2024-04-24 07:20:31

by Dikshita Agarwal

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

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.

Signed-off-by: Dikshita Agarwal <[email protected]>
---
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);
--
2.7.4

2024-04-24 08:57:28

by Bryan O'Donoghue

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

On 24/04/2024 08:17, 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.
>
> Signed-off-by: Dikshita Agarwal <[email protected]>
> ---
> 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);

Needs a Fixes tag

---
bod