diff --git a/server/php/UploadHandler.php b/server/php/UploadHandler.php
index c05a0e0cc..6ca0cd1a4 100644
--- a/server/php/UploadHandler.php
+++ b/server/php/UploadHandler.php
@@ -356,7 +356,8 @@ protected function validate($uploaded_file, $file, $error, $index) {
             return false;
         }
         $content_length = $this->fix_integer_overflow(intval($_SERVER['CONTENT_LENGTH']));
-        if ($content_length > $this->get_config_bytes(ini_get('post_max_size'))) {
+        $post_max_size = $this->get_config_bytes(ini_get('post_max_size'));
+        if ($post_max_size && ($content_length > $post_max_size)) {
             $file->error = $this->get_error_message('post_max_size');
             return false;
         }