Bug #15140 Updated: mcrypt fails for twofish but work properly for all other type of encryption

ID: 15140 Comment by: bguillot@incoretech.com Reported By: bguillot@incoretech.com Status: Assigned Bug Type: mcrypt related Operating System: Redhat 7.2 PHP Version: 4.1.1 Assigned To: derick New Comment: 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 Previous Comments: ------------------------------------------------------------------------ [2002-02-01 03:41:07] bguillot@incoretech.com 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 ------------------------------------------------------------------------ [2002-02-01 02:51:56] derick@php.net 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 ------------------------------------------------------------------------ [2002-02-01 02:35:03] bguillot@incoretech.com 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 ------------------------------------------------------------------------ [2002-02-01 01:17:16] bguillot@incoretech.com 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 ------------------------------------------------------------------------ [2002-01-21 09:48:24] sander@php.net 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. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/?id=15140 Edit this bug report at http://bugs.php.net/?id=15140&edit=1