From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B095CC54FCC for ; Tue, 21 Apr 2020 16:16:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89D27206F4 for ; Tue, 21 Apr 2020 16:16:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587485776; bh=qiXf63zWTCGvTjnG70KB7NRulvFM0OVVL4QXB3MGXmc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pne6XqUP/8B7RWv2pTHRTA4F+LsvAy4lIB8eSqE98/TVvK39VhwomP8uh5Hl8lSTP jeuF07x+zbpHvaReeT7DZerq3SR31Gv/grrXvSd1scZM5HZSUN6VQ3jO1G1lokkbjT QPSUOdnozgMunF8CSgaGLFbMJuLdMxPWuWxSO8EU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729212AbgDUQQP (ORCPT ); Tue, 21 Apr 2020 12:16:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:44356 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729203AbgDUQQN (ORCPT ); Tue, 21 Apr 2020 12:16:13 -0400 Received: from gmail.com (unknown [104.132.1.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 18FB4206E9; Tue, 21 Apr 2020 16:16:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587485773; bh=qiXf63zWTCGvTjnG70KB7NRulvFM0OVVL4QXB3MGXmc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nKDhbbd9U21xz25oia5puKhBJCJQbDmVNbR62oq2SH72dJBmUP6HzF2jOjOPGxcUf QpdCdyfhPdcFJ6HVni4y/N5AXhcgDfGJd1F6GgWMVjj1ENDBgad80jv4C2kTBB23Me cUNc0R4ZZRuwkEZ6jj83pGmM4+1Yn7Bk21FFW1Nk= Date: Tue, 21 Apr 2020 09:16:11 -0700 From: Eric Biggers To: Jes Sorensen Cc: Jes Sorensen , linux-fscrypt@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 3/9] Move fsverity_descriptor definition to libfsverity.h Message-ID: <20200421161611.GA95716@gmail.com> References: <20200312214758.343212-1-Jes.Sorensen@gmail.com> <20200312214758.343212-4-Jes.Sorensen@gmail.com> <20200322045722.GC111151@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-fscrypt-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org On Tue, Apr 21, 2020 at 12:07:07PM -0400, Jes Sorensen wrote: > On 3/22/20 12:57 AM, Eric Biggers wrote: > > On Thu, Mar 12, 2020 at 05:47:52PM -0400, Jes Sorensen wrote: > >> From: Jes Sorensen > >> > >> Signed-off-by: Jes Sorensen > >> --- > >> cmd_sign.c | 19 +------------------ > >> libfsverity.h | 26 +++++++++++++++++++++++++- > >> 2 files changed, 26 insertions(+), 19 deletions(-) > >> > >> diff --git a/cmd_sign.c b/cmd_sign.c > >> index dcc44f8..1792084 100644 > >> --- a/cmd_sign.c > >> +++ b/cmd_sign.c > >> @@ -20,26 +20,9 @@ > >> #include > >> > >> #include "commands.h" > >> -#include "fsverity_uapi.h" > >> +#include "libfsverity.h" > >> #include "hash_algs.h" > >> > >> -/* > >> - * Merkle tree properties. The file measurement is the hash of this structure > >> - * excluding the signature and with the sig_size field set to 0. > >> - */ > >> -struct fsverity_descriptor { > >> - __u8 version; /* must be 1 */ > >> - __u8 hash_algorithm; /* Merkle tree hash algorithm */ > >> - __u8 log_blocksize; /* log2 of size of data and tree blocks */ > >> - __u8 salt_size; /* size of salt in bytes; 0 if none */ > >> - __le32 sig_size; /* size of signature in bytes; 0 if none */ > >> - __le64 data_size; /* size of file the Merkle tree is built over */ > >> - __u8 root_hash[64]; /* Merkle tree root hash */ > >> - __u8 salt[32]; /* salt prepended to each hashed block */ > >> - __u8 __reserved[144]; /* must be 0's */ > >> - __u8 signature[]; /* optional PKCS#7 signature */ > >> -}; > >> - > >> /* > >> * Format in which verity file measurements are signed. This is the same as > >> * 'struct fsverity_digest', except here some magic bytes are prepended to > >> diff --git a/libfsverity.h b/libfsverity.h > >> index ceebae1..396a6ee 100644 > >> --- a/libfsverity.h > >> +++ b/libfsverity.h > >> @@ -13,13 +13,14 @@ > >> > >> #include > >> #include > >> +#include > >> > >> #define FS_VERITY_HASH_ALG_SHA256 1 > >> #define FS_VERITY_HASH_ALG_SHA512 2 > >> > >> struct libfsverity_merkle_tree_params { > >> uint16_t version; > >> - uint16_t hash_algorithm; > >> + uint16_t hash_algorithm; /* Matches the digest_algorithm type */ > >> uint32_t block_size; > >> uint32_t salt_size; > >> const uint8_t *salt; > >> @@ -27,6 +28,7 @@ struct libfsverity_merkle_tree_params { > >> }; > >> > >> struct libfsverity_digest { > >> + char magic[8]; /* must be "FSVerity" */ > >> uint16_t digest_algorithm; > >> uint16_t digest_size; > >> uint8_t digest[]; > >> @@ -38,4 +40,26 @@ struct libfsverity_signature_params { > >> uint64_t reserved[11]; > >> }; > >> > >> +/* > >> + * Merkle tree properties. The file measurement is the hash of this structure > >> + * excluding the signature and with the sig_size field set to 0. > >> + */ > >> +struct fsverity_descriptor { > >> + uint8_t version; /* must be 1 */ > >> + uint8_t hash_algorithm; /* Merkle tree hash algorithm */ > >> + uint8_t log_blocksize; /* log2 of size of data and tree blocks */ > >> + uint8_t salt_size; /* size of salt in bytes; 0 if none */ > >> + __le32 sig_size; /* size of signature in bytes; 0 if none */ > >> + __le64 data_size; /* size of file the Merkle tree is built over */ > >> + uint8_t root_hash[64]; /* Merkle tree root hash */ > >> + uint8_t salt[32]; /* salt prepended to each hashed block */ > >> + uint8_t __reserved[144];/* must be 0's */ > >> + uint8_t signature[]; /* optional PKCS#7 signature */ > >> +}; > >> + > > > > I thought there was no need for this to be part of the library API? > > Hi Eric, > > Been busy working on RPM support, but looking at this again now. Given > that the fsverity signature is a hash of the descriptor, I don't see how > we can avoid this? > struct fsverity_descriptor isn't signed directly; it's hashed as an intermediate step in libfsverity_compute_digest(). So why would the library user need the definition of 'struct fsverity_descriptor'? - Eric