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);
--
2.25.1
