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[76.182.20.124]) by smtp.gmail.com with ESMTPSA id q2-20020a819902000000b0059bc0d766f8sm1084022ywg.34.2023.10.10.13.41.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Oct 2023 13:41:20 -0700 (PDT) From: Josef Bacik To: linux-fscrypt@vger.kernel.org, ebiggers@kernel.org, linux-btrfs@vger.kernel.org Cc: Sweet Tea Dorminy Subject: [PATCH v2 15/36] btrfs: handle nokey names. Date: Tue, 10 Oct 2023 16:40:30 -0400 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Sweet Tea Dorminy 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 Signed-off-by: Josef Bacik --- 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 a64cfddff7f0..897fb5477369 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 6a4e4f63a660..9103da28af7e 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,