Re: Weird behavior of crypt

[Alexandre Garnier <zigarn at gmail dot com>]

2016-01-29 13:09 GMT+01:00 Corinna Vinschen <corinna-cygwin@cygwin.com>:
> On Jan 29 12:39, Marco Atzeri wrote:
>>
>>
>> On 29/01/2016 12:18, Alexandre Garnier wrote:
>> >Hello.
>> >I'm trying to do SHA-512 password encryption, but the result is really
>> >weird on Cygwin:
>> >
>> ># On Cygwin(either 32 or 64) 2.4.1-1, latest updates with crypt 1.1-1,
>> >libcrypt0 1.1-1, libcrypt-devel 1.1-1
>> >$ crypt '$6$7dl4B0fKUimdnR$' test_value
>> >$6wOs/zKP2jDM
>> >
>> >$ python -c 'import crypt; print crypt.crypt("test_value",
>> >"$6$7dl4B0fKUimdnR$")' # Python 2.7.10
>> >$6wOs/zKP2jDM
>> >
>> >$ perl -e 'print crypt("test_value", "\$6\$7dl4B0fKUimdnR\$")."\n"' #
>> >Perl v5.22.1
>> >$6wOs/zKP2jDM
>> >
>> >Am I missing something?
>> >
>> >On other system, I get a more expected result:
>> >
>> ># On Ubuntu 15.04
>> >$ mkpasswd --method=SHA-512 test_value 7dl4B0fKUimdnR
>> >$6$7dl4B0fKUimdnR$f6gCu.3IfrxhsnJKFnusDH.UudC.lLOSB1G3D1bIboWxlixzBy2xO/3rCKHmzfwekCTvmQd11bPdcsJOaLkCJ.
>> >
>
> You're aware that the password field in /etc/passwd is not used, right?
> Passwords are checked against the Windows user DB.  In fact, /etc/passwd
> is not necessary anymore.
>
>> Not SHA-512, see
>> /usr/share/doc/crypt/crypt.README
>>
>> This is the DES-crypt package Version 1.1
>>
>> It provides a static library libcrypt.a as well as a shared library
>> cygcrypt-0.dll together with a link lib libcrypt.dll.a, which export
>> the functions
>>
>>         crypt(3)
>>         encrypt(3)
>>         setkey(3)
>>
>> The passwords created by crypt(3) are 56 bit DES encrypted and are
>> 100% identical to those created by the Linux crypt().
>
> Right.  If you need the hashes for other purposes than /etc/passwd,
> you can use `openssl sha512'

My use case is to generate encrypted password for use later on unix
system (using Python crypt library).
OK for crypt(1) providing only 56 bit DES.
But, could be nice for libcrypt (cygcrypt or crypt(3)) to provide
other algorithms so other libraries working with it (like Python or
Perl crypt libraries) could use those. Or at least raise an error when
not supported prefixes are used (like '$6$').

-- 
Alex

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