Bluetooth: HCI: Use skb_pull_data to parse LE Direct Advertising Report event

This uses skb_pull_data to check the LE Direct Advertising Report
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

@@ -2500,7 +2500,7 @@ struct hci_ev_le_data_len_change {
 
 #define HCI_EV_LE_DIRECT_ADV_REPORT	0x0B
 struct hci_ev_le_direct_adv_info {
-	__u8	 evt_type;
+	__u8	 type;
 	__u8	 bdaddr_type;
 	bdaddr_t bdaddr;
 	__u8	 direct_addr_type;
@@ -2508,6 +2508,11 @@ struct hci_ev_le_direct_adv_info {
 	__s8	 rssi;
 } __packed;
 
+struct hci_ev_le_direct_adv_report {
+	__u8	 num;
+	struct hci_ev_le_direct_adv_info info[];
+} __packed;
+
 #define HCI_EV_LE_PHY_UPDATE_COMPLETE	0x0c
 struct hci_ev_le_phy_update_complete {
 	__u8  status;

net/bluetooth/hci_event.c

@@ -6881,19 +6881,31 @@ static void hci_le_remote_conn_param_req_evt(struct hci_dev *hdev,
 static void hci_le_direct_adv_report_evt(struct hci_dev *hdev,
 					 struct sk_buff *skb)
 {
-	u8 num_reports = skb->data[0];
-	struct hci_ev_le_direct_adv_info *ev = (void *)&skb->data[1];
+	struct hci_ev_le_direct_adv_report *ev;
+	int i;
+
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_DIRECT_ADV_REPORT,
+				sizeof(*ev));
+	if (!ev)
+		return;
 
-	if (!num_reports || skb->len < num_reports * sizeof(*ev) + 1)
+	if (!hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_DIRECT_ADV_REPORT,
+				flex_array_size(ev, info, ev->num)))
+		return;
+
+	if (!ev->num)
 		return;
 
 	hci_dev_lock(hdev);
 
-	for (; num_reports; num_reports--, ev++)
-		process_adv_report(hdev, ev->evt_type, &ev->bdaddr,
-				   ev->bdaddr_type, &ev->direct_addr,
-				   ev->direct_addr_type, ev->rssi, NULL, 0,
+	for (i = 0; i < ev->num; i++) {
+		struct hci_ev_le_direct_adv_info *info = &ev->info[i];
+
+		process_adv_report(hdev, info->type, &info->bdaddr,
+				   info->bdaddr_type, &info->direct_addr,
+				   info->direct_addr_type, info->rssi, NULL, 0,
 				   false);
+	}
 
 	hci_dev_unlock(hdev);
 }