Squashfs: add sanity checks to xattr reading at mount time
These checks add sanity checking of the mount-time xattr structures.
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c
index 51a7bd0..f60fb3c 100644
--- a/fs/squashfs/xattr_id.c
+++ b/fs/squashfs/xattr_id.c
@@ -76,6 +76,17 @@
*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
*xattr_ids = le32_to_cpu(id_table->xattr_ids);
kfree(id_table);
+
+ /* Sanity check values */
+
+ /* there is always at least one xattr id */
+ if (*xattr_ids == 0)
+ return ERR_PTR(-EINVAL);
+
+ /* xattr_table should be less than start */
+ if (*xattr_table_start >= start)
+ return ERR_PTR(-EINVAL);
+
len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
TRACE("In read_xattr_index_table, length %d\n", len);