* [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
@ 2017-12-05 17:16 Nick Desaulniers
2017-12-05 17:19 ` Nick Desaulniers
2017-12-05 19:14 ` Takashi Iwai
0 siblings, 2 replies; 6+ messages in thread
From: Nick Desaulniers @ 2017-12-05 17:16 UTC (permalink / raw)
Cc: keescook, Robb Glasser, Nick Desaulniers, Jaroslav Kysela,
Takashi Iwai, Markus Elfring, Takashi Sakamoto, Arvind Yadav,
alsa-devel, linux-kernel
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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
2017-12-05 17:16 [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info Nick Desaulniers
@ 2017-12-05 17:19 ` Nick Desaulniers
2017-12-05 17:26 ` Greg KH
2017-12-05 19:14 ` Takashi Iwai
1 sibling, 1 reply; 6+ 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] 6+ messages in thread
* Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
2017-12-05 17:19 ` Nick Desaulniers
@ 2017-12-05 17:26 ` Greg KH
0 siblings, 0 replies; 6+ 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] 6+ messages in thread
* Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
2017-12-05 17:16 [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info Nick Desaulniers
2017-12-05 17:19 ` Nick Desaulniers
@ 2017-12-05 19:14 ` Takashi Iwai
2017-12-05 19:29 ` Kees Cook
1 sibling, 1 reply; 6+ messages in thread
From: Takashi Iwai @ 2017-12-05 19:14 UTC (permalink / raw)
To: Nick Desaulniers
Cc: alsa-devel, keescook, Arvind Yadav, Robb Glasser, Jaroslav Kysela,
Takashi Sakamoto, Markus Elfring, linux-kernel
On Tue, 05 Dec 2017 18:16:55 +0100,
Nick Desaulniers 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>
Looks reasonable. Applied with Cc to stable now.
thanks,
Takashi
> ---
> 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
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
2017-12-05 19:14 ` Takashi Iwai
@ 2017-12-05 19:29 ` Kees Cook
2017-12-05 22:30 ` Takashi Iwai
0 siblings, 1 reply; 6+ messages in thread
From: Kees Cook @ 2017-12-05 19:29 UTC (permalink / raw)
To: Takashi Iwai
Cc: Nick Desaulniers, moderated for non-subscribers, Arvind Yadav,
Robb Glasser, Jaroslav Kysela, Takashi Sakamoto, Markus Elfring,
LKML
On Tue, Dec 5, 2017 at 11:14 AM, Takashi Iwai <tiwai@suse.de> wrote:
> On Tue, 05 Dec 2017 18:16:55 +0100,
> Nick Desaulniers 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>
>
> 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.)
-Kees
>
>
> thanks,
>
> Takashi
>
>> ---
>> 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
>>
>>
--
Kees Cook
Pixel Security
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info
2017-12-05 19:29 ` Kees Cook
@ 2017-12-05 22:30 ` Takashi Iwai
0 siblings, 0 replies; 6+ messages in thread
From: Takashi Iwai @ 2017-12-05 22:30 UTC (permalink / raw)
To: Kees Cook
Cc: Nick Desaulniers, moderated for non-subscribers, Arvind Yadav,
Robb Glasser, Jaroslav Kysela, Takashi Sakamoto, Markus Elfring,
LKML
On Tue, 05 Dec 2017 20:29:07 +0100,
Kees Cook wrote:
>
> On Tue, Dec 5, 2017 at 11:14 AM, Takashi Iwai <tiwai@suse.de> wrote:
> > On Tue, 05 Dec 2017 18:16:55 +0100,
> > Nick Desaulniers 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>
> >
> > 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
^ permalink raw reply [flat|nested] 6+ messages in thread
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2017-12-05 17:16 [PATCH] ALSA: pcm: prevent UAF in snd_pcm_info Nick Desaulniers
2017-12-05 17:19 ` Nick Desaulniers
2017-12-05 17:26 ` Greg KH
2017-12-05 19:14 ` Takashi Iwai
2017-12-05 19:29 ` Kees Cook
2017-12-05 22:30 ` Takashi Iwai
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