ALSA: snd-usb: avoid dividing by zero on invalid input

Signed-off-by: Nicolai Krakowiak <nicolai.krakowiak@gmail.com>
Acked-by: Daniel Mack <zonque@gmail.com>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Cc: stable@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index c22fa76e363a..ee9aa087d8b5 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1191,6 +1191,11 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
 
         if (state->mixer->protocol == UAC_VERSION_1) {
                 csize = hdr->bControlSize;
+                if (!csize) {
+                        snd_printdd(KERN_ERR "usbaudio: unit %u: "
+                                    "invalid bControlSize == 0\n", unitid);
+                        return -EINVAL;
+                }
                 channels = (hdr->bLength - 7) / csize - 1;
                 bmaControls = hdr->bmaControls;
         } else {