From 04cadb4fe0341304741ef60a297366b553f0ce36 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 10 Oct 2025 17:10:47 -0700 Subject: [PATCH] lib/crypto: Add FIPS self-tests for SHA-1 and SHA-2 Add FIPS cryptographic algorithm self-tests for all SHA-1 and SHA-2 algorithms. Following the "Implementation Guidance for FIPS 140-3" document, to achieve this it's sufficient to just test a single test vector for each of HMAC-SHA1, HMAC-SHA256, and HMAC-SHA512. Just run these tests in the initcalls, following the example of e.g. crypto/kdf_sp800108.c. Note that this should meet the FIPS self-test requirement even in the built-in case, given that the initcalls run before userspace, storage, network, etc. are accessible. This does not fix a regression, seeing as lib/ has had SHA-1 support since 2005 and SHA-256 support since 2018. Neither ever had FIPS self-tests. Moreover, fips=1 support has always been an unfinished feature upstream. However, with lib/ now being used more widely, it's now seeing more scrutiny and people seem to want these now [1][2]. [1] https://lore.kernel.org/r/3226361.1758126043@warthog.procyon.org.uk/ [2] https://lore.kernel.org/r/f31dbb22-0add-481c-aee0-e337a7731f8e@oracle.com/ Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20251011001047.51886-1-ebiggers@kernel.org Signed-off-by: Eric Biggers --- lib/crypto/fips.h | 38 +++++++++++++++++++++++++++++ lib/crypto/sha1.c | 19 ++++++++++++++- lib/crypto/sha256.c | 26 +++++++++++++++++--- lib/crypto/sha512.c | 19 ++++++++++++++- scripts/crypto/gen-fips-testvecs.py | 32 ++++++++++++++++++++++++ 5 files changed, 128 insertions(+), 6 deletions(-) create mode 100644 lib/crypto/fips.h create mode 100755 scripts/crypto/gen-fips-testvecs.py diff --git a/lib/crypto/fips.h b/lib/crypto/fips.h new file mode 100644 index 0000000000000..78a1bdd33a151 --- /dev/null +++ b/lib/crypto/fips.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* This file was generated by: gen-fips-testvecs.py */ + +#include + +static const u8 fips_test_data[] __initconst __maybe_unused = { + 0x66, 0x69, 0x70, 0x73, 0x20, 0x74, 0x65, 0x73, + 0x74, 0x20, 0x64, 0x61, 0x74, 0x61, 0x00, 0x00, +}; + +static const u8 fips_test_key[] __initconst __maybe_unused = { + 0x66, 0x69, 0x70, 0x73, 0x20, 0x74, 0x65, 0x73, + 0x74, 0x20, 0x6b, 0x65, 0x79, 0x00, 0x00, 0x00, +}; + +static const u8 fips_test_hmac_sha1_value[] __initconst __maybe_unused = { + 0x29, 0xa9, 0x88, 0xb8, 0x5c, 0xb4, 0xaf, 0x4b, + 0x97, 0x2a, 0xee, 0x87, 0x5b, 0x0a, 0x02, 0x55, + 0x99, 0xbf, 0x86, 0x78, +}; + +static const u8 fips_test_hmac_sha256_value[] __initconst __maybe_unused = { + 0x59, 0x25, 0x85, 0xcc, 0x40, 0xe9, 0x64, 0x2f, + 0xe9, 0xbf, 0x82, 0xb7, 0xd3, 0x15, 0x3d, 0x43, + 0x22, 0x0b, 0x4c, 0x00, 0x90, 0x14, 0x25, 0xcf, + 0x9e, 0x13, 0x2b, 0xc2, 0x30, 0xe6, 0xe8, 0x93, +}; + +static const u8 fips_test_hmac_sha512_value[] __initconst __maybe_unused = { + 0x6b, 0xea, 0x5d, 0x27, 0x49, 0x5b, 0x3f, 0xea, + 0xde, 0x2d, 0xfa, 0x32, 0x75, 0xdb, 0x77, 0xc8, + 0x26, 0xe9, 0x4e, 0x95, 0x4d, 0xad, 0x88, 0x02, + 0x87, 0xf9, 0x52, 0x0a, 0xd1, 0x92, 0x80, 0x1d, + 0x92, 0x7e, 0x3c, 0xbd, 0xb1, 0x3c, 0x49, 0x98, + 0x44, 0x9c, 0x8f, 0xee, 0x3f, 0x02, 0x71, 0x51, + 0x57, 0x0b, 0x15, 0x38, 0x95, 0xd8, 0xa3, 0x81, + 0xba, 0xb3, 0x15, 0x37, 0x5c, 0x6d, 0x57, 0x2b, +}; diff --git a/lib/crypto/sha1.c b/lib/crypto/sha1.c index 5904e4ae85d24..52788278cd17f 100644 --- a/lib/crypto/sha1.c +++ b/lib/crypto/sha1.c @@ -12,6 +12,7 @@ #include #include #include +#include "fips.h" static const struct sha1_block_state sha1_iv = { .h = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 }, @@ -330,10 +331,26 @@ void hmac_sha1_usingrawkey(const u8 *raw_key, size_t raw_key_len, } EXPORT_SYMBOL_GPL(hmac_sha1_usingrawkey); -#ifdef sha1_mod_init_arch +#if defined(sha1_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS) static int __init sha1_mod_init(void) { +#ifdef sha1_mod_init_arch sha1_mod_init_arch(); +#endif + if (fips_enabled) { + /* + * FIPS cryptographic algorithm self-test. As per the FIPS + * Implementation Guidance, testing HMAC-SHA1 satisfies the test + * requirement for SHA-1 too. + */ + u8 mac[SHA1_DIGEST_SIZE]; + + hmac_sha1_usingrawkey(fips_test_key, sizeof(fips_test_key), + fips_test_data, sizeof(fips_test_data), + mac); + if (memcmp(fips_test_hmac_sha1_value, mac, sizeof(mac)) != 0) + panic("sha1: FIPS self-test failed\n"); + } return 0; } subsys_initcall(sha1_mod_init); diff --git a/lib/crypto/sha256.c b/lib/crypto/sha256.c index 881b935418cea..5d6b77e7e1416 100644 --- a/lib/crypto/sha256.c +++ b/lib/crypto/sha256.c @@ -17,6 +17,7 @@ #include #include #include +#include "fips.h" static const struct sha256_block_state sha224_iv = { .h = { @@ -269,8 +270,8 @@ void sha256(const u8 *data, size_t len, u8 out[SHA256_DIGEST_SIZE]) EXPORT_SYMBOL(sha256); /* - * Pre-boot environment (as indicated by __DISABLE_EXPORTS being defined) - * doesn't need either HMAC support or interleaved hashing support + * Pre-boot environments (as indicated by __DISABLE_EXPORTS being defined) just + * need the generic SHA-256 code. Omit all other features from them. */ #ifndef __DISABLE_EXPORTS @@ -477,12 +478,27 @@ void hmac_sha256_usingrawkey(const u8 *raw_key, size_t raw_key_len, hmac_sha256_final(&ctx, out); } EXPORT_SYMBOL_GPL(hmac_sha256_usingrawkey); -#endif /* !__DISABLE_EXPORTS */ -#ifdef sha256_mod_init_arch +#if defined(sha256_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS) static int __init sha256_mod_init(void) { +#ifdef sha256_mod_init_arch sha256_mod_init_arch(); +#endif + if (fips_enabled) { + /* + * FIPS cryptographic algorithm self-test. As per the FIPS + * Implementation Guidance, testing HMAC-SHA256 satisfies the + * test requirement for SHA-224, SHA-256, and HMAC-SHA224 too. + */ + u8 mac[SHA256_DIGEST_SIZE]; + + hmac_sha256_usingrawkey(fips_test_key, sizeof(fips_test_key), + fips_test_data, sizeof(fips_test_data), + mac); + if (memcmp(fips_test_hmac_sha256_value, mac, sizeof(mac)) != 0) + panic("sha256: FIPS self-test failed\n"); + } return 0; } subsys_initcall(sha256_mod_init); @@ -493,5 +509,7 @@ static void __exit sha256_mod_exit(void) module_exit(sha256_mod_exit); #endif +#endif /* !__DISABLE_EXPORTS */ + MODULE_DESCRIPTION("SHA-224, SHA-256, HMAC-SHA224, and HMAC-SHA256 library functions"); MODULE_LICENSE("GPL"); diff --git a/lib/crypto/sha512.c b/lib/crypto/sha512.c index d8062188be98a..605eab51aabd5 100644 --- a/lib/crypto/sha512.c +++ b/lib/crypto/sha512.c @@ -17,6 +17,7 @@ #include #include #include +#include "fips.h" static const struct sha512_block_state sha384_iv = { .h = { @@ -405,10 +406,26 @@ void hmac_sha512_usingrawkey(const u8 *raw_key, size_t raw_key_len, } EXPORT_SYMBOL_GPL(hmac_sha512_usingrawkey); -#ifdef sha512_mod_init_arch +#if defined(sha512_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS) static int __init sha512_mod_init(void) { +#ifdef sha512_mod_init_arch sha512_mod_init_arch(); +#endif + if (fips_enabled) { + /* + * FIPS cryptographic algorithm self-test. As per the FIPS + * Implementation Guidance, testing HMAC-SHA512 satisfies the + * test requirement for SHA-384, SHA-512, and HMAC-SHA384 too. + */ + u8 mac[SHA512_DIGEST_SIZE]; + + hmac_sha512_usingrawkey(fips_test_key, sizeof(fips_test_key), + fips_test_data, sizeof(fips_test_data), + mac); + if (memcmp(fips_test_hmac_sha512_value, mac, sizeof(mac)) != 0) + panic("sha512: FIPS self-test failed\n"); + } return 0; } subsys_initcall(sha512_mod_init); diff --git a/scripts/crypto/gen-fips-testvecs.py b/scripts/crypto/gen-fips-testvecs.py new file mode 100755 index 0000000000000..2956f88b764ae --- /dev/null +++ b/scripts/crypto/gen-fips-testvecs.py @@ -0,0 +1,32 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0-or-later +# +# Script that generates lib/crypto/fips.h +# +# Copyright 2025 Google LLC + +import hmac + +fips_test_data = b"fips test data\0\0" +fips_test_key = b"fips test key\0\0\0" + +def print_static_u8_array_definition(name, value): + print('') + print(f'static const u8 {name}[] __initconst __maybe_unused = {{') + for i in range(0, len(value), 8): + line = '\t' + ''.join(f'0x{b:02x}, ' for b in value[i:i+8]) + print(f'{line.rstrip()}') + print('};') + +print('/* SPDX-License-Identifier: GPL-2.0-or-later */') +print(f'/* This file was generated by: gen-fips-testvecs.py */') +print() +print('#include ') + +print_static_u8_array_definition("fips_test_data", fips_test_data) +print_static_u8_array_definition("fips_test_key", fips_test_key) + +for alg in 'sha1', 'sha256', 'sha512': + ctx = hmac.new(fips_test_key, digestmod=alg) + ctx.update(fips_test_data) + print_static_u8_array_definition(f'fips_test_hmac_{alg}_value', ctx.digest()) -- 2.47.3