Incorrect crypt() function behavior

[Sergei Morozov]

The CRYPT_EXT_DES algorithm seems to be enabled but not used for encryption.

The test is:
php -r "echo 'CRYPT_EXT_DES: ', CRYPT_EXT_DES, PHP_EOL, crypt(md5('my passw0rd'), '_.012saltIO.319ikKPU'), PHP_EOL;"

Expected output (depending on whether CRYPT_EXT_DES is enabled):
> CRYPT_EXT_DES: 1
> _.012saltIO.319ikKPU
OR
> CRYPT_EXT_DES: 0
> _.msUWmoj85W6

Actual output:
> CRYPT_EXT_DES: 1
> _.msUWmoj85W6

…which correstponds to standard DES encryption:
php -r "echo 'CRYPT_STD_DES: ', CRYPT_STD_DES, PHP_EOL, crypt(md5('my passw0rd'), '_.012saltIO.319ikKPU'), PHP_EOL;"
> CRYPT_STD_DES: 1
> _.msUWmoj85W6

lsb_release -rd
Description: Ubuntu 12.04.1 LTS
Release: 12.04

$ apt-cache policy php5
php5:
  Installed: 5.3.10-1ubuntu3.2
  Candidate: 5.3.10-1ubuntu3.2
  Version table:
 *** 5.3.10-1ubuntu3.2 0
        500 http://by.archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ precise-security/main amd64 Packages
        100 /var/lib/dpkg/status
     5.3.10-1ubuntu3 0
        500 http://by.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

[Clint Byrum (clint-fewbar)]

Can confirm that Ubuntu/Debian's behavior is different from CentOS 6:

$ php --version
PHP 5.3.3 (cli) (built: Jul 3 2012 16:53:21)
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies
$ php -r "echo 'CRYPT_EXT_DES: ', CRYPT_EXT_DES, PHP_EOL, crypt(md5('my passw0rd'), '_.012saltIO.319ikKPU'), PHP_EOL;"
CRYPT_EXT_DES: 1
_.012saltIO.319ikKPU

**
precise

# php --version
PHP 5.3.10-1ubuntu3.2 with Suhosin-Patch (cli) (built: Jun 13 2012 17:20:55)
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2012 Zend Technologies
# php -r "echo 'CRYPT_EXT_DES: ', CRYPT_EXT_DES, PHP_EOL, crypt(md5('my passw0rd'), '_.012saltIO.319ikKPU'), PHP_EOL;"
CRYPT_EXT_DES: 1
_.msUWmoj85W6

**

However, this is not a regression for Ubuntu.
I tested this all the way back to hardy, which seemed to not have CRYPT_EXT_DES:

**

# php --version
PHP 5.2.4-2ubuntu5.25 with Suhosin-Patch 0.9.6.2 (cli) (built: Jun 13 2012 18:36:37)
Copyright (c) 1997-2007 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies
 php -r "echo 'CRYPT_EXT_DES: ', CRYPT_EXT_DES, PHP_EOL, crypt(md5('my passw0rd'), '_.012saltIO.319ikKPU'), PHP_EOL;"
CRYPT_EXT_DES: 0
_.msUWmoj85W6

[Sergei Morozov (sergeimorozov)]

The regression is not the absence of CRYPT_EXT_DES algorithm but the fact that it's declared available (CRYPT_EXT_DES = 1) but not used (result = _.msUWmoj85W6).

[Clint Byrum (clint-fewbar)]

Sergei, I agree, my comments were misleading. My point is that this has been broken since at least 10.04, and its not even necessarily a regression from one release of Ubuntu to another.

I just tested this on Debian squeeze and wheezy and it is present there as well.I believe this was introduced by this change:

php5 (5.3.2-1) unstable; urgency=high
...
  [ Ondřej Surý ]
...
  * New debian patch always_use_system_crypt.patch (Closes: #572601)
  * New debian patch php_crypt_revamped.patch (Closes: #572601)

 -- Raphael Geissert <email address hidden> Sat, 13 Mar 2010 15:11:48 -0600

I'm building test packages w/o those patches to see if the problem is resolved that way.

[Clint Byrum (clint-fewbar)]

Setting to 'High' as this very quietly and subtly reduces the security of the system.

[Clint Byrum (clint-fewbar)]

Have tested with those patches dropped and the upstream behavior is in fact restored. I've forwarded this on to Debian, though I would consider carrying this as part of Ubuntu's delta if the Debian maintainers decide not to revert the patches, as this seems fairly serious to me.

[Ondřej Surý (ondrej)]

As a temporary workaround, you can just strip salt to 9 characters. The fix is fairly simple, and I'll prepare a patch later today.

[Robie Basak (racb)]

I have run Clint's test case (from the Debian bug) of:

php -r "echo 'CRYPT_EXT_DES: ', CRYPT_EXT_DES, PHP_EOL, crypt(md5('my passw0rd'), '_.012saltIO.319ikKPU'), PHP_EOL;"

on Trusty (php5-cli 5.5.3+dfsg-1ubuntu3).

It returned:

CRYPT_EXT_DES: 1
_.012saltIO.319ikKPU

So I presume this issue is now been fixed in Ubuntu.