Refactor how cipher names are computed
diff --git a/cryptography/bindings/openssl/api.py b/cryptography/bindings/openssl/api.py
index f1a2c08..ced2cf8 100644
--- a/cryptography/bindings/openssl/api.py
+++ b/cryptography/bindings/openssl/api.py
@@ -13,11 +13,23 @@
from __future__ import absolute_import, division, print_function
+import itertools
import sys
import cffi
from cryptography.primitives import interfaces
+from cryptography.primitives.block.ciphers import AES, Camellia
+from cryptography.primitives.block.modes import CBC, ECB, OFB, CFB
+
+
+class GetCipherByName(object):
+ def __init__(self, fmt):
+ self._fmt = fmt
+
+ def __call__(self, api, cipher, mode):
+ cipher_name = self._fmt.format(cipher=cipher, mode=mode).lower()
+ return api.lib.EVP_get_cipherbyname(cipher_name)
class API(object):
@@ -78,6 +90,9 @@
self.lib.OpenSSL_add_all_algorithms()
self.lib.SSL_load_error_strings()
+ self._cipher_registry = {}
+ self._register_default_ciphers()
+
def openssl_version_text(self):
"""
Friendly string name of linked OpenSSL.
@@ -86,20 +101,41 @@
"""
return self.ffi.string(self.lib.OPENSSL_VERSION_TEXT).decode("ascii")
- def supports_cipher(self, ciphername):
- return (self.ffi.NULL !=
- self.lib.EVP_get_cipherbyname(ciphername.encode("ascii")))
+ def supports_cipher(self, cipher, mode):
+ try:
+ adapter = self._cipher_registry[type(cipher), type(mode)]
+ except KeyError:
+ return False
+ evp_cipher = adapter(self, cipher, mode)
+ return self.ffi.NULL != evp_cipher
+
+ def register_cipher_adapter(self, cipher_cls, mode_cls, adapter):
+ if (cipher_cls, mode_cls) in self._cipher_registry:
+ raise ValueError("Duplicate registration for: {0} {1}".format(
+ cipher_cls, mode_cls)
+ )
+ self._cipher_registry[cipher_cls, mode_cls] = adapter
+
+ def _register_default_ciphers(self):
+ for cipher_cls, mode_cls in itertools.product(
+ [AES, Camellia],
+ [CBC, ECB, OFB, CFB],
+ ):
+ self.register_cipher_adapter(
+ cipher_cls,
+ mode_cls,
+ GetCipherByName("{cipher.name}-{cipher.key_size}-{mode.name}")
+ )
def create_block_cipher_context(self, cipher, mode):
ctx = self.ffi.new("EVP_CIPHER_CTX *")
res = self.lib.EVP_CIPHER_CTX_init(ctx)
assert res != 0
ctx = self.ffi.gc(ctx, self.lib.EVP_CIPHER_CTX_cleanup)
- # TODO: compute name using a better algorithm
- ciphername = "{0}-{1}-{2}".format(
- cipher.name, cipher.key_size, mode.name
- ).lower()
- evp_cipher = self.lib.EVP_get_cipherbyname(ciphername.encode("ascii"))
+ evp_cipher = self._cipher_registry[type(cipher), type(mode)](
+ self, cipher, mode
+ )
+
assert evp_cipher != self.ffi.NULL
if isinstance(mode, interfaces.ModeWithInitializationVector):
iv_nonce = mode.initialization_vector
diff --git a/cryptography/primitives/block/base.py b/cryptography/primitives/block/base.py
index b84ca9c..cb68361 100644
--- a/cryptography/primitives/block/base.py
+++ b/cryptography/primitives/block/base.py
@@ -15,8 +15,6 @@
from enum import Enum
-from cryptography.bindings import _default_api
-
class _Operation(Enum):
encrypt = 0
@@ -28,7 +26,7 @@
super(BlockCipher, self).__init__()
if api is None:
- api = _default_api
+ from cryptography.bindings import _default_api as api
self.cipher = cipher
self.mode = mode
diff --git a/tests/bindings/test_openssl.py b/tests/bindings/test_openssl.py
index e5b78d1..2d51330 100644
--- a/tests/bindings/test_openssl.py
+++ b/tests/bindings/test_openssl.py
@@ -30,4 +30,4 @@
assert api.openssl_version_text().startswith("OpenSSL")
def test_supports_cipher(self):
- assert api.supports_cipher("not-a-real-cipher") is False
+ assert api.supports_cipher(None, None) is False
diff --git a/tests/primitives/test_cryptrec.py b/tests/primitives/test_cryptrec.py
index edf9765..56eca3a 100644
--- a/tests/primitives/test_cryptrec.py
+++ b/tests/primitives/test_cryptrec.py
@@ -37,6 +37,6 @@
],
lambda key: ciphers.Camellia(binascii.unhexlify((key))),
lambda key: modes.ECB(),
- only_if=lambda api: api.supports_cipher("camellia-128-ecb"),
+ only_if=lambda api: api.supports_cipher(ciphers.Camellia("\x00" * 16), modes.ECB()),
skip_message="Does not support Camellia ECB",
)
diff --git a/tests/primitives/test_openssl_vectors.py b/tests/primitives/test_openssl_vectors.py
index 6e32eca..f53ade8 100644
--- a/tests/primitives/test_openssl_vectors.py
+++ b/tests/primitives/test_openssl_vectors.py
@@ -32,7 +32,7 @@
["camellia-cbc.txt"],
lambda key, iv: ciphers.Camellia(binascii.unhexlify(key)),
lambda key, iv: modes.CBC(binascii.unhexlify(iv)),
- only_if=lambda api: api.supports_cipher("camellia-128-cbc"),
+ only_if=lambda api: api.supports_cipher(ciphers.Camellia("\x00" * 16), modes.CBC("\x00" * 16)),
skip_message="Does not support Camellia CBC",
)
@@ -44,7 +44,7 @@
["camellia-ofb.txt"],
lambda key, iv: ciphers.Camellia(binascii.unhexlify(key)),
lambda key, iv: modes.OFB(binascii.unhexlify(iv)),
- only_if=lambda api: api.supports_cipher("camellia-128-ofb"),
+ only_if=lambda api: api.supports_cipher(ciphers.Camellia("\x00" * 16), modes.OFB("\x00" * 16)),
skip_message="Does not support Camellia OFB",
)
@@ -56,6 +56,6 @@
["camellia-cfb.txt"],
lambda key, iv: ciphers.Camellia(binascii.unhexlify(key)),
lambda key, iv: modes.CFB(binascii.unhexlify(iv)),
- only_if=lambda api: api.supports_cipher("camellia-128-cfb"),
+ only_if=lambda api: api.supports_cipher(ciphers.Camellia("\x00" * 16), modes.CFB("\x00" * 16)),
skip_message="Does not support Camellia CFB",
)