md5crypt.py
author Anthony Truchet <anthony.truchet@logilab.fr>
Mon, 27 Feb 2012 09:43:15 +0100
changeset 8265 9747ab9230ad
parent 7879 9aae456abab5
child 8317 9c59258e7798
permissions -rw-r--r--
[repo, undo] Finish repository-side implementation of the undo feature (closes #893940) 1) Changes API for undo_transaction in order to raise an exception: the previous API returned a sequence of error, the user of the API needed to be careful to check explicitly. We change this for it to raise an UndoException with the list of errors as an attribute. 2) The server-side support for undoing update actions is finished 3) The configuration for `undo-support` is now a simple boolean Beware of the costs, both in DB space and in number of requests on the RDBMS backend, once this feture is activated. 4) Adds a txuuid param/attribute to the existing NoSuchTransaction exception.

# md5crypt.py
#
# 0423.2000 by michal wallace http://www.sabren.com/
# based on perl's Crypt::PasswdMD5 by Luis Munoz (lem@cantv.net)
# based on /usr/src/libcrypt/crypt.c from FreeBSD 2.2.5-RELEASE
#
# MANY THANKS TO
#
#  Carey Evans - http://home.clear.net.nz/pages/c.evans/
#  Dennis Marti - http://users.starpower.net/marti1/
#
#  For the patches that got this thing working!
#
# modification by logilab:
# * remove usage of the string module
# * don't include the magic string in the output string
#   for true crypt.crypt compatibility
# * use hashlib module instead of md5
#########################################################
"""md5crypt.py - Provides interoperable MD5-based crypt() function

SYNOPSIS

        import md5crypt.py

        cryptedpassword = md5crypt.md5crypt(password, salt);

DESCRIPTION

unix_md5_crypt() provides a crypt()-compatible interface to the
rather new MD5-based crypt() function found in modern operating systems.
It's based on the implementation found on FreeBSD 2.2.[56]-RELEASE and
contains the following license in it:

 "THE BEER-WARE LICENSE" (Revision 42):
 <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
 can do whatever you want with this stuff. If we meet some day, and you think
 this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
"""

MAGIC = '$1$'                        # Magic string
ITOA64 = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"

from hashlib import md5 # pylint: disable=E0611

def to64 (v, n):
    ret = ''
    while (n - 1 >= 0):
        n = n - 1
        ret = ret + ITOA64[v & 0x3f]
        v = v >> 6
    return ret

def crypt(pw, salt, magic=None):
    if isinstance(pw, unicode):
        pw = pw.encode('utf-8')
    if magic is None:
        magic = MAGIC
    # Take care of the magic string if present
    if salt[:len(magic)] == magic:
        salt = salt[len(magic):]
    # salt can have up to 8 characters:
    salt = salt.split('$', 1)[0]
    salt = salt[:8]
    ctx = pw + magic + salt
    final = md5(pw + salt + pw).digest()
    for pl in xrange(len(pw), 0, -16):
        if pl > 16:
            ctx = ctx + final[:16]
        else:
            ctx = ctx + final[:pl]
    # Now the 'weird' xform (??)
    i = len(pw)
    while i:
        if i & 1:
            ctx = ctx + chr(0)  #if ($i & 1) { $ctx->add(pack("C", 0)); }
        else:
            ctx = ctx + pw[0]
        i = i >> 1
    final = md5(ctx).digest()
    # The following is supposed to make
    # things run slower.
    # my question: WTF???
    for i in xrange(1000):
        ctx1 = ''
        if i & 1:
            ctx1 = ctx1 + pw
        else:
            ctx1 = ctx1 + final[:16]
        if i % 3:
            ctx1 = ctx1 + salt
        if i % 7:
            ctx1 = ctx1 + pw
        if i & 1:
            ctx1 = ctx1 + final[:16]
        else:
            ctx1 = ctx1 + pw
        final = md5(ctx1).digest()
    # Final xform
    passwd = ''
    passwd = passwd + to64((int(ord(final[0])) << 16)
                           |(int(ord(final[6])) << 8)
                           |(int(ord(final[12]))),4)
    passwd = passwd + to64((int(ord(final[1])) << 16)
                           |(int(ord(final[7])) << 8)
                           |(int(ord(final[13]))), 4)
    passwd = passwd + to64((int(ord(final[2])) << 16)
                           |(int(ord(final[8])) << 8)
                           |(int(ord(final[14]))), 4)
    passwd = passwd + to64((int(ord(final[3])) << 16)
                           |(int(ord(final[9])) << 8)
                           |(int(ord(final[15]))), 4)
    passwd = passwd + to64((int(ord(final[4])) << 16)
                           |(int(ord(final[10])) << 8)
                           |(int(ord(final[5]))), 4)
    passwd = passwd + to64((int(ord(final[11]))), 2)
    return salt + '$' + passwd