xfs: check that dir block entries don't off the end of the buffer

When we're checking the entries in a directory buffer, make sure that the entry length doesn't push us off the end of the buffer. Found via xfs/388 writing ones to the length fields. Signed-off-by: Darrick J. Wong <[email protected]> Reviewed-by: Brian Foster <[email protected]>
opendata26 · Jul 25, 2017 · 6215894 · 6215894
1 parent cfaf2d0
commit 6215894
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/fs/xfs/libxfs/xfs_dir2_data.c b/fs/xfs/libxfs/xfs_dir2_data.c
@@ -136,6 +136,8 @@ __xfs_dir3_data_check(
 		 */
 		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 			XFS_WANT_CORRUPTED_RETURN(mp, lastfree == 0);
+			XFS_WANT_CORRUPTED_RETURN(mp, endp >=
+					p + be16_to_cpu(dup->length));
 			XFS_WANT_CORRUPTED_RETURN(mp,
 				be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
 					       (char *)dup - (char *)hdr);
@@ -164,6 +166,8 @@ __xfs_dir3_data_check(
 		XFS_WANT_CORRUPTED_RETURN(mp, dep->namelen != 0);
 		XFS_WANT_CORRUPTED_RETURN(mp,
 			!xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
+		XFS_WANT_CORRUPTED_RETURN(mp, endp >=
+				p + ops->data_entsize(dep->namelen));
 		XFS_WANT_CORRUPTED_RETURN(mp,
 			be16_to_cpu(*ops->data_entry_tag_p(dep)) ==
 					       (char *)dep - (char *)hdr);