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From:   Sungwoo Kim <iam@sung-woo.kim>
To:     iam@sung-woo.kim
Cc:     benquike@gmail.com, davem@davemloft.net, daveti@purdue.edu,
        edumazet@google.com, happiness.sung.woo@gmail.com,
        johan.hedberg@gmail.com, kuba@kernel.org,
        linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
        luiz.dentz@gmail.com, marcel@holtmann.org, netdev@vger.kernel.org,
        pabeni@redhat.com, wuruoyu@me.com
Subject: [PATCH] Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_ready_cb
Date:   Fri, 26 May 2023 14:16:48 -0400
Message-Id: <20230526181647.3074391-1-iam@sung-woo.kim>
In-Reply-To: <20230202120902.2827191-1-iam@sung-woo.kim>
References: <20230202120902.2827191-1-iam@sung-woo.kim>
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>    net/bluetooth/l2cap_sock.c: In function 'l2cap_sock_release':
> >> net/bluetooth/l2cap_sock.c:1418:9: error: implicit declaration of function 'l2cap_sock_cleanup_listen'; did you mean 'l2cap_sock_listen'? [-Werror=implicit-function-declaration]

Fix this error

>     1418 |         l2cap_sock_cleanup_listen(sk);
>          |         ^~~~~~~~~~~~~~~~~~~~~~~~~
>          |         l2cap_sock_listen
>    net/bluetooth/l2cap_sock.c: At top level:
> >> net/bluetooth/l2cap_sock.c:1436:13: warning: conflicting types for 'l2cap_sock_cleanup_listen'; have 'void(struct sock *)'
>     1436 | static void l2cap_sock_cleanup_listen(struct sock *parent)
>          |             ^~~~~~~~~~~~~~~~~~~~~~~~~
> >> net/bluetooth/l2cap_sock.c:1436:13: error: static declaration of 'l2cap_sock_cleanup_listen' follows non-static declaration
>    net/bluetooth/l2cap_sock.c:1418:9: note: previous implicit declaration of 'l2cap_sock_cleanup_listen' with type 'void(struct sock *)'
>     1418 |         l2cap_sock_cleanup_listen(sk);
>          |         ^~~~~~~~~~~~~~~~~~~~~~~~~
>    cc1: some warnings being treated as errors

Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
---
 net/bluetooth/l2cap_sock.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index eebe25610..3818e11a8 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -46,6 +46,7 @@ static const struct proto_ops l2cap_sock_ops;
 static void l2cap_sock_init(struct sock *sk, struct sock *parent);
 static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock,
 				     int proto, gfp_t prio, int kern);
+static void l2cap_sock_cleanup_listen(struct sock *parent);
 
 bool l2cap_is_socket(struct socket *sock)
 {
@@ -1414,7 +1415,8 @@ static int l2cap_sock_release(struct socket *sock)
 
 	if (!sk)
 		return 0;
-
+		
+	l2cap_sock_cleanup_listen(sk);
 	bt_sock_unlink(&l2cap_sk_list, sk);
 
 	err = l2cap_sock_shutdown(sock, SHUT_RDWR);
-- 
2.34.1