From mboxrd@z Thu Jan 1 00:00:00 1970 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 7F2A127D770; Fri, 10 Oct 2025 23:31:51 +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=1760139112; cv=none; b=h0mfxt6sWGNwFCc3cMm3wN7t5Ce0nU0L4JEpLZcYw7zSbGLjb83nCIccxi/nS+b9aJ/d4EYTpCJREJjURmiy2iL7CSHTVxNe9lhID9fBwXWJLKzaXvmN122fKjUy9z+zVRjdAo/cLI3YNnsbY0L3+gjoPWb5UYwCyxSHhYnyBNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760139112; c=relaxed/simple; bh=TKRk43KEUUSuLlo1tb5wxFjSobEi0qjdp5/fqI8sX+4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OjCP4ZxqdcWyfRKT4Z0vk/ZMnig53VYcC9lf0yuEXj9wYEeUdiRFphL0io/EYk/SFWzp2wN6oYPm9GYPdbWBEzNTNajy6V0oHhelUc0aKpByyKuEDMNwd6vkMg+zK44YklqVauoaj1Blq6YDjRIKQ70HdyAi2ehIOBYOW7u72oU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QFTQwtB6; 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="QFTQwtB6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD9B0C4CEF1; Fri, 10 Oct 2025 23:31:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760139111; bh=TKRk43KEUUSuLlo1tb5wxFjSobEi0qjdp5/fqI8sX+4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QFTQwtB6UMXjP+PqNLMi3i6b4Bv6FSGzmyit4SAQlpC6jyh82ksqjKDkVMhm7VYrr SDlZEjnkz3JmSXzbW5sPcLoOLgyWG1XESohyLN12FfdVAWqI6RhRbP5O8zDo4f2lrX cIJibGpz8LSJXE9imYaCVjf2cOh9HtD8ClGnOLIoK90EYqWJPo8/ubdSjQvxF31/1e Dfuw8jtCsMp8tQX64Tw8B1azr7KbNvzt/yCjW/1tlVhC0bK5OfdO1Rc5gGwhIYFwxL phsKItwOgsOnRajVTJUe54OVx2qjeerVZ871NGd7TF6wU9G6wWKTZ6kedh0poTu/aJ IJfp/szvbrCrg== Date: Fri, 10 Oct 2025 16:31:49 -0700 From: Eric Biggers To: Ard Biesheuvel Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, "Jason A . Donenfeld" , Vegard Nossum , Joachim Vandersmissen , David Howells , Linus Torvalds Subject: Re: [PATCH] lib/crypto: Add FIPS pre-operational self-test for SHA algorithms Message-ID: <20251010233149.GA20823@quark> References: <20251006172612.75240-1-ebiggers@kernel.org> <20251007011142.GA77681@sol> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Oct 07, 2025 at 10:52:06AM -0700, Ard Biesheuvel wrote: > On Mon, 6 Oct 2025 at 18:13, Eric Biggers wrote: > > > > On Tue, Oct 07, 2025 at 01:53:25AM +0200, Ard Biesheuvel wrote: > > > On Mon, 6 Oct 2025 at 19:28, Eric Biggers wrote: > > > > > > > > Add FIPS pre-operational 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. > > > > > > > > Link: https://lore.kernel.org/linux-crypto/20250917184856.GA2560@quark/ > > > > Signed-off-by: Eric Biggers > > > > --- > > > > > > > > Since there seemed to be more interest in complaining that these are > > > > missing than actually writing a patch, I decided to just do it. > > > > > > > > lib/crypto/fips.h | 38 +++++++++++++++++++++++++++++ > > > > lib/crypto/sha1.c | 19 ++++++++++++++- > > > > lib/crypto/sha256.c | 19 ++++++++++++++- > > > > lib/crypto/sha512.c | 19 ++++++++++++++- > > > > scripts/crypto/gen-fips-testvecs.py | 33 +++++++++++++++++++++++++ > > > > 5 files changed, 125 insertions(+), 3 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..001059cb0fce4 100644 > > > > --- a/lib/crypto/sha1.c > > > > +++ b/lib/crypto/sha1.c > > > > @@ -10,10 +10,11 @@ > > > > #include > > > > #include > > > > #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 }, > > > > }; > > > > > > > > @@ -328,14 +329,30 @@ void hmac_sha1_usingrawkey(const u8 *raw_key, size_t raw_key_len, > > > > hmac_sha1_update(&ctx, data, data_len); > > > > hmac_sha1_final(&ctx, out); > > > > } > > > > 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 pre-operational 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 pre-operational self-test failed\n"); > > > > + } > > > > return 0; > > > > } > > > > subsys_initcall(sha1_mod_init); > > > > > > > > > > In the builtin case, couldn't this execute only after the first calls > > > into the library? That would mean it does not quite fit the > > > requirements of the pre-operational selftest. > > > > Only if other builtin code in the kernel actually calls it before > > subsys_initcall, i.e. during very early boot long before userspace > > starts. Such calls can occur only from within the FIPS module (i.e. the > > kernel) itself, so arbitrary external users need not be considered here. > > > > Good point. We should probably document this, i.e., the fact that this > is before storage and network etc are even accessible and so panicking > at that point is sufficient even in the presence of even earlier > callers. I'll leave a note in the commit message, but as I mentioned the strategy of running FIPS self-tests in an initcall is already used in other places such as crypto/kdf_sp800108.c. This individual patch isn't a great place to document the strategy that the kernel is using to meet FIPS requirements. That's something that belongs in the (nonexistent) documentation file for fips=1... - Eric