Merge pull request #1043 from reaperhulk/support-some-cfb8

add CFB8 support for AES/3DES on CommonCrypto and OpenSSL backends

3 files changed, 29 insertions, 9 deletions

diff --git a/cryptography/hazmat/backends/commoncrypto/backend.py b/cryptography/hazmat/backends/commoncrypto/backend.py
index 4faca73e..91c0721d 100644
--- a/cryptography/hazmat/backends/commoncrypto/backend.py
+++ b/cryptography/hazmat/backends/commoncrypto/backend.py
@@ -28,7 +28,7 @@ from cryptography.hazmat.primitives.ciphers.algorithms import (
     AES, ARC4, Blowfish, CAST5, TripleDES
 )
 from cryptography.hazmat.primitives.ciphers.modes import (
-    CBC, CFB, CTR, ECB, GCM, OFB
+    CBC, CFB, CFB8, CTR, ECB, GCM, OFB
 )
 
 
@@ -165,6 +165,7 @@ class Backend(object):
             (CBC, self._lib.kCCModeCBC),
             (ECB, self._lib.kCCModeECB),
             (CFB, self._lib.kCCModeCFB),
+            (CFB8, self._lib.kCCModeCFB8),
             (OFB, self._lib.kCCModeOFB),
             (CTR, self._lib.kCCModeCTR),
             (GCM, self._lib.kCCModeGCM),
@@ -178,6 +179,7 @@ class Backend(object):
         for mode_cls, mode_const in [
             (CBC, self._lib.kCCModeCBC),
             (CFB, self._lib.kCCModeCFB),
+            (CFB8, self._lib.kCCModeCFB8),
             (OFB, self._lib.kCCModeOFB),
         ]:
             self._register_cipher_adapter(
@@ -264,7 +266,7 @@ class _CipherContext(object):
         # This bug has been filed as rdar://15589470
         self._bytes_processed = 0
         if (isinstance(cipher, interfaces.BlockCipherAlgorithm) and not
-                isinstance(mode, (OFB, CFB, CTR))):
+                isinstance(mode, (OFB, CFB, CFB8, CTR))):
             self._byte_block_size = cipher.block_size // 8
         else:
             self._byte_block_size = 1
diff --git a/cryptography/hazmat/backends/openssl/backend.py b/cryptography/hazmat/backends/openssl/backend.py
index e00be92f..af8fc751 100644
--- a/cryptography/hazmat/backends/openssl/backend.py
+++ b/cryptography/hazmat/backends/openssl/backend.py
@@ -38,7 +38,7 @@ from cryptography.hazmat.primitives.ciphers.algorithms import (
     AES, ARC4, Blowfish, CAST5, Camellia, IDEA, SEED, TripleDES
 )
 from cryptography.hazmat.primitives.ciphers.modes import (
-    CBC, CFB, CTR, ECB, GCM, OFB
+    CBC, CFB, CFB8, CTR, ECB, GCM, OFB
 )
 
 
@@ -147,16 +147,19 @@ class Backend(object):
         self._cipher_registry[cipher_cls, mode_cls] = adapter
 
     def _register_default_ciphers(self):
-        for cipher_cls, mode_cls in itertools.product(
-            [AES, Camellia],
-            [CBC, CTR, ECB, OFB, CFB],
-        ):
+        for mode_cls in [CBC, CTR, ECB, OFB, CFB, CFB8]:
             self.register_cipher_adapter(
-                cipher_cls,
+                AES,
+                mode_cls,
+                GetCipherByName("{cipher.name}-{cipher.key_size}-{mode.name}")
+            )
+        for mode_cls in [CBC, CTR, ECB, OFB, CFB]:
+            self.register_cipher_adapter(
+                Camellia,
                 mode_cls,
                 GetCipherByName("{cipher.name}-{cipher.key_size}-{mode.name}")
             )
-        for mode_cls in [CBC, CFB, OFB]:
+        for mode_cls in [CBC, CFB, CFB8, OFB]:
             self.register_cipher_adapter(
                 TripleDES,
                 mode_cls,
diff --git a/cryptography/hazmat/primitives/ciphers/modes.py b/cryptography/hazmat/primitives/ciphers/modes.py
index 739f23dd..004a68bf 100644
--- a/cryptography/hazmat/primitives/ciphers/modes.py
+++ b/cryptography/hazmat/primitives/ciphers/modes.py
@@ -71,6 +71,21 @@ class CFB(object):
 
 
 @utils.register_interface(interfaces.Mode)
+@utils.register_interface(interfaces.ModeWithInitializationVector)
+class CFB8(object):
+    name = "CFB8"
+
+    def __init__(self, initialization_vector):
+        self.initialization_vector = initialization_vector
+
+    def validate_for_algorithm(self, algorithm):
+        if len(self.initialization_vector) * 8 != algorithm.block_size:
+            raise ValueError("Invalid iv size ({0}) for {1}".format(
+                len(self.initialization_vector), self.name
+            ))
+
+
+@utils.register_interface(interfaces.Mode)
 @utils.register_interface(interfaces.ModeWithNonce)
 class CTR(object):
     name = "CTR"