[dev] passwd and Auth_sql encryption

[Max Kalika]

I don't know who maintains this code, but I wanted to clean up some stuff
here and port over the crypt-md5 and friends over to Auth_sql (as that is
the only Auth driver that uses similar semantics) and I came across some
confusion.

First in Auth/sql.php:

  The ssha and smd5 encryption types will always generate a random salt in
_encryptPassword() but we make a call to that function in _authenticate()
which (if I'm reading this right) will always fail.

Second in passwd/lib/Driver.php

  The ssha and smd5 encryption append the salt to the result of
base64_encode() in _encryptPassword(), but we go ahead and attempt to
base64_decode() in _comparePasswords() without first stripping the salt
off.  How is that supposed to work?

In the latter case can we change the ssha and smd5 cases to:

     case 'ssha':
         $encrypted = preg_replace('|^{SSHA}|', '', $encrypted);
         $salt = substr($encrypted, -20)
         if ($encrypted == base64_encode(mHash(MHASH_SHA1, $plaintext .
$salt) . $salt);
             return true;
         }
         break;
     case 'smd5':
         $encrypted = preg_replace('|^{SMD5}|', '', $encrypted);
         $salt = substr($encrypted, -16)
         if ($encrypted == base64_encode(mHash(MHASH_SMD5, $plaintext .
$salt) . $salt);
             return true;
         }
         break;

The numbers -20 and -16 are what is currently used for substr() in those
two checks, but I know nothing of how these are supposed to work, so if
they're incorrect now is the time to fix.

As far as Auth/sql.php goes, I'd like to add a _comparePasswords() function
to that too to port over all the crypt-* support and (if applicable) fix
the ssha and smd5 portions too.

Thoughts?

BTW:  Eric, I got the composite driver flushed out for password changing.
Huzzah!

---max kalika
--max at lsit.ucsb.edu
-lsit systems administrator