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diff --git a/roundup/password.py b/roundup/password.py
index 6a555bb908ae9c5187db03dc414a6d1545251713..545baeb66690603808961c02c6617cc8ea84e03b 100644 (file)
--- a/roundup/password.py
+++ b/roundup/password.py
"""
__docformat__ = 'restructuredtext'
-import sha, md5, re, string, random
+import re, string, random
+from base64 import b64encode, b64decode
+from roundup.anypy.hashlib_ import md5, sha1
try:
import crypt
-except:
+except ImportError:
crypt = None
- pass
+
+_bempty = ""
+_bjoin = _bempty.join
+
+def getrandbytes(count):
+ return _bjoin(chr(random.randint(0,255)) for i in xrange(count))
+
+#NOTE: PBKDF2 hash is using this variant of base64 to minimize encoding size,
+# and have charset that's compatible w/ unix crypt variants
+def h64encode(data):
+ """encode using variant of base64"""
+ return b64encode(data, "./").strip("=\n")
+
+def h64decode(data):
+ """decode using variant of base64"""
+ off = len(data) % 4
+ if off == 0:
+ return b64decode(data, "./")
+ elif off == 1:
+ raise ValueError("invalid bas64 input")
+ elif off == 2:
+ return b64decode(data + "==", "./")
+ else:
+ return b64decode(data + "=", "./")
+
+try:
+ from M2Crypto.EVP import pbkdf2 as _pbkdf2
+except ImportError:
+ #no m2crypto - make our own pbkdf2 function
+ from struct import pack
+ from hmac import HMAC
+ try:
+ from hashlib import sha1
+ except ImportError:
+ from sha import new as sha1
+
+ def xor_bytes(left, right):
+ "perform bitwise-xor of two byte-strings"
+ return _bjoin(chr(ord(l) ^ ord(r)) for l, r in zip(left, right))
+
+ def _pbkdf2(password, salt, rounds, keylen):
+ digest_size = 20 # sha1 generates 20-byte blocks
+ total_blocks = int((keylen+digest_size-1)/digest_size)
+ hmac_template = HMAC(password, None, sha1)
+ out = _bempty
+ for i in xrange(1, total_blocks+1):
+ hmac = hmac_template.copy()
+ hmac.update(salt + pack(">L",i))
+ block = tmp = hmac.digest()
+ for j in xrange(rounds-1):
+ hmac = hmac_template.copy()
+ hmac.update(tmp)
+ tmp = hmac.digest()
+ #TODO: need to speed up this call
+ block = xor_bytes(block, tmp)
+ out += block
+ return out[:keylen]
+
+def pbkdf2(password, salt, rounds, keylen):
+ """pkcs#5 password-based key derivation v2.0
+
+ :arg password: passphrase to use to generate key (if unicode, converted to utf-8)
+ :arg salt: salt string to use when generating key (if unicode, converted to utf-8)
+ :param rounds: number of rounds to use to generate key
+ :arg keylen: number of bytes to generate
+
+ If M2Crypto is present, uses it's implementation as backend.
+
+ :returns:
+ raw bytes of generated key
+ """
+ if isinstance(password, unicode):
+ password = password.encode("utf-8")
+ if isinstance(salt, unicode):
+ salt = salt.encode("utf-8")
+ if keylen > 40:
+ #NOTE: pbkdf2 allows up to (2**31-1)*20 bytes,
+ # but m2crypto has issues on some platforms above 40,
+ # and such sizes aren't needed for a password hash anyways...
+ raise ValueError, "key length too large"
+ if rounds < 1:
+ raise ValueError, "rounds must be positive number"
+ return _pbkdf2(password, salt, rounds, keylen)
class PasswordValueError(ValueError):
- ''' The password value is not valid '''
+ """ The password value is not valid """
pass
def encodePassword(plaintext, scheme, other=None):
- '''Encrypt the plaintext password.
- '''
+ """Encrypt the plaintext password.
+ """
if plaintext is None:
plaintext = ""
- if scheme == 'SHA':
- s = sha.sha(plaintext).hexdigest()
+ if scheme == "PBKDF2":
+ if other:
+ #assume it has format "{rounds}${salt}${digest}"
+ if isinstance(other, unicode):
+ other = other.encode("ascii")
+ try:
+ rounds, salt, digest = other.split("$")
+ except ValueError:
+ raise PasswordValueError, "invalid PBKDF2 hash (wrong number of separators)"
+ if rounds.startswith("0"):
+ raise PasswordValueError, "invalid PBKDF2 hash (zero-padded rounds)"
+ try:
+ rounds = int(rounds)
+ except ValueError:
+ raise PasswordValueError, "invalid PBKDF2 hash (invalid rounds)"
+ raw_salt = h64decode(salt)
+ else:
+ raw_salt = getrandbytes(20)
+ salt = h64encode(raw_salt)
+ #FIXME: find way to access config, so default rounds
+ # can be altered for faster/slower hosts via config.ini
+ rounds = 10000
+ if rounds < 1000:
+ raise PasswordValueError, "invalid PBKDF2 hash (rounds too low)"
+ raw_digest = pbkdf2(plaintext, raw_salt, rounds, 20)
+ return "%d$%s$%s" % (rounds, salt, h64encode(raw_digest))
+ elif scheme == 'SHA':
+ s = sha1(plaintext).hexdigest()
elif scheme == 'MD5':
- s = md5.md5(plaintext).hexdigest()
+ s = md5(plaintext).hexdigest()
elif scheme == 'crypt' and crypt is not None:
if other is not None:
salt = other
chars = string.letters+string.digits
return ''.join([random.choice(chars) for x in range(length)])
-class Password:
- '''The class encapsulates a Password property type value in the database.
+class JournalPassword:
+ """ Password dummy instance intended for journal operation.
+ We do not store passwords in the journal any longer. The dummy
+ version only reads the encryption scheme from the given
+ encrypted password.
+ """
+ default_scheme = 'PBKDF2' # new encryptions use this scheme
+ pwre = re.compile(r'{(\w+)}(.+)')
+
+ def __init__ (self, encrypted=''):
+ if isinstance(encrypted, self.__class__):
+ self.scheme = encrypted.scheme or self.default_scheme
+ else:
+ m = self.pwre.match(encrypted)
+ if m:
+ self.scheme = m.group(1)
+ else:
+ self.scheme = self.default_scheme
+ self.password = ''
+
+ def dummystr(self):
+ """ return dummy string to store in journal
+ - reports scheme, but nothing else
+ """
+ return "{%s}*encrypted*" % (self.scheme,)
+
+ __str__ = dummystr
+
+ def __cmp__(self, other):
+ """Compare this password against another password."""
+ # check to see if we're comparing instances
+ if isinstance(other, self.__class__):
+ if self.scheme != other.scheme:
+ return cmp(self.scheme, other.scheme)
+ return cmp(self.password, other.password)
+
+ # assume password is plaintext
+ if self.password is None:
+ raise ValueError, 'Password not set'
+ return cmp(self.password, encodePassword(other, self.scheme,
+ self.password or None))
+
+class Password(JournalPassword):
+ """The class encapsulates a Password property type value in the database.
The encoding of the password is one if None, 'SHA', 'MD5' or 'plaintext'.
The encodePassword function is used to actually encode the password from
1
>>> 'not sekrit' != p
1
- '''
+ """
+ #TODO: code to migrate from old password schemes.
- default_scheme = 'SHA' # new encryptions use this scheme
- pwre = re.compile(r'{(\w+)}(.+)')
+ known_schemes = [ "PBKDF2", "SHA", "MD5", "crypt", "plaintext" ]
- def __init__(self, plaintext=None, scheme=None, encrypted=None):
- '''Call setPassword if plaintext is not None.'''
+ def __init__(self, plaintext=None, scheme=None, encrypted=None, strict=False):
+ """Call setPassword if plaintext is not None."""
if scheme is None:
scheme = self.default_scheme
if plaintext is not None:
self.setPassword (plaintext, scheme)
elif encrypted is not None:
- self.unpack(encrypted, scheme)
+ self.unpack(encrypted, scheme, strict=strict)
else:
self.scheme = self.default_scheme
self.password = None
self.plaintext = None
- def unpack(self, encrypted, scheme=None):
- '''Set the password info from the scheme:<encryted info> string
+ def unpack(self, encrypted, scheme=None, strict=False):
+ """Set the password info from the scheme:<encryted info> string
(the inverse of __str__)
- '''
+ """
m = self.pwre.match(encrypted)
if m:
self.scheme = m.group(1)
else:
# currently plaintext - encrypt
self.setPassword(encrypted, scheme)
+ if strict and self.scheme not in self.known_schemes:
+ raise PasswordValueError, "unknown encryption scheme: %r" % (self.scheme,)
def setPassword(self, plaintext, scheme=None):
- '''Sets encrypts plaintext.'''
+ """Sets encrypts plaintext."""
if scheme is None:
scheme = self.default_scheme
self.scheme = scheme
self.password = encodePassword(plaintext, scheme)
self.plaintext = plaintext
- def __cmp__(self, other):
- '''Compare this password against another password.'''
- # check to see if we're comparing instances
- if isinstance(other, Password):
- if self.scheme != other.scheme:
- return cmp(self.scheme, other.scheme)
- return cmp(self.password, other.password)
-
- # assume password is plaintext
- if self.password is None:
- raise ValueError, 'Password not set'
- return cmp(self.password, encodePassword(other, self.scheme,
- self.password))
-
def __str__(self):
- '''Stringify the encrypted password for database storage.'''
+ """Stringify the encrypted password for database storage."""
if self.password is None:
raise ValueError, 'Password not set'
return '{%s}%s'%(self.scheme, self.password)
assert 'sekrit' == p
assert 'not sekrit' != p
+ # PBKDF2 - low level function
+ from binascii import unhexlify
+ k = pbkdf2("password", "ATHENA.MIT.EDUraeburn", 1200, 32)
+ assert k == unhexlify("5c08eb61fdf71e4e4ec3cf6ba1f5512ba7e52ddbc5e5142f708a31e2e62b1e13")
+
+ # PBKDF2 - hash function
+ h = "5000$7BvbBq.EZzz/O0HuwX3iP.nAG3s$g3oPnFFaga2BJaX5PoPRljl4XIE"
+ assert encodePassword("sekrit", "PBKDF2", h) == h
+
+ # PBKDF2 - high level integration
+ p = Password('sekrit', 'PBKDF2')
+ assert p == 'sekrit'
+ assert p != 'not sekrit'
+ assert 'sekrit' == p
+ assert 'not sekrit' != p
+
if __name__ == '__main__':
test()