Re: [syzbot] [sound?] [usb?] UBSAN: shift-out-of-bounds in parse_audio_unit

[Edward Adam Davis]

bLength too small ?

#syz test: upstream a19ea421490d

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 409fc1164694..cc92c989a772 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1999,6 +1999,9 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
 
 	if (state->mixer->protocol == UAC_VERSION_1) {
 		csize = hdr->bControlSize;
+		printk("c: %d, bLen: %d, %c, \n", channels, hdr->bLength, hdr->bLength, __func__ );
+		if (hdr->bLength < 7)
+			return -EINVAL;
 		channels = (hdr->bLength - 7) / csize - 1;
 		bmaControls = hdr->bmaControls;
 	} else if (state->mixer->protocol == UAC_VERSION_2) {