Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in l2cap_recv_frame

[Hillf Danton]

On Sun, 01 Sep 2024 00:39:27 -0700
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    e8784b0aef62 Merge tag 'usb-6.11-rc6' of git://git.kernel...
> git tree:       upstream
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10dfdadb980000

#syz test upstream  e8784b0aef62

--- i/net/bluetooth/l2cap_core.c
+++ l/net/bluetooth/l2cap_core.c
@@ -6826,6 +6826,7 @@ static void l2cap_recv_frame(struct l2ca
 		break;
 
 	case L2CAP_CID_CONN_LESS:
+		*((__le16 *) skb->data) = 0;
 		psm = get_unaligned((__le16 *) skb->data);
 		skb_pull(skb, L2CAP_PSMLEN_SIZE);
 		l2cap_conless_channel(conn, psm, skb);
--