On Wed, 11 Oct 2017 16:28:37 +0200, Johan Hovold wrote:
On Wed, Oct 11, 2017 at 12:36:41PM +0200, Takashi Iwai wrote:
As syzkaller spotted, currently line6 drivers submit a URB with the fixed EP without checking whether it's actually available, which may result in a kernel warning like: usb 1-1: BOGUS urb xfer, pipe 3 != type 1 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 24 at drivers/usb/core/urb.c:449 usb_submit_urb+0xf8a/0x11d0 Modules linked in: CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc2-42613-g1488251d1a98 #238 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: usb_hub_wq hub_event Call Trace: line6_start_listen+0x55f/0x9e0 sound/usb/line6/driver.c:82 line6_init_cap_control sound/usb/line6/driver.c:690 line6_probe+0x7c9/0x1310 sound/usb/line6/driver.c:764 podhd_probe+0x64/0x70 sound/usb/line6/podhd.c:474 usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361 ....
This patch adds a sanity check of validity of EPs at the device initialization phase for avoiding the call with an invalid EP.
Reported-by: Andrey Konovalov andreyknvl@google.com Tested-by: Andrey Konovalov andreyknvl@google.com Signed-off-by: Takashi Iwai tiwai@suse.de
sound/usb/line6/driver.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c index 0ff5a7d2e19f..0da6f68761e3 100644 --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -78,6 +78,13 @@ static int line6_start_listen(struct usb_line6 *line6) line6->buffer_listen, LINE6_BUFSIZE_LISTEN, line6_data_received, line6); }
- /* sanity checks of EP before actually submitting */
- if (usb_urb_ep_type_check(line6->urb_listen)) {
dev_err(line6->ifcdev, "invalid control EP\n");return -EINVAL;- }
You're now doing this check twice (here and in usb_submit_urb) every time this URB is submitted rather just checking it once in probe.
Seems like a quick band-aid to me.
Yes, it is :)
We may split line6_start_listen() to two functions, one for initializing URBs and another for submission, but it'll be more codes and the check is fairly cheap. So again it's a question whether easier to read or to get minor optimization.
thanks,
Takashi