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: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
---
net/bluetooth/l2cap_core.c | 6 ++++++
net/bluetooth/l2cap_sock.c | 3 +++
2 files changed, 9 insertions(+)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index c3d3cfc..5963cd2 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1257,6 +1257,7 @@ 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);
@@ -1264,6 +1265,7 @@ 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);
@@ -3376,11 +3378,13 @@ 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);
@@ -3408,11 +3412,13 @@ 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);
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 0f30785..82b6368 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -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;
--
1.7.10
--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
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