From patchwork Sun Jan 24 14:01:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 12042421 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=-15.8 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 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 9F1DCC43332 for ; Sun, 24 Jan 2021 14:09:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E2E722CAF for ; Sun, 24 Jan 2021 14:09:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726126AbhAXOJt (ORCPT ); Sun, 24 Jan 2021 09:09:49 -0500 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.83]:22338 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725968AbhAXOJo (ORCPT ); Sun, 24 Jan 2021 09:09:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1611497207; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:From: Subject:Sender; bh=zJqo8nf/jHkzH9Q6/0XyhbU/V8rrLtwyZJii/ef29vM=; b=f2kW1Jhbt9M63652XWycanaxWYdh3wcDidKQUFJSNi1UyHbsPjeMiSNjbAfnowzHha +fhaodTtBcVNeUZHNfRJTgSbQ7N8kbbz0jSDACP+NHerMxK+85jg+HRZ3S1ik5oSD7ak mZXJZccaExfz/VqQn0KA4rJ9nj6PpZg8XCkmAd/qvZ62kKvOC+meGwIv+bAlCqhMLD/I UjI4MtvjPB79+onr3Ix6/zkyqR2clmafCd90y4q81Ed/K4W76ImWob6ZXuiJ6Xr2cPvD aaoZrMPrfOjOZv0qfKoWgv0pOL7Bz8Ub31AGPOwtbnfjTXkfr2JqqmbF59l5PAdVTzLY CqyQ== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPZI/ScIzb9" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 47.12.1 DYNA|AUTH) with ESMTPSA id Z04c46x0OE6leib (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Sun, 24 Jan 2021 15:06:47 +0100 (CET) From: Stephan =?iso-8859-1?q?M=FCller?= To: herbert@gondor.apana.org.au Cc: ebiggers@kernel.org, Jarkko Sakkinen , mathew.j.martineau@linux.intel.com, dhowells@redhat.com, linux-crypto@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, simo@redhat.com Subject: [PATCH v2 1/7] crypto: Add key derivation self-test support code Date: Sun, 24 Jan 2021 15:01:43 +0100 Message-ID: <12692814.uLZWGnKmhe@positron.chronox.de> In-Reply-To: <1772794.tdWV9SEqCh@positron.chronox.de> References: <1772794.tdWV9SEqCh@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org As a preparation to add the key derivation implementations, the self-test data structure definition and the common test code is made available. The test framework follows the testing applied by the NIST CAVP test approach. The structure of the test code follows the implementations found in crypto/testmgr.c|h. In case the KDF implementations will be made available via a kernel crypto API templates, the test code is intended to be merged into testmgr.c|h. Signed-off-by: Stephan Mueller --- include/crypto/internal/kdf_selftest.h | 71 ++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 include/crypto/internal/kdf_selftest.h diff --git a/include/crypto/internal/kdf_selftest.h b/include/crypto/internal/kdf_selftest.h new file mode 100644 index 000000000000..373fcb11f2fa --- /dev/null +++ b/include/crypto/internal/kdf_selftest.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2020, Stephan Mueller + */ + +#ifndef _CRYPTO_KDF_SELFTEST_H +#define _CRYPTO_KDF_SELFTEST_H + +#include +#include + +struct kdf_testvec { + unsigned char *key; + size_t keylen; + unsigned char *ikm; + size_t ikmlen; + struct kvec info; + unsigned char *expected; + size_t expectedlen; +}; + +static inline int +kdf_test(const struct kdf_testvec *test, const char *name, + int (*crypto_kdf_setkey)(struct crypto_shash *kmd, + const u8 *key, size_t keylen, + const u8 *ikm, size_t ikmlen), + int (*crypto_kdf_generate)(struct crypto_shash *kmd, + const struct kvec *info, + unsigned int info_nvec, + u8 *dst, unsigned int dlen)) +{ + struct crypto_shash *kmd; + int ret; + u8 *buf = kzalloc(test->expectedlen, GFP_KERNEL); + + if (!buf) + return -ENOMEM; + + kmd = crypto_alloc_shash(name, 0, 0); + if (IS_ERR(kmd)) { + pr_err("alg: kdf: could not allocate hash handle for %s\n", + name); + kfree(buf); + return -ENOMEM; + } + + ret = crypto_kdf_setkey(kmd, test->key, test->keylen, + test->ikm, test->ikmlen); + if (ret) { + pr_err("alg: kdf: could not set key derivation key\n"); + goto err; + } + + ret = crypto_kdf_generate(kmd, &test->info, 1, buf, test->expectedlen); + if (ret) { + pr_err("alg: kdf: could not obtain key data\n"); + goto err; + } + + ret = memcmp(test->expected, buf, test->expectedlen); + if (ret) + ret = -EINVAL; + +err: + crypto_free_shash(kmd); + kfree(buf); + return ret; +} + +#endif /* _CRYPTO_KDF_SELFTEST_H */ From patchwork Sun Jan 24 14:02:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 12042423 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=-15.8 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 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 DC2F2C43381 for ; Sun, 24 Jan 2021 14:10:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B73D022CB1 for ; Sun, 24 Jan 2021 14:10:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726137AbhAXOJu (ORCPT ); Sun, 24 Jan 2021 09:09:50 -0500 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.84]:30599 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725779AbhAXOJp (ORCPT ); Sun, 24 Jan 2021 09:09:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1611497207; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:From: Subject:Sender; bh=k1tLiObOjMEBJYxYaAtS89sk3jS8kmjetw4TumO6KRc=; b=CO1RVKl2h0mcXyyHXPwXd5VbmC2RsEj3GV9jRefhb1oc01hltof62V6BhcOZ+MnpfI zUlSEmlBe/6Nz/2+4h4AhNt3HbvGfdcSfczV7gONbrkwCbE8qOB9sZ8w3bqznwn92b1P PG3b16PjaxSGMldJdV5QaF0lxTsfuifKScfJk1ZT0zelSY163+B0R52rNh2sKT6deJvA 3qw+danMLlo/DJIQjVYJKSM1Kts5xcI/zYuqFNpE4uHaK4SyGDdo6arq/L1Q3M6SlKEC jw8pXE6p4Q25gb7ISJgZ3W3ahIqkGNaAOA87BsP13saNQw3AhYcJL6vqLzHaTOq9HEAK w1Yw== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPZI/ScIzb9" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 47.12.1 DYNA|AUTH) with ESMTPSA id Z04c46x0OE6keia (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Sun, 24 Jan 2021 15:06:46 +0100 (CET) From: Stephan =?iso-8859-1?q?M=FCller?= To: herbert@gondor.apana.org.au Cc: ebiggers@kernel.org, Jarkko Sakkinen , mathew.j.martineau@linux.intel.com, dhowells@redhat.com, linux-crypto@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, simo@redhat.com Subject: [PATCH v2 2/7] crypto: add SP800-108 counter key derivation function Date: Sun, 24 Jan 2021 15:02:07 +0100 Message-ID: <3091021.aeNJFYEL58@positron.chronox.de> In-Reply-To: <1772794.tdWV9SEqCh@positron.chronox.de> References: <1772794.tdWV9SEqCh@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org SP800-108 defines three KDFs - this patch provides the counter KDF implementation. The KDF is implemented as a service function where the caller has to maintain the hash / HMAC state. Apart from this hash/HMAC state, no additional state is required to be maintained by either the caller or the KDF implementation. The key for the KDF is set with the crypto_kdf108_setkey function which is intended to be invoked before the caller requests a key derivation operation via crypto_kdf108_ctr_generate. SP800-108 allows the use of either a HMAC or a hash as crypto primitive for the KDF. When a HMAC primtive is intended to be used, crypto_kdf108_setkey must be used to set the HMAC key. Otherwise, for a hash crypto primitve crypto_kdf108_ctr_generate can be used immediately after allocating the hash handle. Signed-off-by: Stephan Mueller --- crypto/Kconfig | 7 ++ crypto/Makefile | 5 ++ crypto/kdf_sp800108.c | 149 ++++++++++++++++++++++++++++++++++ include/crypto/kdf_sp800108.h | 61 ++++++++++++++ 4 files changed, 222 insertions(+) create mode 100644 crypto/kdf_sp800108.c create mode 100644 include/crypto/kdf_sp800108.h diff --git a/crypto/Kconfig b/crypto/Kconfig index a367fcfeb5d4..9f375c2350f5 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -1862,6 +1862,13 @@ config CRYPTO_JITTERENTROPY random numbers. This Jitterentropy RNG registers with the kernel crypto API and can be used by any caller. +config CRYPTO_KDF800108_CTR + tristate "Counter KDF (SP800-108)" + select CRYPTO_HASH + help + Enable the key derivation function in counter mode compliant to + SP800-108. + config CRYPTO_USER_API tristate diff --git a/crypto/Makefile b/crypto/Makefile index b279483fba50..46845a70850d 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -197,3 +197,8 @@ obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys/ obj-$(CONFIG_CRYPTO_HASH_INFO) += hash_info.o crypto_simd-y := simd.o obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o + +# +# Key derivation function +# +obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o diff --git a/crypto/kdf_sp800108.c b/crypto/kdf_sp800108.c new file mode 100644 index 000000000000..84b45e0cadf5 --- /dev/null +++ b/crypto/kdf_sp800108.c @@ -0,0 +1,149 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * SP800-108 Key-derivation function + * + * Copyright (C) 2020, Stephan Mueller + */ + +#include +#include +#include + +/* + * SP800-108 CTR KDF implementation + */ +int crypto_kdf108_ctr_generate(struct crypto_shash *kmd, + const struct kvec *info, unsigned int info_nvec, + u8 *dst, unsigned int dlen) +{ + SHASH_DESC_ON_STACK(desc, kmd); + __be32 counter = cpu_to_be32(1); + const unsigned int h = crypto_shash_digestsize(kmd), dlen_orig = dlen; + unsigned int i; + int err = 0; + u8 *dst_orig = dst; + + desc->tfm = kmd; + + while (dlen) { + err = crypto_shash_init(desc); + if (err) + goto out; + + err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32)); + if (err) + goto out; + + for (i = 0; i < info_nvec; i++) { + err = crypto_shash_update(desc, info[i].iov_base, + info[i].iov_len); + if (err) + goto out; + } + + if (dlen < h) { + u8 tmpbuffer[HASH_MAX_DIGESTSIZE]; + + err = crypto_shash_final(desc, tmpbuffer); + if (err) + goto out; + memcpy(dst, tmpbuffer, dlen); + memzero_explicit(tmpbuffer, h); + goto out; + } + + err = crypto_shash_final(desc, dst); + if (err) + goto out; + + dlen -= h; + dst += h; + counter = cpu_to_be32(be32_to_cpu(counter) + 1); + } + +out: + if (err) + memzero_explicit(dst_orig, dlen_orig); + shash_desc_zero(desc); + return err; +} +EXPORT_SYMBOL(crypto_kdf108_ctr_generate); + +/* + * The seeding of the KDF + */ +int crypto_kdf108_setkey(struct crypto_shash *kmd, + const u8 *key, size_t keylen, + const u8 *ikm, size_t ikmlen) +{ + unsigned int ds = crypto_shash_digestsize(kmd); + + /* SP800-108 does not support IKM */ + if (ikm || ikmlen) + return -EINVAL; + + /* Check according to SP800-108 section 7.2 */ + if (ds > keylen) + return -EINVAL; + + /* + * We require that we operate on a MAC -- if we do not operate on a + * MAC, this function returns an error. + */ + return crypto_shash_setkey(kmd, key, keylen); +} +EXPORT_SYMBOL(crypto_kdf108_setkey); + +/* + * Test vector obtained from + * http://csrc.nist.gov/groups/STM/cavp/documents/KBKDF800-108/CounterMode.zip + */ +static const struct kdf_testvec kdf_ctr_hmac_sha256_tv_template[] = { + { + .key = "\xdd\x1d\x91\xb7\xd9\x0b\x2b\xd3" + "\x13\x85\x33\xce\x92\xb2\x72\xfb" + "\xf8\xa3\x69\x31\x6a\xef\xe2\x42" + "\xe6\x59\xcc\x0a\xe2\x38\xaf\xe0", + .keylen = 32, + .ikm = NULL, + .ikmlen = 0, + .info = { + .iov_base = "\x01\x32\x2b\x96\xb3\x0a\xcd\x19" + "\x79\x79\x44\x4e\x46\x8e\x1c\x5c" + "\x68\x59\xbf\x1b\x1c\xf9\x51\xb7" + "\xe7\x25\x30\x3e\x23\x7e\x46\xb8" + "\x64\xa1\x45\xfa\xb2\x5e\x51\x7b" + "\x08\xf8\x68\x3d\x03\x15\xbb\x29" + "\x11\xd8\x0a\x0e\x8a\xba\x17\xf3" + "\xb4\x13\xfa\xac", + .iov_len = 60 + }, + .expected = "\x10\x62\x13\x42\xbf\xb0\xfd\x40" + "\x04\x6c\x0e\x29\xf2\xcf\xdb\xf0", + .expectedlen = 16 + } +}; + +static int __init crypto_kdf108_init(void) +{ + int ret = kdf_test(&kdf_ctr_hmac_sha256_tv_template[0], "hmac(sha256)", + crypto_kdf108_setkey, crypto_kdf108_ctr_generate); + + if (ret) + pr_warn("alg: self-tests for CTR-KDF (hmac(sha256)) failed (rc=%d)\n", + ret); + else + pr_info("alg: self-tests for CTR-KDF (hmac(sha256)) passed\n"); + + return ret; +} + +static void __exit crypto_kdf108_exit(void) { } + +module_init(crypto_kdf108_init); +module_exit(crypto_kdf108_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Stephan Mueller "); +MODULE_DESCRIPTION("Key Derivation Function conformant to SP800-108"); diff --git a/include/crypto/kdf_sp800108.h b/include/crypto/kdf_sp800108.h new file mode 100644 index 000000000000..fdc360bd9cd6 --- /dev/null +++ b/include/crypto/kdf_sp800108.h @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2020, Stephan Mueller + */ + +#ifndef _CRYPTO_KDF108_H +#define _CRYPTO_KDF108_H + +#include +#include + +/** + * Counter KDF generate operation according to SP800-108 section 5.1 + * as well as SP800-56A section 5.8.1 (Single-step KDF). + * + * @kmd Keyed message digest whose key was set with crypto_kdf108_setkey or + * unkeyed message digest + * @info optional context and application specific information - this may be + * NULL + * @info_vec number of optional context/application specific information entries + * @dst destination buffer that the caller already allocated + * @dlen length of the destination buffer - the KDF derives that amount of + * bytes. + * + * To comply with SP800-108, the caller must provide Label || 0x00 || Context + * in the info parameter. + * + * @return 0 on success, < 0 on error + */ +int crypto_kdf108_ctr_generate(struct crypto_shash *kmd, + const struct kvec *info, unsigned int info_nvec, + u8 *dst, unsigned int dlen); + +/** + * Counter KDF setkey operation + * + * @kmd Keyed message digest allocated by the caller. The key should not have + * been set. + * @key Seed key to be used to initialize the keyed message digest context. + * @keylen This length of the key buffer. + * @ikm The SP800-108 KDF does not support IKM - this parameter must be NULL + * @ikmlen This parameter must be 0. + * + * According to SP800-108 section 7.2, the seed key must be at least as large as + * the message digest size of the used keyed message digest. This limitation + * is enforced by the implementation. + * + * SP800-108 allows the use of either a HMAC or a hash primitive. When + * the caller intends to use a hash primitive, the call to + * crypto_kdf108_setkey is not required and the key derivation operation can + * immediately performed using crypto_kdf108_ctr_generate after allocating + * a handle. + * + * @return 0 on success, < 0 on error + */ +int crypto_kdf108_setkey(struct crypto_shash *kmd, + const u8 *key, size_t keylen, + const u8 *ikm, size_t ikmlen); + +#endif /* _CRYPTO_KDF108_H */ From patchwork Sun Jan 24 14:03:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 12042425 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=-15.8 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 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 CE95BC433E9 for ; Sun, 24 Jan 2021 14:10:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A362722D0A for ; Sun, 24 Jan 2021 14:10:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726159AbhAXOJu (ORCPT ); Sun, 24 Jan 2021 09:09:50 -0500 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.80]:27581 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725940AbhAXOJn (ORCPT ); Sun, 24 Jan 2021 09:09:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1611497206; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:From: Subject:Sender; bh=jTliJRtWd9fL4foVJuIH7ysCahklwqG1wM+fR6LKSqE=; b=oVuEcdDAXipzQ8zj6EObVqA7stKr/vKm0Ez7Goc3tqZXPOS+hAUPKPSj10Uj+kFszq Ar5QJkZQHEpE0zLcrWJ1bjnQ1CxMWcLBJOZwB7/GTrBr5mJeL9FuE96mwJ4NLlZAjAgX qc7322gCNvF3sqYF+ExHRuJmlWfpu404yRE5IgVt3JHjnO2UEjkTc/wpwKx27R41aKvg Z0i6OH+EYacMXUf/2isWNcIHC6kHzunyWzZF9Ti022AkqY2mILEST5OVOdrC5uz4qVwm UjWD7agehk1SJUfmtO/KzeXbgzSVEkIZeARlVBHHFvt2lWMXHdaNV79l1R6MSESIl2bt hdIA== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPZI/ScIzb9" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 47.12.1 DYNA|AUTH) with ESMTPSA id Z04c46x0OE6jeiZ (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Sun, 24 Jan 2021 15:06:45 +0100 (CET) From: Stephan =?iso-8859-1?q?M=FCller?= To: herbert@gondor.apana.org.au Cc: ebiggers@kernel.org, Jarkko Sakkinen , mathew.j.martineau@linux.intel.com, dhowells@redhat.com, linux-crypto@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, simo@redhat.com Subject: [PATCH v2 3/7] crypto: add RFC5869 HKDF Date: Sun, 24 Jan 2021 15:03:28 +0100 Message-ID: <7864824.T7Z3S40VBb@positron.chronox.de> In-Reply-To: <1772794.tdWV9SEqCh@positron.chronox.de> References: <1772794.tdWV9SEqCh@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org RFC5869 specifies an extract and expand two-step key derivation function. The HKDF implementation is provided as a service function that operates on a caller-provided HMAC handle. The caller has to allocate the HMAC shash handle and then can invoke the HKDF service functions. The HKDF implementation ensures that the entire state is kept with the HMAC shash handle which implies that no additional state is required to be maintained by the HKDF implementation. The extract function is invoked via the crypto_hkdf_extract call. RFC5869 allows two optional parameters to be provided to the extract operation: the salt and input key material (IKM). Both are to be provided with the seed parameter where the salt is the first entry of the seed parameter and all subsequent entries are handled as IKM. If the caller intends to invoke the HKDF without salt, it has to provide a NULL/0 entry as first entry in seed. The expand function is invoked via crypto_hkdf_expand and can be invoked multiple times. This function allows the caller to provide a context for the key derivation operation. As specified in RFC5869, it is optional. In case such context is not provided, the caller must provide NULL / 0 for the info / info_nvec parameters. Signed-off-by: Stephan Mueller --- crypto/Kconfig | 7 ++ crypto/Makefile | 1 + crypto/hkdf.c | 199 ++++++++++++++++++++++++++++++++++++++++++ include/crypto/hkdf.h | 48 ++++++++++ 4 files changed, 255 insertions(+) create mode 100644 crypto/hkdf.c create mode 100644 include/crypto/hkdf.h diff --git a/crypto/Kconfig b/crypto/Kconfig index 9f375c2350f5..661287d7283b 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -1862,6 +1862,13 @@ config CRYPTO_JITTERENTROPY random numbers. This Jitterentropy RNG registers with the kernel crypto API and can be used by any caller. +config CRYPTO_HKDF + tristate "Extract and Expand HKDF (RFC 5869)" + select CRYPTO_HASH + help + Enable the extract and expand key derivation function compliant + to RFC 5869. + config CRYPTO_KDF800108_CTR tristate "Counter KDF (SP800-108)" select CRYPTO_HASH diff --git a/crypto/Makefile b/crypto/Makefile index 46845a70850d..55a4d8c31a45 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -201,4 +201,5 @@ obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o # # Key derivation function # +obj-$(CONFIG_CRYPTO_HKDF) += hkdf.o obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o diff --git a/crypto/hkdf.c b/crypto/hkdf.c new file mode 100644 index 000000000000..8e80eca202e7 --- /dev/null +++ b/crypto/hkdf.c @@ -0,0 +1,199 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * HMAC-based Extract-and-Expand Key Derivation Function (conformant to RFC5869) + * + * Copyright (C) 2020, Stephan Mueller + */ + +#include +#include +#include + +/* + * HKDF expand phase + */ +int crypto_hkdf_expand(struct crypto_shash *kmd, + const struct kvec *info, unsigned int info_nvec, + u8 *dst, unsigned int dlen) +{ + SHASH_DESC_ON_STACK(desc, kmd); + const unsigned int h = crypto_shash_digestsize(kmd), dlen_orig = dlen; + unsigned int i; + int err = 0; + u8 *dst_orig = dst; + const u8 *prev = NULL; + u8 ctr = 0x01; + + if (dlen > h * 255) + return -EINVAL; + + desc->tfm = kmd; + + /* T(1) and following */ + while (dlen) { + err = crypto_shash_init(desc); + if (err) + goto out; + + if (prev) { + err = crypto_shash_update(desc, prev, h); + if (err) + goto out; + } + + for (i = 0; i < info_nvec; i++) { + err = crypto_shash_update(desc, info[i].iov_base, + info[i].iov_len); + if (err) + goto out; + } + + if (dlen < h) { + u8 tmpbuffer[HASH_MAX_DIGESTSIZE]; + + err = crypto_shash_finup(desc, &ctr, 1, tmpbuffer); + if (err) + goto out; + memcpy(dst, tmpbuffer, dlen); + memzero_explicit(tmpbuffer, h); + goto out; + } + + err = crypto_shash_finup(desc, &ctr, 1, dst); + if (err) + goto out; + + prev = dst; + dst += h; + dlen -= h; + ctr++; + } + +out: + if (err) + memzero_explicit(dst_orig, dlen_orig); + shash_desc_zero(desc); + return err; +} +EXPORT_SYMBOL(crypto_hkdf_expand); + +/* + * HKDF extract phase. + */ +int crypto_hkdf_extract(struct crypto_shash *kmd, + const u8 *salt, size_t saltlen, + const u8 *ikm, size_t ikmlen) +{ + SHASH_DESC_ON_STACK(desc, kmd); + unsigned int h = crypto_shash_digestsize(kmd); + int err; + static const u8 null_salt[HASH_MAX_DIGESTSIZE] = { 0 }; + u8 prk[HASH_MAX_DIGESTSIZE]; + + desc->tfm = kmd; + + if (salt && saltlen) { + /* Set the salt as HMAC key */ + err = crypto_shash_setkey(kmd, salt, saltlen); + } else { + /* Set the default HMAC key as none was provided */ + err = crypto_shash_setkey(kmd, null_salt, h); + } + + if (err) + return err; + + /* Extract the PRK */ + err = crypto_shash_init(desc); + if (err) + goto err; + + err = crypto_shash_finup(desc, ikm, ikmlen, prk); + if (err) + goto err; + + /* Set the PRK for the expand phase */ + err = crypto_shash_setkey(kmd, prk, h); + +err: + shash_desc_zero(desc); + memzero_explicit(prk, h); + return err; +} +EXPORT_SYMBOL(crypto_hkdf_extract); + +/* Test vectors from RFC 5869 appendix A */ +static const struct kdf_testvec hkdf_hmac_sha256_tv_template[] = { + { + /* salt */ + .key = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c", + .keylen = 13, + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikmlen = 22, + .info = { + .iov_base = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7" + "\xf8\xf9", + .iov_len = 10 + }, + .expected = "\x3c\xb2\x5f\x25\xfa\xac\xd5\x7a" + "\x90\x43\x4f\x64\xd0\x36\x2f\x2a" + "\x2d\x2d\x0a\x90\xcf\x1a\x5a\x4c" + "\x5d\xb0\x2d\x56\xec\xc4\xc5\xbf" + "\x34\x00\x72\x08\xd5\xb8\x87\x18" + "\x58\x65", + .expectedlen = 42 + }, { + /* salt */ + .key = NULL, + .keylen = 0, + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikmlen = 22, + .info = { + .iov_base = NULL, + .iov_len = 0 + }, + .expected = "\x8d\xa4\xe7\x75\xa5\x63\xc1\x8f" + "\x71\x5f\x80\x2a\x06\x3c\x5a\x31" + "\xb8\xa1\x1f\x5c\x5e\xe1\x87\x9e" + "\xc3\x45\x4e\x5f\x3c\x73\x8d\x2d" + "\x9d\x20\x13\x95\xfa\xa4\xb6\x1a" + "\x96\xc8", + .expectedlen = 42 + } +}; + +static int __init crypto_hkdf_init(void) +{ + unsigned int i; + int ret; + + for (i = 0; i < ARRAY_SIZE(hkdf_hmac_sha256_tv_template); i++) { + ret = kdf_test(&hkdf_hmac_sha256_tv_template[i], "hmac(sha256)", + crypto_hkdf_extract, crypto_hkdf_expand); + + if (ret) { + pr_warn("alg: self-tests for HKDF (hmac(sha256)) failed (rc=%d)\n", + ret); + return ret; + } + } + + pr_info("alg: self-tests for HKDF (hmac(sha256)) passed\n"); + + return 0; +} + +static void __exit crypto_hkdf_exit(void) { } + +module_init(crypto_hkdf_init); +module_exit(crypto_hkdf_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Stephan Mueller "); +MODULE_DESCRIPTION("HKDF HMAC-based Extract-and-Expand Key Derivation Function (conformant to RFC5869)"); diff --git a/include/crypto/hkdf.h b/include/crypto/hkdf.h new file mode 100644 index 000000000000..c6989f786860 --- /dev/null +++ b/include/crypto/hkdf.h @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2020, Stephan Mueller + */ + +#ifndef _CRYPTO_HKDF_H +#define _CRYPTO_HKDF_H + +#include +#include + +/** + * RFC 5869 HKDF expand operation + * + * @kmd Keyed message digest whose key was set with crypto_hkdf_extract + * @info optional context and application specific information - this may be + * NULL + * @info_vec number of optional context/application specific information entries + * @dst destination buffer that the caller already allocated + * @dlen length of the destination buffer - the KDF derives that amount of + * bytes. + * + * @return 0 on success, < 0 on error + */ +int crypto_hkdf_expand(struct crypto_shash *kmd, + const struct kvec *info, unsigned int info_nvec, + u8 *dst, unsigned int dlen); + +/** + * RFC 5869 HKDF extract operation + * + * @kmd Keyed message digest allocated by the caller. The key should not have + * been set. + * @salt The salt used for the KDF. It is permissible to provide NULL as salt + * which implies that the default salt is used. + * @saltlen Length of the salt buffer. + * @ikm The input key material (IKM). It is permissible to provide NULL as IKM. + * @ikmlen Length of the IKM buffer + * @seed_nvec number of seed entries (must be at least 1) + * + * @return 0 on success, < 0 on error + */ +int crypto_hkdf_extract(struct crypto_shash *kmd, + const u8 *salt, size_t saltlen, + const u8 *ikm, size_t ikmlen); + +#endif /* _CRYPTO_HKDF_H */ From patchwork Sun Jan 24 14:03:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 12042427 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=-15.8 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 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 CA2AAC43381 for ; Sun, 24 Jan 2021 14:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5B7A22CF6 for ; Sun, 24 Jan 2021 14:10:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725899AbhAXOK0 (ORCPT ); Sun, 24 Jan 2021 09:10:26 -0500 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.83]:21964 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725838AbhAXOJi (ORCPT ); Sun, 24 Jan 2021 09:09:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1611497205; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:From: Subject:Sender; bh=Fyc0rzVotIOUtUm7++3lcJ+qWnVjlyTyBLMUYptLgRk=; b=R5qniK8GEUCy+q1km8pHfRA3ZfmLr+g/RtQOxgxGrUG31E+a94HlTLQqPa4PhbvdVO 8IMgkD+SnbP85DqsK8rVCbHQGfM/w94dkKzhFk4vS9qZPYFJr5EoUaJFgL9czZxAOtUN osKIQlZgsxcuRzuZoMdb/F1Tav/te7zODIapdp/9sJV0NhTaDRbqNAQF1poFrc0WbKqI l4jR88czOkLizwOT2XCKtSF4hjGPX65aEN3X3xTiM2dcgPL2HbqmVUSS4MABFKtXJQef WJYNluT5SXZsO2JRx8meWbgDBk7Q1XrcikwhafslEFpFJqm05wKiRtMEI+GHiusp+vnY d6ag== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPZI/ScIzb9" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 47.12.1 DYNA|AUTH) with ESMTPSA id Z04c46x0OE6jeiX (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Sun, 24 Jan 2021 15:06:45 +0100 (CET) From: Stephan =?iso-8859-1?q?M=FCller?= To: herbert@gondor.apana.org.au Cc: ebiggers@kernel.org, Jarkko Sakkinen , mathew.j.martineau@linux.intel.com, dhowells@redhat.com, linux-crypto@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, simo@redhat.com Subject: [PATCH v2 4/7] security: DH - remove dead code for zero padding Date: Sun, 24 Jan 2021 15:03:50 +0100 Message-ID: <2129848.iZASKD2KPV@positron.chronox.de> In-Reply-To: <1772794.tdWV9SEqCh@positron.chronox.de> References: <1772794.tdWV9SEqCh@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org Remove the specific code that adds a zero padding that was intended to be invoked when the DH operation result was smaller than the modulus. However, this cannot occur any more these days because the function mpi_write_to_sgl is used in the code path that calculates the shared secret in dh_compute_value. This MPI service function guarantees that leading zeros are introduced as needed to ensure the resulting data is exactly as long as the modulus. This implies that the specific code to add zero padding is dead code which can be safely removed. Signed-off-by: Stephan Mueller --- security/keys/dh.c | 25 ++++--------------------- 1 file changed, 4 insertions(+), 21 deletions(-) diff --git a/security/keys/dh.c b/security/keys/dh.c index 1abfa70ed6e1..56e12dae4534 100644 --- a/security/keys/dh.c +++ b/security/keys/dh.c @@ -141,7 +141,7 @@ static void kdf_dealloc(struct kdf_sdesc *sdesc) * 'dlen' must be a multiple of the digest size. */ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen, - u8 *dst, unsigned int dlen, unsigned int zlen) + u8 *dst, unsigned int dlen) { struct shash_desc *desc = &sdesc->shash; unsigned int h = crypto_shash_digestsize(desc->tfm); @@ -158,22 +158,6 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen, if (err) goto err; - if (zlen && h) { - u8 tmpbuffer[32]; - size_t chunk = min_t(size_t, zlen, sizeof(tmpbuffer)); - memset(tmpbuffer, 0, chunk); - - do { - err = crypto_shash_update(desc, tmpbuffer, - chunk); - if (err) - goto err; - - zlen -= chunk; - chunk = min_t(size_t, zlen, sizeof(tmpbuffer)); - } while (zlen); - } - if (src && slen) { err = crypto_shash_update(desc, src, slen); if (err) @@ -198,7 +182,7 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen, static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc, char __user *buffer, size_t buflen, - uint8_t *kbuf, size_t kbuflen, size_t lzero) + uint8_t *kbuf, size_t kbuflen) { uint8_t *outbuf = NULL; int ret; @@ -211,7 +195,7 @@ static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc, goto err; } - ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, outbuf_len, lzero); + ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, outbuf_len); if (ret) goto err; @@ -384,8 +368,7 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params, } ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf, - req->dst_len + kdfcopy->otherinfolen, - outlen - req->dst_len); + req->dst_len + kdfcopy->otherinfolen); } else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) { ret = req->dst_len; } else { From patchwork Sun Jan 24 14:04:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 12042419 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=-15.8 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 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 3A93EC4332D for ; Sun, 24 Jan 2021 14:09:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0538722D3E for ; Sun, 24 Jan 2021 14:09:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726070AbhAXOJn (ORCPT ); Sun, 24 Jan 2021 09:09:43 -0500 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.81]:36640 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725798AbhAXOJj (ORCPT ); Sun, 24 Jan 2021 09:09:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1611497204; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:From: Subject:Sender; bh=UJu2Jvh1nCXdU612niCLGD96cRpQm9KprkqF1VzUH4c=; b=O1sp8nZFfVBbVwsoxCyo8shb0N04546U1JvOFdq78GhTVjlJpJd70yDmqTGcCei/EI LcbKe8UlARGjcR/OfPKBaXPpO+L+iclQzzYEGx6WLoeX40vEX1g83wBscMfQdwO+cpsE TI/YQIptsLWnlFtiAJyPzIG2oW5wXPNgoZraidhx2O8sW8CZvk6RBORZXehiM2zy0uAK KUUdiTPnV1wBO97PP5331e2E9dBbQDLzd40mVTrLplOo5lXNiRBP2jz96u00lYT+ZMOb IV2d3z3p/y2Zd74sor9H3u77xsIDTUhgYD8JOYGd5L9JwJIo0expXcz7vDHA+kC+DJuL ni/Q== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPZI/ScIzb9" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 47.12.1 DYNA|AUTH) with ESMTPSA id Z04c46x0OE6heiW (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Sun, 24 Jan 2021 15:06:43 +0100 (CET) From: Stephan =?iso-8859-1?q?M=FCller?= To: herbert@gondor.apana.org.au Cc: ebiggers@kernel.org, Jarkko Sakkinen , mathew.j.martineau@linux.intel.com, dhowells@redhat.com, linux-crypto@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, simo@redhat.com Subject: [PATCH v2 5/7] security: DH - use KDF implementation from crypto API Date: Sun, 24 Jan 2021 15:04:11 +0100 Message-ID: <20932396.EfDdHjke4D@positron.chronox.de> In-Reply-To: <1772794.tdWV9SEqCh@positron.chronox.de> References: <1772794.tdWV9SEqCh@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org The kernel crypto API provides the SP800-108 counter KDF implementation. Thus, the separate implementation provided as part of the keys subsystem can be replaced with calls to the KDF offered by the kernel crypto API. The keys subsystem uses the counter KDF with a hash primitive. Thus, it only uses the call to crypto_kdf108_ctr_generate. Signed-off-by: Stephan Mueller --- security/keys/Kconfig | 2 +- security/keys/dh.c | 97 +++++++------------------------------------ 2 files changed, 15 insertions(+), 84 deletions(-) diff --git a/security/keys/Kconfig b/security/keys/Kconfig index 83bc23409164..e6604499f0a8 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -106,7 +106,7 @@ config KEY_DH_OPERATIONS bool "Diffie-Hellman operations on retained keys" depends on KEYS select CRYPTO - select CRYPTO_HASH + select CRYPTO_KDF800108_CTR select CRYPTO_DH help This option provides support for calculating Diffie-Hellman diff --git a/security/keys/dh.c b/security/keys/dh.c index 56e12dae4534..46fa442b81ec 100644 --- a/security/keys/dh.c +++ b/security/keys/dh.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include "internal.h" @@ -79,16 +80,9 @@ static void dh_crypto_done(struct crypto_async_request *req, int err) complete(&compl->completion); } -struct kdf_sdesc { - struct shash_desc shash; - char ctx[]; -}; - -static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) +static int kdf_alloc(struct crypto_shash **hash, char *hashname) { struct crypto_shash *tfm; - struct kdf_sdesc *sdesc; - int size; int err; /* allocate synchronous hash */ @@ -102,14 +96,7 @@ static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) if (crypto_shash_digestsize(tfm) == 0) goto out_free_tfm; - err = -ENOMEM; - size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm); - sdesc = kmalloc(size, GFP_KERNEL); - if (!sdesc) - goto out_free_tfm; - sdesc->shash.tfm = tfm; - - *sdesc_ret = sdesc; + *hash = tfm; return 0; @@ -118,76 +105,20 @@ static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) return err; } -static void kdf_dealloc(struct kdf_sdesc *sdesc) -{ - if (!sdesc) - return; - - if (sdesc->shash.tfm) - crypto_free_shash(sdesc->shash.tfm); - - kfree_sensitive(sdesc); -} - -/* - * Implementation of the KDF in counter mode according to SP800-108 section 5.1 - * as well as SP800-56A section 5.8.1 (Single-step KDF). - * - * SP800-56A: - * The src pointer is defined as Z || other info where Z is the shared secret - * from DH and other info is an arbitrary string (see SP800-56A section - * 5.8.1.2). - * - * 'dlen' must be a multiple of the digest size. - */ -static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen, - u8 *dst, unsigned int dlen) +static void kdf_dealloc(struct crypto_shash *hash) { - struct shash_desc *desc = &sdesc->shash; - unsigned int h = crypto_shash_digestsize(desc->tfm); - int err = 0; - u8 *dst_orig = dst; - __be32 counter = cpu_to_be32(1); - - while (dlen) { - err = crypto_shash_init(desc); - if (err) - goto err; - - err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32)); - if (err) - goto err; - - if (src && slen) { - err = crypto_shash_update(desc, src, slen); - if (err) - goto err; - } - - err = crypto_shash_final(desc, dst); - if (err) - goto err; - - dlen -= h; - dst += h; - counter = cpu_to_be32(be32_to_cpu(counter) + 1); - } - - return 0; - -err: - memzero_explicit(dst_orig, dlen); - return err; + if (hash) + crypto_free_shash(hash); } -static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc, +static int keyctl_dh_compute_kdf(struct crypto_shash *hash, char __user *buffer, size_t buflen, uint8_t *kbuf, size_t kbuflen) { + struct kvec kbuf_iov = { .iov_base = kbuf, .iov_len = kbuflen }; uint8_t *outbuf = NULL; int ret; - size_t outbuf_len = roundup(buflen, - crypto_shash_digestsize(sdesc->shash.tfm)); + size_t outbuf_len = roundup(buflen, crypto_shash_digestsize(hash)); outbuf = kmalloc(outbuf_len, GFP_KERNEL); if (!outbuf) { @@ -195,7 +126,7 @@ static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc, goto err; } - ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, outbuf_len); + ret = crypto_kdf108_ctr_generate(hash, &kbuf_iov, 1, outbuf, outbuf_len); if (ret) goto err; @@ -224,7 +155,7 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params, struct kpp_request *req; uint8_t *secret; uint8_t *outbuf; - struct kdf_sdesc *sdesc = NULL; + struct crypto_shash *hash = NULL; if (!params || (!buffer && buflen)) { ret = -EINVAL; @@ -257,7 +188,7 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params, } /* allocate KDF from the kernel crypto API */ - ret = kdf_alloc(&sdesc, hashname); + ret = kdf_alloc(&hash, hashname); kfree(hashname); if (ret) goto out1; @@ -367,7 +298,7 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params, goto out6; } - ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf, + ret = keyctl_dh_compute_kdf(hash, buffer, buflen, outbuf, req->dst_len + kdfcopy->otherinfolen); } else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) { ret = req->dst_len; @@ -386,7 +317,7 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params, out2: dh_free_data(&dh_inputs); out1: - kdf_dealloc(sdesc); + kdf_dealloc(hash); return ret; } From patchwork Sun Jan 24 14:04:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 12042417 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=-15.8 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 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 C8842C433E0 for ; Sun, 24 Jan 2021 14:09:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FB3B22D3E for ; 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Sun, 24 Jan 2021 15:06:43 +0100 (CET) From: Stephan =?iso-8859-1?q?M=FCller?= To: herbert@gondor.apana.org.au Cc: ebiggers@kernel.org, Jarkko Sakkinen , mathew.j.martineau@linux.intel.com, dhowells@redhat.com, linux-crypto@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, simo@redhat.com Subject: [PATCH v2 6/7] fs: use HKDF implementation from kernel crypto API Date: Sun, 24 Jan 2021 15:04:31 +0100 Message-ID: <3577027.kQq0lBPeGt@positron.chronox.de> In-Reply-To: <1772794.tdWV9SEqCh@positron.chronox.de> References: <1772794.tdWV9SEqCh@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org As the kernel crypto API implements HKDF, replace the file-system-specific HKDF implementation with the generic HKDF implementation. Signed-off-by: Stephan Mueller --- fs/crypto/Kconfig | 2 +- fs/crypto/hkdf.c | 98 +++++++++-------------------------------------- 2 files changed, 20 insertions(+), 80 deletions(-) diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig index a5f5c30368a2..9450e958f1d1 100644 --- a/fs/crypto/Kconfig +++ b/fs/crypto/Kconfig @@ -2,7 +2,7 @@ config FS_ENCRYPTION bool "FS Encryption (Per-file encryption)" select CRYPTO - select CRYPTO_HASH + select CRYPTO_HKDF select CRYPTO_SKCIPHER select CRYPTO_LIB_SHA256 select KEYS diff --git a/fs/crypto/hkdf.c b/fs/crypto/hkdf.c index e0ec21055505..ae236b42b1f0 100644 --- a/fs/crypto/hkdf.c +++ b/fs/crypto/hkdf.c @@ -9,7 +9,7 @@ * Copyright 2019 Google LLC */ -#include +#include #include #include "fscrypt_private.h" @@ -37,23 +37,7 @@ * unnecessarily long master keys. Thus fscrypt still does HKDF-Extract. No * salt is used, since fscrypt master keys should already be pseudorandom and * there's no way to persist a random salt per master key from kernel mode. - */ - -/* HKDF-Extract (RFC 5869 section 2.2), unsalted */ -static int hkdf_extract(struct crypto_shash *hmac_tfm, const u8 *ikm, - unsigned int ikmlen, u8 prk[HKDF_HASHLEN]) -{ - static const u8 default_salt[HKDF_HASHLEN]; - int err; - - err = crypto_shash_setkey(hmac_tfm, default_salt, HKDF_HASHLEN); - if (err) - return err; - - return crypto_shash_tfm_digest(hmac_tfm, ikm, ikmlen, prk); -} - -/* + * * Compute HKDF-Extract using the given master key as the input keying material, * and prepare an HMAC transform object keyed by the resulting pseudorandom key. * @@ -64,7 +48,6 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, unsigned int master_key_size) { struct crypto_shash *hmac_tfm; - u8 prk[HKDF_HASHLEN]; int err; hmac_tfm = crypto_alloc_shash(HKDF_HMAC_ALG, 0, 0); @@ -74,16 +57,14 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, return PTR_ERR(hmac_tfm); } - if (WARN_ON(crypto_shash_digestsize(hmac_tfm) != sizeof(prk))) { + if (WARN_ON(crypto_shash_digestsize(hmac_tfm) != HKDF_HASHLEN)) { err = -EINVAL; goto err_free_tfm; } - err = hkdf_extract(hmac_tfm, master_key, master_key_size, prk); - if (err) - goto err_free_tfm; - - err = crypto_shash_setkey(hmac_tfm, prk, sizeof(prk)); + /* HKDF-Extract (RFC 5869 section 2.2), unsalted */ + err = crypto_hkdf_extract(hmac_tfm, NULL, 0, + master_key, master_key_size); if (err) goto err_free_tfm; @@ -93,7 +74,6 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, err_free_tfm: crypto_free_shash(hmac_tfm); out: - memzero_explicit(prk, sizeof(prk)); return err; } @@ -112,62 +92,22 @@ int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context, const u8 *info, unsigned int infolen, u8 *okm, unsigned int okmlen) { - SHASH_DESC_ON_STACK(desc, hkdf->hmac_tfm); - u8 prefix[9]; - unsigned int i; - int err; - const u8 *prev = NULL; - u8 counter = 1; - u8 tmp[HKDF_HASHLEN]; - - if (WARN_ON(okmlen > 255 * HKDF_HASHLEN)) - return -EINVAL; - - desc->tfm = hkdf->hmac_tfm; - - memcpy(prefix, "fscrypt\0", 8); - prefix[8] = context; - - for (i = 0; i < okmlen; i += HKDF_HASHLEN) { + const struct kvec info_iov[] = { { + .iov_base = "fscrypt\0", + .iov_len = 8, + }, { + .iov_base = &context, + .iov_len = 1, + }, { + .iov_base = (u8 *)info, + .iov_len = infolen, + } }; + int err = crypto_hkdf_expand(hkdf->hmac_tfm, + info_iov, ARRAY_SIZE(info_iov), + okm, okmlen); - err = crypto_shash_init(desc); - if (err) - goto out; - - if (prev) { - err = crypto_shash_update(desc, prev, HKDF_HASHLEN); - if (err) - goto out; - } - - err = crypto_shash_update(desc, prefix, sizeof(prefix)); - if (err) - goto out; - - err = crypto_shash_update(desc, info, infolen); - if (err) - goto out; - - BUILD_BUG_ON(sizeof(counter) != 1); - if (okmlen - i < HKDF_HASHLEN) { - err = crypto_shash_finup(desc, &counter, 1, tmp); - if (err) - goto out; - memcpy(&okm[i], tmp, okmlen - i); - memzero_explicit(tmp, sizeof(tmp)); - } else { - err = crypto_shash_finup(desc, &counter, 1, &okm[i]); - if (err) - goto out; - } - counter++; - prev = &okm[i]; - } - err = 0; -out: if (unlikely(err)) memzero_explicit(okm, okmlen); /* so caller doesn't need to */ - shash_desc_zero(desc); return err; } From patchwork Sun Jan 24 14:04:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 12042415 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=-15.8 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 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 A0DBEC433DB for ; Sun, 24 Jan 2021 14:09:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69C3822CB1 for ; 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Sun, 24 Jan 2021 15:06:41 +0100 (CET) From: Stephan =?iso-8859-1?q?M=FCller?= To: herbert@gondor.apana.org.au Cc: ebiggers@kernel.org, Jarkko Sakkinen , mathew.j.martineau@linux.intel.com, dhowells@redhat.com, linux-crypto@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, simo@redhat.com Subject: [PATCH v2 7/7] fs: HKDF - remove duplicate memory clearing Date: Sun, 24 Jan 2021 15:04:50 +0100 Message-ID: <8714658.CDJkKcVGEf@positron.chronox.de> In-Reply-To: <1772794.tdWV9SEqCh@positron.chronox.de> References: <1772794.tdWV9SEqCh@positron.chronox.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org The clearing of the OKM memory buffer in case of an error is already performed by the HKDF implementation crypto_hkdf_expand. Thus, the code clearing is not needed any more in the file system code base. Signed-off-by: Stephan Mueller --- fs/crypto/hkdf.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/fs/crypto/hkdf.c b/fs/crypto/hkdf.c index ae236b42b1f0..c48dd8ca3a46 100644 --- a/fs/crypto/hkdf.c +++ b/fs/crypto/hkdf.c @@ -102,13 +102,10 @@ int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context, .iov_base = (u8 *)info, .iov_len = infolen, } }; - int err = crypto_hkdf_expand(hkdf->hmac_tfm, - info_iov, ARRAY_SIZE(info_iov), - okm, okmlen); - if (unlikely(err)) - memzero_explicit(okm, okmlen); /* so caller doesn't need to */ - return err; + return crypto_hkdf_expand(hkdf->hmac_tfm, + info_iov, ARRAY_SIZE(info_iov), + okm, okmlen); } void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf)