Bluetooth: Host: Add missing buffer length check

Modified to check the length of the remaining data in buffer
before processing the next report. The length check is missing
in the cont routine.

Signed-off-by: Eunkyu Lee <mochaccino.00.00@gmail.com>
(cherry picked from commit e491f22)

subsys/bluetooth/host/scan.c

@@ -602,6 +602,24 @@ void bt_hci_le_adv_ext_report(struct net_buf *buf)
 		is_report_complete = data_status == BT_HCI_LE_ADV_EVT_TYPE_DATA_STATUS_COMPLETE;
 		more_to_come = data_status == BT_HCI_LE_ADV_EVT_TYPE_DATA_STATUS_PARTIAL;
 
+		if (evt->length > buf->len) {
+			LOG_WRN("Adv report corrupted (wants %u out of %u)", evt->length, buf->len);
+
+			net_buf_reset(buf);
+
+			if (evt_type & BT_HCI_LE_ADV_EVT_TYPE_LEGACY) {
+				return;
+			}
+
+			/* Start discarding irrespective of the `more_to_come` flag. We
+			 * assume we may have lost a partial adv report in the truncated
+			 * data.
+			 */
+			reassembling_advertiser.state = FRAG_ADV_DISCARDING;
+
+			return;
+		}
+
 		if (evt_type & BT_HCI_LE_ADV_EVT_TYPE_LEGACY) {
 			/* Legacy advertising reports are complete.
 			 * Create event immediately.