PageCache/AccessList: Fix validation, handle multi value

Author: tdgroot

app/code/Magento/PageCache/Model/System/Config/Backend/AccessList.php

@@ -24,11 +24,22 @@ public function beforeSave()
         parent::beforeSave();
 
         $value = $this->getValue();
-        if (!is_string($value) || !preg_match('/^[\w\s\.\-\,\:(\/\d+)?]+$/', $value)) {
+
+        if (is_string($value)) {
+            foreach (explode(',', $value) as $item) {
+                if (!preg_match('/^[\w\.\-\:]+(\/(?:[0-9]|[12][0-9]|3[0-2]))?$/', trim($item))) {
+                    throw new LocalizedException(
+                        new Phrase(
+                            'Access List value "%1" is not valid because of item "%2". Please use only IP addresses and host names.',
+                            [$value, $item]
+                        )
+                    );
+                }
+            }
+        } else {
             throw new LocalizedException(
                 new Phrase(
-                    'Access List value "%1" is not valid. '
-                    . 'Please use only IP addresses and host names.',
+                    'Access List value "%1" is not valid. Please use only IP addresses and host names.',
                     [$value]
                 )
             );

app/code/Magento/PageCache/Test/Unit/Model/System/Config/Backend/AccessListTest.php

@@ -48,6 +48,7 @@ protected function setUp(): void
     public static function getValidValues(): array
     {
         return [
+            ['', 'localhost'],
             ['localhost', 'localhost'],
             [null, 'localhost'],
             ['127.0.0.1', '127.0.0.1'],
@@ -74,9 +75,11 @@ public function testBeforeSave($value, $expectedValue)
     public static function getInvalidValues(): array
     {
         return [
+            [123],
             ['\\bull val\\'],
             ['{*I am not an IP*}'],
             ['{*I am not an IP*}, 127.0.0.1'],
+            ['172.16.0.1/33'],
         ];
     }