The Script as it is will work using Triple DES

Uncomment the TWOFISH Line At The Bottom of the code and you will get the Segmentation Fault.

I'll check this out, please file a bug report for mcrypt too (about not passing make test).

Derick

That was quick.

I am also sending a Bug Report to mcrypt.

Testing with GOST Fail in the Same Way. 
Works for the others listed below.
 
//T($user_id, MCRYPT_TWOFISH);  // Generates Seg Fault.
//T($user_id, MCRYPT_GOST);         // Crash The System like TWOFISH

T($user_id, MCRYPT_TripleDES);  // Good
T($user_id, MCRYPT_BLOWFISH);     // Good
T($user_id, MCRYPT_DES);        // Good
T($user_id, MCRYPT_RC2);              // Good

To be completely clear, Derick asked to file a bugreport in the PHP-bugs-system about mcrypt not passing some PHP-tests, not to send the mcrypt-folks a bugreport.

Derick,

Closer to a solution...

Mcrypt Bug is found but not fixed.

OK Here is the symptoms:
     In The PHP Code the function  mcrypt_generic_init (td, key_s, key_size,iv_s) is called with key_size=19. (should be 16 and I don't know why yet)

This will gives the segfault.

Try it in mcrypt-2.4.18/doc/example.c
change the line at the beginning of the main
    int keysize=16; /* 128 bits */ to
    int keysize=19; /* 128 bits */

Compile and BOOM Crash Segfault.


Ok Now why is php thinks the keysize should be 19.....

to test check this code:

The Culprit code is in <yourphpsource>/ext/mcrypt/mcrypt.c line 494 php-4.1.1
add the two line. You will see that Part 12 will never get executed for twofish.
and keysize is 19.

added>>> fprintf(stderr, "MCRYPT Debug Part 11\nKey_s:%s, \nKey_Size:%d,\nIV:%s, \nIV_S:%s, \n",key_s, key_size, iv_s);
        result = mcrypt_generic_init (td, key_s, key_size, iv_s);
added>>> fprintf(stderr, "MCRYPT Debug Part 12\n");

Will come back with an answer


BG

Problem found in libmcrypt...

The cause of the SEGFAULT is due to the key being of the wrong length. The only accepted values for key length are 16,24 and 32 bytes. Otherwise this cause libmcrypt to generate a segfault for twofish.
Hope to find a way to correct libmcrypt to report gracefully that the key length is wrong. If not it may need to be implemented in php (That would be the BAD Way of doing it).

BG

Well, PHP works around a lot of those issues in libmcrypt, and actually, the extension should work around it in this case too IMO. I guess mcrypt_enc_get_supported_key_sizes should be used in mcrypt_generic_init in some way.
Can you see if this is feasable?

Derick

Yeap, 
    It is already coded in the internal_init_mcrypt function but a small bug in libmcrypt seem to be present. The free(sizes) is too high up it should be moved down to out of the if/else/else/... I submitted a patch to libmcrypt and wainting for a comment from Nickos.

Thanks again

Derick,
    last thing as with the new patch I get no more problem. Here is two test phpt for mcrypt to test this bug

See Ya

File 002.phpt
--TEST--
Bug #15140 Test TripleDES (Should be ok)
--SKIPIF--
<?php if (!extension_loaded("mcrypt")) print "skip"; ?>
--POST--
--GET--
--FILE--
<?php
// Problem with TWOFISH and mcrypt under PHP 4.0.6 and 4.1.1
// Tested with libmcrypt 2.4.11 2.4.13 2.4.18 2.4.19 (Broken does not pass make check)
// When Loading This Page you should see the time and a Cookie Number.
// If you test with TWOFISH It give a Segmentation Failure in the Apache Error Log
// But Will Work With 3DES.
//
// I now use libmcrypt 2.4.18
//
// Strange.
// bguillot@NOSPAMincoretech.com REMOVE NOSPAM
//

function T ( $user_id, $Encryption ) {
        $session_serial = $user_id . "A_TEXT_TO_TEST_THE_KEY_GENERATION";

        echo "Cypher: " . $Encryption . "\n";

        $sessionKey="SessionKeyYouChoose"; // Obviously not the one we use....:)

        // Fails with TWOFISH but Works with TripleDES
        // Code Fail to produce Code.
        $td = mcrypt_module_open($Encryption, "", MCRYPT_MODE_ECB, "");

        $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size ($td), MCRYPT_RAND);
        mcrypt_generic_init($td, $sessionKey, $iv);
        $encrypted_session_serial = mcrypt_generic($td, $session_serial);
        mcrypt_generic_end($td);
        $session_serial_hash = md5($encrypted_session_serial.$sessionKey);
        $session_serial_cookie = base64_encode($encrypted_session_serial).'-'.$session_serial_hash;

        return $session_serial_cookie;
}

// If you don't see the time number increasing it is because Apache child seg fault
// Check your apache/logs/error_log that is the problem.

$user_id=120804;

//$test  = T($user_id, MCRYPT_TWOFISH);
$test  = T($user_id, MCRYPT_TripleDES);

echo "Cookie is : $test\n";
echo "The End\n";

?>
--EXPECT--
Cypher: tripledes
Cookie is : OXYSlBYiGQb2c65SfOjv1nIGlm9v05aeFUNtMbpCyppWfz2b/LtpPw==-426e3b6216305dac2467bd99c270740e
The End



File 003.phpt

--TEST--
Bug #15140 Test TwoFish with Key not 16,24 or 32.
--SKIPIF--
<?php if (!extension_loaded("mcrypt")) print "skip"; ?>
--POST--
--GET--
--FILE--
<?php
// Problem with TWOFISH and mcrypt under PHP 4.0.6 and 4.1.1
// Tested with libmcrypt 2.4.11 2.4.13 2.4.18 2.4.19 (Broken does not pass make check)
// When Loading This Page you should see the time and a Cookie Number.
// If you test with TWOFISH It give a Segmentation Failure in the Apache Error Log
// But Will Work With 3DES.
//

function T ( $user_id, $Encryption ) {
        $session_serial = $user_id . "A_TEXT_TO_TEST_THE_KEY_GENERATION";

        echo "Cypher: " . $Encryption . "\n";

        $sessionKey="SessionKeyYouChoose"; // if it is not 16,24 or 32 bytes long would fail with SEGFAULT....:)
                                           // 19 Failed bigtime on most CPU.

        // Fails with TWOFISH but Works with TripleDES
        // Code Fail to produce Code.
        $td = mcrypt_module_open($Encryption, "", MCRYPT_MODE_ECB, "");

        $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size ($td), MCRYPT_RAND);
        mcrypt_generic_init($td, $sessionKey, $iv);
        $encrypted_session_serial = mcrypt_generic($td, $session_serial);
        mcrypt_generic_end($td);
        $session_serial_hash = md5($encrypted_session_serial.$sessionKey);
        $session_serial_cookie = base64_encode($encrypted_session_serial).'-'.$session_serial_hash;

        return $session_serial_cookie;
}

// If you don't see the time number increasing it is because Apache child seg fault
// Check your apache/logs/error_log that is the problem.

$user_id=120804;

$test  = T($user_id, MCRYPT_TWOFISH);
//$test  = T($user_id, MCRYPT_TripleDES);

echo "Cookie is : $test\n";
echo "The End\n";

?>
--EXPECT--
Cypher: twofish
Cookie is : rq6VWCfWb8WtBmVZseA4zBjkC2OEAzfZCI1DotaxgYrFRPT3LZW0WAQQM31XWYsC-4dfc43e86267d859b8a1a64c563bb2da
The End

Seems to be fixed now, closing...

Derick