mirror of
https://github.com/PiBrewing/craftbeerpi4.git
synced 2024-11-23 15:38:14 +01:00
77 lines
2.9 KiB
Python
77 lines
2.9 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 (
|
||
|
|
InvalidSignature,
|
||
|
|
UnsupportedAlgorithm,
|
||
|
|
_Reasons,
|
||
|
|
)
|
||
|
|
from cryptography.hazmat.primitives import constant_time, hashes
|
||
|
|
|
||
|
|
|
||
|
|
@utils.register_interface(hashes.HashContext)
|
||
|
|
class _HMACContext(object):
|
||
|
|
def __init__(self, backend, key, algorithm, ctx=None):
|
||
|
|
self._algorithm = algorithm
|
||
|
|
self._backend = backend
|
||
|
|
|
||
|
|
if ctx is None:
|
||
|
|
ctx = self._backend._lib.HMAC_CTX_new()
|
||
|
|
self._backend.openssl_assert(ctx != self._backend._ffi.NULL)
|
||
|
|
ctx = self._backend._ffi.gc(ctx, self._backend._lib.HMAC_CTX_free)
|
||
|
|
evp_md = self._backend._evp_md_from_algorithm(algorithm)
|
||
|
|
if evp_md == self._backend._ffi.NULL:
|
||
|
|
raise UnsupportedAlgorithm(
|
||
|
|
"{} is not a supported hash on this backend".format(
|
||
|
|
algorithm.name
|
||
|
|
),
|
||
|
|
_Reasons.UNSUPPORTED_HASH,
|
||
|
|
)
|
||
|
|
key_ptr = self._backend._ffi.from_buffer(key)
|
||
|
|
res = self._backend._lib.HMAC_Init_ex(
|
||
|
|
ctx, key_ptr, len(key), evp_md, self._backend._ffi.NULL
|
||
|
|
)
|
||
|
|
self._backend.openssl_assert(res != 0)
|
||
|
|
|
||
|
|
self._ctx = ctx
|
||
|
|
self._key = key
|
||
|
|
|
||
|
|
algorithm = utils.read_only_property("_algorithm")
|
||
|
|
|
||
|
|
def copy(self):
|
||
|
|
copied_ctx = self._backend._lib.HMAC_CTX_new()
|
||
|
|
self._backend.openssl_assert(copied_ctx != self._backend._ffi.NULL)
|
||
|
|
copied_ctx = self._backend._ffi.gc(
|
||
|
|
copied_ctx, self._backend._lib.HMAC_CTX_free
|
||
|
|
)
|
||
|
|
res = self._backend._lib.HMAC_CTX_copy(copied_ctx, self._ctx)
|
||
|
|
self._backend.openssl_assert(res != 0)
|
||
|
|
return _HMACContext(
|
||
|
|
self._backend, self._key, self.algorithm, ctx=copied_ctx
|
||
|
|
)
|
||
|
|
|
||
|
|
def update(self, data):
|
||
|
|
data_ptr = self._backend._ffi.from_buffer(data)
|
||
|
|
res = self._backend._lib.HMAC_Update(self._ctx, data_ptr, len(data))
|
||
|
|
self._backend.openssl_assert(res != 0)
|
||
|
|
|
||
|
|
def finalize(self):
|
||
|
|
buf = self._backend._ffi.new(
|
||
|
|
"unsigned char[]", self._backend._lib.EVP_MAX_MD_SIZE
|
||
|
|
)
|
||
|
|
outlen = self._backend._ffi.new("unsigned int *")
|
||
|
|
res = self._backend._lib.HMAC_Final(self._ctx, buf, outlen)
|
||
|
|
self._backend.openssl_assert(res != 0)
|
||
|
|
self._backend.openssl_assert(outlen[0] == self.algorithm.digest_size)
|
||
|
|
return self._backend._ffi.buffer(buf)[: outlen[0]]
|
||
|
|
|
||
|
|
def verify(self, signature):
|
||
|
|
digest = self.finalize()
|
||
|
|
if not constant_time.bytes_eq(digest, signature):
|
||
|
|
raise InvalidSignature("Signature did not match digest.")
|