[PATCH 3.18 13/50] Bluetooth: Fix potential NULL dereference

From: Greg Kroah-Hartman
Date: Fri Aug 04 2017 - 19:31:36 EST


3.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Johan Hedberg <johan.hedberg@xxxxxxxxx>

commit 88d9077c27d0c1a7c022d9dc987640beecf23560 upstream.

The bnep_get_device function may be triggered by an ioctl just after a
connection has gone down. In such a case the respective L2CAP chan->conn
pointer will get set to NULL (by l2cap_chan_del). This patch adds a
missing NULL check for this case in the bnep_get_device() function.

Reported-by: Patrik Flykt <patrik.flykt@xxxxxxxxxxxxxxx>
Signed-off-by: Johan Hedberg <johan.hedberg@xxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/bluetooth/bnep/core.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

--- a/net/bluetooth/bnep/core.c
+++ b/net/bluetooth/bnep/core.c
@@ -511,13 +511,12 @@ static int bnep_session(void *arg)

static struct device *bnep_get_device(struct bnep_session *session)
{
- struct hci_conn *conn;
+ struct l2cap_conn *conn = l2cap_pi(session->sock->sk)->chan->conn;

- conn = l2cap_pi(session->sock->sk)->chan->conn->hcon;
- if (!conn)
+ if (!conn || !conn->hcon)
return NULL;

- return &conn->dev;
+ return &conn->hcon->dev;
}

static struct device_type bnep_type = {