mirror of
https://github.com/PiBrewing/craftbeerpi4.git
synced 2024-11-26 08:55:28 +01:00
231 lines
8.4 KiB
Python
231 lines
8.4 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
|
|
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
|
|
# for complete details.
|
|
|
|
from __future__ import absolute_import, division, print_function
|
|
|
|
from cryptography import utils
|
|
from cryptography.exceptions import InvalidTag, UnsupportedAlgorithm, _Reasons
|
|
from cryptography.hazmat.primitives import ciphers
|
|
from cryptography.hazmat.primitives.ciphers import modes
|
|
|
|
|
|
@utils.register_interface(ciphers.CipherContext)
|
|
@utils.register_interface(ciphers.AEADCipherContext)
|
|
@utils.register_interface(ciphers.AEADEncryptionContext)
|
|
@utils.register_interface(ciphers.AEADDecryptionContext)
|
|
class _CipherContext(object):
|
|
_ENCRYPT = 1
|
|
_DECRYPT = 0
|
|
_MAX_CHUNK_SIZE = 2 ** 30 - 1
|
|
|
|
def __init__(self, backend, cipher, mode, operation):
|
|
self._backend = backend
|
|
self._cipher = cipher
|
|
self._mode = mode
|
|
self._operation = operation
|
|
self._tag = None
|
|
|
|
if isinstance(self._cipher, ciphers.BlockCipherAlgorithm):
|
|
self._block_size_bytes = self._cipher.block_size // 8
|
|
else:
|
|
self._block_size_bytes = 1
|
|
|
|
ctx = self._backend._lib.EVP_CIPHER_CTX_new()
|
|
ctx = self._backend._ffi.gc(
|
|
ctx, self._backend._lib.EVP_CIPHER_CTX_free
|
|
)
|
|
|
|
registry = self._backend._cipher_registry
|
|
try:
|
|
adapter = registry[type(cipher), type(mode)]
|
|
except KeyError:
|
|
raise UnsupportedAlgorithm(
|
|
"cipher {} in {} mode is not supported "
|
|
"by this backend.".format(
|
|
cipher.name, mode.name if mode else mode
|
|
),
|
|
_Reasons.UNSUPPORTED_CIPHER,
|
|
)
|
|
|
|
evp_cipher = adapter(self._backend, cipher, mode)
|
|
if evp_cipher == self._backend._ffi.NULL:
|
|
msg = "cipher {0.name} ".format(cipher)
|
|
if mode is not None:
|
|
msg += "in {0.name} mode ".format(mode)
|
|
msg += (
|
|
"is not supported by this backend (Your version of OpenSSL "
|
|
"may be too old. Current version: {}.)"
|
|
).format(self._backend.openssl_version_text())
|
|
raise UnsupportedAlgorithm(msg, _Reasons.UNSUPPORTED_CIPHER)
|
|
|
|
if isinstance(mode, modes.ModeWithInitializationVector):
|
|
iv_nonce = self._backend._ffi.from_buffer(
|
|
mode.initialization_vector
|
|
)
|
|
elif isinstance(mode, modes.ModeWithTweak):
|
|
iv_nonce = self._backend._ffi.from_buffer(mode.tweak)
|
|
elif isinstance(mode, modes.ModeWithNonce):
|
|
iv_nonce = self._backend._ffi.from_buffer(mode.nonce)
|
|
elif isinstance(cipher, modes.ModeWithNonce):
|
|
iv_nonce = self._backend._ffi.from_buffer(cipher.nonce)
|
|
else:
|
|
iv_nonce = self._backend._ffi.NULL
|
|
# begin init with cipher and operation type
|
|
res = self._backend._lib.EVP_CipherInit_ex(
|
|
ctx,
|
|
evp_cipher,
|
|
self._backend._ffi.NULL,
|
|
self._backend._ffi.NULL,
|
|
self._backend._ffi.NULL,
|
|
operation,
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
# set the key length to handle variable key ciphers
|
|
res = self._backend._lib.EVP_CIPHER_CTX_set_key_length(
|
|
ctx, len(cipher.key)
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
if isinstance(mode, modes.GCM):
|
|
res = self._backend._lib.EVP_CIPHER_CTX_ctrl(
|
|
ctx,
|
|
self._backend._lib.EVP_CTRL_AEAD_SET_IVLEN,
|
|
len(iv_nonce),
|
|
self._backend._ffi.NULL,
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
if mode.tag is not None:
|
|
res = self._backend._lib.EVP_CIPHER_CTX_ctrl(
|
|
ctx,
|
|
self._backend._lib.EVP_CTRL_AEAD_SET_TAG,
|
|
len(mode.tag),
|
|
mode.tag,
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
self._tag = mode.tag
|
|
|
|
# pass key/iv
|
|
res = self._backend._lib.EVP_CipherInit_ex(
|
|
ctx,
|
|
self._backend._ffi.NULL,
|
|
self._backend._ffi.NULL,
|
|
self._backend._ffi.from_buffer(cipher.key),
|
|
iv_nonce,
|
|
operation,
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
# We purposely disable padding here as it's handled higher up in the
|
|
# API.
|
|
self._backend._lib.EVP_CIPHER_CTX_set_padding(ctx, 0)
|
|
self._ctx = ctx
|
|
|
|
def update(self, data):
|
|
buf = bytearray(len(data) + self._block_size_bytes - 1)
|
|
n = self.update_into(data, buf)
|
|
return bytes(buf[:n])
|
|
|
|
def update_into(self, data, buf):
|
|
total_data_len = len(data)
|
|
if len(buf) < (total_data_len + self._block_size_bytes - 1):
|
|
raise ValueError(
|
|
"buffer must be at least {} bytes for this "
|
|
"payload".format(len(data) + self._block_size_bytes - 1)
|
|
)
|
|
|
|
data_processed = 0
|
|
total_out = 0
|
|
outlen = self._backend._ffi.new("int *")
|
|
baseoutbuf = self._backend._ffi.from_buffer(buf)
|
|
baseinbuf = self._backend._ffi.from_buffer(data)
|
|
|
|
while data_processed != total_data_len:
|
|
outbuf = baseoutbuf + total_out
|
|
inbuf = baseinbuf + data_processed
|
|
inlen = min(self._MAX_CHUNK_SIZE, total_data_len - data_processed)
|
|
|
|
res = self._backend._lib.EVP_CipherUpdate(
|
|
self._ctx, outbuf, outlen, inbuf, inlen
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
data_processed += inlen
|
|
total_out += outlen[0]
|
|
|
|
return total_out
|
|
|
|
def finalize(self):
|
|
if (
|
|
self._operation == self._DECRYPT
|
|
and isinstance(self._mode, modes.ModeWithAuthenticationTag)
|
|
and self.tag is None
|
|
):
|
|
raise ValueError(
|
|
"Authentication tag must be provided when decrypting."
|
|
)
|
|
|
|
buf = self._backend._ffi.new("unsigned char[]", self._block_size_bytes)
|
|
outlen = self._backend._ffi.new("int *")
|
|
res = self._backend._lib.EVP_CipherFinal_ex(self._ctx, buf, outlen)
|
|
if res == 0:
|
|
errors = self._backend._consume_errors()
|
|
|
|
if not errors and isinstance(self._mode, modes.GCM):
|
|
raise InvalidTag
|
|
|
|
self._backend.openssl_assert(
|
|
errors[0]._lib_reason_match(
|
|
self._backend._lib.ERR_LIB_EVP,
|
|
self._backend._lib.EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH,
|
|
),
|
|
errors=errors,
|
|
)
|
|
raise ValueError(
|
|
"The length of the provided data is not a multiple of "
|
|
"the block length."
|
|
)
|
|
|
|
if (
|
|
isinstance(self._mode, modes.GCM)
|
|
and self._operation == self._ENCRYPT
|
|
):
|
|
tag_buf = self._backend._ffi.new(
|
|
"unsigned char[]", self._block_size_bytes
|
|
)
|
|
res = self._backend._lib.EVP_CIPHER_CTX_ctrl(
|
|
self._ctx,
|
|
self._backend._lib.EVP_CTRL_AEAD_GET_TAG,
|
|
self._block_size_bytes,
|
|
tag_buf,
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
self._tag = self._backend._ffi.buffer(tag_buf)[:]
|
|
|
|
res = self._backend._lib.EVP_CIPHER_CTX_cleanup(self._ctx)
|
|
self._backend.openssl_assert(res == 1)
|
|
return self._backend._ffi.buffer(buf)[: outlen[0]]
|
|
|
|
def finalize_with_tag(self, tag):
|
|
if len(tag) < self._mode._min_tag_length:
|
|
raise ValueError(
|
|
"Authentication tag must be {} bytes or longer.".format(
|
|
self._mode._min_tag_length
|
|
)
|
|
)
|
|
res = self._backend._lib.EVP_CIPHER_CTX_ctrl(
|
|
self._ctx, self._backend._lib.EVP_CTRL_AEAD_SET_TAG, len(tag), tag
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
self._tag = tag
|
|
return self.finalize()
|
|
|
|
def authenticate_additional_data(self, data):
|
|
outlen = self._backend._ffi.new("int *")
|
|
res = self._backend._lib.EVP_CipherUpdate(
|
|
self._ctx,
|
|
self._backend._ffi.NULL,
|
|
outlen,
|
|
self._backend._ffi.from_buffer(data),
|
|
len(data),
|
|
)
|
|
self._backend.openssl_assert(res != 0)
|
|
|
|
tag = utils.read_only_property("_tag")
|