MDL-78215 core: support checking if 0.0.0.0 is in subnet

lib/classes/files/curl_security_helper.php

@@ -223,7 +223,7 @@ class curl_security_helper extends curl_security_helper_base {
     protected function address_explicitly_blocked($addr) {
         $blockedhosts = $this->get_blocked_hosts_by_category();
         $iphostsblocked = array_merge($blockedhosts['ipv4'], $blockedhosts['ipv6']);
-        return address_in_subnet($addr, implode(',', $iphostsblocked));
+        return address_in_subnet($addr, implode(',', $iphostsblocked), true);
     }
 
     /**

lib/moodlelib.php

@@ -9067,11 +9067,12 @@ function make_unique_id_code($extra = '') {
  *
  * @param string $addr    The address you are checking
  * @param string $subnetstr    The string of subnet addresses
+ * @param bool $checkallzeros    The state to whether check for 0.0.0.0
  * @return bool
  */
-function address_in_subnet($addr, $subnetstr) {
+function address_in_subnet($addr, $subnetstr, $checkallzeros = false) {
 
-    if ($addr == '0.0.0.0') {
+    if ($addr == '0.0.0.0' && !$checkallzeros) {
         return false;
     }
     $subnets = explode(',', $subnetstr);

lib/upgrade.txt

@@ -1,6 +1,9 @@
 This files describes API changes in core libraries and APIs,
 information provided here is intended especially for developers.
 
+=== 4.2.1 ===
+* Added a new parameter in address_in_subnet to give us the ability to check for 0.0.0.0 or not.
+
 === 4.2 ===
 
 * All context classes were moved to \core\context namespace while keeping full backwards compatibility.