/usr/share/pyshared/passlib/handlers/bcrypt.py is in python-passlib 1.6.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 | """passlib.bcrypt -- implementation of OpenBSD's BCrypt algorithm.
TODO:
* support 2x and altered-2a hashes?
http://www.openwall.com/lists/oss-security/2011/06/27/9
* deal with lack of PY3-compatibile c-ext implementation
"""
#=============================================================================
# imports
#=============================================================================
from __future__ import with_statement, absolute_import
# core
import os
import re
import logging; log = logging.getLogger(__name__)
from warnings import warn
# site
try:
from bcrypt import hashpw as pybcrypt_hashpw
except ImportError: # pragma: no cover
pybcrypt_hashpw = None
try:
from bcryptor.engine import Engine as bcryptor_engine
except ImportError: # pragma: no cover
bcryptor_engine = None
# pkg
from passlib.exc import PasslibHashWarning
from passlib.utils import bcrypt64, safe_crypt, repeat_string, \
classproperty, rng, getrandstr, test_crypt
from passlib.utils.compat import bytes, b, u, uascii_to_str, unicode, str_to_uascii
import passlib.utils.handlers as uh
# local
__all__ = [
"bcrypt",
]
#=============================================================================
# support funcs & constants
#=============================================================================
_builtin_bcrypt = None
def _load_builtin():
global _builtin_bcrypt
if _builtin_bcrypt is None:
from passlib.utils._blowfish import raw_bcrypt as _builtin_bcrypt
IDENT_2 = u("$2$")
IDENT_2A = u("$2a$")
IDENT_2X = u("$2x$")
IDENT_2Y = u("$2y$")
_BNULL = b('\x00')
#=============================================================================
# handler
#=============================================================================
class bcrypt(uh.HasManyIdents, uh.HasRounds, uh.HasSalt, uh.HasManyBackends, uh.GenericHandler):
"""This class implements the BCrypt password hash, and follows the :ref:`password-hash-api`.
It supports a fixed-length salt, and a variable number of rounds.
The :meth:`~passlib.ifc.PasswordHash.encrypt` and :meth:`~passlib.ifc.PasswordHash.genconfig` methods accept the following optional keywords:
:type salt: str
:param salt:
Optional salt string.
If not specified, one will be autogenerated (this is recommended).
If specified, it must be 22 characters, drawn from the regexp range ``[./0-9A-Za-z]``.
:type rounds: int
:param rounds:
Optional number of rounds to use.
Defaults to 12, must be between 4 and 31, inclusive.
This value is logarithmic, the actual number of iterations used will be :samp:`2**{rounds}`
-- increasing the rounds by +1 will double the amount of time taken.
:type ident: str
:param ident:
Specifies which version of the BCrypt algorithm will be used when creating a new hash.
Typically this option is not needed, as the default (``"2a"``) is usually the correct choice.
If specified, it must be one of the following:
* ``"2"`` - the first revision of BCrypt, which suffers from a minor security flaw and is generally not used anymore.
* ``"2a"`` - latest revision of the official BCrypt algorithm, and the current default.
* ``"2y"`` - format specific to the *crypt_blowfish* BCrypt implementation,
identical to ``"2a"`` in all but name.
: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
.. versionchanged:: 1.6
This class now supports ``"2y"`` hashes, and recognizes
(but does not support) the broken ``"2x"`` hashes.
(see the :ref:`crypt_blowfish bug <crypt-blowfish-bug>`
for details).
.. versionchanged:: 1.6
Added a pure-python backend.
"""
#===================================================================
# class attrs
#===================================================================
#--GenericHandler--
name = "bcrypt"
setting_kwds = ("salt", "rounds", "ident")
checksum_size = 31
checksum_chars = bcrypt64.charmap
#--HasManyIdents--
default_ident = u("$2a$")
ident_values = (u("$2$"), IDENT_2A, IDENT_2X, IDENT_2Y)
ident_aliases = {u("2"): u("$2$"), u("2a"): IDENT_2A, u("2y"): IDENT_2Y}
#--HasSalt--
min_salt_size = max_salt_size = 22
salt_chars = bcrypt64.charmap
# NOTE: 22nd salt char must be in bcrypt64._padinfo2[1], not full charmap
#--HasRounds--
default_rounds = 12 # current passlib default
min_rounds = 4 # bcrypt spec specified minimum
max_rounds = 31 # 32-bit integer limit (since real_rounds=1<<rounds)
rounds_cost = "log2"
#===================================================================
# formatting
#===================================================================
@classmethod
def from_string(cls, hash):
ident, tail = cls._parse_ident(hash)
if ident == IDENT_2X:
raise ValueError("crypt_blowfish's buggy '2x' hashes are not "
"currently supported")
rounds_str, data = tail.split(u("$"))
rounds = int(rounds_str)
if rounds_str != u('%02d') % (rounds,):
raise uh.exc.MalformedHashError(cls, "malformed cost field")
salt, chk = data[:22], data[22:]
return cls(
rounds=rounds,
salt=salt,
checksum=chk or None,
ident=ident,
)
def to_string(self):
hash = u("%s%02d$%s%s") % (self.ident, self.rounds, self.salt,
self.checksum or u(''))
return uascii_to_str(hash)
def _get_config(self, ident=None):
"internal helper to prepare config string for backends"
if ident is None:
ident = self.ident
if ident == IDENT_2Y:
ident = IDENT_2A
else:
assert ident != IDENT_2X
config = u("%s%02d$%s") % (ident, self.rounds, self.salt)
return uascii_to_str(config)
#===================================================================
# specialized salt generation - fixes passlib issue 25
#===================================================================
@classmethod
def _bind_needs_update(cls, **settings):
return cls._needs_update
@classmethod
def _needs_update(cls, hash, secret):
if isinstance(hash, bytes):
hash = hash.decode("ascii")
# check for incorrect padding bits (passlib issue 25)
if hash.startswith(IDENT_2A) and hash[28] not in bcrypt64._padinfo2[1]:
return True
# TODO: try to detect incorrect $2x$ hashes using *secret*
return False
@classmethod
def normhash(cls, hash):
"helper to normalize hash, correcting any bcrypt padding bits"
if cls.identify(hash):
return cls.from_string(hash).to_string()
else:
return hash
def _generate_salt(self, salt_size):
# override to correct generate salt bits
salt = super(bcrypt, self)._generate_salt(salt_size)
return bcrypt64.repair_unused(salt)
def _norm_salt(self, salt, **kwds):
salt = super(bcrypt, self)._norm_salt(salt, **kwds)
assert salt is not None, "HasSalt didn't generate new salt!"
changed, salt = bcrypt64.check_repair_unused(salt)
if changed:
# FIXME: if salt was provided by user, this message won't be
# correct. not sure if we want to throw error, or use different warning.
warn(
"encountered a bcrypt salt with incorrectly set padding bits; "
"you may want to use bcrypt.normhash() "
"to fix this; see Passlib 1.5.3 changelog.",
PasslibHashWarning)
return salt
def _norm_checksum(self, checksum):
checksum = super(bcrypt, self)._norm_checksum(checksum)
if not checksum:
return None
changed, checksum = bcrypt64.check_repair_unused(checksum)
if changed:
warn(
"encountered a bcrypt hash with incorrectly set padding bits; "
"you may want to use bcrypt.normhash() "
"to fix this; see Passlib 1.5.3 changelog.",
PasslibHashWarning)
return checksum
#===================================================================
# primary interface
#===================================================================
backends = ("pybcrypt", "bcryptor", "os_crypt", "builtin")
@classproperty
def _has_backend_pybcrypt(cls):
return pybcrypt_hashpw is not None
@classproperty
def _has_backend_bcryptor(cls):
return bcryptor_engine is not None
@classproperty
def _has_backend_builtin(cls):
if os.environ.get("PASSLIB_BUILTIN_BCRYPT") not in ["enable","enabled"]:
return False
# look at it cross-eyed, and it loads itself
_load_builtin()
return True
@classproperty
def _has_backend_os_crypt(cls):
# XXX: what to do if only h2 is supported? h1 is *very* rare.
h1 = '$2$04$......................1O4gOrCYaqBG3o/4LnT2ykQUt1wbyju'
h2 = '$2a$04$......................qiOQjkB8hxU8OzRhS.GhRMa4VUnkPty'
return test_crypt("test",h1) and test_crypt("test", h2)
@classmethod
def _no_backends_msg(cls):
return "no bcrypt backends available - please install py-bcrypt"
def _calc_checksum_os_crypt(self, secret):
config = self._get_config()
hash = safe_crypt(secret, config)
if hash:
assert hash.startswith(config) and len(hash) == len(config)+31
return hash[-31:]
else:
# NOTE: it's unlikely any other backend will be available,
# but checking before we bail, just in case.
for name in self.backends:
if name != "os_crypt" and self.has_backend(name):
func = getattr(self, "_calc_checksum_" + name)
return func(secret)
raise uh.exc.MissingBackendError(
"password can't be handled by os_crypt, "
"recommend installing py-bcrypt.",
)
def _calc_checksum_pybcrypt(self, secret):
# py-bcrypt behavior:
# py2: unicode secret/hash encoded as ascii bytes before use,
# bytes taken as-is; returns ascii bytes.
# py3: not supported (patch submitted)
if isinstance(secret, unicode):
secret = secret.encode("utf-8")
if _BNULL in secret:
raise uh.exc.NullPasswordError(self)
config = self._get_config()
hash = pybcrypt_hashpw(secret, config)
assert hash.startswith(config) and len(hash) == len(config)+31
return str_to_uascii(hash[-31:])
def _calc_checksum_bcryptor(self, secret):
# bcryptor behavior:
# py2: unicode secret/hash encoded as ascii bytes before use,
# bytes taken as-is; returns ascii bytes.
# py3: not supported
if isinstance(secret, unicode):
secret = secret.encode("utf-8")
if _BNULL in secret:
# NOTE: especially important to forbid NULLs for bcryptor,
# since it happily accepts them, and then silently truncates
# the password at first one it encounters :(
raise uh.exc.NullPasswordError(self)
if self.ident == IDENT_2:
# bcryptor doesn't support $2$ hashes; but we can fake $2$ behavior
# using the $2a$ algorithm, by repeating the password until
# it's at least 72 chars in length.
if secret:
secret = repeat_string(secret, 72)
config = self._get_config(IDENT_2A)
else:
config = self._get_config()
hash = bcryptor_engine(False).hash_key(secret, config)
assert hash.startswith(config) and len(hash) == len(config)+31
return str_to_uascii(hash[-31:])
def _calc_checksum_builtin(self, secret):
if isinstance(secret, unicode):
secret = secret.encode("utf-8")
if _BNULL in secret:
raise uh.exc.NullPasswordError(self)
chk = _builtin_bcrypt(secret, self.ident.strip("$"),
self.salt.encode("ascii"), self.rounds)
return chk.decode("ascii")
#===================================================================
# eoc
#===================================================================
#=============================================================================
# eof
#=============================================================================
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