Bluetooth: Fix potential memory leak

If command is added to req then it should be freed in case if
hdev is down or HCI_ADVERTISING flag is set.

This introduces a helper in hci_request to purge the cmd_q
to make cmd_q internal to hci_request which is used to fix
the leak.

This also replace accessing of cmd_q in hci_conn with the
new helper.
Signed-off-by: Jaganath Kanakkassery <jaganathx.kanakkassery@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_conn.c

@@ -907,7 +907,7 @@ struct hci_conn *hci_connect_le(struct hci_dev *hdev, bdaddr_t *dst,
 		 */
 		if (hci_dev_test_flag(hdev, HCI_LE_SCAN) &&
 		    hdev->le_scan_type == LE_SCAN_ACTIVE) {
-			skb_queue_purge(&req.cmd_q);
+			hci_req_purge(&req);
 			hci_conn_del(conn);
 			return ERR_PTR(-EBUSY);
 		}

net/bluetooth/hci_request.c

@@ -41,6 +41,11 @@ void hci_req_init(struct hci_request *req, struct hci_dev *hdev)
 	req->err = 0;
 }
 
+void hci_req_purge(struct hci_request *req)
+{
+	skb_queue_purge(&req->cmd_q);
+}
+
 static int req_run(struct hci_request *req, hci_req_complete_t complete,
 		   hci_req_complete_skb_t complete_skb)
 {

net/bluetooth/hci_request.h

@@ -36,6 +36,7 @@ struct hci_request {
 };
 
 void hci_req_init(struct hci_request *req, struct hci_dev *hdev);
+void hci_req_purge(struct hci_request *req);
 int hci_req_run(struct hci_request *req, hci_req_complete_t complete);
 int hci_req_run_skb(struct hci_request *req, hci_req_complete_skb_t complete);
 void hci_req_add(struct hci_request *req, u16 opcode, u32 plen,

net/bluetooth/mgmt.c

@@ -6383,6 +6383,7 @@ static int remove_advertising(struct sock *sk, struct hci_dev *hdev,
 	if (skb_queue_empty(&req.cmd_q) ||
 	    !hdev_is_powered(hdev) ||
 	    hci_dev_test_flag(hdev, HCI_ADVERTISING)) {
+		hci_req_purge(&req);
 		rp.instance = cp->instance;
 		err = mgmt_cmd_complete(sk, hdev->id,
 					MGMT_OP_REMOVE_ADVERTISING,