MDL-40676 ignore null bytes

lib/configonlylib.php

@@ -95,6 +95,9 @@ function min_fix_utf8($value) {
         error_reporting($olderror ^ E_NOTICE);
     }
 
+    // No null bytes expected in our data, so let's remove it.
+    $value = str_replace("\0", '', $value);
+
     static $buggyiconv = null;
     if ($buggyiconv === null) {
         $buggyiconv = (!function_exists('iconv') or iconv('UTF-8', 'UTF-8//IGNORE', '100'.chr(130).'€') !== '100€');

lib/dml/mssql_native_moodle_database.php

@@ -648,6 +648,7 @@ class mssql_native_moodle_database extends moodle_database {
 
             } else {
                 $param = str_replace("'", "''", $param);
+                $param = str_replace("\0", "", $param);
                 $return .= "N'$param'";
             }
 

lib/dml/sqlsrv_native_moodle_database.php

@@ -727,6 +727,7 @@ class sqlsrv_native_moodle_database extends moodle_database {
                 $return .= $param;
             } else {
                 $param = str_replace("'", "''", $param);
+                $param = str_replace("\0", "", $param);
                 $return .= "N'$param'";
             }
 

lib/moodlelib.php

@@ -1181,6 +1181,8 @@ function fix_utf8($value) {
             // shortcut
             return $value;
         }
+        // No null bytes expected in our data, so let's remove it.
+        $value = str_replace("\0", '', $value);
 
         // Lower error reporting because glibc throws bogus notices.
         $olderror = error_reporting();

lib/tests/moodlelib_test.php

@@ -486,7 +486,7 @@ class moodlelib_testcase extends advanced_testcase {
         $this->assertEquals($object, fix_utf8($object));
 
         // valid utf8 string
-        $this->assertSame("žlutý koníček přeskočil potůček \n\t\r\0", fix_utf8("žlutý koníček přeskočil potůček \n\t\r\0"));
+        $this->assertSame("žlutý koníček přeskočil potůček \n\t\r", fix_utf8("žlutý koníček přeskočil potůček \n\t\r\0"));
 
         // invalid utf8 string
         $this->assertSame('aš', fix_utf8('a'.chr(130).'š'), 'This fails with buggy iconv() when mbstring extenstion is not available as fallback.');