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authorSu Yue <suy.fnst@cn.fujitsu.com>2017-06-06 12:57:00 +0300
committerDavid Sterba <dsterba@suse.com>2017-06-21 20:16:04 +0300
commit19c6dcbfa74674ac5ab5d18096ee813f858668c3 (patch)
treefc86826db4b41589e939aa3a4dff56be67056273 /fs/btrfs/dir-item.c
parent66b4993e95c17e0ee30f0d72f0d6e00e5c035a98 (diff)
downloadlinux-19c6dcbfa74674ac5ab5d18096ee813f858668c3.tar.xz
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/btrfs/dir-item.c')
-rw-r--r--fs/btrfs/dir-item.c72
1 files changed, 72 insertions, 0 deletions
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index c24d615e3d7f..5b6c6fb7c800 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;
+}