[PATCH v2] cifs: fix use-after-free on the link name

[Steve French]

tentatively merged into cifs-2.6.git for-next pending additional testing

On Fri, Nov 4, 2022 at 12:57 PM Paulo Alcantara via samba-technical <
samba-technical at lists.samba.org> wrote:

> ChenXiaoSong <chenxiaosong2 at huawei.com> writes:
>
> > When opened a symlink, link name is from 'inode->i_link', but it may be
> > reset to a new value when revalidate the dentry. If some processes get
> the
> > link name on the race scenario, then UAF will happen on link name.
> >
> > Fix this by implementing 'get_link' interface to duplicate the link name.
> >
> > Fixes: 76894f3e2f71 ("cifs: improve symlink handling for smb2+")
> > Signed-off-by: ChenXiaoSong <chenxiaosong2 at huawei.com>
> > ---
> >  fs/cifs/cifsfs.c | 26 +++++++++++++++++++++++++-
> >  fs/cifs/inode.c  |  5 -----
> >  2 files changed, 25 insertions(+), 6 deletions(-)
>
> Reviewed-by: Paulo Alcantara (SUSE) <pc at cjr.nz>
>
>

-- 
Thanks,

Steve