[PATCH v2] ASoC: soc-pcm: Add NULL check in BE reparenting

[PATCH v2] ASoC: soc-pcm: Add NULL check in BE reparenting

[Srinivasa Rao Mandadapu]

Add NULL check in dpcm_be_reparent API, to handle
kernel NULL pointer dereference error.
The issue occurred in fuzzing test.

Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
---
Changes Since V1:
    -- Update commit title.

 sound/soc/soc-pcm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 493f003..a7810c7 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1247,6 +1247,8 @@ static void dpcm_be_reparent(struct snd_soc_pcm_runtime *fe,
 		return;
 
 	be_substream = snd_soc_dpcm_get_substream(be, stream);
+	if (!be_substream)
+		return;
 
 	for_each_dpcm_fe(be, stream, dpcm) {
 		if (dpcm->fe == fe)
-- 
2.7.4

Re: [PATCH v2] ASoC: soc-pcm: Add NULL check in BE reparenting

[Mark Brown]

On Tue, 22 Nov 2022 12:01:13 +0530, Srinivasa Rao Mandadapu wrote:
> Add NULL check in dpcm_be_reparent API, to handle
> kernel NULL pointer dereference error.
> The issue occurred in fuzzing test.
> 
> 

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: soc-pcm: Add NULL check in BE reparenting
      commit: db8f91d424fe0ea6db337aca8bc05908bbce1498

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

Re: [PATCH v2] ASoC: soc-pcm: Add NULL check in BE reparenting

[Cezary Rojewski]

On 2022-11-22 7:31 AM, Srinivasa Rao Mandadapu wrote:
> Add NULL check in dpcm_be_reparent API, to handle
> kernel NULL pointer dereference error.
> The issue occurred in fuzzing test.
> 
> Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
> ---
> Changes Since V1:
>      -- Update commit title.
> 
>   sound/soc/soc-pcm.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
> index 493f003..a7810c7 100644
> --- a/sound/soc/soc-pcm.c
> +++ b/sound/soc/soc-pcm.c
> @@ -1247,6 +1247,8 @@ static void dpcm_be_reparent(struct snd_soc_pcm_runtime *fe,
>   		return;
>   
>   	be_substream = snd_soc_dpcm_get_substream(be, stream);
> +	if (!be_substream)
> +		return;
>   
>   	for_each_dpcm_fe(be, stream, dpcm) {
>   		if (dpcm->fe == fe)

The explanation provided is hardly satisfactory. The reason I asked, is 
that be_substream should never be null by the time we get to 
dpcm_be_reparent(). There is a number of invocations of 
snd_soc_dpcm_get_substream() within sound/soc/*.c and yet most of them 
are not checked - as they do not need to be.

I believe that the problem may lie elsewhere and this patch just covered 
things up.


Regards,
Czarek

Re: [PATCH v2] ASoC: soc-pcm: Add NULL check in BE reparenting

[Cezary Rojewski]

On 2022-11-22 7:31 AM, Srinivasa Rao Mandadapu wrote:
> Add NULL check in dpcm_be_reparent API, to handle
> kernel NULL pointer dereference error.
> The issue occurred in fuzzing test.
> 
> Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
> ---
> Changes Since V1:
>      -- Update commit title.
> 
>   sound/soc/soc-pcm.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
> index 493f003..a7810c7 100644
> --- a/sound/soc/soc-pcm.c
> +++ b/sound/soc/soc-pcm.c
> @@ -1247,6 +1247,8 @@ static void dpcm_be_reparent(struct snd_soc_pcm_runtime *fe,
>   		return;
>   
>   	be_substream = snd_soc_dpcm_get_substream(be, stream);
> +	if (!be_substream)
> +		return;
>   
>   	for_each_dpcm_fe(be, stream, dpcm) {
>   		if (dpcm->fe == fe)

The explanation provided is hardly satisfactory. The reason I asked, is 
that be_substream should never be null by the time we get to 
dpcm_be_reparent(). There is a number of invocations of 
snd_soc_dpcm_get_substream() within sound/soc/*.c and yet most of them 
are not checked - as they do not need to be.

I believe that the problem may lie elsewhere and this patch just covered 
things up.


Regards,
Czarek