[SRU][Trusty][CVE-2017-13220][PATCH] Bluetooth: hidp_connection_add() unsafe use of l2cap_pi()

[Kleber Sacilotto de Souza]

From: Al Viro <viro at zeniv.linux.org.uk>

CVE-2017-13220

it's OK after we'd verified the sockets, but not before that.

Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Marcel Holtmann <marcel at holtmann.org>
(backported from commit 51bda2bca53b265715ca1852528f38dc67429d9a)
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>
---
 net/bluetooth/hidp/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 2495dbc25899..89e6bf91f7cc 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -1435,13 +1435,14 @@ int hidp_connection_add(struct hidp_connadd_req *req,
 {
 	struct hidp_session *session;
 	struct l2cap_conn *conn;
-	struct l2cap_chan *chan = l2cap_pi(ctrl_sock->sk)->chan;
+	struct l2cap_chan *chan;
 	int ret;
 
 	ret = hidp_verify_sockets(ctrl_sock, intr_sock);
 	if (ret)
 		return ret;
 
+	chan = l2cap_pi(ctrl_sock->sk)->chan;
 	conn = NULL;
 	l2cap_chan_lock(chan);
 	if (chan->conn) {
-- 
2.14.1