Util: more checks in `get_dns_txt_records_base`

src/util.cpp

@@ -508,22 +508,29 @@ bool get_dns_txt_records_base(const std::string& host, Callback<void, const char
 	}
 
 #ifdef _WIN32
-	PDNS_RECORD pQueryResults;
-	if (DnsQuery(host.c_str(), DNS_TYPE_TEXT, DNS_QUERY_STANDARD, NULL, &pQueryResults, NULL) != 0) {
-		return false;
-	}
+	try {
+		PDNS_RECORD pQueryResults;
+		if (DnsQuery(host.c_str(), DNS_TYPE_TEXT, DNS_QUERY_STANDARD, NULL, &pQueryResults, NULL) != 0) {
+			return false;
+		}
 
-	for (PDNS_RECORD p = pQueryResults; p; p = p->pNext) {
-		for (size_t j = 0; j < p->Data.TXT.dwStringCount; ++j) {
-			const char* s = p->Data.TXT.pStringArray[j];
-			const size_t n = strlen(s);
-			if (n > 0) {
-				callback(s, n);
+		for (PDNS_RECORD p = pQueryResults; p; p = p->pNext) {
+			for (size_t j = 0; j < p->Data.TXT.dwStringCount; ++j) {
+				const char* s = p->Data.TXT.pStringArray[j];
+				if (s) {
+					const size_t n = strlen(s);
+					if (n > 0) {
+						callback(s, n);
+					}
+				}
 			}
 		}
-	}
 
-	DnsRecordListFree(pQueryResults, DnsFreeRecordList);
+		DnsRecordListFree(pQueryResults, DnsFreeRecordList);
+	}
+	catch (...) {
+		return false;
+	}
 
 	return true;
 #elif defined(HAVE_RES_QUERY)