3D 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..197dc84552e9 =2D-- /dev/null +++ b/drivers/char/lrng/lrng_kcapi.c @@ -0,0 +1,228 @@ +// 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 - 2020, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +#include "lrng_kcapi_hash.h" + +static char *drng_name =3D NULL; +module_param(drng_name, charp, 0444); +MODULE_PARM_DESC(drng_name, "Kernel crypto API name of DRNG"); + +static char *pool_hash =3D "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 ent= ropy pool"); + +static char *seed_hash =3D 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 D= RNG 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 =3D (struct lrng_drng_info *)drng; + struct crypto_rng *kcapi_rng =3D lrng_drng_info->kcapi_rng; + void *hash =3D lrng_drng_info->lrng_hash; + u32 digestsize =3D 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 =3D lrng_kcapi_hash_init(shash, hash) ?: + lrng_kcapi_hash_update(shash, inbuf, inbuflen) ?: + lrng_kcapi_hash_final(shash, digest); + if (ret) + return ret; + + ret =3D 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 =3D (struct lrng_drng_info *)drng; + struct crypto_rng *kcapi_rng =3D lrng_drng_info->kcapi_rng; + int ret =3D 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 =3D ERR_PTR(-ENOMEM); + + if (!drng_name) { + pr_err("DRNG name missing\n"); + return ERR_PTR(-EINVAL); + } + + if (!memcmp(drng_name, "drbg", 4)) { + pr_err("SP800-90A DRBG cannot be allocated using lrng_kcapi backend, use= lrng_drbg backend instead\n"); + return ERR_PTR(-EINVAL); + } + + if (!memcmp(drng_name, "stdrng", 6)) { + pr_err("stdrng cannot be allocated using lrng_kcapi backend, it is too u= nspecific and potentially may allocate the DRBG\n"); + return ERR_PTR(-EINVAL); + } + + lrng_drng_info =3D kmalloc(sizeof(*lrng_drng_info), GFP_KERNEL); + if (!lrng_drng_info) + return ERR_PTR(-ENOMEM); + + kcapi_rng =3D crypto_alloc_rng(drng_name, 0, 0); + if (IS_ERR(kcapi_rng)) { + pr_err("DRNG %s cannot be allocated\n", drng_name); + ret =3D ERR_CAST(kcapi_rng); + goto free; + } + lrng_drng_info->kcapi_rng =3D kcapi_rng; + + seedsize =3D crypto_rng_seedsize(kcapi_rng); + + if (sec_strength > seedsize) + pr_info("Seedsize DRNG (%u bits) lower than security strength of LRNG no= ise 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 =3D "sha256"; + break; + case 48: + seed_hash =3D "sha384"; + break; + case 64: + seed_hash =3D "sha512"; + break; + default: + pr_err("Seed size %d cannot be processed\n", + seedsize); + goto dealloc; + } + } + + lrng_hash =3D lrng_kcapi_hash_alloc(seed_hash); + if (IS_ERR(lrng_hash)) { + ret =3D ERR_CAST(lrng_hash); + goto dealloc; + } + + if (seedsize !=3D 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 =3D ERR_PTR(-EINVAL); + goto dealloc; + } + + lrng_drng_info->lrng_hash =3D lrng_hash; + + pr_info("Seed hash %s allocated\n", seed_hash); + } else { + lrng_drng_info->lrng_hash =3D 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 =3D (struct lrng_drng_info *)drng; + struct crypto_rng *kcapi_rng =3D 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 =3D { + .lrng_drng_name =3D lrng_kcapi_drng_name, + .lrng_hash_name =3D lrng_kcapi_pool_hash, + .lrng_drng_alloc =3D lrng_kcapi_drng_alloc, + .lrng_drng_dealloc =3D lrng_kcapi_drng_dealloc, + .lrng_drng_seed_helper =3D lrng_kcapi_drng_seed_helper, + .lrng_drng_generate_helper =3D lrng_kcapi_drng_generate_helper, + .lrng_hash_alloc =3D lrng_kcapi_drng_hash_alloc, + .lrng_hash_dealloc =3D lrng_kcapi_hash_dealloc, + .lrng_hash_digestsize =3D lrng_kcapi_hash_digestsize, + .lrng_hash_init =3D lrng_kcapi_hash_init, + .lrng_hash_update =3D lrng_kcapi_hash_update, + .lrng_hash_final =3D lrng_kcapi_hash_final, +}; + +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"); =2D-=20 2.26.2