diff options
Diffstat (limited to 'Core/Util/StringUtils.php')
| -rw-r--r-- | Core/Util/StringUtils.php | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/Core/Util/StringUtils.php b/Core/Util/StringUtils.php index d47bd4b..5e13037 100644 --- a/Core/Util/StringUtils.php +++ b/Core/Util/StringUtils.php @@ -35,23 +35,19 @@ class StringUtils */ public static function equals($knownString, $userInput) { - // Prevent issues if string length is 0 - $knownString .= chr(0); - $userInput .= chr(0); - $knownLen = strlen($knownString); $userLen = strlen($userInput); + // Extend the known string to avoid uninitialized string offsets + $knownString .= $userInput; + // Set the result to the difference between the lengths $result = $knownLen - $userLen; // Note that we ALWAYS iterate over the user-supplied length // This is to prevent leaking length information for ($i = 0; $i < $userLen; $i++) { - // Using % here is a trick to prevent notices - // It's safe, since if the lengths are different - // $result is already non-0 - $result |= (ord($knownString[$i % $knownLen]) ^ ord($userInput[$i])); + $result |= (ord($knownString[$i]) ^ ord($userInput[$i])); } // They are only identical strings if $result is exactly 0... |