Re: [PATCH v4] media: venus: fix use after free in vdec_close

[Vikash Garodia]

On 5/9/2024 10:44 AM, Dikshita Agarwal wrote:
> There appears to be a possible use after free with vdec_close().
> The firmware will add buffer release work to the work queue through
> HFI callbacks as a normal part of decoding. Randomly closing the
> decoder device from userspace during normal decoding can incur
> a read after free for inst.
> 
> Fix it by cancelling the work in vdec_close.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: af2c3834c8ca ("[media] media: venus: adding core part and helper functions")
> Signed-off-by: Dikshita Agarwal <quic_dikshita@xxxxxxxxxxx>
> ---
> Changes since v3:
> - Fixed style issue with fixes tag 
> 
> Changes since v2:
> - Fixed email id
> 
> Changes since v1:
> - Added fixes and stable tags
> 
>  drivers/media/platform/qcom/venus/vdec.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
> index 29130a9..56f8a25 100644
> --- a/drivers/media/platform/qcom/venus/vdec.c
> +++ b/drivers/media/platform/qcom/venus/vdec.c
> @@ -1747,6 +1747,7 @@ static int vdec_close(struct file *file)
>  
>  	vdec_pm_get(inst);
>  
> +	cancel_work_sync(&inst->delayed_process_work);
>  	v4l2_m2m_ctx_release(inst->m2m_ctx);
>  	v4l2_m2m_release(inst->m2m_dev);
>  	vdec_ctrl_deinit(inst);

Acked-by: Vikash Garodia <quic_vgarodia@xxxxxxxxxxx>