From: Takashi Iwai tiwai@suse.de
commit 9435f2bb66874a0c4dd25e7c978957a7ca2c93b1 upstream.
snd_usb_mixer_controls_badd() that parses UAC3 BADD profiles misses a NULL check for the given interfaces. When a malformed USB descriptor is passed, this may lead to an Oops, as spotted by syzkaller. Skip the iteration if the interface doesn't exist for avoiding the crash.
Fixes: 17156f23e93c ("ALSA: usb: add UAC3 BADD profiles support") Reported-by: syzbot+a36ab65c6653d7ccdd62@syzkaller.appspotmail.com Suggested-by: Dan Carpenter dan.carpenter@oracle.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191122112840.24797-1-tiwai@suse.de Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/usb/mixer.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -2949,6 +2949,9 @@ static int snd_usb_mixer_controls_badd(s continue;
iface = usb_ifnum_to_if(dev, intf); + if (!iface) + continue; + num = iface->num_altsetting;
if (num < 2)