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 <andreyk...@google.com>
> Tested-by: Andrey Konovalov <andreyk...@google.com>
> Signed-off-by: Takashi Iwai <ti...@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.
> +
> line6->urb_listen->actual_length = 0;
> err = usb_submit_urb(line6->urb_listen, GFP_ATOMIC);
> return err;
Johan
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