From patchwork Tue Aug 8 17:12:10 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: 13346809 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 1592FC001DB for ; Tue, 8 Aug 2023 18:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234135AbjHHSyu (ORCPT ); Tue, 8 Aug 2023 14:54:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231582AbjHHSyb (ORCPT ); Tue, 8 Aug 2023 14:54:31 -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 C23041B046; Tue, 8 Aug 2023 10:12:37 -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 568118343D; Tue, 8 Aug 2023 13:12:37 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1691514757; bh=vZtFoQKKsLfpwHLBX9gD6fBDzJ/9AqqYRAOFzdVkosE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uG811T2FMO1JW4X+P10AWUFIXCj+pjs0SkzPJyJIJJCwkIr6THA3lIHzg/ca51l1y SpEzSWSjVBvdRT9gEKr3u8qGj54sVCu2HMX1eR0Ffvj6SXizjKIE8hYjOC+oXw5Cet TZY4rMxs0lWO2VuQLx0UhyRTvl5npdMVnLhKwuX8iOIq7/E8WNIYOOpB6N3k73/68b lPRTNEA7Yhplh3X2Fjzd8XEqs5ZguMuBtGWfJata1UDrse7BnTpBrPGuA8ZX9VSLNi 5gYR6Os9x4kB1MCq8Cb5cJFHtUhFJwr8ZjR65zCTY+QrMI563xfyNS9SgRxO3VcI1X 4jA61lIKnngfQ== From: Sweet Tea Dorminy To: Chris Mason , Josef Bacik , David Sterba , "Theodore Y . Ts'o" , Jaegeuk Kim , kernel-team@meta.com, linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org, Eric Biggers Cc: Sweet Tea Dorminy Subject: [PATCH v3 08/17] btrfs: handle nokey names. Date: Tue, 8 Aug 2023 13:12:10 -0400 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org For encrypted or unencrypted names, we calculate the offset for the dir item by hashing the name for the dir item. However, this doesn't work for a long nokey name, where we do not have the complete ciphertext. Instead, fscrypt stores the filesystem-provided hash in the nokey name, and we can extract it from the fscrypt_name structure in such a case. Additionally, for nokey names, if we find the nokey name on disk we can update the fscrypt_name with the disk name, so add that to searching for diritems. Signed-off-by: Sweet Tea Dorminy --- fs/btrfs/dir-item.c | 37 +++++++++++++++++++++++++++++++++++-- fs/btrfs/fscrypt.c | 27 +++++++++++++++++++++++++++ fs/btrfs/fscrypt.h | 11 +++++++++++ 3 files changed, 73 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c index da95ae411d72..ee7dad888f53 100644 --- a/fs/btrfs/dir-item.c +++ b/fs/btrfs/dir-item.c @@ -231,6 +231,28 @@ struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, return di; } +/* + * If appropriate, populate the disk name for a fscrypt_name looked up without + * a key. + * + * @path: The path to the extent buffer in which the name was found. + * @di: The dir item corresponding. + * @fname: The fscrypt_name to perhaps populate. + * + * Returns: 0 if the name is already populated or the dir item doesn't exist + * or the name was successfully populated, else an error code. + */ +static int ensure_disk_name_from_dir_item(struct btrfs_path *path, + struct btrfs_dir_item *di, + struct fscrypt_name *name) +{ + if (name->disk_name.name || !di) + return 0; + + return btrfs_fscrypt_get_disk_name(path->nodes[0], di, + &name->disk_name); +} + /* * Lookup for a directory item by fscrypt_name. * @@ -257,8 +279,12 @@ struct btrfs_dir_item *btrfs_lookup_dir_item_fname(struct btrfs_trans_handle *tr key.objectid = dir; key.type = BTRFS_DIR_ITEM_KEY; - key.offset = btrfs_name_hash(name->disk_name.name, name->disk_name.len); - /* XXX get the right hash for no-key names */ + + if (!name->disk_name.name) + key.offset = name->hash | ((u64)name->minor_hash << 32); + else + key.offset = btrfs_name_hash(name->disk_name.name, + name->disk_name.len); ret = btrfs_search_slot(trans, root, &key, path, mod, -mod); if (ret == 0) @@ -266,6 +292,8 @@ struct btrfs_dir_item *btrfs_lookup_dir_item_fname(struct btrfs_trans_handle *tr if (ret == -ENOENT || (di && IS_ERR(di) && PTR_ERR(di) == -ENOENT)) return NULL; + if (ret == 0) + ret = ensure_disk_name_from_dir_item(path, di, name); if (ret < 0) di = ERR_PTR(ret); @@ -382,7 +410,12 @@ btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path, btrfs_for_each_slot(root, &key, &key, path, ret) { if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY) break; + di = btrfs_match_dir_item_fname(root->fs_info, path, name); + if (di) + ret = ensure_disk_name_from_dir_item(path, di, name); + if (ret) + break; if (di) return di; } diff --git a/fs/btrfs/fscrypt.c b/fs/btrfs/fscrypt.c index fcd926907f82..bdd58415f93c 100644 --- a/fs/btrfs/fscrypt.c +++ b/fs/btrfs/fscrypt.c @@ -14,6 +14,33 @@ #include "transaction.h" #include "xattr.h" +/* + * From a given location in a leaf, read a name into a qstr (usually a + * fscrypt_name's disk_name), allocating the required buffer. Used for + * nokey names. + */ +int btrfs_fscrypt_get_disk_name(struct extent_buffer *leaf, + struct btrfs_dir_item *dir_item, + struct fscrypt_str *name) +{ + unsigned long de_name_len = btrfs_dir_name_len(leaf, dir_item); + unsigned long de_name = (unsigned long)(dir_item + 1); + /* + * For no-key names, we use this opportunity to find the disk + * name, so future searches don't need to deal with nokey names + * and we know what the encrypted size is. + */ + name->name = kmalloc(de_name_len, GFP_NOFS); + + if (!name->name) + return -ENOMEM; + + read_extent_buffer(leaf, name->name, de_name, de_name_len); + + name->len = de_name_len; + return 0; +} + /* * This function is extremely similar to fscrypt_match_name() but uses an * extent_buffer. diff --git a/fs/btrfs/fscrypt.h b/fs/btrfs/fscrypt.h index 1647bbbcd609..c08fd52c99b4 100644 --- a/fs/btrfs/fscrypt.h +++ b/fs/btrfs/fscrypt.h @@ -9,11 +9,22 @@ #include "fs.h" #ifdef CONFIG_FS_ENCRYPTION +int btrfs_fscrypt_get_disk_name(struct extent_buffer *leaf, + struct btrfs_dir_item *di, + struct fscrypt_str *qstr); + bool btrfs_fscrypt_match_name(struct fscrypt_name *fname, struct extent_buffer *leaf, unsigned long de_name, u32 de_name_len); #else +static inline int btrfs_fscrypt_get_disk_name(struct extent_buffer *leaf, + struct btrfs_dir_item *di, + struct fscrypt_str *qstr) +{ + return 0; +} + static inline bool btrfs_fscrypt_match_name(struct fscrypt_name *fname, struct extent_buffer *leaf, unsigned long de_name,