On Thu, 13 Jun 2019 11:11:22 +0200,
Greg Kroah-Hartman wrote:
>
> On Thu, Jun 13, 2019 at 11:02:54AM +0200, Takashi Iwai wrote:
> > On Thu, 13 Jun 2019 10:33:44 +0200,
> > Greg Kroah-Hartman wrote:
> > >
> > > [ Upstream commit feb689025fbb6f0aa6297d3ddf97de945ea4ad32 ]
> > >
> > > ALSA OSS sequencer calls the ioctl function indirectly via
> > > snd_seq_kernel_client_ctl(). While we already applied the protection
> > > against races between the normal ioctls and writes via the client's
> > > ioctl_mutex, this code path was left untouched. And this seems to be
> > > the cause of still remaining some rare UAF as spontaneously triggered
> > > by syzkaller.
> > >
> > > For the sake of robustness, wrap the ioctl_mutex also for the call via
> > > snd_seq_kernel_client_ctl(), too.
> > >
> > > Reported-by: syzbot+e4c8abb920efa77bace9@xxxxxxxxxxxxxxxxxxxxxxxxx
> > > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> >
> > This commit is reverted later by commit f0654ba94e33.
> > So please drop this. The proper fix is done later by commit
> > 7c32ae35fbf9 ("ALSA: seq: Cover unsubscribe_port() in list_mutex")
> >
> > Ditto for 4.19.y and 5.1.y.
>
> Now dropped everywhere, and I added 7c32ae35fbf9 ("ALSA: seq: Cover
> unsubscribe_port() in list_mutex") everywhere instead.
Thanks!
BTW, do we have a systematic check whether the selected stable commit
is reverted in a later commit? At least, you can track it as long as
Fixes tag is properly set.
Takashi
