linux-kernel - Re: [syzbot] [bluetooth?] general protection fault in l2cap_sock_recv

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Date: Tue, 11 Jun 2024 09:47:48 +0800
From: Edward Adam Davis <eadavis@...com>
To: syzbot+b7f6f8c9303466e16c8a@...kaller.appspotmail.com
Cc: linux-kernel@...r.kernel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bluetooth?] general protection fault in l2cap_sock_recv_cb

please test null ptr defref in l2cap_sock_recv_cb

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cc8ed4d0a848

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 6db60946c627..68b57ef01c7d 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1506,7 +1506,9 @@ static int l2cap_sock_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
 
 	err = __sock_queue_rcv_skb(sk, skb);
 
+	sock_hold(sk);
 	l2cap_publish_rx_avail(chan);
+	sock_put(sk);
 
 	/* For ERTM and LE, handle a skb that doesn't fit into the recv
 	 * buffer.  This is important to do because the data frames