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author | Su Yue <suy.fnst@cn.fujitsu.com> | 2017-06-06 17:57:00 +0800 |
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committer | David Sterba <dsterba@suse.com> | 2017-06-21 19:16:04 +0200 |
commit | 19c6dcbfa74674ac5ab5d18096ee813f858668c3 (patch) | |
tree | fc86826db4b41589e939aa3a4dff56be67056273 /fs | |
parent | 66b4993e95c17e0ee30f0d72f0d6e00e5c035a98 (diff) | |
download | op-kernel-dev-19c6dcbfa74674ac5ab5d18096ee813f858668c3.zip op-kernel-dev-19c6dcbfa74674ac5ab5d18096ee813f858668c3.tar.gz |
btrfs: Introduce btrfs_is_name_len_valid to avoid reading beyond boundary
Introduce function btrfs_is_name_len_valid.
The function compares parameter @name_len with item boundary then
returns true if name_len is valid.
Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ s/btrfs_leaf_data/BTRFS_LEAF_DATA_OFFSET/ ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/btrfs/ctree.h | 2 | ||||
-rw-r--r-- | fs/btrfs/dir-item.c | 72 |
2 files changed, 74 insertions, 0 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 15a77e6..d182ce7 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3042,6 +3042,8 @@ struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info, struct btrfs_path *path, const char *name, int name_len); +bool btrfs_is_name_len_valid(struct extent_buffer *leaf, int slot, + unsigned long start, u16 name_len); /* orphan.c */ int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c index c24d615..5b6c6fb 100644 --- a/fs/btrfs/dir-item.c +++ b/fs/btrfs/dir-item.c @@ -484,3 +484,75 @@ int verify_dir_item(struct btrfs_fs_info *fs_info, return 0; } + +bool btrfs_is_name_len_valid(struct extent_buffer *leaf, int slot, + unsigned long start, u16 name_len) +{ + struct btrfs_fs_info *fs_info = leaf->fs_info; + struct btrfs_key key; + u32 read_start; + u32 read_end; + u32 item_start; + u32 item_end; + u32 size; + bool ret = true; + + ASSERT(start > BTRFS_LEAF_DATA_OFFSET); + + read_start = start - BTRFS_LEAF_DATA_OFFSET; + read_end = read_start + name_len; + item_start = btrfs_item_offset_nr(leaf, slot); + item_end = btrfs_item_end_nr(leaf, slot); + + btrfs_item_key_to_cpu(leaf, &key, slot); + + switch (key.type) { + case BTRFS_DIR_ITEM_KEY: + case BTRFS_XATTR_ITEM_KEY: + case BTRFS_DIR_INDEX_KEY: + size = sizeof(struct btrfs_dir_item); + break; + case BTRFS_INODE_REF_KEY: + size = sizeof(struct btrfs_inode_ref); + break; + case BTRFS_INODE_EXTREF_KEY: + size = sizeof(struct btrfs_inode_extref); + break; + case BTRFS_ROOT_REF_KEY: + case BTRFS_ROOT_BACKREF_KEY: + size = sizeof(struct btrfs_root_ref); + break; + default: + ret = false; + goto out; + } + + if (read_start < item_start) { + ret = false; + goto out; + } + if (read_end > item_end) { + ret = false; + goto out; + } + + /* there shall be item(s) before name */ + if (read_start - item_start < size) { + ret = false; + goto out; + } + + /* + * This may be the last item in the slot + * Or same type item(s) is left between read_end and item_end + */ + if (item_end != read_end && item_end - read_end < size) { + ret = false; + goto out; + } +out: + if (!ret) + btrfs_crit(fs_info, "invalid dir item name len: %u", + (unsigned int)name_len); + return ret; +} |