Re: [PATCH v5.10] ceph: fix up non-directory creation in SGID directories

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Dec 23, 2021 at 11:31:29AM +0100, Christian Brauner wrote:
> On Thu, Dec 23, 2021 at 11:20:07AM +0100, Greg KH wrote:
> > On Thu, Dec 23, 2021 at 10:57:33AM +0100, Christian Brauner wrote:
> > > From: Christian Brauner <christian.brauner@ubuntu.com>
> > > 
> > > Ceph always inherits the SGID bit if it is set on the parent inode,
> > > while the generic inode_init_owner does not do this in a few cases where
> > > it can create a possible security problem (cf. [1]).
> > > 
> > > Update ceph to strip the SGID bit just as inode_init_owner would.
> > > 
> > > This bug was detected by the mapped mount testsuite in [3]. The
> > > testsuite tests all core VFS functionality and semantics with and
> > > without mapped mounts. That is to say it functions as a generic VFS
> > > testsuite in addition to a mapped mount testsuite. While working on
> > > mapped mount support for ceph, SIGD inheritance was the only failing
> > > test for ceph after the port.
> > > 
> > > The same bug was detected by the mapped mount testsuite in XFS in
> > > January 2021 (cf. [2]).
> > > 
> > > [1]: commit 0fa3ecd87848 ("Fix up non-directory creation in SGID directories")
> > > [2]: commit 01ea173e103e ("xfs: fix up non-directory creation in SGID directories")
> > > [3]: https://git.kernel.org/fs/xfs/xfstests-dev.git
> > > 
> > > Cc: stable@vger.kernel.org (adapted to v5.10)
> > > Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> > > Reviewed-by: Jeff Layton <jlayton@kernel.org>
> > > Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
> > > ---
> > >  fs/ceph/file.c | 18 +++++++++++++++---
> > >  1 file changed, 15 insertions(+), 3 deletions(-)
> > 
> > What is the git commit id in Linus's tree?
> 
> commit fd84bfdddd169c219c3a637889a8b87f70a072c2
> Author: Christian Brauner <christian.brauner@ubuntu.com>
> Date:   Mon Nov 29 12:16:39 2021 +0100
> 
>     ceph: fix up non-directory creation in SGID directories

Great, now queued up, thanks.

greg k-h