qcacld-3.0: validate NLA attr in wlan_hdd_cfg80211_extscan_set_significant_change

NLA attr QCA_WLAN_VENDOR_ATTR_EXTSCAN_AP_THRESHOLD_PARAM
used without validation.

validate NLA attribute.

CRs-Fixed: 2025678
Change-Id: Iee9a8f91cc1b5a6c76c5abaef48c0fa29110062e

core/hdd/src/wlan_hdd_ext_scan.c

@@ -2229,6 +2229,10 @@ __wlan_hdd_cfg80211_extscan_set_significant_change(struct wiphy *wiphy,
 	hdd_debug("Number of AP %d Session Id %d",
 		pReqMsg->numAp, pReqMsg->sessionId);
 
+	if (!tb[QCA_WLAN_VENDOR_ATTR_EXTSCAN_AP_THRESHOLD_PARAM]) {
+		hdd_err("attr ap threshold failed");
+		goto fail;
+	}
 	i = 0;
 	nla_for_each_nested(apTh,
 			    tb[QCA_WLAN_VENDOR_ATTR_EXTSCAN_AP_THRESHOLD_PARAM],