Revert password values back to the config file if submitted empty

Author: TheSyscall

library/Icinga/Web/Form/ConfigForm.php

@@ -8,6 +8,7 @@
 use Exception;
 use Icinga\Application\Config;
 use Icinga\Web\Widget\ShowConfiguration;
+use ipl\Html\FormElement\PasswordElement;
 use ipl\Stdlib\Str;
 use ipl\Web\Common\CsrfCounterMeasure;
 use ipl\Web\Compat\CompatForm;
@@ -95,6 +96,23 @@ protected function getConfigValue(string $name, mixed $default = null): mixed
         return $this->config->get($section, $key, $default);
     }
 
+    /**
+     * Checks if the element should be reverted to the value from the INI file if empty.
+     * This is useful for elements that aren't populated from the INI file.
+     *
+     * @param string $elementName The name of the element to check
+     *
+     * @return bool
+     */
+    protected function shouldRevertIfEmpty(string $elementName): bool
+    {
+        $element = $this->getElement($elementName);
+        return match (true) {
+            $element instanceof PasswordElement => true,
+            default => false,
+        };
+    }
+
     /**
      * Persist the current configuration to disk
      *
@@ -108,7 +126,9 @@ protected function save(): void
                 continue;
             }
             [$section, $key] = $parts;
-
+            if (Str::isEmpty($value) && $this->shouldRevertIfEmpty($element)) {
+                $value = $this->config->get($section, $key);
+            }
             $configSection = $this->config->getSection($section);
             if (Str::isEmpty($value)) {
                 unset($configSection[$key]);

library/Icinga/Web/Form/ConfigSectionForm.php

@@ -408,6 +408,9 @@ protected function shouldRename(): bool
     protected function save(): void
     {
         foreach ($this->getValues() as $element => $value) {
+            if (Str::isEmpty($value) && $this->shouldRevertIfEmpty($element)) {
+                $value = $this->config->get($this->section, $element);
+            }
             $configSection = $this->config->getSection($this->section);
             if (Str::isEmpty($value)) {
                 unset($configSection[$element]);