| Message ID | 20230313151909.3658925-1-zyytlz.wz@163.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] media: hantro: fix use after free bug in hantro_remove due to race condition | expand |
diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c index b0aeedae7b65..496024b21b51 100644 --- a/drivers/media/platform/verisilicon/hantro_drv.c +++ b/drivers/media/platform/verisilicon/hantro_drv.c @@ -1099,6 +1099,7 @@ static int hantro_remove(struct platform_device *pdev) v4l2_info(&vpu->v4l2_dev, "Removing %s\n", pdev->name); + cancel_delayed_work_sync(&vpu->watchdog_work); media_device_unregister(&vpu->mdev); hantro_remove_dec_func(vpu); hantro_remove_enc_func(vpu);
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 remove the module which will call hantro_remove to make cleanup, there may be an unfinished work. The possible sequence is as follows, which will cause a typical UAF bug. Fix it by canceling the work before cleanup in hantro_remove. 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@163.com> --- v2: - move the cancel-work-related code to hantro_remove suggested by Hans Verkuil --- drivers/media/platform/verisilicon/hantro_drv.c | 1 + 1 file changed, 1 insertion(+)