diff mbox series

ALSA: usb-audio: Fix NULL dereference at parsing BADD

Message ID 20191122112840.24797-1-tiwai@suse.de (mailing list archive)
State New, archived
Headers show
Series ALSA: usb-audio: Fix NULL dereference at parsing BADD | expand

Commit Message

Takashi Iwai Nov. 22, 2019, 11:28 a.m. UTC
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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/mixer.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

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)