* Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
[not found] <20171205171657.74392-1-ndesaulniers@google.com>
@ 2017-12-05 17:19 ` Nick Desaulniers
2017-12-05 17:26 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Nick Desaulniers @ 2017-12-05 17:19 UTC (permalink / raw)
Cc: Kees Cook, Robb Glasser, Jaroslav Kysela, Takashi Iwai,
Markus Elfring, Takashi Sakamoto, Arvind Yadav, alsa-devel, LKML,
stable
+ stable
On Tue, Dec 5, 2017 at 9:16 AM, Nick Desaulniers
<ndesaulniers@google.com> wrote:
> From: Robb Glasser <rglasser@google.com>
>
> 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@google.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> sound/core/pcm.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/sound/core/pcm.c b/sound/core/pcm.c
> index 9070f277f8db..09ee8c6b9f75 100644
> --- a/sound/core/pcm.c
> +++ b/sound/core/pcm.c
> @@ -153,7 +153,9 @@ static int snd_pcm_control_ioctl(struct snd_card *card,
> err = -ENXIO;
> goto _error;
> }
> + mutex_lock(&pcm->open_mutex);
> err = snd_pcm_info_user(substream, info);
> + mutex_unlock(&pcm->open_mutex);
> _error:
> mutex_unlock(®ister_mutex);
> return err;
> --
> 2.15.0.531.g2ccb3012c9-goog
>
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
2017-12-05 17:19 ` [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info Nick Desaulniers
@ 2017-12-05 17:26 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2017-12-05 17:26 UTC (permalink / raw)
To: Nick Desaulniers
Cc: Kees Cook, Robb Glasser, Jaroslav Kysela, Takashi Iwai,
Markus Elfring, Takashi Sakamoto, Arvind Yadav, alsa-devel, LKML,
stable
On Tue, Dec 05, 2017 at 09:19:32AM -0800, Nick Desaulniers wrote:
> + stable
>
> On Tue, Dec 5, 2017 at 9:16 AM, Nick Desaulniers
> <ndesaulniers@google.com> wrote:
> > From: Robb Glasser <rglasser@google.com>
> >
> > 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@google.com>
> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > ---
> > sound/core/pcm.c | 2 ++
> > 1 file changed, 2 insertions(+)
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-12-05 17:19 ` [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info Nick Desaulniers
2017-12-05 17:26 ` Greg KH
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