Edit report at https://bugs.php.net/bug.php?id=68238&edit=1

 ID:                 68238
 Comment by:         ni...@php.net
 Reported by:        gm dot outside+php at gmail dot com
 Summary:            mcrypt_encode tests are broken
 Status:             Not a bug
 Type:               Bug
 Package:            Testing related
 Operating System:   Linux
 PHP Version:        5.6.1
 Block user comment: N
 Private report:     N

 New Comment:

The bug you linked has nothing to do with issue, it is a generic complaint from 
someone using broken crypto code, which is rejected by the stricter input 
requirements in PHP 5.6.

When you say that mcrypt_encrypt on your PHP 5.5.12 build works correctly, do 
you mean that it provides the correct output for this test script (whereas PHP 
5.6 does not)? This test was only added in PHP 5.6, so just running `make test` 
will not be enough to check it - you have to manually run the file from the 5.6 
tree.


Previous Comments:
------------------------------------------------------------------------
[2014-10-15 18:36:06] gm dot outside+php at gmail dot com

Related To: Bug #67286

------------------------------------------------------------------------
[2014-10-15 18:30:09] gm dot outside+php at gmail dot com

@nikic, I'm running the latest available mcrypt, which is 2.5.8.  The library 
passed all its internal tests.  Also, PHP 5.5.12 is working on the same box and 
does not have any issues with mcrypt_encode().

Additionally to this there are other bug reports pointing to the same issue, 
e.g. bug #67286 , so I would not dismiss this bug this easy.

Finally, the gcov test at php.net itself is failing the test on mcrypt.  The 
following tests was performed less than 2 days ago: 
http://gcov.php.net/viewer.php?version=PHP_HEAD&func=tests&file=ext%2Fmcrypt%2Ftests%2Fbug62102_rfc2144.phpt

So, let's try to pinpoint the issue? :)  Or at least let's fix the test case...

------------------------------------------------------------------------
[2014-10-15 18:12:49] ni...@php.net

This is a bug in your mcrypt library, which does not properly support Cast-128 
with keys <= 80 bits. Padding the keys with NUL bytes is not the same, because  
Cast-128 uses only 12 rounds (instead of 16) if the key is <= 80 bits.

Updating your libmcrypt version will probably fix this.

------------------------------------------------------------------------
[2014-10-15 17:32:24] gm dot outside+php at gmail dot com

I did more testing, and I was a bit wrong about the strlen() part.  Manually 
padding the keys with '\0' actually works, but the result does not match the 
ciphertext provided in RFC-2144 B.1 anymore.  Additionally to that I was wrong 
re: the keysize requirement for that cipher should be 16 bytes (128-bit) as 
cipher's name 'cast-128' suggests.

Once the keys are properly padded with '\0' to be 128-bit the test returns the 
following differences:

002+ 80-bit: 753de29f5d167d03
003+ 40-bit: f00b0530833d7444
002- 80-bit: eb6a711a2c02271b
003- 40-bit: 7ac816d16e9b302e

So, something else was also changed that the mcrypt extension no longer 
conforms to RFC-2144 B.1.

------------------------------------------------------------------------
[2014-10-15 17:16:27] gm dot outside+php at gmail dot com

Description:
------------
There was a recent commit 
(http://git.php.net/?p=php-src.git;a=commit;h=a861a3a93d89a50ce58e1ab1abef1eb501f97483)
 that changed behaviour of the mcrypt_encode() function.  After that commit the 
key is required to be at least the expected key length long, otherwise a 
warning message is issued and the mcrypt_encode() routine returns a failure.

The corresponding test in ext/mcrypt/tests/bug62102_rfc2144.php supplies 10 
bytes key instead of 16 for cast-128 80-bit encryption and 5 bytes key instead 
of 10 for cast-128 40-bit encryption.

A quick fix to the test would be to pad the keys with '\0' manually (RFC-2144 
B.1), e.g.

mcrypt_encrypt('cast-128', 
"\x01\x23\x45\x67\x12\x34\x56\x78\x23\x45\0\0\0\0\0\0", $plaintext, 'ecb')

but unfortunately due to the way changed code treats key data (as a null 
terminated string) and due to calculating the key size as strlen() of that 
string there is no way to satisfy the RFC-2144 B.1 since all trailing '\0' will 
be ignored.


Expected result:
----------------
That the RFC-2144 test would be passed with the explicitly specified vector and 
that mcrypt_encrypt() would honour the key argument as a binary string that can 
include '\0' anywhere in the string.

Actual result:
--------------
All trailing '\0' in the key argument are ignored, therefore it's impossible to 
pass RFC-2144 test to match section B.1.


------------------------------------------------------------------------



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