From patchwork Mon Apr 10 10:16:22 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: 13206259 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 934FDC77B6F for ; Mon, 10 Apr 2023 10:26:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229698AbjDJK05 (ORCPT ); Mon, 10 Apr 2023 06:26:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbjDJK0x (ORCPT ); Mon, 10 Apr 2023 06:26:53 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6EC11270B for ; Mon, 10 Apr 2023 03:26:52 -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 D923F80587; Mon, 10 Apr 2023 06:16:42 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121803; bh=0U7CtMhh9K/iXHKqS7GrVj7GsERFNB+8IfVyVDOBuJA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EDsFjzVZQHQHf/YAF0RML8RE/3TnRPCoiorIDM0SejUIoJTTwdmXNoFs7vZzLoUHT +SolKmMx4mL+kvdEUZxc9jqBj6utrWGPqJceb2SJs57A+8ZSUg3r3cXtP29/xCqidR xZPnPXnlu0tYDdbbRui/KfE+bUNrK2aDjdJ1CceG3hUbhKgePdQ7bdj24AEOz8fXKY Txp3tJWQuBeYmx+dT/wT/t4kB6/Hw1KMi/0UxYkgdRaFRaYhaDy7tIUDakUzyIMLxZ CALdELf8rO4hYEZJ72/y9TKxQfEi4ZO9vpfcQ/d1vugApDOE/bd8t2wwlCLCdl/kSA t1CRMyC4Sa15g== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 01/10] fscrypt: split and rename setup_file_encryption_key() Date: Mon, 10 Apr 2023 06:16:22 -0400 Message-Id: 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 | 75 ++++++++++++++++++++++++++++---------------- 1 file changed, 48 insertions(+), 27 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index b89c32ad19fb..5989d53971ca 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 +502,13 @@ 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. - */ - return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci); + *mk_ret = NULL; + return 0; } down_read(&mk->mk_sem); @@ -491,21 +523,6 @@ 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 +597,11 @@ 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 Mon Apr 10 10:16:23 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: 13206262 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 2708DC77B71 for ; Mon, 10 Apr 2023 10:27:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229728AbjDJK07 (ORCPT ); Mon, 10 Apr 2023 06:26:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229722AbjDJK0y (ORCPT ); Mon, 10 Apr 2023 06:26:54 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 03B761AB for ; Mon, 10 Apr 2023 03:26:52 -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 87BF780581; Mon, 10 Apr 2023 06:16:44 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121804; bh=5nRHX81h0KqwjjUiKDGpJl8ybfFXjI7s7YYv/VC9bSY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AJVcg1PcFZOvTPds2tvJy3JV7Bp97cVXTFdwlGwIG5ZkFQm8tioyMMomNPwNjbNIN woMddE90gvKQQ/XRk7zAq4G403EcJntsbQw96VA1Flji9C4dfLc2YQcrqiz6wLq5rL 62+eDn4/lm5AlAGHRFP1rNXOdnog9CGKlVKluUiyyF4+BgBAp/yzBeQCZCQKNMGfZu 5h9uo4FaUzJzP0bM+BwynXt6kG1pBw2RU3fO4Y0jbYqEX62RJ4rkn/nhKU62VJ2xUH 0C77WbsV8lQNPswzqpe0lfhjnk/IzxRGdOdadJHTXI80UvP3yRx+VSO/ZAbGVwhsp8 qyJgA2UiuB+4A== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 02/10] fscrypt: split and rename setup_per_mode_enc_key() Date: Mon, 10 Apr 2023 06:16:23 -0400 Message-Id: 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. So, the new find_mode_prepared_key() decides if a pre-prepared key already exists. If not, the renamed setup_new_mode_prepared_key() deals with taking the mode setup lock and creating the new prepared key for the master key. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 57 ++++++++++++++++++++++++++++---------------- 1 file changed, 36 insertions(+), 21 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 5989d53971ca..7a3147382033 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); @@ -231,14 +221,39 @@ static int setup_per_mode_enc_key(struct fscrypt_info *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 +309,7 @@ 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 +359,7 @@ 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 +369,7 @@ 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 Mon Apr 10 10:16:24 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: 13206253 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 E9DE4C77B61 for ; Mon, 10 Apr 2023 10:26:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229683AbjDJK0x (ORCPT ); Mon, 10 Apr 2023 06:26:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbjDJK0w (ORCPT ); Mon, 10 Apr 2023 06:26:52 -0400 X-Greylist: delayed 607 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 10 Apr 2023 03:26:50 PDT Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A690A198 for ; Mon, 10 Apr 2023 03:26:50 -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 46FDF80599; Mon, 10 Apr 2023 06:16:46 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121806; bh=XX6bp4kajq0S7zO6XE9nIj+N7dA6CHFnrbOmyU/7MpI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EDJQvEg9GoUTA5sIWLxZhDFJj/gq2AjFf4+gVE2OlwdHDoJoTJZ9s79304KTZfplC KljB8QHoW4/+qAZOsJRnbCFuGqUpTji8uB2JzP5SNanuPDitsnc881X0GdtDGeO6cY ZE75Naq2KLCgI25UCZn1W/ky0XmlOBlXSAIrR/Q4tIQzYL7Xi38Ba/ZVnCMnmhm1M0 AUX+ziWis7sgLW4fT4JT79rq8EiYul9H4BzvTYTYXZk1MOpXcX3EsM1WOyT5EAW5pW z+8WRdhYUEyaB+NklnKg35V0JVOaYxDjEmp53bZE9EU3SitxycO51Ib8IXeKfAvzbe naYQylumMsLwg== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 03/10] fscrypt: move dirhash key setup away from IO key setup Date: Mon, 10 Apr 2023 06:16:24 -0400 Message-Id: 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 | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 7a3147382033..82589c370b14 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -345,8 +345,7 @@ 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; @@ -391,13 +390,6 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, 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; } @@ -405,8 +397,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * 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; @@ -428,7 +419,7 @@ 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); @@ -616,10 +607,26 @@ 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 Mon Apr 10 10:16:25 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: 13206254 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 ECAF1C77B71 for ; Mon, 10 Apr 2023 10:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229579AbjDJK0z (ORCPT ); Mon, 10 Apr 2023 06:26:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229679AbjDJK0x (ORCPT ); Mon, 10 Apr 2023 06:26:53 -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 0DC8FE6A for ; Mon, 10 Apr 2023 03:26:50 -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 3F334805A9; Mon, 10 Apr 2023 06:16:48 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121808; bh=y6IVwyuZ/Z1XtDZG1uz1sPuBXx4FiG1yBF2gK/UM5Ik=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jrpv+7h1wYqrDkaT4rGDfzrxtMyhqxMbjJ90tczAJKgFJ6b4T4A3OXcTeXsTK57io ybK4wHdzsFdsN4202VWkITac5F5++S1kzueJghVhOXCNvCUwtHWUlIzpZL8Oueti5I 4IUWjgz1llpra1axBaLK9ff9a7WQS0KkgyYwJv9idKnJi6zrwkxbWHeJyX/Y6vqwhE fhRYFno/YN+PwakpmOSGJGEL399IkoaymdqoPOqQf50XLQXJPOAPKUq+kVUqQO+r9H EL00P1A3DE+5ISzVNS46SoZct1wNVjVicXebNgWfGhTNuWRhIXTssDYeQU1hGC4Lyw 1Ta/EbBYcWlGQ== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 04/10] fscrypt: reduce special-casing of IV_INO_LBLK_32 Date: Mon, 10 Apr 2023 06:16:25 -0400 Message-Id: <554458a72a729c94cdc06a277b0e98d83eb0cc81.1681116739.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 | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 82589c370b14..8b32200dbbc0 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -304,16 +304,10 @@ 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)) { @@ -335,12 +329,6 @@ static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci, return err; } - /* - * 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; } @@ -373,7 +361,9 @@ 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]; @@ -627,6 +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 Mon Apr 10 10:16:26 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: 13206257 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 5BF0FC76196 for ; Mon, 10 Apr 2023 10:26:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229679AbjDJK0z (ORCPT ); Mon, 10 Apr 2023 06:26:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229685AbjDJK0x (ORCPT ); Mon, 10 Apr 2023 06:26:53 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 611BD1FF0 for ; Mon, 10 Apr 2023 03:26:52 -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 30B2D8060B; Mon, 10 Apr 2023 06:16:49 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121810; bh=/xrIvuueTIYi8PCgwp8TTqp87peagz23ImqhwA+SXoo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hDm96r2rmTYTGTnA66ZVG9BEPVdau01GQtnAN3aMiCY3hqmY36sE+TIoUUKinwjCZ fz7DQUcArm5o+zzeHJqDz43KXPevZqYHgdXaFL+6Vp0boQbXIthsJD7UWn2qJykC9a 3nmcGpI94mhpyCGevd0KSK1guNiArcQr42DVxcJ3Emr4zR5gK/MZurAOyB9KIOuptB 9ogy8uRWHqhN+pPu+LpuBBmt70ylLfG8HRd5pBgRLqYbpibkzti4xOWpOdb3V2lD3C zGOA4BnUTTgZySmjZQeA43aD8ZO2IxtW8sJ/NPdheyNYDYD0BGEMcaHnv7QNbK2QWe SDqHoCTMrxZsA== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 05/10] fscrypt: make infos have a pointer to prepared keys Date: Mon, 10 Apr 2023 06:16:26 -0400 Message-Id: <4ec283b09d403eadd5c6217b9978487e1001ab69.1681116739.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 8b32200dbbc0..f07e3b9579cf 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -181,7 +181,11 @@ 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 int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, @@ -242,7 +246,7 @@ static int find_mode_prepared_key(struct fscrypt_info *ci, prep_key = &keys[mode_num]; 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, hkdf_context, @@ -250,7 +254,7 @@ static int find_mode_prepared_key(struct fscrypt_info *ci, if (err) return err; - ci->ci_enc_key = *prep_key; + ci->ci_enc_key = prep_key; return 0; } @@ -537,9 +541,11 @@ 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(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 Mon Apr 10 10:16:27 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: 13206256 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 8072AC77B74 for ; Mon, 10 Apr 2023 10:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229611AbjDJK0y (ORCPT ); Mon, 10 Apr 2023 06:26:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229579AbjDJK0x (ORCPT ); Mon, 10 Apr 2023 06:26:53 -0400 X-Greylist: delayed 607 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 10 Apr 2023 03:26:50 PDT 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 EDBE1131 for ; Mon, 10 Apr 2023 03:26:50 -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 3B52B80637; Mon, 10 Apr 2023 06:16:52 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121812; bh=dITwpJXBFQATzfqUa2IKjEtpeXr+UJkEsha1AtXZA34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xAHKNJv4U8votjijpTkIyY3yLXV/QR94zEeasCAN5rYgriVlDH+OXdjCexYxFSrEv Uf0X56gxP9LHx7OcYziEPX54P4QlUeCwNlJSKC5I3zssi+5rJ3CS76yoVF2oVz2rYT spYN/+Qy5nbWszCQxhh6RZuaMG4veBRnw3PwqfvIX9d/4Vy65c7TIHt++aMj/SJ63C 4vNxOEtpivWJobHPpGjBkG1rbLQPMw2QqnL9xx3udueBFOfzZ5rl9lvfdmayu8zS5z 1vIm2q7/FZ3bPj30RlX5maka0eoMw1MHfLgMTFBaB14yAUWK2mAmrQ1ECH6vjC+2N5 htvWdVJuZeScA== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 06/10] fscrypt: move all the shared mode key setup deeper Date: Mon, 10 Apr 2023 06:16:27 -0400 Message-Id: <553bf33a8264e8f6c0ec61a1039bda5f0b91bd4f.1681116740.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. fill_hkdf_info() deals with filling in the hkdf info as necessary for a particular policy. And hkdf_context_for_policy() translates policy into hkdf context for key derivation. 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 | 120 ++++++++++++++++++++++++++++--------------- 1 file changed, 79 insertions(+), 41 deletions(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index f07e3b9579cf..845a92203c87 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -78,6 +78,11 @@ struct fscrypt_mode fscrypt_modes[] = { static DEFINE_MUTEX(fscrypt_mode_key_setup_mutex); +static const u8 FSCRYPT_POLICY_FLAGS_KEY_MASK = + (FSCRYPT_POLICY_FLAG_DIRECT_KEY + | FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 + | FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32); + static struct fscrypt_mode * select_encryption_mode(const union fscrypt_policy *policy, const struct inode *inode) @@ -188,10 +193,57 @@ 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(const struct fscrypt_info *ci, u8 *hkdf_info) +{ + 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 u8 hkdf_context_for_policy(const union fscrypt_policy *policy) +{ + switch (fscrypt_policy_flags(policy) & FSCRYPT_POLICY_FLAGS_KEY_MASK) { + case FSCRYPT_POLICY_FLAG_DIRECT_KEY: + return HKDF_CONTEXT_DIRECT_KEY; + case FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64: + return HKDF_CONTEXT_IV_INO_LBLK_64_KEY; + case FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32: + return HKDF_CONTEXT_IV_INO_LBLK_32_KEY; + default: + return 0; + } +} + 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; @@ -200,8 +252,23 @@ static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, 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 = hkdf_context_for_policy(&ci->ci_policy); int err; + /* + * 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)) @@ -210,12 +277,8 @@ 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); - } + hkdf_infolen = fill_hkdf_info(ci, hkdf_info); + err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, hkdf_context, hkdf_info, hkdf_infolen, mode_key, mode->keysize); @@ -232,9 +295,7 @@ static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, } 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_master_key *mk) { struct fscrypt_mode *mode = ci->ci_mode; const u8 mode_num = mode - fscrypt_modes; @@ -244,13 +305,15 @@ 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; @@ -341,33 +404,8 @@ 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 = find_mode_prepared_key(ci, mk); } else { u8 derived_key[FSCRYPT_MAX_KEY_SIZE]; From patchwork Mon Apr 10 10:16:28 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: 13206258 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 01B1AC77B71 for ; Mon, 10 Apr 2023 10:26:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229685AbjDJK04 (ORCPT ); Mon, 10 Apr 2023 06:26:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229698AbjDJK0x (ORCPT ); Mon, 10 Apr 2023 06:26:53 -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 83571273A for ; Mon, 10 Apr 2023 03:26:52 -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 1060880606; Mon, 10 Apr 2023 06:16:53 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121814; bh=T/GWz5x9N9tt4cSe2QC2OCcSFKjxdBbLNMYUMT75UCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ESLEhBeen0IrmdKJocUZdwlFu5Ud9s6YBd6Mxb7sDIXY5i7+79a+on5p2Ri8emcWE eQfdglhZzpEkwa6D352hp8LQIIgw3LVS8d5dtCMzs1Y/M44iATI81aJ6JOaUny2Fdn 4Djj8HnTN3eJMV/jakTt4U3bPTobnWehhQ6Xlq4PbL7NqHmRYM6vumuDIqvrCHsQY/ pFVpifXM7OJLLLZiejzlXSVgcqbFeD5kwo03VpkqbRvj6RYN5v/RqbEUUPCqDTB6tG OA6tPzVy4t0WvATVAAB7Zc8z25A0fBCcNI+2lNNRHpWmagq8QyPO9OlBTNEk6T7tKf Ux2UvOdALUufw== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 07/10] fscrypt: make ci->ci_direct_key a bool not a pointer Date: Mon, 10 Apr 2023 06:16:28 -0400 Message-Id: <5001d8e2c732cf905744ef6e55ab5ee00f57d658.1681116740.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 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. Thus we can make ci_direct_key a bool instead of a pointer, saving a few bytes. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/fscrypt_private.h | 7 +++---- fs/crypto/keysetup.c | 2 +- fs/crypto/keysetup_v1.c | 7 +++++-- 3 files changed, 9 insertions(+), 7 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 5011737b60b3..b575fb58a506 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -234,10 +234,9 @@ 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. + * If true, then encryption is done using the master key directly. */ - struct fscrypt_direct_key *ci_direct_key; + bool ci_direct_key; /* * This inode's hash key for filenames. This is a 128-bit SipHash-2-4 @@ -641,7 +640,7 @@ 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 845a92203c87..d81001bf0a51 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -578,7 +578,7 @@ static void put_crypt_info(struct fscrypt_info *ci) return; if (ci->ci_direct_key) - fscrypt_put_direct_key(ci->ci_direct_key); + fscrypt_put_direct_key(ci->ci_enc_key); else if (ci->ci_owns_key) { fscrypt_destroy_prepared_key(ci->ci_inode->i_sb, ci->ci_enc_key); diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index e1d761e8067f..09de84c65368 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); @@ -258,7 +261,7 @@ 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_direct_key = true; ci->ci_enc_key = &dk->dk_key; return 0; } From patchwork Mon Apr 10 10:16:29 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: 13206252 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 9E040C76196 for ; Mon, 10 Apr 2023 10:26:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229644AbjDJK0w (ORCPT ); Mon, 10 Apr 2023 06:26:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229579AbjDJK0w (ORCPT ); Mon, 10 Apr 2023 06:26:52 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A76651AB for ; Mon, 10 Apr 2023 03:26:50 -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 035EC80649; Mon, 10 Apr 2023 06:16:55 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121816; bh=5qI9lseYBOQjFI+MjnBOC8vBkDnenCRrDv0FmOHY7eo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mN0reyzw9sAMsY9qY3pFH/aouMpnAiZ8UPEXQXAnkTgrrwHAW2mR/Usqe7qBTCHe7 iFtrurFCnLD3xR7ya1BzlrrZIkHtG2zUQiQWsx/WxhHTBbBwFE65M0DtpHR6XwEGeA s5fAWQmH9QN0IJX+FZTiXiKxSePZmIyWG+nTZvOu+iduMqoxhvrUn798JssM1AAalI r0OGDfymze6P9bxOGVSzo5DjyWZcRJ1zzs4FhwF+dNy5EANb98vJqqXG1oPcMn7F1X VvrfrUG38aWOPTBX71R7RDwjX80p8D6403mG1+eySWVdchtjP8jCPIghilvGmpyM/I Q8qULqb/O7l8w== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 08/10] fscrypt: make prepared keys record their type. Date: Mon, 10 Apr 2023 06:16:29 -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. This 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 is 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. This will also make it easy to record that a prepared key is part of the pooled prepared keys when extent-based encryption is used. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/fscrypt_private.h | 28 ++++++++++++++++++++++------ fs/crypto/keysetup.c | 19 ++++++++++++------- fs/crypto/keysetup_v1.c | 2 +- 3 files changed, 35 insertions(+), 14 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index b575fb58a506..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; }; /* @@ -233,11 +254,6 @@ struct fscrypt_info { */ struct list_head ci_master_key_link; - /* - * If true, then encryption is done using the master key directly. - */ - bool 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 diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index d81001bf0a51..f338bb544932 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -185,11 +185,11 @@ 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); } @@ -284,6 +284,7 @@ static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, mode_key, mode->keysize); if (err) goto out_unlock; + prep_key->type = FSCRYPT_KEY_MASTER_KEY; err = fscrypt_prepare_key(prep_key, mode_key, ci); memzero_explicit(mode_key, mode->keysize); if (err) @@ -577,12 +578,16 @@ static void put_crypt_info(struct fscrypt_info *ci) if (!ci) return; - if (ci->ci_direct_key) - fscrypt_put_direct_key(ci->ci_enc_key); - else if (ci->ci_owns_key) { - fscrypt_destroy_prepared_key(ci->ci_inode->i_sb, - ci->ci_enc_key); - kfree(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(ci->ci_enc_key); + } } mk = ci->ci_master_key; diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index 09de84c65368..1e785cedead0 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -238,6 +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; @@ -261,7 +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 = true; ci->ci_enc_key = &dk->dk_key; return 0; } From patchwork Mon Apr 10 10:16:30 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: 13206261 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 346FAC77B61 for ; Mon, 10 Apr 2023 10:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229485AbjDJK06 (ORCPT ); Mon, 10 Apr 2023 06:26:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229717AbjDJK0y (ORCPT ); Mon, 10 Apr 2023 06:26:54 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E782D198 for ; Mon, 10 Apr 2023 03:26:52 -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 8BCB28064B; Mon, 10 Apr 2023 06:16:57 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121817; bh=fPISzagGl1bOo9aNSqDTkAyacC799poKs6aM3P+PRaY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qXVJAVoq/RHIC/LHsqEr6Qs02LXB6ZGTTzEO9S8Wo787xfr9olMAJrcjqkTfoe2WP hmXGUjUdMIAOdagGbWR824walIvd93FMVQTPYQ4liyJhXBI1KtqRwFbwXdwVatPuBa 6zQxq4XOIKkkPaDGUyYkaaf/5lFZbWrICSED+uWVzSIBwql1IDs9ADe0RVXKm3bjCr L6lTdAcuYaju2nFY+TwxtDqOpKNG101KsIwdLJyFBbR5cbCcxFV2mt8TJB397Ik1MH GY5Ib0QRy+b7wgSoban1Juk+ytNJgFqL8kHtAI7GssTYI8XBvrhGcik2uaqMSkxSKx waxKvYDMU3d3g== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 09/10] fscrypt: explicitly track prepared parts of key Date: Mon, 10 Apr 2023 06:16:30 -0400 Message-Id: <7d901a1dfebb32fe84ea63938a2503f145480b02.1681116740.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 So far, it has sufficed to allocate and prepare the block key or the TFM completely before ever setting the relevant field in the prepared key. This is necessary for mode keys -- because multiple inodes could be trying to set up the same per-mode prepared key at the same time on different threads, we currently must not set the prepared key's tfm or block key pointer until that key is completely set up. Otherwise, another inode could see the key to be present and attempt to use it before it is fully set up. But when using pooled prepared keys, we'll have pre-allocated fields, and if we separate allocating the fields of a prepared key from preparing the fields, that inherently sets the fields before they're ready to use. So, either pooled prepared keys must use different allocation and setup functions, or we can split allocation and preparation for all prepared keys and use some other mechanism to signal that the key is fully prepared. In order to avoid having similar yet different functions, this function adds a new field to the prepared key to explicitly track which parts of it are prepared, setting it explicitly. The same acquire/release semantics are used to check it in the case of shared mode keys; the cost lies in the extra byte per prepared key recording which members are fully prepared. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/fscrypt_private.h | 26 +++++++++++++++----------- fs/crypto/inline_crypt.c | 8 +------- fs/crypto/keysetup.c | 36 ++++++++++++++++++++++++++---------- 3 files changed, 42 insertions(+), 28 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index e726a1fb9f7e..7253cdb5e4d8 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -197,6 +197,8 @@ enum fscrypt_prepared_key_type { * @tfm: crypto API transform object * @blk_key: key for blk-crypto * @type: records the ownership type of the prepared key + * @prepared_members: records which of @tfm and @blk_key are prepared. tfm + * corresponds to bit 0; blk_key corresponds to bit 1. * * Normally only one of @tfm and @blk_key will be non-NULL, although it is * possible if @type is FSCRYPT_KEY_MASTER_KEY. @@ -207,6 +209,7 @@ struct fscrypt_prepared_key { struct blk_crypto_key *blk_key; #endif enum fscrypt_prepared_key_type type; + u8 prepared_members; }; /* @@ -363,24 +366,25 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb, struct fscrypt_prepared_key *prep_key); /* - * Check whether the crypto transform or blk-crypto key has been allocated in + * Check whether the crypto transform or blk-crypto key has been prepared in * @prep_key, depending on which encryption implementation the file will use. */ static inline bool fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, const struct fscrypt_info *ci) { + u8 prepared_members = smp_load_acquire(&prep_key->prepared_members); + bool inlinecrypt = fscrypt_using_inline_encryption(ci); + /* - * The two smp_load_acquire()'s here pair with the smp_store_release()'s - * in fscrypt_prepare_inline_crypt_key() and fscrypt_prepare_key(). - * I.e., in some cases (namely, if this prep_key is a per-mode - * encryption key) another task can publish blk_key or tfm concurrently, - * executing a RELEASE barrier. We need to use smp_load_acquire() here - * to safely ACQUIRE the memory the other task published. + * The smp_load_acquire() here pairs with the smp_store_release() + * in fscrypt_prepare_key(). I.e., in some cases (namely, if this + * prep_key is a per-mode encryption key) another task can publish + * blk_key or tfm concurrently, executing a RELEASE barrier. We need + * to use smp_load_acquire() here to safely ACQUIRE the memory the + * other task published. */ - if (fscrypt_using_inline_encryption(ci)) - return smp_load_acquire(&prep_key->blk_key) != NULL; - return smp_load_acquire(&prep_key->tfm) != NULL; + return prepared_members & (1U << inlinecrypt); } #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ @@ -415,7 +419,7 @@ static inline bool fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, const struct fscrypt_info *ci) { - return smp_load_acquire(&prep_key->tfm) != NULL; + return smp_load_acquire(&prep_key->prepared_members); } #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 2063f7941ce6..ce952dedba77 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -191,13 +191,7 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, goto fail; } - /* - * Pairs with the smp_load_acquire() in fscrypt_is_key_prepared(). - * I.e., here we publish ->blk_key with a RELEASE barrier so that - * concurrent tasks can ACQUIRE it. Note that this concurrency is only - * possible for per-mode keys, not for per-file keys. - */ - smp_store_release(&prep_key->blk_key, blk_key); + prep_key->blk_key = blk_key; return 0; fail: diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index f338bb544932..6efac89d49ec 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -155,21 +155,37 @@ fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key, int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, const struct fscrypt_info *ci) { - struct crypto_skcipher *tfm; + int err; + bool inlinecrypt = fscrypt_using_inline_encryption(ci); + u8 prepared_member = (1 << inlinecrypt); - if (fscrypt_using_inline_encryption(ci)) - return fscrypt_prepare_inline_crypt_key(prep_key, raw_key, ci); + if (inlinecrypt) { + err = fscrypt_prepare_inline_crypt_key(prep_key, raw_key, ci); + } else { + struct crypto_skcipher *tfm; + + tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + } + + prep_key->tfm = tfm; + } - tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode); - if (IS_ERR(tfm)) - return PTR_ERR(tfm); /* * Pairs with the smp_load_acquire() in fscrypt_is_key_prepared(). - * I.e., here we publish ->tfm with a RELEASE barrier so that - * concurrent tasks can ACQUIRE it. Note that this concurrency is only - * possible for per-mode keys, not for per-file keys. + * I.e., here we publish ->prepared_members with a RELEASE barrier so + * that concurrent tasks can ACQUIRE it. + * + * Note that this concurrency is only possible for per-mode keys, + * not for per-file keys. For per-mode keys, we have smp_load_acquire'd + * the value of ->prepared_members after taking a lock serializing + * preparing this key, so the value is stable and no other thread can + * have modified it since the read. So another thread can't be trying + * to run this same code in parallel, and we don't need to use cmpxchg. */ - smp_store_release(&prep_key->tfm, tfm); + smp_store_release(&prep_key->prepared_members, + prep_key->prepared_members | prepared_member); return 0; } From patchwork Mon Apr 10 10:16:31 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: 13206260 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 75E57C77B75 for ; Mon, 10 Apr 2023 10:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229717AbjDJK06 (ORCPT ); Mon, 10 Apr 2023 06:26:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229706AbjDJK0y (ORCPT ); Mon, 10 Apr 2023 06:26:54 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 841252D55 for ; Mon, 10 Apr 2023 03:26:52 -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 DB4928064C; Mon, 10 Apr 2023 06:16:58 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1681121819; bh=zPytnI5w1Dm6mI8xuoYOVg3YESk3cLqrpGxHE/74AM4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U5qTWAX5s3ffuOFNaW34va7xGWex2ZOtx9C0oYuNJAUcHZdshfU9jaamp3JeOXTZ1 rRsaBcQnCtNoIfWiv+PP9fQrBX526Pkcv/go/ThnOBGrDUmM0f466RVmPVCnUIRZ7U wdW6yIYAWHjG8v761UDGuW4V7Lb4zK+9aedAsZTUDaOvoSRlzp/dcu1IdSKyoCxJLh 2FjfPDzeTxrwA97LfQEi5KNwk1QsLNLu820Bx+2XI9bqStCkHF+roW0ClQR5SX67Oj HIwxLMbJVru36W96EQPdj7JzofFLA5NiQer6ZcUt1qZTlkmkT4mzvu17jeRsZBw1/d 8HYCu4pslfvhA== From: Sweet Tea Dorminy To: ebiggers@kernel.org, tytso@mit.edu, jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v1 10/10] fscrypt: split key alloc and preparation Date: Mon, 10 Apr 2023 06:16:31 -0400 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org For extent-based encryption, we plan to use pooled prepared keys, since it's unsafe to allocate a new crypto_skcipher when performing IO. This will require being able to set up a pre-allocated prepared key, while the current code requires allocating and setting up simultaneously. This pulls apart fscrypt_allocate_skcipher() to only allocate; pulls allocation out of fscrypt_prepare_inline_crypt_key(); creates a new function fscrypt_allocate_key_member() that allocates the appropriate member of a prepared key; and reflects these changes throughout. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/fscrypt_private.h | 14 +++++++++++ fs/crypto/inline_crypt.c | 20 ++++++++++------ fs/crypto/keysetup.c | 47 ++++++++++++++++++++++++++----------- fs/crypto/keysetup_v1.c | 4 ++++ 4 files changed, 64 insertions(+), 21 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 7253cdb5e4d8..97323b1e71e7 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -358,6 +358,9 @@ fscrypt_using_inline_encryption(const struct fscrypt_info *ci) return ci->ci_inlinecrypt; } +int fscrypt_allocate_inline_crypt_key(struct fscrypt_prepared_key *prep_key, + const struct fscrypt_info *ci); + int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, const struct fscrypt_info *ci); @@ -400,6 +403,14 @@ fscrypt_using_inline_encryption(const struct fscrypt_info *ci) return false; } +static inline int +fscrypt_allocate_inline_crypt_key(struct fscrypt_prepared_key *prep_key, + const struct fscrypt_info *ci) +{ + WARN_ON(1); + return -EOPNOTSUPP; +} + static inline int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, @@ -616,6 +627,9 @@ struct fscrypt_mode { extern struct fscrypt_mode fscrypt_modes[]; +int fscrypt_allocate_key_member(struct fscrypt_prepared_key *prep_key, + const struct fscrypt_info *ci); + int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, const struct fscrypt_info *ci); diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index ce952dedba77..7b3b96b8a916 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -157,16 +157,12 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, const struct inode *inode = ci->ci_inode; struct super_block *sb = inode->i_sb; enum blk_crypto_mode_num crypto_mode = ci->ci_mode->blk_crypto_mode; - struct blk_crypto_key *blk_key; + struct blk_crypto_key *blk_key = prep_key->blk_key; struct block_device **devs; unsigned int num_devs; unsigned int i; int err; - blk_key = kmalloc(sizeof(*blk_key), GFP_KERNEL); - if (!blk_key) - return -ENOMEM; - err = blk_crypto_init_key(blk_key, raw_key, crypto_mode, fscrypt_get_dun_bytes(ci), sb->s_blocksize); if (err) { @@ -190,8 +186,6 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, fscrypt_err(inode, "error %d starting to use blk-crypto", err); goto fail; } - - prep_key->blk_key = blk_key; return 0; fail: @@ -199,6 +193,18 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, return err; } +int fscrypt_allocate_inline_crypt_key(struct fscrypt_prepared_key *prep_key, + const struct fscrypt_info *ci) +{ + struct blk_crypto_key *blk_key = kmalloc(sizeof(*blk_key), GFP_KERNEL); + + if (!blk_key) + return -ENOMEM; + + prep_key->blk_key = blk_key; + return 0; +} + void fscrypt_destroy_inline_crypt_key(struct super_block *sb, struct fscrypt_prepared_key *prep_key) { diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 6efac89d49ec..7fc7dc632b3e 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -100,9 +100,9 @@ select_encryption_mode(const union fscrypt_policy *policy, return ERR_PTR(-EINVAL); } -/* Create a symmetric cipher object for the given encryption mode and key */ +/* Create a symmetric cipher object for the given encryption mode */ static struct crypto_skcipher * -fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key, +fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const struct inode *inode) { struct crypto_skcipher *tfm; @@ -135,10 +135,6 @@ fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key, goto err_free_tfm; } crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); - err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize); - if (err) - goto err_free_tfm; - return tfm; err_free_tfm: @@ -146,11 +142,28 @@ fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key, return ERR_PTR(err); } +/* Allocate the relevant encryption member for the prepared key */ +int fscrypt_allocate_key_member(struct fscrypt_prepared_key *prep_key, + const struct fscrypt_info *ci) +{ + struct crypto_skcipher *tfm; + + if (fscrypt_using_inline_encryption(ci)) + return fscrypt_allocate_inline_crypt_key(prep_key, ci); + + tfm = fscrypt_allocate_skcipher(ci->ci_mode, ci->ci_inode); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + prep_key->tfm = tfm; + return 0; +} + /* * Prepare the crypto transform object or blk-crypto key in @prep_key, given the * raw key, encryption mode (@ci->ci_mode), flag indicating which encryption * implementation (fs-layer or blk-crypto) will be used (@ci->ci_inlinecrypt), - * and IV generation method (@ci->ci_policy.flags). + * and IV generation method (@ci->ci_policy.flags). The relevant member must + * already be allocated and set in @prep_key. */ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, const struct fscrypt_info *ci) @@ -162,14 +175,10 @@ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, if (inlinecrypt) { err = fscrypt_prepare_inline_crypt_key(prep_key, raw_key, ci); } else { - struct crypto_skcipher *tfm; + err = crypto_skcipher_setkey(prep_key->tfm, raw_key, + ci->ci_mode->keysize); - tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode); - if (IS_ERR(tfm)) - return PTR_ERR(tfm); - } - prep_key->tfm = tfm; } /* @@ -186,7 +195,7 @@ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, */ smp_store_release(&prep_key->prepared_members, prep_key->prepared_members | prepared_member); - return 0; + return err; } /* Destroy a crypto transform object and/or blk-crypto key. */ @@ -201,11 +210,17 @@ 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) { + int err; + 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; + err = fscrypt_allocate_key_member(ci->ci_enc_key, ci); + if (err) + return err; + return fscrypt_prepare_key(ci->ci_enc_key, raw_key, ci); } @@ -290,6 +305,10 @@ static int setup_new_mode_prepared_key(struct fscrypt_master_key *mk, if (fscrypt_is_key_prepared(prep_key, ci)) goto out_unlock; + err = fscrypt_allocate_key_member(prep_key, ci); + if (err) + goto out_unlock; + BUILD_BUG_ON(sizeof(mode_num) != 1); BUILD_BUG_ON(sizeof(sb->s_uuid) != 16); BUILD_BUG_ON(sizeof(hkdf_info) != 17); diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index 1e785cedead0..760efa8eeb3a 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -239,6 +239,10 @@ fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key) refcount_set(&dk->dk_refcount, 1); dk->dk_mode = ci->ci_mode; dk->dk_key.type = FSCRYPT_KEY_DIRECT_V1; + err = fscrypt_allocate_key_member(&dk->dk_key, ci); + if (err) + goto err_free_dk; + err = fscrypt_prepare_key(&dk->dk_key, raw_key, ci); if (err) goto err_free_dk;