Bluetooth: HCI: Use skb_pull_data to parse Number of Complete Packets event

This uses skb_pull_data to check the Number of Complete Packets events
received have the minimum required length.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci.h

@@ -2139,7 +2139,7 @@ struct hci_comp_pkts_info {
 } __packed;
 
 struct hci_ev_num_comp_pkts {
-	__u8     num_hndl;
+	__u8     num;
 	struct hci_comp_pkts_info handles[];
 } __packed;
 

net/bluetooth/hci_event.c

@@ -4465,23 +4465,25 @@ static void hci_role_change_evt(struct hci_dev *hdev, struct sk_buff *skb)
 
 static void hci_num_comp_pkts_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hci_ev_num_comp_pkts *ev = (void *) skb->data;
+	struct hci_ev_num_comp_pkts *ev;
 	int i;
 
-	if (hdev->flow_ctl_mode != HCI_FLOW_CTL_MODE_PACKET_BASED) {
-		bt_dev_err(hdev, "wrong event for mode %d", hdev->flow_ctl_mode);
+	ev = hci_ev_skb_pull(hdev, skb, HCI_EV_NUM_COMP_PKTS, sizeof(*ev));
+	if (!ev)
 		return;
-	}
 
-	if (skb->len < sizeof(*ev) ||
-	    skb->len < struct_size(ev, handles, ev->num_hndl)) {
-		BT_DBG("%s bad parameters", hdev->name);
+	if (!hci_ev_skb_pull(hdev, skb, HCI_EV_NUM_COMP_PKTS,
+			     flex_array_size(ev, handles, ev->num)))
+		return;
+
+	if (hdev->flow_ctl_mode != HCI_FLOW_CTL_MODE_PACKET_BASED) {
+		bt_dev_err(hdev, "wrong event for mode %d", hdev->flow_ctl_mode);
 		return;
 	}
 
-	BT_DBG("%s num_hndl %d", hdev->name, ev->num_hndl);
+	BT_DBG("%s num %d", hdev->name, ev->num);
 
-	for (i = 0; i < ev->num_hndl; i++) {
+	for (i = 0; i < ev->num; i++) {
 		struct hci_comp_pkts_info *info = &ev->handles[i];
 		struct hci_conn *conn;
 		__u16  handle, count;