[39/90] ALSA: snd-usb: avoid dividing by zero on invalid input

[Greg KH]

3.0-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Nicolai Krakowiak <nicolai.krakowiak@xxxxxxxxx>

commit 60c961a9e1ed879a4d151df6076bf1203f595f73 upstream.

Signed-off-by: Nicolai Krakowiak <nicolai.krakowiak@xxxxxxxxx>
Acked-by: Daniel Mack <zonque@xxxxxxxxx>
Acked-by: Clemens Ladisch <clemens@xxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 sound/usb/mixer.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1191,6 +1191,11 @@ static int parse_audio_feature_unit(stru
 
 	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 {


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