From patchwork Mon Dec 2 14:29:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 847436 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CE15376F1 for ; Mon, 2 Dec 2024 14:30:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733149813; cv=none; b=LRvAVYDH4amtEk2ahYPLid4v3v5nSRH53RD+n+9xStiKeSlobZvolFdszoiPxk4pSljnFfvTIu48v4t7IiBHAK0MLzLwpdCZovolHLfyX/JxqXUOrgA0ifMGy1KZd+V8+aXcWozDiLVZEXi0PPZT10U46Q4XgiCvTcTLa+QILdI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733149813; c=relaxed/simple; bh=VxNmjVC55Bixx++00nhQOYnSMgS1l3+P7Z+UwkPjATA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=CBSZGAbnHc2HbZes/KWDTE6JHRSttX0DbG19W8Arghl/lK3BqEdN8gYXWna/eDU7EbfNsLHZ7m7c0l/ATor3YEtjdKP6sCx1gGvyKbPxBXqsq4+mepN7B1Tyx367Q5ry+fMx9l/Mm7Sc8/S176wsC4mn+99ar5FgQZbNF5spL9Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a7YVZJ3/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="a7YVZJ3/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3CA32C4CED1; Mon, 2 Dec 2024 14:30:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733149812; bh=VxNmjVC55Bixx++00nhQOYnSMgS1l3+P7Z+UwkPjATA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a7YVZJ3/wmyvoDY2CD5hEoU+V1RtTDi8fCLiQHQClL5XrqeY0KsvOTMb2a8CBHs2a 17B3P3jBbOIKIHt7lxkby1MsC0Zprj4xlqmZKOoRMiWxoLaYon1bP5CtH9sLOghN0r 6YipLutsZ9d57Lw9YZdGdP9Zo2CGNfboCKgMVrSbpHJajsTBzSlMPIFvNln3yAH2ra RLzq9dFZ1tAtFF/qVEDlRLNoDUZ9dBeLWjofs5q5kdo4FglSmUFBPOvvW25JaNYZYL EgSlHWVBYl7pWWZZc579walzpE+l77Ie53cNMMKrlMloiy62O9UKkHhOVwAy6ksAam dTTdCLGVdElRQ== From: Hannes Reinecke To: Christoph Hellwig Cc: Keith Busch , Sagi Grimberg , linux-nvme@lists.infradead.org, Eric Biggers , linux-crypto@vger.kernel.org, Hannes Reinecke Subject: [PATCH 01/10] crypto,fs: Separate out hkdf_extract() and hkdf_expand() Date: Mon, 2 Dec 2024 15:29:50 +0100 Message-Id: <20241202142959.81321-2-hare@kernel.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20241202142959.81321-1-hare@kernel.org> References: <20241202142959.81321-1-hare@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Separate out the HKDF functions into a separate module to to make them available to other callers. And add a testsuite to the module with test vectors from RFC 5869 (and additional vectors for SHA384 and SHA512) to ensure the integrity of the algorithm. Signed-off-by: Hannes Reinecke Cc: Eric Biggers Cc: linux-crypto@vger.kernel.org --- crypto/Kconfig | 6 + crypto/Makefile | 1 + crypto/hkdf.c | 573 ++++++++++++++++++++++++++++++++++++++++++ fs/crypto/Kconfig | 1 + fs/crypto/hkdf.c | 85 ++----- include/crypto/hkdf.h | 20 ++ 6 files changed, 616 insertions(+), 70 deletions(-) create mode 100644 crypto/hkdf.c create mode 100644 include/crypto/hkdf.h diff --git a/crypto/Kconfig b/crypto/Kconfig index a779cab668c2..03656e7b55bb 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -141,6 +141,12 @@ config CRYPTO_ACOMP select CRYPTO_ALGAPI select CRYPTO_ACOMP2 +config CRYPTO_HKDF + tristate + select CRYPTO_SHA256 if !CONFIG_CRYPTO_MANAGER_DISABLE_TESTS + select CRYPTO_SHA512 if !CONFIG_CRYPTO_MANAGER_DISABLE_TESTS + select CRYPTO_HASH2 + config CRYPTO_MANAGER tristate "Cryptographic algorithm manager" select CRYPTO_MANAGER2 diff --git a/crypto/Makefile b/crypto/Makefile index 4c99e5d376f6..5ec5b994d9ae 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_CRYPTO_HASH2) += crypto_hash.o obj-$(CONFIG_CRYPTO_AKCIPHER2) += akcipher.o obj-$(CONFIG_CRYPTO_SIG2) += sig.o obj-$(CONFIG_CRYPTO_KPP2) += kpp.o +obj-$(CONFIG_CRYPTO_HKDF) += hkdf.o dh_generic-y := dh.o dh_generic-y += dh_helper.o diff --git a/crypto/hkdf.c b/crypto/hkdf.c new file mode 100644 index 000000000000..2434c5c42545 --- /dev/null +++ b/crypto/hkdf.c @@ -0,0 +1,573 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Implementation of HKDF ("HMAC-based Extract-and-Expand Key Derivation + * Function"), aka RFC 5869. See also the original paper (Krawczyk 2010): + * "Cryptographic Extraction and Key Derivation: The HKDF Scheme". + * + * Copyright 2019 Google LLC + */ + +#include +#include +#include +#include + +/* + * HKDF consists of two steps: + * + * 1. HKDF-Extract: extract a pseudorandom key from the input keying material + * and optional salt. + * 2. HKDF-Expand: expand the pseudorandom key into output keying material of + * any length, parameterized by an application-specific info string. + * + */ + +/** + * hkdf_extract - HKDF-Extract (RFC 5869 section 2.2) + * @hmac_tfm: an HMAC transform using the hash function desired for HKDF. The + * caller is responsible for setting the @prk afterwards. + * @ikm: input keying material + * @ikmlen: length of @ikm + * @salt: input salt value + * @saltlen: length of @salt + * @prk: resulting pseudorandom key + * + * Extracts a pseudorandom key @prk from the input keying material + * @ikm with length @ikmlen and salt @salt with length @saltlen. + * The length of @prk is given by the digest size of @hmac_tfm. + * For an 'unsalted' version of HKDF-Extract @salt must be set + * to all zeroes and @saltlen must be set to the length of @prk. + * + * Returns 0 on success with the pseudorandom key stored in @prk, + * or a negative errno value otherwise. + */ +int hkdf_extract(struct crypto_shash *hmac_tfm, const u8 *ikm, + unsigned int ikmlen, const u8 *salt, unsigned int saltlen, + u8 *prk) +{ + int err; + + err = crypto_shash_setkey(hmac_tfm, salt, saltlen); + if (!err) + err = crypto_shash_tfm_digest(hmac_tfm, ikm, ikmlen, prk); + + return err; +} +EXPORT_SYMBOL_GPL(hkdf_extract); + +/** + * hkdf_expand - HKDF-Expand (RFC 5869 section 2.3) + * @hmac_tfm: hash context keyed with pseudorandom key + * @info: application-specific information + * @infolen: length of @info + * @okm: output keying material + * @okmlen: length of @okm + * + * This expands the pseudorandom key, which was already keyed into @hmac_tfm, + * into @okmlen bytes of output keying material parameterized by the + * application-specific @info of length @infolen bytes. + * This is thread-safe and may be called by multiple threads in parallel. + * + * Returns 0 on success with output keying material stored in @okm, + * or a negative errno value otherwise. + */ +int hkdf_expand(struct crypto_shash *hmac_tfm, + const u8 *info, unsigned int infolen, + u8 *okm, unsigned int okmlen) +{ + SHASH_DESC_ON_STACK(desc, hmac_tfm); + unsigned int i, hashlen = crypto_shash_digestsize(hmac_tfm); + int err; + const u8 *prev = NULL; + u8 counter = 1; + u8 tmp[HASH_MAX_DIGESTSIZE] = {}; + + if (WARN_ON(okmlen > 255 * hashlen)) + return -EINVAL; + + desc->tfm = hmac_tfm; + + for (i = 0; i < okmlen; i += hashlen) { + err = crypto_shash_init(desc); + if (err) + goto out; + + if (prev) { + err = crypto_shash_update(desc, prev, hashlen); + if (err) + goto out; + } + + if (infolen) { + err = crypto_shash_update(desc, info, infolen); + if (err) + goto out; + } + + BUILD_BUG_ON(sizeof(counter) != 1); + if (okmlen - i < 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); + memzero_explicit(tmp, HASH_MAX_DIGESTSIZE); + return err; +} +EXPORT_SYMBOL_GPL(hkdf_expand); + +struct hkdf_testvec { + const char *test; + const u8 *ikm; + const u8 *salt; + const u8 *info; + const u8 *prk; + const u8 *okm; + u16 ikm_size; + u16 salt_size; + u16 info_size; + u16 prk_size; + u16 okm_size; +}; + +/* + * HKDF test vectors from RFC5869 + * + * Additional HKDF test vectors from + * https://github.com/brycx/Test-Vector-Generation/blob/master/HKDF/hkdf-hmac-sha2-test-vectors.md + */ +static const struct hkdf_testvec hkdf_sha256_tv[] = { + { + .test = "basic hdkf test", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 22, + .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c", + .salt_size = 13, + .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9", + .info_size = 10, + .prk = "\x07\x77\x09\x36\x2c\x2e\x32\xdf\x0d\xdc\x3f\x0d\xc4\x7b\xba\x63" + "\x90\xb6\xc7\x3b\xb5\x0f\x9c\x31\x22\xec\x84\x4a\xd7\xc2\xb3\xe5", + .prk_size = 32, + .okm = "\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", + .okm_size = 42, + }, { + .test = "hkdf test with long input", + .ikm = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" + "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" + "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f" + "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f" + "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f", + .ikm_size = 80, + .salt = "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f" + "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f" + "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f" + "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f" + "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf", + .salt_size = 80, + .info = "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf" + "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf" + "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf" + "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef" + "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff", + .info_size = 80, + .prk = "\x06\xa6\xb8\x8c\x58\x53\x36\x1a\x06\x10\x4c\x9c\xeb\x35\xb4\x5c" + "\xef\x76\x00\x14\x90\x46\x71\x01\x4a\x19\x3f\x40\xc1\x5f\xc2\x44", + .prk_size = 32, + .okm = "\xb1\x1e\x39\x8d\xc8\x03\x27\xa1\xc8\xe7\xf7\x8c\x59\x6a\x49\x34" + "\x4f\x01\x2e\xda\x2d\x4e\xfa\xd8\xa0\x50\xcc\x4c\x19\xaf\xa9\x7c" + "\x59\x04\x5a\x99\xca\xc7\x82\x72\x71\xcb\x41\xc6\x5e\x59\x0e\x09" + "\xda\x32\x75\x60\x0c\x2f\x09\xb8\x36\x77\x93\xa9\xac\xa3\xdb\x71" + "\xcc\x30\xc5\x81\x79\xec\x3e\x87\xc1\x4c\x01\xd5\xc1\xf3\x43\x4f" + "\x1d\x87", + .okm_size = 82, + }, { + .test = "hkdf test with zero salt and info", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 22, + .salt = NULL, + .salt_size = 0, + .info = NULL, + .info_size = 0, + .prk = "\x19\xef\x24\xa3\x2c\x71\x7b\x16\x7f\x33\xa9\x1d\x6f\x64\x8b\xdf" + "\x96\x59\x67\x76\xaf\xdb\x63\x77\xac\x43\x4c\x1c\x29\x3c\xcb\x04", + .prk_size = 32, + .okm = "\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", + .okm_size = 42, + }, { + .test = "hkdf test with short input", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 11, + .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c", + .salt_size = 13, + .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9", + .info_size = 10, + .prk = "\x82\x65\xf6\x9d\x7f\xf7\xe5\x01\x37\x93\x01\x5c\xa0\xef\x92\x0c" + "\xb1\x68\x21\x99\xc8\xbc\x3a\x00\xda\x0c\xab\x47\xb7\xb0\x0f\xdf", + .prk_size = 32, + .okm = "\x58\xdc\xe1\x0d\x58\x01\xcd\xfd\xa8\x31\x72\x6b\xfe\xbc\xb7\x43" + "\xd1\x4a\x7e\xe8\x3a\xa0\x57\xa9\x3d\x59\xb0\xa1\x31\x7f\xf0\x9d" + "\x10\x5c\xce\xcf\x53\x56\x92\xb1\x4d\xd5", + .okm_size = 42, + }, { + .test = "unsalted hkdf test with zero info", + .ikm = "\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c" + "\x0c\x0c\x0c\x0c\x0c\x0c", + .ikm_size = 22, + .salt = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", + .salt_size = 32, + .info = NULL, + .info_size = 0, + .prk = "\xaa\x84\x1e\x1f\x35\x74\xf3\x2d\x13\xfb\xa8\x00\x5f\xcd\x9b\x8d" + "\x77\x67\x82\xa5\xdf\xa1\x92\x38\x92\xfd\x8b\x63\x5d\x3a\x89\xdf", + .prk_size = 32, + .okm = "\x59\x68\x99\x17\x9a\xb1\xbc\x00\xa7\xc0\x37\x86\xff\x43\xee\x53" + "\x50\x04\xbe\x2b\xb9\xbe\x68\xbc\x14\x06\x63\x6f\x54\xbd\x33\x8a" + "\x66\xa2\x37\xba\x2a\xcb\xce\xe3\xc9\xa7", + .okm_size = 42, + } +}; + +static const struct hkdf_testvec hkdf_sha384_tv[] = { + { + .test = "basic hkdf test", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 22, + .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c", + .salt_size = 13, + .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9", + .info_size = 10, + .prk = "\x70\x4b\x39\x99\x07\x79\xce\x1d\xc5\x48\x05\x2c\x7d\xc3\x9f\x30" + "\x35\x70\xdd\x13\xfb\x39\xf7\xac\xc5\x64\x68\x0b\xef\x80\xe8\xde" + "\xc7\x0e\xe9\xa7\xe1\xf3\xe2\x93\xef\x68\xec\xeb\x07\x2a\x5a\xde", + .prk_size = 48, + .okm = "\x9b\x50\x97\xa8\x60\x38\xb8\x05\x30\x90\x76\xa4\x4b\x3a\x9f\x38" + "\x06\x3e\x25\xb5\x16\xdc\xbf\x36\x9f\x39\x4c\xfa\xb4\x36\x85\xf7" + "\x48\xb6\x45\x77\x63\xe4\xf0\x20\x4f\xc5", + .okm_size = 42, + }, { + .test = "hkdf test with long input", + .ikm = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" + "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" + "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f" + "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f" + "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f", + .ikm_size = 80, + .salt = "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f" + "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f" + "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f" + "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f" + "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf", + .salt_size = 80, + .info = "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf" + "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf" + "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf" + "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef" + "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff", + .info_size = 80, + .prk = "\xb3\x19\xf6\x83\x1d\xff\x93\x14\xef\xb6\x43\xba\xa2\x92\x63\xb3" + "\x0e\x4a\x8d\x77\x9f\xe3\x1e\x9c\x90\x1e\xfd\x7d\xe7\x37\xc8\x5b" + "\x62\xe6\x76\xd4\xdc\x87\xb0\x89\x5c\x6a\x7d\xc9\x7b\x52\xce\xbb", + .prk_size = 48, + .okm = "\x48\x4c\xa0\x52\xb8\xcc\x72\x4f\xd1\xc4\xec\x64\xd5\x7b\x4e\x81" + "\x8c\x7e\x25\xa8\xe0\xf4\x56\x9e\xd7\x2a\x6a\x05\xfe\x06\x49\xee" + "\xbf\x69\xf8\xd5\xc8\x32\x85\x6b\xf4\xe4\xfb\xc1\x79\x67\xd5\x49" + "\x75\x32\x4a\x94\x98\x7f\x7f\x41\x83\x58\x17\xd8\x99\x4f\xdb\xd6" + "\xf4\xc0\x9c\x55\x00\xdc\xa2\x4a\x56\x22\x2f\xea\x53\xd8\x96\x7a" + "\x8b\x2e", + .okm_size = 82, + }, { + .test = "hkdf test with zero salt and info", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 22, + .salt = NULL, + .salt_size = 0, + .info = NULL, + .info_size = 0, + .prk = "\x10\xe4\x0c\xf0\x72\xa4\xc5\x62\x6e\x43\xdd\x22\xc1\xcf\x72\x7d" + "\x4b\xb1\x40\x97\x5c\x9a\xd0\xcb\xc8\xe4\x5b\x40\x06\x8f\x8f\x0b" + "\xa5\x7c\xdb\x59\x8a\xf9\xdf\xa6\x96\x3a\x96\x89\x9a\xf0\x47\xe5", + .prk_size = 48, + .okm = "\xc8\xc9\x6e\x71\x0f\x89\xb0\xd7\x99\x0b\xca\x68\xbc\xde\xc8\xcf" + "\x85\x40\x62\xe5\x4c\x73\xa7\xab\xc7\x43\xfa\xde\x9b\x24\x2d\xaa" + "\xcc\x1c\xea\x56\x70\x41\x5b\x52\x84\x9c", + .okm_size = 42, + }, { + .test = "hkdf test with short input", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 11, + .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c", + .salt_size = 13, + .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9", + .info_size = 10, + .prk = "\x6d\x31\x69\x98\x28\x79\x80\x88\xb3\x59\xda\xd5\x0b\x8f\x01\xb0" + "\x15\xf1\x7a\xa3\xbd\x4e\x27\xa6\xe9\xf8\x73\xb7\x15\x85\xca\x6a" + "\x00\xd1\xf0\x82\x12\x8a\xdb\x3c\xf0\x53\x0b\x57\xc0\xf9\xac\x72", + .prk_size = 48, + .okm = "\xfb\x7e\x67\x43\xeb\x42\xcd\xe9\x6f\x1b\x70\x77\x89\x52\xab\x75" + "\x48\xca\xfe\x53\x24\x9f\x7f\xfe\x14\x97\xa1\x63\x5b\x20\x1f\xf1" + "\x85\xb9\x3e\x95\x19\x92\xd8\x58\xf1\x1a", + .okm_size = 42, + }, { + .test = "unsalted hkdf test with zero info", + .ikm = "\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c" + "\x0c\x0c\x0c\x0c\x0c\x0c", + .ikm_size = 22, + .salt = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", + .salt_size = 48, + .info = NULL, + .info_size = 0, + .prk = "\x9d\x2d\xa5\x06\x6f\x05\xd1\x6c\x59\xfe\xdf\x6c\x5f\x32\xc7\x5e" + "\xda\x9a\x47\xa7\x9c\x93\x6a\xa4\x4c\xb7\x63\xa8\xe2\x2f\xfb\xfc" + "\xd8\xfe\x55\x43\x58\x53\x47\x21\x90\x39\xd1\x68\x28\x36\x33\xf5", + .prk_size = 48, + .okm = "\x6a\xd7\xc7\x26\xc8\x40\x09\x54\x6a\x76\xe0\x54\x5d\xf2\x66\x78" + "\x7e\x2b\x2c\xd6\xca\x43\x73\xa1\xf3\x14\x50\xa7\xbd\xf9\x48\x2b" + "\xfa\xb8\x11\xf5\x54\x20\x0e\xad\x8f\x53", + .okm_size = 42, + } +}; + +static const struct hkdf_testvec hkdf_sha512_tv[] = { + { + .test = "basic hkdf test", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 22, + .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c", + .salt_size = 13, + .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9", + .info_size = 10, + .prk = "\x66\x57\x99\x82\x37\x37\xde\xd0\x4a\x88\xe4\x7e\x54\xa5\x89\x0b" + "\xb2\xc3\xd2\x47\xc7\xa4\x25\x4a\x8e\x61\x35\x07\x23\x59\x0a\x26" + "\xc3\x62\x38\x12\x7d\x86\x61\xb8\x8c\xf8\x0e\xf8\x02\xd5\x7e\x2f" + "\x7c\xeb\xcf\x1e\x00\xe0\x83\x84\x8b\xe1\x99\x29\xc6\x1b\x42\x37", + .prk_size = 64, + .okm = "\x83\x23\x90\x08\x6c\xda\x71\xfb\x47\x62\x5b\xb5\xce\xb1\x68\xe4" + "\xc8\xe2\x6a\x1a\x16\xed\x34\xd9\xfc\x7f\xe9\x2c\x14\x81\x57\x93" + "\x38\xda\x36\x2c\xb8\xd9\xf9\x25\xd7\xcb", + .okm_size = 42, + }, { + .test = "hkdf test with long input", + .ikm = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" + "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" + "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f" + "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f" + "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f", + .ikm_size = 80, + .salt = "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f" + "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f" + "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f" + "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f" + "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf", + .salt_size = 80, + .info = "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf" + "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf" + "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf" + "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef" + "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff", + .info_size = 80, + .prk = "\x35\x67\x25\x42\x90\x7d\x4e\x14\x2c\x00\xe8\x44\x99\xe7\x4e\x1d" + "\xe0\x8b\xe8\x65\x35\xf9\x24\xe0\x22\x80\x4a\xd7\x75\xdd\xe2\x7e" + "\xc8\x6c\xd1\xe5\xb7\xd1\x78\xc7\x44\x89\xbd\xbe\xb3\x07\x12\xbe" + "\xb8\x2d\x4f\x97\x41\x6c\x5a\x94\xea\x81\xeb\xdf\x3e\x62\x9e\x4a", + .prk_size = 64, + .okm = "\xce\x6c\x97\x19\x28\x05\xb3\x46\xe6\x16\x1e\x82\x1e\xd1\x65\x67" + "\x3b\x84\xf4\x00\xa2\xb5\x14\xb2\xfe\x23\xd8\x4c\xd1\x89\xdd\xf1" + "\xb6\x95\xb4\x8c\xbd\x1c\x83\x88\x44\x11\x37\xb3\xce\x28\xf1\x6a" + "\xa6\x4b\xa3\x3b\xa4\x66\xb2\x4d\xf6\xcf\xcb\x02\x1e\xcf\xf2\x35" + "\xf6\xa2\x05\x6c\xe3\xaf\x1d\xe4\x4d\x57\x20\x97\xa8\x50\x5d\x9e" + "\x7a\x93", + .okm_size = 82, + }, { + .test = "hkdf test with zero salt and info", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b" + "\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 22, + .salt = NULL, + .salt_size = 0, + .info = NULL, + .info_size = 0, + .prk = "\xfd\x20\x0c\x49\x87\xac\x49\x13\x13\xbd\x4a\x2a\x13\x28\x71\x21" + "\x24\x72\x39\xe1\x1c\x9e\xf8\x28\x02\x04\x4b\x66\xef\x35\x7e\x5b" + "\x19\x44\x98\xd0\x68\x26\x11\x38\x23\x48\x57\x2a\x7b\x16\x11\xde" + "\x54\x76\x40\x94\x28\x63\x20\x57\x8a\x86\x3f\x36\x56\x2b\x0d\xf6", + .prk_size = 64, + .okm = "\xf5\xfa\x02\xb1\x82\x98\xa7\x2a\x8c\x23\x89\x8a\x87\x03\x47\x2c" + "\x6e\xb1\x79\xdc\x20\x4c\x03\x42\x5c\x97\x0e\x3b\x16\x4b\xf9\x0f" + "\xff\x22\xd0\x48\x36\xd0\xe2\x34\x3b\xac", + .okm_size = 42, + }, { + .test = "hkdf test with short input", + .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b", + .ikm_size = 11, + .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c", + .salt_size = 13, + .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9", + .info_size = 10, + .prk = "\x67\x40\x9c\x9c\xac\x28\xb5\x2e\xe9\xfa\xd9\x1c\x2f\xda\x99\x9f" + "\x7c\xa2\x2e\x34\x34\xf0\xae\x77\x28\x63\x83\x65\x68\xad\x6a\x7f" + "\x10\xcf\x11\x3b\xfd\xdd\x56\x01\x29\xa5\x94\xa8\xf5\x23\x85\xc2" + "\xd6\x61\xd7\x85\xd2\x9c\xe9\x3a\x11\x40\x0c\x92\x06\x83\x18\x1d", + .prk_size = 64, + .okm = "\x74\x13\xe8\x99\x7e\x02\x06\x10\xfb\xf6\x82\x3f\x2c\xe1\x4b\xff" + "\x01\x87\x5d\xb1\xca\x55\xf6\x8c\xfc\xf3\x95\x4d\xc8\xaf\xf5\x35" + "\x59\xbd\x5e\x30\x28\xb0\x80\xf7\xc0\x68", + .okm_size = 42, + }, { + .test = "unsalted hkdf test with zero info", + .ikm = "\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c" + "\x0c\x0c\x0c\x0c\x0c\x0c", + .ikm_size = 22, + .salt = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", + .salt_size = 64, + .info = NULL, + .info_size = 0, + .prk = "\x53\x46\xb3\x76\xbf\x3a\xa9\xf8\x4f\x8f\x6e\xd5\xb1\xc4\xf4\x89" + "\x17\x2e\x24\x4d\xac\x30\x3d\x12\xf6\x8e\xcc\x76\x6e\xa6\x00\xaa" + "\x88\x49\x5e\x7f\xb6\x05\x80\x31\x22\xfa\x13\x69\x24\xa8\x40\xb1" + "\xf0\x71\x9d\x2d\x5f\x68\xe2\x9b\x24\x22\x99\xd7\x58\xed\x68\x0c", + .prk_size = 64, + .okm = "\x14\x07\xd4\x60\x13\xd9\x8b\xc6\xde\xce\xfc\xfe\xe5\x5f\x0f\x90" + "\xb0\xc7\xf6\x3d\x68\xeb\x1a\x80\xea\xf0\x7e\x95\x3c\xfc\x0a\x3a" + "\x52\x40\xa1\x55\xd6\xe4\xda\xa9\x65\xbb", + .okm_size = 42, + } +}; + +static int hkdf_test(const char *shash, const struct hkdf_testvec *tv) +{ struct crypto_shash *tfm = NULL; + u8 *prk = NULL, *okm = NULL; + unsigned int prk_size; + const char *driver; + int err; + + tfm = crypto_alloc_shash(shash, 0, 0); + if (IS_ERR(tfm)) { + pr_err("%s(%s): failed to allocate transform: %ld\n", + tv->test, shash, PTR_ERR(tfm)); + return PTR_ERR(tfm); + } + driver = crypto_shash_driver_name(tfm); + + prk_size = crypto_shash_digestsize(tfm); + prk = kzalloc(prk_size, GFP_KERNEL); + if (!prk) { + err = -ENOMEM; + goto out_free; + } + + if (tv->prk_size != prk_size) { + pr_err("%s(%s): prk size mismatch (vec %u, digest %u\n", + tv->test, driver, tv->prk_size, prk_size); + err = -EINVAL; + goto out_free; + } + + err = hkdf_extract(tfm, tv->ikm, tv->ikm_size, + tv->salt, tv->salt_size, prk); + if (err) { + pr_err("%s(%s): hkdf_extract failed with %d\n", + tv->test, driver, err); + goto out_free; + } + + if (memcmp(prk, tv->prk, tv->prk_size)) { + pr_err("%s(%s): hkdf_extract prk mismatch\n", + tv->test, driver); + print_hex_dump(KERN_ERR, "prk: ", DUMP_PREFIX_NONE, + 16, 1, prk, tv->prk_size, false); + err = -EINVAL; + goto out_free; + } + + okm = kzalloc(tv->okm_size, GFP_KERNEL); + if (!okm) { + err = -ENOMEM; + goto out_free; + } + + err = crypto_shash_setkey(tfm, tv->prk, tv->prk_size); + if (err) { + pr_err("%s(%s): failed to set prk, error %d\n", + tv->test, driver, err); + goto out_free; + } + + err = hkdf_expand(tfm, tv->info, tv->info_size, + okm, tv->okm_size); + if (err) { + pr_err("%s(%s): hkdf_expand() failed with %d\n", + tv->test, driver, err); + } else if (memcmp(okm, tv->okm, tv->okm_size)) { + pr_err("%s(%s): hkdf_expand() okm mismatch\n", + tv->test, driver); + print_hex_dump(KERN_ERR, "okm: ", DUMP_PREFIX_NONE, + 16, 1, okm, tv->okm_size, false); + err = -EINVAL; + } +out_free: + kfree(okm); + kfree(prk); + crypto_free_shash(tfm); + return err; +} + +static int __init crypto_hkdf_module_init(void) +{ + int ret = 0, i; + + if (IS_ENABLED(CONFIG_CRYPTO_MANAGER_DISABLE_TESTS)) + return 0; + + for (i = 0; i < ARRAY_SIZE(hkdf_sha256_tv); i++) { + ret = hkdf_test("hmac(sha256)", &hkdf_sha256_tv[i]); + if (ret) + return ret; + } + for (i = 0; i < ARRAY_SIZE(hkdf_sha384_tv); i++) { + ret = hkdf_test("hmac(sha384)", &hkdf_sha384_tv[i]); + if (ret) + return ret; + } + for (i = 0; i < ARRAY_SIZE(hkdf_sha512_tv); i++) { + ret = hkdf_test("hmac(sha512)", &hkdf_sha512_tv[i]); + if (ret) + return ret; + } + return 0; +} + +static void __exit crypto_hkdf_module_exit(void) {} + +module_init(crypto_hkdf_module_init); +module_exit(crypto_hkdf_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("HMAC-based Key Derivation Function (HKDF)"); diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig index 5aff5934baa1..0ea56f588a4a 100644 --- a/fs/crypto/Kconfig +++ b/fs/crypto/Kconfig @@ -3,6 +3,7 @@ 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 5a384dad2c72..855a0f4b7318 100644 --- a/fs/crypto/hkdf.c +++ b/fs/crypto/hkdf.c @@ -1,9 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 /* - * Implementation of HKDF ("HMAC-based Extract-and-Expand Key Derivation - * Function"), aka RFC 5869. See also the original paper (Krawczyk 2010): - * "Cryptographic Extraction and Key Derivation: The HKDF Scheme". - * * This is used to derive keys from the fscrypt master keys. * * Copyright 2019 Google LLC @@ -11,6 +7,7 @@ #include #include +#include #include "fscrypt_private.h" @@ -44,20 +41,6 @@ * 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. @@ -69,6 +52,7 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, unsigned int master_key_size) { struct crypto_shash *hmac_tfm; + static const u8 default_salt[HKDF_HASHLEN]; u8 prk[HKDF_HASHLEN]; int err; @@ -84,7 +68,8 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, goto err_free_tfm; } - err = hkdf_extract(hmac_tfm, master_key, master_key_size, prk); + err = hkdf_extract(hmac_tfm, master_key, master_key_size, + default_salt, HKDF_HASHLEN, prk); if (err) goto err_free_tfm; @@ -118,61 +103,21 @@ int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context, u8 *okm, unsigned int okmlen) { SHASH_DESC_ON_STACK(desc, hkdf->hmac_tfm); - u8 prefix[9]; - unsigned int i; + u8 *full_info; int err; - const u8 *prev = NULL; - u8 counter = 1; - u8 tmp[HKDF_HASHLEN]; - - if (WARN_ON_ONCE(okmlen > 255 * HKDF_HASHLEN)) - return -EINVAL; + full_info = kzalloc(infolen + 9, GFP_KERNEL); + if (!full_info) + return -ENOMEM; desc->tfm = hkdf->hmac_tfm; - memcpy(prefix, "fscrypt\0", 8); - prefix[8] = context; - - for (i = 0; i < okmlen; i += HKDF_HASHLEN) { - - 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); + memcpy(full_info, "fscrypt\0", 8); + full_info[8] = context; + memcpy(full_info + 9, info, infolen); + + err = hkdf_expand(hkdf->hmac_tfm, full_info, infolen + 9, + okm, okmlen); + kfree_sensitive(full_info); return err; } diff --git a/include/crypto/hkdf.h b/include/crypto/hkdf.h new file mode 100644 index 000000000000..6a9678f508f5 --- /dev/null +++ b/include/crypto/hkdf.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * HKDF: HMAC-based Key Derivation Function (HKDF), RFC 5869 + * + * Extracted from fs/crypto/hkdf.c, which has + * Copyright 2019 Google LLC + */ + +#ifndef _CRYPTO_HKDF_H +#define _CRYPTO_HKDF_H + +#include + +int hkdf_extract(struct crypto_shash *hmac_tfm, const u8 *ikm, + unsigned int ikmlen, const u8 *salt, unsigned int saltlen, + u8 *prk); +int hkdf_expand(struct crypto_shash *hmac_tfm, + const u8 *info, unsigned int infolen, + u8 *okm, unsigned int okmlen); +#endif