Bluetooth: hidp: verify l2cap sockets

commit b3916db upstream. We need to verify that the given sockets actually are l2cap sockets. If they aren't, we are not supposed to access bt_sk(sock) and we shouldn't start the session if the offsets turn out to be valid local BT addresses. That is, if someone passes a TCP socket to HIDCONNADD, then we access some random offset in the TCP socket (which isn't even guaranteed to be valid). Fix this by checking that the socket is an l2cap socket. Change-Id: I401bca741588b34876a1c835d8d4567852b4ec75 Signed-off-by: David Herrmann <[email protected]> Acked-by: Marcel Holtmann <[email protected]> Signed-off-by: Gustavo Padovan <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> Signed-off-by: Francisco Franco <[email protected]>
franciscofranco · May 11, 2018 · 73f7063 · 73f7063
1 parent 1465728
commit 73f7063
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diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
@@ -667,6 +667,7 @@ extern struct bt_sock_list l2cap_sk_list;
 
 int l2cap_init_sockets(void);
 void l2cap_cleanup_sockets(void);
+bool l2cap_is_socket(struct socket *sock);
 
 u8 l2cap_get_ident(struct l2cap_conn *conn);
 void l2cap_send_cmd(struct l2cap_conn *conn, u8 ident, u8 code, u16 len, void *data);

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
@@ -849,6 +849,8 @@ int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock,
 
 	BT_DBG("");
 
+	if (!l2cap_is_socket(ctrl_sock) || !l2cap_is_socket(intr_sock))
+		return -EINVAL;
 	if (bacmp(&bt_sk(ctrl_sock->sk)->src, &bt_sk(intr_sock->sk)->src) ||
 			bacmp(&bt_sk(ctrl_sock->sk)->dst, &bt_sk(intr_sock->sk)->dst))
 		return -ENOTUNIQ;

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
@@ -124,6 +124,12 @@ static struct sock *__l2cap_get_sock_by_addr(__le16 psm, bdaddr_t *src)
 	return sk;
 }
 
+bool l2cap_is_socket(struct socket *sock)
+{
+	return sock && sock->ops == &l2cap_sock_ops;
+}
+EXPORT_SYMBOL(l2cap_is_socket);
+
 static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
 {
 	struct sock *sk = sock->sk;