From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:58814 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751664AbeEJXOI (ORCPT ); Thu, 10 May 2018 19:14:08 -0400 From: "Luis R. Rodriguez" To: viro@zeniv.linux.org.uk, darrick.wong@oracle.com, tytso@mit.edu, adilger.kernel@dilger.ca, clm@fb.com, jbacik@fb.com, dsterba@suse.com Cc: sandeen@sandeen.net, dhowells@redhat.com, fliu@suse.com, jack@suse.cz, jeffm@suse.com, nborisov@suse.com, jake.norris@suse.com, mtk.manpages@gmail.com, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, "Luis R. Rodriguez" Subject: [RFC v2 3/4] ext4: add verifier check for symlink with append/immutable flags Date: Thu, 10 May 2018 16:13:58 -0700 Message-Id: <20180510231359.16899-4-mcgrof@kernel.org> In-Reply-To: <20180510231359.16899-1-mcgrof@kernel.org> References: <20180510231359.16899-1-mcgrof@kernel.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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 --- fs/ext4/inode.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 37a2f7a2b66a..6acf0dd6b6e6 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4947,6 +4947,13 @@ 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); -- 2.17.0