Commit 6815a0b4 authored by Takashi Iwai's avatar Takashi Iwai

ALSA: bcd2000: Add a sanity check for invalid EPs

As syzkaller spotted, currently bcd2000 driver submits 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 1 != type 3
  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 1846 at drivers/usb/core/urb.c:449
  Modules linked in:
  CPU: 0 PID: 1846 Comm: kworker/0:2 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:
   bcd2000_init_device sound/usb/bcd2000/bcd2000.c:289
   bcd2000_init_midi sound/usb/bcd2000/bcd2000.c:345
   bcd2000_probe+0xe64/0x19e0 sound/usb/bcd2000/bcd2000.c:406
   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: default avatarAndrey Konovalov <>
Tested-by: default avatarAndrey Konovalov <>
Signed-off-by: default avatarTakashi Iwai <>
parent e901b987
......@@ -342,6 +342,13 @@ static int bcd2000_init_midi(struct bcd2000 *bcd2k)
bcd2k->midi_out_buf, BUFSIZE,
bcd2000_output_complete, bcd2k, 1);
/* sanity checks of EPs before actually submitting */
if (usb_urb_ep_type_check(bcd2k->midi_in_urb) ||
usb_urb_ep_type_check(bcd2k->midi_out_urb)) {
dev_err(&bcd2k->dev->dev, "invalid MIDI EP\n");
return -EINVAL;
return 0;
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