6.1-stable review patch. If anyone has any objections, please let me know.
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From: Murad Masimov m.masimov@mt-integration.ru
commit f656cfbc7a293a039d6a0c7100e1c846845148c1 upstream.
Syzkaller has reported a general protection fault at function ir_raw_event_store_with_filter(). This crash is caused by a NULL pointer dereference of dev->raw pointer, even though it is checked for NULL in the same function, which means there is a race condition. It occurs due to the incorrect order of actions in the streamzap_disconnect() function: rc_unregister_device() is called before usb_kill_urb(). The dev->raw pointer is freed and set to NULL in rc_unregister_device(), and only after that usb_kill_urb() waits for in-progress requests to finish.
If rc_unregister_device() is called while streamzap_callback() handler is not finished, this can lead to accessing freed resources. Thus rc_unregister_device() should be called after usb_kill_urb().
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 8e9e60640067 ("V4L/DVB: staging/lirc: port lirc_streamzap to ir-core") Cc: stable@vger.kernel.org Reported-by: syzbot+34008406ee9a31b13c73@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=34008406ee9a31b13c73 Signed-off-by: Murad Masimov m.masimov@mt-integration.ru Signed-off-by: Sean Young sean@mess.org Signed-off-by: Hans Verkuil hverkuil@xs4all.nl Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/media/rc/streamzap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/media/rc/streamzap.c +++ b/drivers/media/rc/streamzap.c @@ -385,8 +385,8 @@ static void streamzap_disconnect(struct if (!sz) return;
- rc_unregister_device(sz->rdev); usb_kill_urb(sz->urb_in); + rc_unregister_device(sz->rdev); usb_free_urb(sz->urb_in); usb_free_coherent(usbdev, sz->buf_in_len, sz->buf_in, sz->dma_in);