From 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Fri, 27 Apr 2012 16:50:50 -0700 Subject: [PATCH] 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: Mat Martineau Signed-off-by: Gustavo Padovan --- 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 1192c943bf8e..b854d284d42a 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -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); diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 2b5e7e81c3c0..6bf8ff75d95f 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; -- GitLab