mirror of http://git.sairate.top/sairate/doc.git
212 lines
6.8 KiB
Python
212 lines
6.8 KiB
Python
# Copyright 2013 Donald Stufft and individual contributors
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from typing import cast
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import nacl.bindings
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import nacl.encoding
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from nacl import exceptions as exc
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from nacl.exceptions import ensure
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_strbytes_plus_one = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_STRBYTES
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AVAILABLE = nacl.bindings.has_crypto_pwhash_scryptsalsa208sha256
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STRPREFIX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_STRPREFIX
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SALTBYTES = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_SALTBYTES
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PASSWD_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_PASSWD_MIN
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PASSWD_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_PASSWD_MAX
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PWHASH_SIZE = _strbytes_plus_one - 1
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BYTES_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_BYTES_MIN
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BYTES_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_BYTES_MAX
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MEMLIMIT_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_MIN
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MEMLIMIT_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_MAX
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OPSLIMIT_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_MIN
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OPSLIMIT_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_MAX
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OPSLIMIT_INTERACTIVE = (
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nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE
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)
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MEMLIMIT_INTERACTIVE = (
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nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE
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)
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OPSLIMIT_SENSITIVE = (
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nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_SENSITIVE
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)
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MEMLIMIT_SENSITIVE = (
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nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_SENSITIVE
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)
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OPSLIMIT_MODERATE = 8 * OPSLIMIT_INTERACTIVE
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MEMLIMIT_MODERATE = 8 * MEMLIMIT_INTERACTIVE
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def kdf(
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size: int,
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password: bytes,
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salt: bytes,
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opslimit: int = OPSLIMIT_SENSITIVE,
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memlimit: int = MEMLIMIT_SENSITIVE,
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encoder: nacl.encoding.Encoder = nacl.encoding.RawEncoder,
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) -> bytes:
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"""
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Derive a ``size`` bytes long key from a caller-supplied
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``password`` and ``salt`` pair using the scryptsalsa208sha256
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memory-hard construct.
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the enclosing module provides the constants
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- :py:const:`.OPSLIMIT_INTERACTIVE`
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- :py:const:`.MEMLIMIT_INTERACTIVE`
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- :py:const:`.OPSLIMIT_SENSITIVE`
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- :py:const:`.MEMLIMIT_SENSITIVE`
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- :py:const:`.OPSLIMIT_MODERATE`
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- :py:const:`.MEMLIMIT_MODERATE`
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as a guidance for correct settings respectively for the
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interactive login and the long term key protecting sensitive data
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use cases.
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:param size: derived key size, must be between
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:py:const:`.BYTES_MIN` and
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:py:const:`.BYTES_MAX`
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:type size: int
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:param password: password used to seed the key derivation procedure;
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it length must be between
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:py:const:`.PASSWD_MIN` and
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:py:const:`.PASSWD_MAX`
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:type password: bytes
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:param salt: **RANDOM** salt used in the key derivation procedure;
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its length must be exactly :py:const:`.SALTBYTES`
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:type salt: bytes
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:param opslimit: the time component (operation count)
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of the key derivation procedure's computational cost;
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it must be between
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:py:const:`.OPSLIMIT_MIN` and
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:py:const:`.OPSLIMIT_MAX`
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:type opslimit: int
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:param memlimit: the memory occupation component
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of the key derivation procedure's computational cost;
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it must be between
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:py:const:`.MEMLIMIT_MIN` and
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:py:const:`.MEMLIMIT_MAX`
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:type memlimit: int
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:rtype: bytes
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:raises nacl.exceptions.UnavailableError: If called when using a
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minimal build of libsodium.
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.. versionadded:: 1.2
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"""
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ensure(
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AVAILABLE,
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"Not available in minimal build",
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raising=exc.UnavailableError,
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)
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ensure(
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len(salt) == SALTBYTES,
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"The salt must be exactly %s, not %s bytes long"
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% (SALTBYTES, len(salt)),
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raising=exc.ValueError,
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)
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n_log2, r, p = nacl.bindings.nacl_bindings_pick_scrypt_params(
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opslimit, memlimit
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)
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maxmem = memlimit + (2 ** 16)
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return encoder.encode(
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nacl.bindings.crypto_pwhash_scryptsalsa208sha256_ll(
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password,
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salt,
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# Cast safety: n_log2 is a positive integer, and so 2 ** n_log2 is also
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# a positive integer. Mypy+typeshed can't deduce this, because there's no
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# way to for them to know that n_log2: int is positive.
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cast(int, 2 ** n_log2),
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r,
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p,
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maxmem=maxmem,
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dklen=size,
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)
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)
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def str(
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password: bytes,
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opslimit: int = OPSLIMIT_INTERACTIVE,
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memlimit: int = MEMLIMIT_INTERACTIVE,
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) -> bytes:
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"""
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Hashes a password with a random salt, using the memory-hard
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scryptsalsa208sha256 construct and returning an ascii string
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that has all the needed info to check against a future password
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The default settings for opslimit and memlimit are those deemed
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correct for the interactive user login case.
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:param bytes password:
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:param int opslimit:
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:param int memlimit:
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:rtype: bytes
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:raises nacl.exceptions.UnavailableError: If called when using a
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minimal build of libsodium.
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.. versionadded:: 1.2
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"""
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ensure(
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AVAILABLE,
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"Not available in minimal build",
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raising=exc.UnavailableError,
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)
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return nacl.bindings.crypto_pwhash_scryptsalsa208sha256_str(
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password, opslimit, memlimit
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)
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def verify(password_hash: bytes, password: bytes) -> bool:
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"""
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Takes the output of scryptsalsa208sha256 and compares it against
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a user provided password to see if they are the same
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:param password_hash: bytes
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:param password: bytes
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:rtype: boolean
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:raises nacl.exceptions.UnavailableError: If called when using a
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minimal build of libsodium.
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.. versionadded:: 1.2
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"""
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ensure(
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AVAILABLE,
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"Not available in minimal build",
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raising=exc.UnavailableError,
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)
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ensure(
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len(password_hash) == PWHASH_SIZE,
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"The password hash must be exactly %s bytes long"
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% nacl.bindings.crypto_pwhash_scryptsalsa208sha256_STRBYTES,
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raising=exc.ValueError,
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)
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return nacl.bindings.crypto_pwhash_scryptsalsa208sha256_str_verify(
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password_hash, password
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)
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