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;