Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info

[Takashi Iwai]

On Tue, 05 Dec 2017 20:29:07 +0100,
Kees Cook wrote:
> 
> On Tue, Dec 5, 2017 at 11:14 AM, Takashi Iwai <tiwai@xxxxxxx> wrote:
> > On Tue, 05 Dec 2017 18:16:55 +0100,
> > Nick Desaulniers wrote:
> >>
> >> From: Robb Glasser <rglasser@xxxxxxxxxx>
> >>
> >> When the device descriptor is closed, the `substream->runtime` pointer
> >> is freed. But another thread may be in the ioctl handler, case
> >> SNDRV_CTL_IOCTL_PCM_INFO. This case calls snd_pcm_info_user() which
> >> calls snd_pcm_info() which accesses the now freed `substream->runtime`.
> >>
> >> Signed-off-by: Robb Glasser <rglasser@xxxxxxxxxx>
> >> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> >
> > Looks reasonable.  Applied with Cc to stable now.
> 
> FWIW, this was assigned CVE-2017-0861. (Best to get it into the commit
> log if possible.)

OK, I updated the changelog.  Thanks for information.


Takashi