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Commit 61d6ef3e authored by Mat Martineau's avatar Mat Martineau Committed by Gustavo Padovan
Browse files

Bluetooth: Make better use of l2cap_chan reference counting 



L2CAP sockets contain a pointer to l2cap_chan that needs to be
reference counted in order to prevent a possible dangling pointer when
the channel is freed.

There were a few other cases where an l2cap_chan pointer on the stack
was dereferenced after a call to l2cap_chan_del. Those pointers are
also now reference counted.

Signed-off-by: default avatarMat Martineau <mathewm@codeaurora.org>
Signed-off-by: default avatarGustavo Padovan <gustavo@padovan.org>
parent dbd89fdd

net/bluetooth/l2cap_core.c

+6 −0
Original line number Diff line number Diff line
@@ -1256,6 +1256,7 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) 


	/* Kill channels */

	list_for_each_entry_safe(chan, l, &conn->chan_l, list) {

		l2cap_chan_hold(chan);

		l2cap_chan_lock(chan);



		l2cap_chan_del(chan, err);
@@ -1263,6 +1264,7 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) 
		l2cap_chan_unlock(chan);



		chan->ops->close(chan->data);

		l2cap_chan_put(chan);

	}



	mutex_unlock(&conn->chan_lock);
@@ -3375,11 +3377,13 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd 
	sk->sk_shutdown = SHUTDOWN_MASK;

	release_sock(sk);



	l2cap_chan_hold(chan);

	l2cap_chan_del(chan, ECONNRESET);



	l2cap_chan_unlock(chan);



	chan->ops->close(chan->data);

	l2cap_chan_put(chan);



	mutex_unlock(&conn->chan_lock);
@@ -3407,11 +3411,13 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd 


	l2cap_chan_lock(chan);



	l2cap_chan_hold(chan);

	l2cap_chan_del(chan, 0);



	l2cap_chan_unlock(chan);



	chan->ops->close(chan->data);

	l2cap_chan_put(chan);



	mutex_unlock(&conn->chan_lock);

net/bluetooth/l2cap_sock.c

+3 −0
Original line number Diff line number Diff line
@@ -956,6 +956,7 @@ static void l2cap_sock_destruct(struct sock *sk) 
{

	BT_DBG("sk %p", sk);



	l2cap_chan_put(l2cap_pi(sk)->chan);

	if (l2cap_pi(sk)->rx_busy_skb) {

		kfree_skb(l2cap_pi(sk)->rx_busy_skb);

		l2cap_pi(sk)->rx_busy_skb = NULL;
@@ -1057,6 +1058,8 @@ static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock, int p 
		return NULL;

	}



	l2cap_chan_hold(chan);



	chan->sk = sk;



	l2cap_pi(sk)->chan = chan;