Forwarded: Re: [syzbot] [sound?] [usb?] KASAN: slab-out-of-bounds Write in copy_to_urb

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Subject: Re: [syzbot] [sound?] [usb?] KASAN: slab-out-of-bounds Write in copy_to_urb
Author: lizhi.xu@windriver.com

#syz test

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 54d01dfd820f..a4c0ea685b8a 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1606,6 +1606,9 @@ static int prepare_playback_urb(struct snd_usb_substream *subs,
 				    subs->cur_audiofmt->dsd_bitrev)) {
 			fill_playback_urb_dsd_bitrev(subs, urb, bytes);
 		} else {
+			if (bytes > ctx->buffer_size)
+				return -EPIPE;
+
 			/* usual PCM */
 			if (!subs->tx_length_quirk)
 				copy_to_urb(subs, urb, 0, stride, bytes);