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: 13296485 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 D7306EB64DD for ; Thu, 29 Jun 2023 00:35:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231372AbjF2Afl (ORCPT ); Wed, 28 Jun 2023 20:35:41 -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-btrfs@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