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|
"""passlib.handlers.fshp
"""
#=============================================================================
# imports
#=============================================================================
# core
from base64 import b64encode, b64decode
import re
import logging; log = logging.getLogger(__name__)
# site
# pkg
from passlib.utils import to_unicode
import passlib.utils.handlers as uh
from passlib.utils.compat import bascii_to_str, u
from passlib.crypto.digest import pbkdf1
# local
__all__ = [
'fshp',
]
#=============================================================================
# sha1-crypt
#=============================================================================
class fshp(uh.HasRounds, uh.HasRawSalt, uh.HasRawChecksum, uh.GenericHandler):
"""This class implements the FSHP password hash, and follows the :ref:`password-hash-api`.
It supports a variable-length salt, and a variable number of rounds.
The :meth:`~passlib.ifc.PasswordHash.using` method accepts the following optional keywords:
:param salt:
Optional raw salt string.
If not specified, one will be autogenerated (this is recommended).
:param salt_size:
Optional number of bytes to use when autogenerating new salts.
Defaults to 16 bytes, but can be any non-negative value.
:param rounds:
Optional number of rounds to use.
Defaults to 480000, must be between 1 and 4294967295, inclusive.
:param variant:
Optionally specifies variant of FSHP to use.
* ``0`` - uses SHA-1 digest (deprecated).
* ``1`` - uses SHA-2/256 digest (default).
* ``2`` - uses SHA-2/384 digest.
* ``3`` - uses SHA-2/512 digest.
:type relaxed: bool
:param relaxed:
By default, providing an invalid value for one of the other
keywords will result in a :exc:`ValueError`. If ``relaxed=True``,
and the error can be corrected, a :exc:`~passlib.exc.PasslibHashWarning`
will be issued instead. Correctable errors include ``rounds``
that are too small or too large, and ``salt`` strings that are too long.
.. versionadded:: 1.6
"""
#===================================================================
# class attrs
#===================================================================
#--GenericHandler--
name = "fshp"
setting_kwds = ("salt", "salt_size", "rounds", "variant")
checksum_chars = uh.PADDED_BASE64_CHARS
ident = u"{FSHP"
# checksum_size is property() that depends on variant
#--HasRawSalt--
default_salt_size = 16 # current passlib default, FSHP uses 8
max_salt_size = None
#--HasRounds--
# FIXME: should probably use different default rounds
# based on the variant. setting for default variant (sha256) for now.
default_rounds = 480000 # current passlib default, FSHP uses 4096
min_rounds = 1 # set by FSHP
max_rounds = 4294967295 # 32-bit integer limit - not set by FSHP
rounds_cost = "linear"
#--variants--
default_variant = 1
_variant_info = {
# variant: (hash name, digest size)
0: ("sha1", 20),
1: ("sha256", 32),
2: ("sha384", 48),
3: ("sha512", 64),
}
_variant_aliases = dict(
[(str(k),k) for k in _variant_info] +
[(v[0],k) for k,v in _variant_info.items()]
)
#===================================================================
# configuration
#===================================================================
@classmethod
def using(cls, variant=None, **kwds):
subcls = super(fshp, cls).using(**kwds)
if variant is not None:
subcls.default_variant = cls._norm_variant(variant)
return subcls
#===================================================================
# instance attrs
#===================================================================
variant = None
#===================================================================
# init
#===================================================================
def __init__(self, variant=None, **kwds):
# NOTE: variant must be set first, since it controls checksum size, etc.
self.use_defaults = kwds.get("use_defaults") # load this early
if variant is not None:
variant = self._norm_variant(variant)
elif self.use_defaults:
variant = self.default_variant
assert self._norm_variant(variant) == variant, "invalid default variant: %r" % (variant,)
else:
raise TypeError("no variant specified")
self.variant = variant
super(fshp, self).__init__(**kwds)
@classmethod
def _norm_variant(cls, variant):
if isinstance(variant, bytes):
variant = variant.decode("ascii")
if isinstance(variant, str):
try:
variant = cls._variant_aliases[variant]
except KeyError:
raise ValueError("invalid fshp variant")
if not isinstance(variant, int):
raise TypeError("fshp variant must be int or known alias")
if variant not in cls._variant_info:
raise ValueError("invalid fshp variant")
return variant
@property
def checksum_alg(self):
return self._variant_info[self.variant][0]
@property
def checksum_size(self):
return self._variant_info[self.variant][1]
#===================================================================
# formatting
#===================================================================
_hash_regex = re.compile(u(r"""
^
\{FSHP
(\d+)\| # variant
(\d+)\| # salt size
(\d+)\} # rounds
([a-zA-Z0-9+/]+={0,3}) # digest
$"""), re.X)
@classmethod
def from_string(cls, hash):
hash = to_unicode(hash, "ascii", "hash")
m = cls._hash_regex.match(hash)
if not m:
raise uh.exc.InvalidHashError(cls)
variant, salt_size, rounds, data = m.group(1,2,3,4)
variant = int(variant)
salt_size = int(salt_size)
rounds = int(rounds)
try:
data = b64decode(data.encode("ascii"))
except TypeError:
raise uh.exc.MalformedHashError(cls)
salt = data[:salt_size]
chk = data[salt_size:]
return cls(salt=salt, checksum=chk, rounds=rounds, variant=variant)
def to_string(self):
chk = self.checksum
salt = self.salt
data = bascii_to_str(b64encode(salt+chk))
return "{FSHP%d|%d|%d}%s" % (self.variant, len(salt), self.rounds, data)
#===================================================================
# backend
#===================================================================
def _calc_checksum(self, secret):
if isinstance(secret, str):
secret = secret.encode("utf-8")
# NOTE: for some reason, FSHP uses pbkdf1 with password & salt reversed.
# this has only a minimal impact on security,
# but it is worth noting this deviation.
return pbkdf1(
digest=self.checksum_alg,
secret=self.salt,
salt=secret,
rounds=self.rounds,
keylen=self.checksum_size,
)
#===================================================================
# eoc
#===================================================================
#=============================================================================
# eof
#=============================================================================
|
