/usr/lib/python3/dist-packages/passlib/crypto/_md4.py is in python3-passlib 1.7.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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passlib.crypto._md4 -- fallback implementation of MD4
Helper implementing insecure and obsolete md4 algorithm.
used for NTHASH format, which is also insecure and broken,
since it's just md4(password).
Implementated based on rfc at http://www.faqs.org/rfcs/rfc1320.html
.. note::
This shouldn't be imported directly, it's merely used conditionally
by ``passlib.crypto.lookup_hash()`` when a native implementation can't be found.
"""
#=============================================================================
# imports
#=============================================================================
# core
from binascii import hexlify
import struct
# site
from passlib.utils.compat import bascii_to_str, irange, PY3
# local
__all__ = ["md4"]
#=============================================================================
# utils
#=============================================================================
def F(x,y,z):
return (x&y) | ((~x) & z)
def G(x,y,z):
return (x&y) | (x&z) | (y&z)
##def H(x,y,z):
## return x ^ y ^ z
MASK_32 = 2**32-1
#=============================================================================
# main class
#=============================================================================
class md4(object):
"""pep-247 compatible implementation of MD4 hash algorithm
.. attribute:: digest_size
size of md4 digest in bytes (16 bytes)
.. method:: update
update digest by appending additional content
.. method:: copy
create clone of digest object, including current state
.. method:: digest
return bytes representing md4 digest of current content
.. method:: hexdigest
return hexadecimal version of digest
"""
# FIXME: make this follow hash object PEP better.
# FIXME: this isn't threadsafe
name = "md4"
digest_size = digestsize = 16
block_size = 64
_count = 0 # number of 64-byte blocks processed so far (not including _buf)
_state = None # list of [a,b,c,d] 32 bit ints used as internal register
_buf = None # data processed in 64 byte blocks, this holds leftover from last update
def __init__(self, content=None):
self._count = 0
self._state = [0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476]
self._buf = b''
if content:
self.update(content)
# round 1 table - [abcd k s]
_round1 = [
[0,1,2,3, 0,3],
[3,0,1,2, 1,7],
[2,3,0,1, 2,11],
[1,2,3,0, 3,19],
[0,1,2,3, 4,3],
[3,0,1,2, 5,7],
[2,3,0,1, 6,11],
[1,2,3,0, 7,19],
[0,1,2,3, 8,3],
[3,0,1,2, 9,7],
[2,3,0,1, 10,11],
[1,2,3,0, 11,19],
[0,1,2,3, 12,3],
[3,0,1,2, 13,7],
[2,3,0,1, 14,11],
[1,2,3,0, 15,19],
]
# round 2 table - [abcd k s]
_round2 = [
[0,1,2,3, 0,3],
[3,0,1,2, 4,5],
[2,3,0,1, 8,9],
[1,2,3,0, 12,13],
[0,1,2,3, 1,3],
[3,0,1,2, 5,5],
[2,3,0,1, 9,9],
[1,2,3,0, 13,13],
[0,1,2,3, 2,3],
[3,0,1,2, 6,5],
[2,3,0,1, 10,9],
[1,2,3,0, 14,13],
[0,1,2,3, 3,3],
[3,0,1,2, 7,5],
[2,3,0,1, 11,9],
[1,2,3,0, 15,13],
]
# round 3 table - [abcd k s]
_round3 = [
[0,1,2,3, 0,3],
[3,0,1,2, 8,9],
[2,3,0,1, 4,11],
[1,2,3,0, 12,15],
[0,1,2,3, 2,3],
[3,0,1,2, 10,9],
[2,3,0,1, 6,11],
[1,2,3,0, 14,15],
[0,1,2,3, 1,3],
[3,0,1,2, 9,9],
[2,3,0,1, 5,11],
[1,2,3,0, 13,15],
[0,1,2,3, 3,3],
[3,0,1,2, 11,9],
[2,3,0,1, 7,11],
[1,2,3,0, 15,15],
]
def _process(self, block):
"""process 64 byte block"""
# unpack block into 16 32-bit ints
X = struct.unpack("<16I", block)
# clone state
orig = self._state
state = list(orig)
# round 1 - F function - (x&y)|(~x & z)
for a,b,c,d,k,s in self._round1:
t = (state[a] + F(state[b],state[c],state[d]) + X[k]) & MASK_32
state[a] = ((t<<s) & MASK_32) + (t>>(32-s))
# round 2 - G function
for a,b,c,d,k,s in self._round2:
t = (state[a] + G(state[b],state[c],state[d]) + X[k] + 0x5a827999) & MASK_32
state[a] = ((t<<s) & MASK_32) + (t>>(32-s))
# round 3 - H function - x ^ y ^ z
for a,b,c,d,k,s in self._round3:
t = (state[a] + (state[b] ^ state[c] ^ state[d]) + X[k] + 0x6ed9eba1) & MASK_32
state[a] = ((t<<s) & MASK_32) + (t>>(32-s))
# add back into original state
for i in irange(4):
orig[i] = (orig[i]+state[i]) & MASK_32
def update(self, content):
if not isinstance(content, bytes):
if PY3:
raise TypeError("expected bytes")
else:
# replicate behavior of hashlib under py2
content = content.encode("ascii")
buf = self._buf
if buf:
content = buf + content
idx = 0
end = len(content)
while True:
next = idx + 64
if next <= end:
self._process(content[idx:next])
self._count += 1
idx = next
else:
self._buf = content[idx:]
return
def copy(self):
other = md4()
other._count = self._count
other._state = list(self._state)
other._buf = self._buf
return other
def digest(self):
# NOTE: backing up state so we can restore it after _process is called,
# in case object is updated again (this is only attr altered by this method)
orig = list(self._state)
# final block: buf + 0x80,
# then 0x00 padding until congruent w/ 56 mod 64 bytes
# then last 8 bytes = msg length in bits
buf = self._buf
msglen = self._count*512 + len(buf)*8
block = buf + b'\x80' + b'\x00' * ((119-len(buf)) % 64) + \
struct.pack("<2I", msglen & MASK_32, (msglen>>32) & MASK_32)
if len(block) == 128:
self._process(block[:64])
self._process(block[64:])
else:
assert len(block) == 64
self._process(block)
# render digest & restore un-finalized state
out = struct.pack("<4I", *self._state)
self._state = orig
return out
def hexdigest(self):
return bascii_to_str(hexlify(self.digest()))
#===================================================================
# eoc
#===================================================================
#=============================================================================
# eof
#=============================================================================
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