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; }