Files
linux/ipc
NeilBrown c9ba789dad VFS: introduce start_creating_noperm() and start_removing_noperm()
xfs, fuse, ipc/mqueue need variants of start_creating or start_removing
which do not check permissions.
This patch adds _noperm versions of these functions.

Note that do_mq_open() was only calling mntget() so it could call
path_put() - it didn't really need an extra reference on the mnt.
Now it doesn't call mntget() and uses end_creating() which does
the dput() half of path_put().

Also mq_unlink() previously passed
   d_inode(dentry->d_parent)
as the dir inode to vfs_unlink().  This is after locking
   d_inode(mnt->mnt_root)
These two inodes are the same, but normally calls use the textual
parent.
So I've changes the vfs_unlink() call to be given d_inode(mnt->mnt_root).

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>

--
changes since v2:
 - dir arg passed to vfs_unlink() in mq_unlink() changed to match
   the dir passed to lookup_noperm()
 - restore assignment to path->mnt even though the mntget() is removed.

Link: https://patch.msgid.link/20251113002050.676694-7-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-14 13:15:56 +01:00
..
2025-09-19 14:26:15 +02:00
2019-11-15 14:38:27 +01:00
2023-12-20 19:26:31 -05:00