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authorTakashi Iwai <tiwai@suse.de>2019-11-22 12:28:40 +0100
committerTakashi Iwai <tiwai@suse.de>2019-11-22 14:08:31 +0100
commit9435f2bb66874a0c4dd25e7c978957a7ca2c93b1 (patch)
tree9d6c452b0de15fb400d64f2cb8575a9b952f0eef
parentce3cba788a1b7b8aed9380c3035d9e850884bd2d (diff)
downloadlinux-9435f2bb66874a0c4dd25e7c978957a7ca2c93b1.tar.bz2
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 <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>
-rw-r--r--sound/usb/mixer.c3
1 files changed, 3 insertions, 0 deletions
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)