From patchwork Thu Jun 29 00:28:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296461 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95319EB64D7 for ; Thu, 29 Jun 2023 00:35:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231450AbjF2Afl (ORCPT ); Wed, 28 Jun 2023 20:35:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231290AbjF2AfW (ORCPT ); Wed, 28 Jun 2023 20:35:22 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6CEC210E; Wed, 28 Jun 2023 17:35:19 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id 9383E8079D; Wed, 28 Jun 2023 20:29:10 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998550; bh=g0b35MrtF2uGyl8iDzN5bX4Wn/xb7o1sAgwZ2In2a1o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KzBiXw++myjXzO26U4YjM+kDm2tABjv2ds31/P3BmSkbXKCQOYUe95Pg8hX1bxZyo mcRR9YrKef7n/GlzxmLrj/2yrXf77SJLtPkFVI7mBGnRPZkez5qdSdmRvusLwhrNbe 2aNmqnn7AxD3F3YsJgGu0HT3vJfvW+arb/kdnUCljJdCOzGm//AtE1vrL8/f2tF+gx ggsSAPz3PsISfV4VHFB1CTyTp2Q4QHGF+jSgMxYz39JkjuQCZclJz9lqtDobKBNaDD XNTCREok7mt1olhg5owvCbOaUFnxR6vEcX5SHz7W48mTxLQh1vjJP0JQ3sHyi/XcIQ QFT1UL/lIPEHg== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 1/8] fscrypt: move inline crypt decision to info setup Date: Wed, 28 Jun 2023 20:28:51 -0400 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org setup_file_encryption_key() is doing a lot of things at the moment -- setting the crypt_info's inline encryption bit, finding and locking a master key, and calling the functions to get the appropriate prepared key for this info. Since setting the inline encryption bit has nothing to do with finding the master key, it's easy and hopefully clearer to select the encryption implementation in fscrypt_setup_encryption_info(), the main fscrypt_info setup function, instead of in setup_file_encryption_key() which will long-term only deal in setting up the prepared key for the info. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 361f41ef46c7..b89c32ad19fb 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -443,10 +443,6 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, struct fscrypt_master_key *mk; int err; - err = fscrypt_select_encryption_impl(ci); - if (err) - return err; - err = fscrypt_policy_to_key_spec(&ci->ci_policy, &mk_spec); if (err) return err; @@ -580,6 +576,10 @@ fscrypt_setup_encryption_info(struct inode *inode, WARN_ON_ONCE(mode->ivsize > FSCRYPT_MAX_IV_SIZE); crypt_info->ci_mode = mode; + res = fscrypt_select_encryption_impl(crypt_info); + if (res) + goto out; + res = setup_file_encryption_key(crypt_info, need_dirhash_key, &mk); if (res) goto out; From patchwork Thu Jun 29 00:28:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296462 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F63EEB64DA for ; Thu, 29 Jun 2023 00:35:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231443AbjF2Afo (ORCPT ); Wed, 28 Jun 2023 20:35:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231359AbjF2AfW (ORCPT ); Wed, 28 Jun 2023 20:35:22 -0400 Received: from box.fidei.email (box.fidei.email [IPv6:2605:2700:0:2:a800:ff:feba:dc44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1363F2961; Wed, 28 Jun 2023 17:35:19 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id D1509807A9; Wed, 28 Jun 2023 20:29:12 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998553; bh=zpbsNmNWpCCseiP3oLkRBDQESuU4ORz8TCsKQNmW/kg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dyPiF14BwnSAp66L4ZgdGkD47oR0m93nb5iJY4kzvD6G0Jvq0u4Uv2f0yuDbGM/B7 OkC5gGFdbgzo++rJDLTaJY/dXRWlYPhYW57A0Jy7E/YwJ/8Y5gbjNNo6MTBz+SyzNO GpVJWOXwwzQc+87IpD2ZAJULoUEY+3Xtuhgc2wGcUISTLJ6bVy7iOW3Ul1pXx6TXXR TNOH7KnE3YCetskxW36Jd1voiuMzj47LPHfBsh4KXgfH+cMWwbfct3ya0oNOZDfJfk S0E9j5fBo3cnng9uHk+XY3ZKMmwl116Cv7vW7AN70sQwH2DqIe5O0tUSUzMaAsEq0/ olFQPsd3WORTA== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 2/8] fscrypt: split and rename setup_file_encryption_key() Date: Wed, 28 Jun 2023 20:28:52 -0400 Message-Id: <741d936ed04b00a6122f0043c00f261116bee8b3.1687988119.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org At present, setup_file_encryption_key() does several things: it finds and locks the master key, and then calls into the appropriate functions to setup the prepared key for the fscrypt_info. The code is clearer to follow if these functions are divided. Thus, move calling the appropriate file key setup function into a new fscrypt_setup_file_key() function. After the file key setup functions are moved, the remaining function can take a const fscrypt_info, and is renamed find_and_lock_master_key() to precisely describe its action. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 77 ++++++++++++++++++++++++++++++-------------- 1 file changed, 52 insertions(+), 25 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index b89c32ad19fb..727d473b6b03 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -386,6 +386,43 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, return 0; } +/* + * Find or create the appropriate prepared key for an info. + */ +static int fscrypt_setup_file_key(struct fscrypt_info *ci, + struct fscrypt_master_key *mk, + bool need_dirhash_key) +{ + int err; + + if (!mk) { + if (ci->ci_policy.version != FSCRYPT_POLICY_V1) + return -ENOKEY; + + /* + * As a legacy fallback for v1 policies, search for the key in + * the current task's subscribed keyrings too. Don't move this + * to before the search of ->s_master_keys, since users + * shouldn't be able to override filesystem-level keys. + */ + return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci); + } + + switch (ci->ci_policy.version) { + case FSCRYPT_POLICY_V1: + err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw); + break; + case FSCRYPT_POLICY_V2: + err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key); + break; + default: + WARN_ON_ONCE(1); + err = -EINVAL; + break; + } + return err; +} + /* * Check whether the size of the given master key (@mk) is appropriate for the * encryption settings which a particular file will use (@ci). @@ -426,7 +463,7 @@ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk, } /* - * Find the master key, then set up the inode's actual encryption key. + * Find and lock the master key. * * If the master key is found in the filesystem-level keyring, then it is * returned in *mk_ret with its semaphore read-locked. This is needed to ensure @@ -434,9 +471,8 @@ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk, * multiple tasks may race to create an fscrypt_info for the same inode), and to * synchronize the master key being removed with a new inode starting to use it. */ -static int setup_file_encryption_key(struct fscrypt_info *ci, - bool need_dirhash_key, - struct fscrypt_master_key **mk_ret) +static int find_and_lock_master_key(const struct fscrypt_info *ci, + struct fscrypt_master_key **mk_ret) { struct super_block *sb = ci->ci_inode->i_sb; struct fscrypt_key_specifier mk_spec; @@ -466,17 +502,19 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, mk = fscrypt_find_master_key(sb, &mk_spec); } } + if (unlikely(!mk)) { if (ci->ci_policy.version != FSCRYPT_POLICY_V1) return -ENOKEY; /* - * As a legacy fallback for v1 policies, search for the key in - * the current task's subscribed keyrings too. Don't move this - * to before the search of ->s_master_keys, since users - * shouldn't be able to override filesystem-level keys. + * This might be the case of a v1 policy using a process + * subscribed keyring to get the key, so there may not be + * a relevant master key. */ - return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci); + + *mk_ret = NULL; + return 0; } down_read(&mk->mk_sem); @@ -491,21 +529,6 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, goto out_release_key; } - switch (ci->ci_policy.version) { - case FSCRYPT_POLICY_V1: - err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw); - break; - case FSCRYPT_POLICY_V2: - err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key); - break; - default: - WARN_ON_ONCE(1); - err = -EINVAL; - break; - } - if (err) - goto out_release_key; - *mk_ret = mk; return 0; @@ -580,7 +603,11 @@ fscrypt_setup_encryption_info(struct inode *inode, if (res) goto out; - res = setup_file_encryption_key(crypt_info, need_dirhash_key, &mk); + res = find_and_lock_master_key(crypt_info, &mk); + if (res) + goto out; + + res = fscrypt_setup_file_key(crypt_info, mk, need_dirhash_key); if (res) goto out; From patchwork Thu Jun 29 00:28:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296456 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65D25EB64DA for ; Thu, 29 Jun 2023 00:35:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231406AbjF2AfW (ORCPT ); Wed, 28 Jun 2023 20:35:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231163AbjF2AfT (ORCPT ); Wed, 28 Jun 2023 20:35:19 -0400 Received: from box.fidei.email (box.fidei.email [IPv6:2605:2700:0:2:a800:ff:feba:dc44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC1D02974; Wed, 28 Jun 2023 17:35:16 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id 41954807AB; Wed, 28 Jun 2023 20:29:14 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998554; bh=MhssaHe42P1YaJLQvR8+R97cFL/z5+llAHC0nxnZQIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DUvpcW3l4CMbdTWE8C7OjX0NbUVMsVdiPnUyU2aUwvvLLmZi4hbKN3lzonlVSJfA5 fAnTXGRVWom8IEg07758IFF5YWzaxzji6WYD9ItEKCj6W1cHKfDBuCcspXrz/pHNq4 orchyJFgqu84UWsAD5Gu5P29Ya+COMvPlSqsuLZNc8CAP6CeyfLbmUoZxCtkirkKs0 7+kyBtwQq6ULOuYBoKwJR4YoZZvTDkCCfTlHJ5O1D/nK/lw8TyMzYH376F5Dm0HSZM Pr8SuGGTZKzvjFjG0ko8BeA832In7/8Of0AX97rLOIOpnaShptCw4HSw5LKgcDToiw s1VP5l+p5Xvxg== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 3/8] fscrypt: split setup_per_mode_enc_key() Date: Wed, 28 Jun 2023 20:28:53 -0400 Message-Id: <0ba2cb228aa367aea1442b8f1433f229040fe8dd.1687988119.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org At present, setup_per_mode_enc_key() tries to find, within an array of mode keys in the master key, an already prepared key, and if it doesn't find a pre-prepared key, sets up a new one. This caching is not super clear, at least to me, and splitting this function makes it clearer. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 59 +++++++++++++++++++++++++++----------------- 1 file changed, 36 insertions(+), 23 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 727d473b6b03..69bd27b7e9d8 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -184,34 +184,24 @@ int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key) return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci); } -static int setup_per_mode_enc_key(struct fscrypt_info *ci, - struct fscrypt_master_key *mk, - struct fscrypt_prepared_key *keys, - u8 hkdf_context, bool include_fs_uuid) +static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, + struct fscrypt_prepared_key *prep_key, + const struct fscrypt_info *ci, + u8 hkdf_context, bool include_fs_uuid) { const struct inode *inode = ci->ci_inode; const struct super_block *sb = inode->i_sb; struct fscrypt_mode *mode = ci->ci_mode; const u8 mode_num = mode - fscrypt_modes; - struct fscrypt_prepared_key *prep_key; u8 mode_key[FSCRYPT_MAX_KEY_SIZE]; u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)]; unsigned int hkdf_infolen = 0; int err; - if (WARN_ON_ONCE(mode_num > FSCRYPT_MODE_MAX)) - return -EINVAL; - - prep_key = &keys[mode_num]; - if (fscrypt_is_key_prepared(prep_key, ci)) { - ci->ci_enc_key = *prep_key; - return 0; - } - mutex_lock(&fscrypt_mode_key_setup_mutex); if (fscrypt_is_key_prepared(prep_key, ci)) - goto done_unlock; + goto out_unlock; BUILD_BUG_ON(sizeof(mode_num) != 1); BUILD_BUG_ON(sizeof(sb->s_uuid) != 16); @@ -229,16 +219,39 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci, goto out_unlock; err = fscrypt_prepare_key(prep_key, mode_key, ci); memzero_explicit(mode_key, mode->keysize); - if (err) - goto out_unlock; -done_unlock: - ci->ci_enc_key = *prep_key; - err = 0; + out_unlock: mutex_unlock(&fscrypt_mode_key_setup_mutex); return err; } +static int find_mode_prepared_key(struct fscrypt_info *ci, + struct fscrypt_master_key *mk, + struct fscrypt_prepared_key *keys, + u8 hkdf_context, bool include_fs_uuid) +{ + struct fscrypt_mode *mode = ci->ci_mode; + const u8 mode_num = mode - fscrypt_modes; + struct fscrypt_prepared_key *prep_key; + int err; + + if (WARN_ON_ONCE(mode_num > FSCRYPT_MODE_MAX)) + return -EINVAL; + + prep_key = &keys[mode_num]; + if (fscrypt_is_key_prepared(prep_key, ci)) { + ci->ci_enc_key = *prep_key; + return 0; + } + err = setup_new_mode_prepared_key(mk, prep_key, ci, hkdf_context, + include_fs_uuid); + if (err) + return err; + + ci->ci_enc_key = *prep_key; + return 0; +} + /* * Derive a SipHash key from the given fscrypt master key and the given * application-specific information string. @@ -294,7 +307,7 @@ static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci, { int err; - err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_32_keys, + err = find_mode_prepared_key(ci, mk, mk->mk_iv_ino_lblk_32_keys, HKDF_CONTEXT_IV_INO_LBLK_32_KEY, true); if (err) return err; @@ -344,7 +357,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * encryption key. This ensures that the master key is * consistently used only for HKDF, avoiding key reuse issues. */ - err = setup_per_mode_enc_key(ci, mk, mk->mk_direct_keys, + err = find_mode_prepared_key(ci, mk, mk->mk_direct_keys, HKDF_CONTEXT_DIRECT_KEY, false); } else if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) { @@ -354,7 +367,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * the IVs. This format is optimized for use with inline * encryption hardware compliant with the UFS standard. */ - err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_64_keys, + err = find_mode_prepared_key(ci, mk, mk->mk_iv_ino_lblk_64_keys, HKDF_CONTEXT_IV_INO_LBLK_64_KEY, true); } else if (ci->ci_policy.v2.flags & From patchwork Thu Jun 29 00:28:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296457 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44B30EB64DD for ; Thu, 29 Jun 2023 00:35:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231300AbjF2Af1 (ORCPT ); Wed, 28 Jun 2023 20:35:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231253AbjF2AfT (ORCPT ); Wed, 28 Jun 2023 20:35:19 -0400 Received: from box.fidei.email (box.fidei.email [IPv6:2605:2700:0:2:a800:ff:feba:dc44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49E63297C; Wed, 28 Jun 2023 17:35:16 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id CB774807B7; Wed, 28 Jun 2023 20:29:15 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998556; bh=YqRRDWI4Q3S+nsoV4rR7qxoo++Y30XsC6x8HLIhWvkQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SZ1Vd1SKJ1X2CtCTuhtuxgVbtLoLVJFmEa0f4scBw8OgUodlXjidgqX8IB50sYlSf Km5VGglTbkOi71y0UJftEt2pWHbD24x55Yqt7Ac9l1XPshS5OE2VmzViAWpsic6OWe XJyhmSUMtmmkFBKsP3rafPrDguFsMUOj+gppQH6FA3096VzHhdjhe93SCAQ8lU9pkm kn3H6plI2bq8deaBSa+klDcq/T+Ir05NwDYt4h4AjjLbXjREsap7S2y4ZnJMXUmWKZ blDa/5y8SJ34Pex3SyuCUMdKmDlbxzqlUJgwyZcNp9TuHMIEjnpDn/Xu8jaUN5M8vb FJdTHp9XqBCcQ== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 4/8] fscrypt: move dirhash key setup away from IO key setup Date: Wed, 28 Jun 2023 20:28:54 -0400 Message-Id: <143406026caa2f73865dbc448533fb96735f896d.1687988119.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org The function named fscrypt_setup_v2_file_key() has as its main focus the setting up of the fscrypt_info's ci_enc_key member, the prepared key with which filenames or file contents are encrypted or decrypted. However, it currently also sets up the dirhash key, used by some directories, based on a parameter. There are no dependencies on setting up the dirhash key beyond having the master key locked, and it's clearer having fscrypt_setup_file_key() be only about setting up the prepared key for IO. Thus, move dirhash key setup to fscrypt_setup_encryption_info(), which calls out to each function setting up parts of the fscrypt_info, and stop passing the need_dirhash_key parameter around. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 69bd27b7e9d8..302a1ccde439 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -343,8 +343,7 @@ static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci, } static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, - struct fscrypt_master_key *mk, - bool need_dirhash_key) + struct fscrypt_master_key *mk) { int err; @@ -386,25 +385,15 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, err = fscrypt_set_per_file_enc_key(ci, derived_key); memzero_explicit(derived_key, ci->ci_mode->keysize); } - if (err) - return err; - /* Derive a secret dirhash key for directories that need it. */ - if (need_dirhash_key) { - err = fscrypt_derive_dirhash_key(ci, mk); - if (err) - return err; - } - - return 0; + return err; } /* * Find or create the appropriate prepared key for an info. */ static int fscrypt_setup_file_key(struct fscrypt_info *ci, - struct fscrypt_master_key *mk, - bool need_dirhash_key) + struct fscrypt_master_key *mk) { int err; @@ -426,7 +415,7 @@ static int fscrypt_setup_file_key(struct fscrypt_info *ci, err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw); break; case FSCRYPT_POLICY_V2: - err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key); + err = fscrypt_setup_v2_file_key(ci, mk); break; default: WARN_ON_ONCE(1); @@ -620,10 +609,26 @@ fscrypt_setup_encryption_info(struct inode *inode, if (res) goto out; - res = fscrypt_setup_file_key(crypt_info, mk, need_dirhash_key); + res = fscrypt_setup_file_key(crypt_info, mk); if (res) goto out; + /* + * Derive a secret dirhash key for directories that need it. It + * should be impossible to set flags such that a v1 policy sets + * need_dirhash_key, but check it anyway. + */ + if (need_dirhash_key) { + if (WARN_ON_ONCE(policy->version == FSCRYPT_POLICY_V1)) { + res = -EINVAL; + goto out; + } + + res = fscrypt_derive_dirhash_key(crypt_info, mk); + if (res) + goto out; + } + /* * For existing inodes, multiple tasks may race to set ->i_crypt_info. * So use cmpxchg_release(). This pairs with the smp_load_acquire() in From patchwork Thu Jun 29 00:28:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296454 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A6DEEB64D7 for ; Thu, 29 Jun 2023 00:35:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230492AbjF2AfU (ORCPT ); Wed, 28 Jun 2023 20:35:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231208AbjF2AfT (ORCPT ); Wed, 28 Jun 2023 20:35:19 -0400 Received: from box.fidei.email (box.fidei.email [IPv6:2605:2700:0:2:a800:ff:feba:dc44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 192D02979; Wed, 28 Jun 2023 17:35:16 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id 40469807BF; Wed, 28 Jun 2023 20:29:17 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998557; bh=+8DZxpJFKaFfo1GwUlCINDS5EWG3O4GW/P3hhF6pzcA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S3heQ/4RouvtPrKerWNnwxB6ka3+sN5urA2BxuanKZ6AxiqE/3oHgBKSR3tFHg82x IJ4xe1BC3Ghyw6pxPlWnkJaSn+AE4JBNHImix7byUz4jzfM7znwk3ZPZSYgSN/Dn+r JrkWdXcpfJuHomkUTJJnQMbl6wTkec6wPZzRdoyCS/a8vYmU1cxlXRu9t6mtYSB8gf JyocU8OL/6kTROA9umhmoJZ38lUhrXWHuA/TgbaLjyPFX5Us5tHa6ue8qeAr7J4iZE FQuvSREOQRyIsdMKadXoHtdvaC7NP+q10WO2BXGygPKq44Gq/g2E7fIShiGpzwdnuJ nYHixs8RK2RMQ== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 5/8] fscrypt: reduce special-casing of IV_INO_LBLK_32 Date: Wed, 28 Jun 2023 20:28:55 -0400 Message-Id: <761a44f07219a83c7b5d30990922f07363a4e305.1687988119.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Right now, the IV_INO_LBLK_32 policy is handled by its own function called in fscrypt_setup_v2_file_key(), different from all other policies which just call find_mode_prepared_key() with various parameters. The function additionally sets up the relevant inode hashing key in the master key, and uses it to hash the inode number if possible. This is not particularly relevant to setting up a prepared key, so this change tries to make it clear that every non-default policy uses basically the same setup mechanism for its prepared key. The other setup is moved to be called from the top crypt_info setup function. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 62 +++++++++++++++++++++++--------------------- 1 file changed, 32 insertions(+), 30 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 302a1ccde439..0648ae22ecc4 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -302,44 +302,30 @@ void fscrypt_hash_inode_number(struct fscrypt_info *ci, &mk->mk_ino_hash_key); } -static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci, - struct fscrypt_master_key *mk) +static int fscrypt_setup_ino_hash_key(struct fscrypt_master_key *mk) { int err; - err = find_mode_prepared_key(ci, mk, mk->mk_iv_ino_lblk_32_keys, - HKDF_CONTEXT_IV_INO_LBLK_32_KEY, true); - if (err) - return err; - /* pairs with smp_store_release() below */ - if (!smp_load_acquire(&mk->mk_ino_hash_key_initialized)) { + if (smp_load_acquire(&mk->mk_ino_hash_key_initialized)) + return 0; - mutex_lock(&fscrypt_mode_key_setup_mutex); + mutex_lock(&fscrypt_mode_key_setup_mutex); - if (mk->mk_ino_hash_key_initialized) - goto unlock; + if (mk->mk_ino_hash_key_initialized) + goto unlock; - err = fscrypt_derive_siphash_key(mk, - HKDF_CONTEXT_INODE_HASH_KEY, - NULL, 0, &mk->mk_ino_hash_key); - if (err) - goto unlock; - /* pairs with smp_load_acquire() above */ - smp_store_release(&mk->mk_ino_hash_key_initialized, true); + err = fscrypt_derive_siphash_key(mk, + HKDF_CONTEXT_INODE_HASH_KEY, + NULL, 0, &mk->mk_ino_hash_key); + if (err) + goto unlock; + /* pairs with smp_load_acquire() above */ + smp_store_release(&mk->mk_ino_hash_key_initialized, true); unlock: - mutex_unlock(&fscrypt_mode_key_setup_mutex); - if (err) - return err; - } + mutex_unlock(&fscrypt_mode_key_setup_mutex); - /* - * New inodes may not have an inode number assigned yet. - * Hashing their inode number is delayed until later. - */ - if (ci->ci_inode->i_ino) - fscrypt_hash_inode_number(ci, mk); - return 0; + return err; } static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, @@ -371,7 +357,9 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, true); } else if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) { - err = fscrypt_setup_iv_ino_lblk_32_key(ci, mk); + err = find_mode_prepared_key(ci, mk, mk->mk_iv_ino_lblk_32_keys, + HKDF_CONTEXT_IV_INO_LBLK_32_KEY, + true); } else { u8 derived_key[FSCRYPT_MAX_KEY_SIZE]; @@ -629,6 +617,20 @@ fscrypt_setup_encryption_info(struct inode *inode, goto out; } + /* + * The IV_INO_LBLK_32 policy needs a hashed inode number, but new + * inodes may not have an inode number assigned yet. + */ + if (policy->version == FSCRYPT_POLICY_V2 && + (policy->v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) { + res = fscrypt_setup_ino_hash_key(mk); + if (res) + goto out; + + if (inode->i_ino) + fscrypt_hash_inode_number(crypt_info, mk); + } + /* * For existing inodes, multiple tasks may race to set ->i_crypt_info. * So use cmpxchg_release(). This pairs with the smp_load_acquire() in From patchwork Thu Jun 29 00:28:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296455 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50DCFEB64D7 for ; Thu, 29 Jun 2023 00:35:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231273AbjF2AfZ (ORCPT ); Wed, 28 Jun 2023 20:35:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231249AbjF2AfT (ORCPT ); Wed, 28 Jun 2023 20:35:19 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39596297B; Wed, 28 Jun 2023 17:35:16 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id BB4FC807D8; Wed, 28 Jun 2023 20:29:18 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998559; bh=tKGg0Y0E/v95hp35rLNHlzWWV3bK2WTyoT2Z8orPn4k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bt2sJhragF1CQrICtdpOW0F8IBGvSO3avOuQEbRWaLHgbNNGdjE99zdSyMyCZpTqg B+9xnFCmzczIl3FRWvcEXoVgT6LHzsz+zC5kz5IiN+nzAPOAqFRJwFmm3zROtuC33v zmARubiAwRBgxxmcf4aSRHh/PDeGrkjz7tXMxfiGf/if2X8vZRsf4tO2lGLNKXCrv6 CIR3EcEBCpqTL+Lf/LC41+rcRtHrZOFN/DsBoVSlbdYeAHEbtnqGf2f4FzWSR8dVZY 6S/coDTm8Qfhp7NLgnqXmiGOZKOlqcTgArscfxDUsbQbagx0CGNChcd8JEMhKQz3WU ei35eRgYmzUrA== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 6/8] fscrypt: move all the shared mode key setup deeper Date: Wed, 28 Jun 2023 20:28:56 -0400 Message-Id: <60c9f5833997e942a7c5ebda7a54d0ee7d21f524.1687988119.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Currently, fscrypt_setup_v2_file_key() has a set of ifs which encode various information about how to set up a new mode key if necessary for a shared-key policy (DIRECT or IV_INO_LBLK_*). This is somewhat awkward -- this information is only needed at the point that we need to setup a new key, which is not the common case; the setup details are recorded as function parameters relatively far from where they're actually used; and at the point we use the parameters, we can derive the information equally well. So this moves mode and policy checking as deep into the callstack as possible. mk_prepared_key_for_mode_policy() deals with the array lookup within a master key. And fill_hkdf_info_for mode_key() deals with filling in the hkdf info as necessary for a particular policy. These seem a little clearer in broad strokes, emphasizing the similarities between the policies, but it does spread out the information on how the key is derived for a particular policy more. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 131 +++++++++++++++++++++++++++++-------------- 1 file changed, 88 insertions(+), 43 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 0648ae22ecc4..111940b91456 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -13,6 +13,17 @@ #include "fscrypt_private.h" +#define MAX_MODE_KEY_HKDF_INFO_SIZE 17 + +/* + * Constant defining the various policy flags which require a non-default key + * policy. + */ +#define FSCRYPT_POLICY_FLAGS_KEY_MASK \ + (FSCRYPT_POLICY_FLAG_DIRECT_KEY \ + | FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 \ + | FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) + struct fscrypt_mode fscrypt_modes[] = { [FSCRYPT_MODE_AES_256_XTS] = { .friendly_name = "AES-256-XTS", @@ -184,20 +195,83 @@ int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key) return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci); } +static struct fscrypt_prepared_key * +mk_prepared_key_for_mode_policy(struct fscrypt_master_key *mk, + union fscrypt_policy *policy, + struct fscrypt_mode *mode) +{ + const u8 mode_num = mode - fscrypt_modes; + + switch (policy->v2.flags & FSCRYPT_POLICY_FLAGS_KEY_MASK) { + case FSCRYPT_POLICY_FLAG_DIRECT_KEY: + return &mk->mk_direct_keys[mode_num]; + case FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64: + return &mk->mk_iv_ino_lblk_64_keys[mode_num]; + case FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32: + return &mk->mk_iv_ino_lblk_32_keys[mode_num]; + default: + return ERR_PTR(-EINVAL); + } +} + +static size_t +fill_hkdf_info_for_mode_key(const struct fscrypt_info *ci, + u8 hkdf_info[MAX_MODE_KEY_HKDF_INFO_SIZE]) +{ + const u8 mode_num = ci->ci_mode - fscrypt_modes; + const struct super_block *sb = ci->ci_inode->i_sb; + u8 hkdf_infolen = 0; + + hkdf_info[hkdf_infolen++] = mode_num; + if (!(ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)) { + memcpy(&hkdf_info[hkdf_infolen], &sb->s_uuid, + sizeof(sb->s_uuid)); + hkdf_infolen += sizeof(sb->s_uuid); + } + return hkdf_infolen; +} + static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, struct fscrypt_prepared_key *prep_key, - const struct fscrypt_info *ci, - u8 hkdf_context, bool include_fs_uuid) + const struct fscrypt_info *ci) { const struct inode *inode = ci->ci_inode; const struct super_block *sb = inode->i_sb; + unsigned int policy_flags = fscrypt_policy_flags(&ci->ci_policy); struct fscrypt_mode *mode = ci->ci_mode; const u8 mode_num = mode - fscrypt_modes; u8 mode_key[FSCRYPT_MAX_KEY_SIZE]; u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)]; unsigned int hkdf_infolen = 0; + u8 hkdf_context = 0; int err; + switch (policy_flags & FSCRYPT_POLICY_FLAGS_KEY_MASK) { + case FSCRYPT_POLICY_FLAG_DIRECT_KEY: + hkdf_context = HKDF_CONTEXT_DIRECT_KEY; + break; + case FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64: + hkdf_context = HKDF_CONTEXT_IV_INO_LBLK_64_KEY; + break; + case FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32: + hkdf_context = HKDF_CONTEXT_IV_INO_LBLK_32_KEY; + break; + } + + /* + * For DIRECT_KEY policies: instead of deriving per-file encryption + * keys, the per-file nonce will be included in all the IVs. But + * unlike v1 policies, for v2 policies in this case we don't encrypt + * with the master key directly but rather derive a per-mode encryption + * key. This ensures that the master key is consistently used only for + * HKDF, avoiding key reuse issues. + * + * For IV_INO_LBLK policies: encryption keys are derived from + * (master_key, mode_num, filesystem_uuid), and inode number is + * included in the IVs. This format is optimized for use with inline + * encryption hardware compliant with the UFS standard. + */ + mutex_lock(&fscrypt_mode_key_setup_mutex); if (fscrypt_is_key_prepared(prep_key, ci)) @@ -205,13 +279,9 @@ static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, BUILD_BUG_ON(sizeof(mode_num) != 1); BUILD_BUG_ON(sizeof(sb->s_uuid) != 16); - BUILD_BUG_ON(sizeof(hkdf_info) != 17); - hkdf_info[hkdf_infolen++] = mode_num; - if (include_fs_uuid) { - memcpy(&hkdf_info[hkdf_infolen], &sb->s_uuid, - sizeof(sb->s_uuid)); - hkdf_infolen += sizeof(sb->s_uuid); - } + BUILD_BUG_ON(sizeof(hkdf_info) != MAX_MODE_KEY_HKDF_INFO_SIZE); + hkdf_infolen = fill_hkdf_info_for_mode_key(ci, hkdf_info); + err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, hkdf_context, hkdf_info, hkdf_infolen, mode_key, mode->keysize); @@ -225,10 +295,8 @@ static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, return err; } -static int find_mode_prepared_key(struct fscrypt_info *ci, - struct fscrypt_master_key *mk, - struct fscrypt_prepared_key *keys, - u8 hkdf_context, bool include_fs_uuid) +static int setup_mode_prepared_key(struct fscrypt_info *ci, + struct fscrypt_master_key *mk) { struct fscrypt_mode *mode = ci->ci_mode; const u8 mode_num = mode - fscrypt_modes; @@ -238,13 +306,15 @@ static int find_mode_prepared_key(struct fscrypt_info *ci, if (WARN_ON_ONCE(mode_num > FSCRYPT_MODE_MAX)) return -EINVAL; - prep_key = &keys[mode_num]; + prep_key = mk_prepared_key_for_mode_policy(mk, &ci->ci_policy, mode); + if (IS_ERR(prep_key)) + return PTR_ERR(prep_key); + if (fscrypt_is_key_prepared(prep_key, ci)) { ci->ci_enc_key = *prep_key; return 0; } - err = setup_new_mode_prepared_key(mk, prep_key, ci, hkdf_context, - include_fs_uuid); + err = setup_new_mode_prepared_key(mk, prep_key, ci); if (err) return err; @@ -333,33 +403,8 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, { int err; - if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { - /* - * DIRECT_KEY: instead of deriving per-file encryption keys, the - * per-file nonce will be included in all the IVs. But unlike - * v1 policies, for v2 policies in this case we don't encrypt - * with the master key directly but rather derive a per-mode - * encryption key. This ensures that the master key is - * consistently used only for HKDF, avoiding key reuse issues. - */ - err = find_mode_prepared_key(ci, mk, mk->mk_direct_keys, - HKDF_CONTEXT_DIRECT_KEY, false); - } else if (ci->ci_policy.v2.flags & - FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) { - /* - * IV_INO_LBLK_64: encryption keys are derived from (master_key, - * mode_num, filesystem_uuid), and inode number is included in - * the IVs. This format is optimized for use with inline - * encryption hardware compliant with the UFS standard. - */ - err = find_mode_prepared_key(ci, mk, mk->mk_iv_ino_lblk_64_keys, - HKDF_CONTEXT_IV_INO_LBLK_64_KEY, - true); - } else if (ci->ci_policy.v2.flags & - FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) { - err = find_mode_prepared_key(ci, mk, mk->mk_iv_ino_lblk_32_keys, - HKDF_CONTEXT_IV_INO_LBLK_32_KEY, - true); + if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAGS_KEY_MASK) { + err = setup_mode_prepared_key(ci, mk); } else { u8 derived_key[FSCRYPT_MAX_KEY_SIZE]; From patchwork Thu Jun 29 00:28:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296459 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65256C001B0 for ; Thu, 29 Jun 2023 00:35:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231446AbjF2Aff (ORCPT ); Wed, 28 Jun 2023 20:35:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230449AbjF2AfU (ORCPT ); Wed, 28 Jun 2023 20:35:20 -0400 Received: from box.fidei.email (box.fidei.email [IPv6:2605:2700:0:2:a800:ff:feba:dc44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A68312D4A; Wed, 28 Jun 2023 17:35:16 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id 38F2C80811; Wed, 28 Jun 2023 20:29:20 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998560; bh=sWteOZQmqe6p4PhoK8+a2qziKg+IVCqvfBlrEgzZKH0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MwHw5S9/T7GOzaSxYagssRIumpAZrbUigQQG0P+6l25JZmHbNPToTFYwZZmfpviMi dkT1q7llyfKzOvKCJnCbnMwQuBQPtGteBiVxUmTjCr0Vr00DrX40EYLWyvn63nYS3D wXezLglhjI5x7MQz0b6npVuB7CtCZteE24Daq2p8Qr5i42gSri1FzF8mXgvHr+11Xo ye4advXF7kZoORiIJtK3UdtPPnZUtzNUmZONQzg9frOdBjJ+NCXHVXGMyv2Q9Lze1u Rlo9F0CeWCTzleAyra7KXlNgTBKh88C1tDIUEAoyN2lX1pGssOv4PsA3UzDBv/dNZY Z4TbLAXjW3KHw== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 7/8] fscrypt: make infos have a pointer to prepared keys Date: Wed, 28 Jun 2023 20:28:57 -0400 Message-Id: <0c0d927b34726e3887714960ede14a6e00a0e285.1687988119.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org At present, it's not entirely clear who owns a prepared key. Under default policies, infos own the prepared key; but under any of the policy flag key policies, or with some v1 policies, the info merely has a copy of the authoritative prepared key; the authoritative copy of the prepared key lives in the master key or the direct key, but the info has no way to get to the authoritative key or get updates from it. A scenario which could occur is the following: -A directory tree is set up to use v2 policy DIRECT_KEY, mode adiantum. -One directory is opened, gets a prepared key with a crypto_skcipher. -A file within it is opened, sets up and gets the 'same' prepared key, but it's set up the blk_crypto_key in the prepared key. -Another directory in the tree is opened, and gets the 'same' prepared key, but it's now got a pointer to the blk_crypto_key too. -The two directories' ci_enc_key values are different, even though for practical purposes they are the same. While it has no correctness implications, it's confusing for debugging when two directories with the same mode/policy have different prepared key contents depending on what else happened. Adding a layer of indirection makes everything clearer at the cost of another pointer. Now everyone sharing a prepared key within a direct key or a master key have the same pointer to the single prepared key. Followups move information from the crypt_info into the prepared key, which ends up reducing memory usage slightly. And, it makes using pooled, pre-allocated objects which could be stolen from a dormant fscrypt_info much easier. So this change makes crypt_info->ci_enc_key a pointer and updates all users thereof. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/crypto.c | 2 +- fs/crypto/fname.c | 4 ++-- fs/crypto/fscrypt_private.h | 2 +- fs/crypto/inline_crypt.c | 4 ++-- fs/crypto/keysetup.c | 16 +++++++++++----- fs/crypto/keysetup_v1.c | 2 +- 6 files changed, 18 insertions(+), 12 deletions(-) diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 6a837e4b80dc..9f3bda18c797 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -108,7 +108,7 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, DECLARE_CRYPTO_WAIT(wait); struct scatterlist dst, src; struct fscrypt_info *ci = inode->i_crypt_info; - struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; + struct crypto_skcipher *tfm = ci->ci_enc_key->tfm; int res = 0; if (WARN_ON_ONCE(len <= 0)) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 6eae3f12ad50..edb78cd1b0e7 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -101,7 +101,7 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, struct skcipher_request *req = NULL; DECLARE_CRYPTO_WAIT(wait); const struct fscrypt_info *ci = inode->i_crypt_info; - struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; + struct crypto_skcipher *tfm = ci->ci_enc_key->tfm; union fscrypt_iv iv; struct scatterlist sg; int res; @@ -158,7 +158,7 @@ static int fname_decrypt(const struct inode *inode, DECLARE_CRYPTO_WAIT(wait); struct scatterlist src_sg, dst_sg; const struct fscrypt_info *ci = inode->i_crypt_info; - struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; + struct crypto_skcipher *tfm = ci->ci_enc_key->tfm; union fscrypt_iv iv; int res; diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 7ab5a7b7eef8..5011737b60b3 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -198,7 +198,7 @@ struct fscrypt_prepared_key { struct fscrypt_info { /* The key in a form prepared for actual encryption/decryption */ - struct fscrypt_prepared_key ci_enc_key; + struct fscrypt_prepared_key *ci_enc_key; /* True if ci_enc_key should be freed when this fscrypt_info is freed */ bool ci_owns_key; diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 8bfb3ce86476..2063f7941ce6 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -273,7 +273,7 @@ void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode, ci = inode->i_crypt_info; fscrypt_generate_dun(ci, first_lblk, dun); - bio_crypt_set_ctx(bio, ci->ci_enc_key.blk_key, dun, gfp_mask); + bio_crypt_set_ctx(bio, ci->ci_enc_key->blk_key, dun, gfp_mask); } EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx); @@ -360,7 +360,7 @@ bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, * uses the same pointer. I.e., there's currently no need to support * merging requests where the keys are the same but the pointers differ. */ - if (bc->bc_key != inode->i_crypt_info->ci_enc_key.blk_key) + if (bc->bc_key != inode->i_crypt_info->ci_enc_key->blk_key) return false; fscrypt_generate_dun(inode->i_crypt_info, next_lblk, next_dun); diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 111940b91456..74c0b2b0db63 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -192,7 +192,11 @@ void fscrypt_destroy_prepared_key(struct super_block *sb, int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key) { ci->ci_owns_key = true; - return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci); + ci->ci_enc_key = kzalloc(sizeof(*ci->ci_enc_key), GFP_KERNEL); + if (!ci->ci_enc_key) + return -ENOMEM; + + return fscrypt_prepare_key(ci->ci_enc_key, raw_key, ci); } static struct fscrypt_prepared_key * @@ -311,14 +315,14 @@ static int setup_mode_prepared_key(struct fscrypt_info *ci, return PTR_ERR(prep_key); if (fscrypt_is_key_prepared(prep_key, ci)) { - ci->ci_enc_key = *prep_key; + ci->ci_enc_key = prep_key; return 0; } err = setup_new_mode_prepared_key(mk, prep_key, ci); if (err) return err; - ci->ci_enc_key = *prep_key; + ci->ci_enc_key = prep_key; return 0; } @@ -582,9 +586,11 @@ static void put_crypt_info(struct fscrypt_info *ci) if (ci->ci_direct_key) fscrypt_put_direct_key(ci->ci_direct_key); - else if (ci->ci_owns_key) + else if (ci->ci_owns_key) { fscrypt_destroy_prepared_key(ci->ci_inode->i_sb, - &ci->ci_enc_key); + ci->ci_enc_key); + kfree_sensitive(ci->ci_enc_key); + } mk = ci->ci_master_key; if (mk) { diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index 75dabd9b27f9..e1d761e8067f 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -259,7 +259,7 @@ static int setup_v1_file_key_direct(struct fscrypt_info *ci, if (IS_ERR(dk)) return PTR_ERR(dk); ci->ci_direct_key = dk; - ci->ci_enc_key = dk->dk_key; + ci->ci_enc_key = &dk->dk_key; return 0; } From patchwork Thu Jun 29 00:28:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13296460 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A86EEB64D7 for ; Thu, 29 Jun 2023 00:35:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231208AbjF2Afj (ORCPT ); Wed, 28 Jun 2023 20:35:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231395AbjF2AfW (ORCPT ); Wed, 28 Jun 2023 20:35:22 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B0E22972; Wed, 28 Jun 2023 17:35:19 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id 8A4BA80844; Wed, 28 Jun 2023 20:29:21 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1687998561; bh=eLnr7rXLQqX2dUlJuRB/7H9wlOmMKkUL0Bw75rctfRY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kcH/9Wv8bLQ+dxT2zAEks+i3Hke6pg85z9eVxGDqR/Y25suD9DOfBzQxYB+RfcN/7 158q7marPYjJxvESi0aVQogsZnJcAhRn8ik7CrkRMGJHOlThTKpCioRA1lfWs6v4QG JyeChI5hTTaJ2RHigXD7WrwMWlbPYha2EwtkwuLKxmX6N687RvLen+s0Xucu6CIAwt Apq30SOwOaYo+jiQbpp6pCZ1sZ9af8eTePddI6U62Jm3nKc+mN+aO8umierStIafkX YQhrTgDry9Gl9XcRp+vSWCLdcJgxtXMrDUhyZk8vKG8z1UbSnSRpDyo0zeVN+Lufnl qTsC7O3rXEllw== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , Eric Biggers , "Theodore Y. Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v4 8/8] fscrypt: make prepared keys record their type Date: Wed, 28 Jun 2023 20:28:58 -0400 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Right now fscrypt_infos have two fields dedicated solely to recording what type of prepared key the info has: whether it solely owns the prepared key, or has borrowed it from a master key, or from a direct key. The ci_direct_key field is only used for v1 direct key policies, recording the direct key that needs to have its refcount reduced when the crypt_info is freed. However, now that crypt_info->ci_enc_key is a pointer to the authoritative prepared key -- embedded in the direct key, in this case, we no longer need to keep a full pointer to the direct key -- we can use container_of() to go from the prepared key to its surrounding direct key. The key ownership information doesn't change during the lifetime of a prepared key. Since at worst there's a prepared key per info, and at best many infos share a single prepared key, it can be slightly more efficient to store this ownership info in the prepared key instead of in the fscrypt_info, especially since we can squash both fields down into a single enum. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/fscrypt_private.h | 31 +++++++++++++++++++++++-------- fs/crypto/keysetup.c | 21 +++++++++++++-------- fs/crypto/keysetup_v1.c | 7 +++++-- 3 files changed, 41 insertions(+), 18 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 5011737b60b3..e726a1fb9f7e 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -174,18 +174,39 @@ struct fscrypt_symlink_data { char encrypted_path[1]; } __packed; +/** + * enum fscrypt_prepared_key_type - records a prepared key's ownership + * + * @FSCRYPT_KEY_PER_INFO: this prepared key is allocated for a specific info + * and is never shared. + * @FSCRYPT_KEY_DIRECT_V1: this prepared key is embedded in a fscrypt_direct_key + * used in v1 direct key policies. + * @FSCRYPT_KEY_MASTER_KEY: this prepared key is a per-mode and policy key, + * part of a fscrypt_master_key, shared between all + * users of this master key having this mode and + * policy. + */ +enum fscrypt_prepared_key_type { + FSCRYPT_KEY_PER_INFO = 1, + FSCRYPT_KEY_DIRECT_V1, + FSCRYPT_KEY_MASTER_KEY, +} __packed; + /** * struct fscrypt_prepared_key - a key prepared for actual encryption/decryption * @tfm: crypto API transform object * @blk_key: key for blk-crypto + * @type: records the ownership type of the prepared key * - * Normally only one of the fields will be non-NULL. + * Normally only one of @tfm and @blk_key will be non-NULL, although it is + * possible if @type is FSCRYPT_KEY_MASTER_KEY. */ struct fscrypt_prepared_key { struct crypto_skcipher *tfm; #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT struct blk_crypto_key *blk_key; #endif + enum fscrypt_prepared_key_type type; }; /* @@ -233,12 +254,6 @@ struct fscrypt_info { */ struct list_head ci_master_key_link; - /* - * If non-NULL, then encryption is done using the master key directly - * and ci_enc_key will equal ci_direct_key->dk_key. - */ - struct fscrypt_direct_key *ci_direct_key; - /* * This inode's hash key for filenames. This is a 128-bit SipHash-2-4 * key. This is only set for directories that use a keyed dirhash over @@ -641,7 +656,7 @@ static inline int fscrypt_require_key(struct inode *inode) /* keysetup_v1.c */ -void fscrypt_put_direct_key(struct fscrypt_direct_key *dk); +void fscrypt_put_direct_key(struct fscrypt_prepared_key *prep_key); int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key); diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 74c0b2b0db63..be3a84508806 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -191,11 +191,11 @@ void fscrypt_destroy_prepared_key(struct super_block *sb, /* Given a per-file encryption key, set up the file's crypto transform object */ int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key) { - ci->ci_owns_key = true; ci->ci_enc_key = kzalloc(sizeof(*ci->ci_enc_key), GFP_KERNEL); if (!ci->ci_enc_key) return -ENOMEM; + ci->ci_enc_key->type = FSCRYPT_KEY_PER_INFO; return fscrypt_prepare_key(ci->ci_enc_key, raw_key, ci); } @@ -290,7 +290,8 @@ static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, hkdf_context, hkdf_info, hkdf_infolen, mode_key, mode->keysize); if (err) - goto out_unlock; + return err; + prep_key->type = FSCRYPT_KEY_MASTER_KEY; err = fscrypt_prepare_key(prep_key, mode_key, ci); memzero_explicit(mode_key, mode->keysize); @@ -584,12 +585,16 @@ static void put_crypt_info(struct fscrypt_info *ci) if (!ci) return; - if (ci->ci_direct_key) - fscrypt_put_direct_key(ci->ci_direct_key); - else if (ci->ci_owns_key) { - fscrypt_destroy_prepared_key(ci->ci_inode->i_sb, - ci->ci_enc_key); - kfree_sensitive(ci->ci_enc_key); + if (ci->ci_enc_key) { + enum fscrypt_prepared_key_type type = ci->ci_enc_key->type; + + if (type == FSCRYPT_KEY_DIRECT_V1) + fscrypt_put_direct_key(ci->ci_enc_key); + if (type == FSCRYPT_KEY_PER_INFO) { + fscrypt_destroy_prepared_key(ci->ci_inode->i_sb, + ci->ci_enc_key); + kfree_sensitive(ci->ci_enc_key); + } } mk = ci->ci_master_key; diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index e1d761e8067f..1e785cedead0 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -160,8 +160,11 @@ static void free_direct_key(struct fscrypt_direct_key *dk) } } -void fscrypt_put_direct_key(struct fscrypt_direct_key *dk) +void fscrypt_put_direct_key(struct fscrypt_prepared_key *prep_key) { + struct fscrypt_direct_key *dk = + container_of(prep_key, struct fscrypt_direct_key, dk_key); + if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock)) return; hash_del(&dk->dk_node); @@ -235,6 +238,7 @@ fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key) dk->dk_sb = ci->ci_inode->i_sb; refcount_set(&dk->dk_refcount, 1); dk->dk_mode = ci->ci_mode; + dk->dk_key.type = FSCRYPT_KEY_DIRECT_V1; err = fscrypt_prepare_key(&dk->dk_key, raw_key, ci); if (err) goto err_free_dk; @@ -258,7 +262,6 @@ static int setup_v1_file_key_direct(struct fscrypt_info *ci, dk = fscrypt_get_direct_key(ci, raw_master_key); if (IS_ERR(dk)) return PTR_ERR(dk); - ci->ci_direct_key = dk; ci->ci_enc_key = &dk->dk_key; return 0; }