On 07/03/2023 16:35, Zheng Wang wrote:
> In hantro_probe, vpu->watchdog_work is bound with
> hantro_watchdog. Then hantro_end_prepare_run may
> be called to start the work.
>
> If we close the file or remove the module which will
> call hantro_release and hantro_remove to make cleanup,
> there may be a unfinished work. The possible sequence
> is as follows, which will cause a typical UAF bug.
>
> The same thing will happen in hantro_release, and use
> ctx after freeing it.
>
> Fix it by canceling the work before cleanup in hantro_release.
>
> CPU0 CPU1
>
> |hantro_watchdog
> hantro_remove |
> v4l2_m2m_release |
> kfree(m2m_dev); |
> |
> | v4l2_m2m_get_curr_priv
> | m2m_dev->curr_ctx //use
>
> Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
> ---
> drivers/media/platform/verisilicon/hantro_drv.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c
> index b0aeedae7b65..cf00ccaa7829 100644
> --- a/drivers/media/platform/verisilicon/hantro_drv.c
> +++ b/drivers/media/platform/verisilicon/hantro_drv.c
> @@ -601,6 +601,7 @@ static int hantro_release(struct file *filp)
> * No need for extra locking because this was the last reference
> * to this file.
> */
> + cancel_delayed_work(&vpu->watchdog_work);
> v4l2_m2m_ctx_release(ctx->fh.m2m_ctx);
> v4l2_fh_del(&ctx->fh);
> v4l2_fh_exit(&ctx->fh);
drivers/media/platform/verisilicon/hantro_drv.c: In function ‘hantro_release’:
drivers/media/platform/verisilicon/hantro_drv.c:604:30: error: ‘vpu’ undeclared (first use in this function); did you mean ‘fpu’?
604 | cancel_delayed_work(&vpu->watchdog_work);
| ^~~
| fpu
drivers/media/platform/verisilicon/hantro_drv.c:604:30: note: each undeclared identifier is reported only once for each function it appears in
You clearly didn't compile this patch!
Regards,
Hans
