[PATCH] media: hantro: fix use after free bug in hantro_release due to race condition
hverkuil at xs4all.nl
Mon Mar 13 06:17:55 PDT 2023
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_remove |
> v4l2_m2m_release |
> kfree(m2m_dev); |
> | v4l2_m2m_get_curr_priv
> | m2m_dev->curr_ctx //use
> Signed-off-by: Zheng Wang <zyytlz.wz at 163.com>
> 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);
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);
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!
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