From 6390d33bf5d9b24fd4f96e415b6888f59c8494f9 Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Sun, 13 May 2018 16:45:56 -0400 Subject: [PATCH] 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 Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara --- fs/ext4/inode.c | 7 +++++++ 1 file changed, 7 insertions(+) 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); -- 2.7.4