ext4: add verifier check for symlink with append/immutable flags
The Linux VFS does not allow a way to set append/immuttable
attributes to symlinks, this is just not possible. If this is
detected inform the user as the filesystem must be corrupted.
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0eb64e8..9d512fa 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4965,6 +4965,13 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
inode->i_op = &ext4_dir_inode_operations;
inode->i_fop = &ext4_dir_operations;
} else if (S_ISLNK(inode->i_mode)) {
+ /* VFS does not allow setting these so must be corruption */
+ if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
+ EXT4_ERROR_INODE(inode,
+ "immutable or append flags not allowed on symlinks");
+ ret = -EFSCORRUPTED;
+ goto bad_inode;
+ }
if (ext4_encrypted_inode(inode)) {
inode->i_op = &ext4_encrypted_symlink_inode_operations;
ext4_set_aops(inode);
