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

This uses skb_pull_data to check the LE Extended 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

@@ -2517,8 +2517,8 @@ struct hci_ev_le_phy_update_complete {
 } __packed;
 
 #define HCI_EV_LE_EXT_ADV_REPORT    0x0d
-struct hci_ev_le_ext_adv_report {
-	__le16 	 evt_type;
+struct hci_ev_le_ext_adv_info {
+	__le16   type;
 	__u8	 bdaddr_type;
 	bdaddr_t bdaddr;
 	__u8	 primary_phy;
@@ -2533,6 +2533,11 @@ struct hci_ev_le_ext_adv_report {
 	__u8     data[];
 } __packed;
 
+struct hci_ev_le_ext_adv_report {
+	__u8     num;
+	struct hci_ev_le_ext_adv_info info[];
+} __packed;
+
 #define HCI_EV_LE_ENHANCED_CONN_COMPLETE    0x0a
 struct hci_ev_le_enh_conn_complete {
 	__u8      status;

net/bluetooth/hci_event.c

@@ -6649,26 +6649,40 @@ static u8 ext_evt_type_to_legacy(struct hci_dev *hdev, u16 evt_type)
 
 static void hci_le_ext_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	u8 num_reports = skb->data[0];
-	void *ptr = &skb->data[1];
+	struct hci_ev_le_ext_adv_report *ev;
+
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_EXT_ADV_REPORT,
+				sizeof(*ev));
+	if (!ev)
+		return;
+
+	if (!ev->num)
+		return;
 
 	hci_dev_lock(hdev);
 
-	while (num_reports--) {
-		struct hci_ev_le_ext_adv_report *ev = ptr;
+	while (ev->num--) {
+		struct hci_ev_le_ext_adv_info *info;
 		u8 legacy_evt_type;
 		u16 evt_type;
 
-		evt_type = __le16_to_cpu(ev->evt_type);
+		info = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_EXT_ADV_REPORT,
+					  sizeof(*info));
+		if (!info)
+			break;
+
+		if (!hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_EXT_ADV_REPORT,
+					info->length))
+			break;
+
+		evt_type = __le16_to_cpu(info->type);
 		legacy_evt_type = ext_evt_type_to_legacy(hdev, evt_type);
 		if (legacy_evt_type != LE_ADV_INVALID) {
-			process_adv_report(hdev, legacy_evt_type, &ev->bdaddr,
-					   ev->bdaddr_type, NULL, 0, ev->rssi,
-					   ev->data, ev->length,
+			process_adv_report(hdev, legacy_evt_type, &info->bdaddr,
+					   info->bdaddr_type, NULL, 0,
+					   info->rssi, info->data, info->length,
 					   !(evt_type & LE_EXT_ADV_LEGACY_PDU));
 		}
-
-		ptr += sizeof(*ev) + ev->length;
 	}
 
 	hci_dev_unlock(hdev);
@@ -7019,7 +7033,7 @@ static void hci_store_wake_reason(struct hci_dev *hdev, u8 event,
 {
 	struct hci_ev_le_advertising_info *adv;
 	struct hci_ev_le_direct_adv_info *direct_adv;
-	struct hci_ev_le_ext_adv_report *ext_adv;
+	struct hci_ev_le_ext_adv_info *ext_adv;
 	const struct hci_ev_conn_complete *conn_complete = (void *)skb->data;
 	const struct hci_ev_conn_request *conn_request = (void *)skb->data;