From 9435f2bb66874a0c4dd25e7c978957a7ca2c93b1 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 22 Nov 2019 12:28:40 +0100 Subject: ALSA: usb-audio: Fix NULL dereference at parsing BADD 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 Cc: Link: https://lore.kernel.org/r/20191122112840.24797-1-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/usb/mixer.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'sound') diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 45eee5cc312e..6cd4ff09c5ee 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -2930,6 +2930,9 @@ static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer, continue; iface = usb_ifnum_to_if(dev, intf); + if (!iface) + continue; + num = iface->num_altsetting; if (num < 2) -- cgit