Bluetooth: L2CAP: Fix use-after-free

Fix potential use-after-free in l2cap_le_command_rej.

Signed-off-by: Zhengping Jiang <jiangzp@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index c5e8798..17ca13e 100644 (file)
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -6374,9 +6374,14 @@ static inline int l2cap_le_command_rej(struct l2cap_conn *conn,
        if (!chan)
                goto done;
 
+       chan = l2cap_chan_hold_unless_zero(chan);
+       if (!chan)
+               goto done;
+
        l2cap_chan_lock(chan);
        l2cap_chan_del(chan, ECONNREFUSED);
        l2cap_chan_unlock(chan);
+       l2cap_chan_put(chan);
 
 done:
        mutex_unlock(&conn->chan_lock);