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Fix issue #13 (multibyte strings) #22

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Merged
defuse merged 2 commits into from
Jul 29, 2014
Merged

Fix issue #13 (multibyte strings) #22

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4c74f29
Fix #13
narfbg Jul 12, 2014
c803f32
Fix substr()
narfbg Jul 12, 2014
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57 changes: 38 additions & 19 deletions Crypto.php
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Original file line number Diff line number Diff line change
Expand Up @@ -127,7 +127,7 @@ public static function Encrypt($plaintext, $key)
{
Crypto::RuntimeTest();

if (strlen($key) !== self::KEY_BYTE_SIZE)
if (self::strlen($key) !== self::KEY_BYTE_SIZE)
{
throw new CannotPerformOperationException("Bad key.");
}
Expand Down Expand Up @@ -165,14 +165,14 @@ public static function Decrypt($ciphertext, $key)
Crypto::RuntimeTest();

// Extract the HMAC from the front of the ciphertext.
if(strlen($ciphertext) <= self::MAC_BYTE_SIZE) {
if (self::strlen($ciphertext) <= self::MAC_BYTE_SIZE) {
throw new InvalidCiphertextException();
}
$hmac = substr($ciphertext, 0, self::MAC_BYTE_SIZE);
$hmac = self::substr($ciphertext, 0, self::MAC_BYTE_SIZE);
if ($hmac === FALSE) {
throw new CannotPerformOperationException();
}
$ciphertext = substr($ciphertext, self::MAC_BYTE_SIZE);
$ciphertext = self::substr($ciphertext, self::MAC_BYTE_SIZE);
if ($ciphertext === FALSE) {
throw new CannotPerformOperationException();
}
Expand All @@ -192,14 +192,14 @@ public static function Decrypt($ciphertext, $key)
if ($ivsize === FALSE || $ivsize <= 0) {
throw new CannotPerformOperationException();
}
if(strlen($ciphertext) <= $ivsize) {
if (self::strlen($ciphertext) <= $ivsize) {
throw new InvalidCiphertextException();
}
$iv = substr($ciphertext, 0, $ivsize);
$iv = self::substr($ciphertext, 0, $ivsize);
if ($iv === FALSE) {
throw new CannotPerformOperationException();
}
$ciphertext = substr($ciphertext, $ivsize);
$ciphertext = self::substr($ciphertext, $ivsize);
if ($ciphertext === FALSE) {
throw new CannotPerformOperationException();
}
Expand Down Expand Up @@ -244,7 +244,7 @@ public static function RuntimeTest()
self::HKDFTestVector();

self::TestEncryptDecrypt();
if (strlen(Crypto::CreateNewRandomKey()) != self::KEY_BYTE_SIZE) {
if (self::strlen(Crypto::CreateNewRandomKey()) != self::KEY_BYTE_SIZE) {
throw new CryptoTestFailedException();
}

Expand Down Expand Up @@ -275,7 +275,7 @@ private static function PlainEncrypt($plaintext, $key, $iv)
// Pad the plaintext to a multiple of the block size.
self::EnsureFunctionExists("mcrypt_enc_get_block_size");
$block = mcrypt_enc_get_block_size($crypt);
$pad = $block - (strlen($plaintext) % $block);
$pad = $block - (self::strlen($plaintext) % $block);
$plaintext .= str_repeat(chr($pad), $pad);

self::EnsureFunctionExists("mcrypt_generic_init");
Expand Down Expand Up @@ -331,11 +331,11 @@ private static function PlainDecrypt($ciphertext, $key, $iv)
}

// Remove the padding.
$pad = ord($plaintext[strlen($plaintext) - 1]);
$pad = ord($plaintext[self::strlen($plaintext) - 1]);
if ($pad <= 0 || $pad > $block) {
throw new CannotPerformOperationException();
}
$plaintext = substr($plaintext, 0, strlen($plaintext) - $pad);
$plaintext = self::substr($plaintext, 0, self::strlen($plaintext) - $pad);
if ($plaintext === FALSE) {
throw new CannotPerformOperationException();
}
Expand Down Expand Up @@ -366,7 +366,7 @@ private static function HKDF($hash, $ikm, $length, $info = '', $salt = NULL)
// Find the correct digest length as quickly as we can.
$digest_length = self::MAC_BYTE_SIZE;
if ($hash != self::HASH_FUNCTION) {
$digest_length = strlen(hash_hmac($hash, '', '', true));
$digest_length = self::strlen(hash_hmac($hash, '', '', true));
}

// Sanity-check the desired output length.
Expand All @@ -388,14 +388,14 @@ private static function HKDF($hash, $ikm, $length, $info = '', $salt = NULL)
// HKDF-Expand:

// This check is useless, but it serves as a reminder to the spec.
if (strlen($prk) < $digest_length) {
if (self::strlen($prk) < $digest_length) {
throw new CannotPerformOperationException();
}

// T(0) = ''
$t = '';
$last_block = '';
for ($block_index = 1; strlen($t) < $length; $block_index++) {
for ($block_index = 1; self::strlen($t) < $length; $block_index++) {
// T(i) = HMAC-Hash(PRK, T(i-1) | info | 0x??)
$last_block = hash_hmac(
$hash,
Expand All @@ -408,7 +408,7 @@ private static function HKDF($hash, $ikm, $length, $info = '', $salt = NULL)
}

// ORM = first L octets of T
$orm = substr($t, 0, $length);
$orm = self::substr($t, 0, $length);
if ($orm === FALSE) {
throw new CannotPerformOperationException();
}
Expand All @@ -427,7 +427,7 @@ private static function VerifyHMAC($correct_hmac, $message, $key)

// NOTE: This leaks information when the strings are not the same
// length, but they should always be the same length here. Enforce it:
if (strlen($correct_hmac) !== strlen($message_hmac)) {
if (self::strlen($correct_hmac) !== self::strlen($message_hmac)) {
throw new CannotPerformOperationException();
}

Expand Down Expand Up @@ -584,6 +584,28 @@ private static function EnsureFunctionExists($name)
}
}

private static function strlen($str)
{
return function_exists('mb_strlen')
? mb_strlen($str, '8bit')
: strlen($str);
}

private static function substr($str, $start, $length = NULL)
{
if (function_exists('mb_substr'))
{
// mb_substr($str, 0, null, '8bit') returns an empty string on PHP 5.3
isset($length) OR $length = ($start >= 0 ? self::strlen($str) - $start : -$start);
return mb_substr($str, $start, $length, '8bit');
}

// Unlike mb_substr(), substr() doesn't accept NULL for length
return isset($length)
? substr($str, $start, $length)
: substr($str, $start);
}

}

/*
Expand Down Expand Up @@ -629,6 +651,3 @@ public function __destruct() {
}

$crypto_exception_handler_object_dont_touch_me = new CryptoExceptionHandler();


?>