add cbc, cfb, ofb support to CAST5 (aka CAST128) for openssl & cc

fixes #393

3 files changed, 70 insertions, 12 deletions

diff --git a/cryptography/hazmat/backends/commoncrypto/backend.py b/cryptography/hazmat/backends/commoncrypto/backend.py
index 523aac82..5c08a356 100644
--- a/cryptography/hazmat/backends/commoncrypto/backend.py
+++ b/cryptography/hazmat/backends/commoncrypto/backend.py
@@ -198,12 +198,18 @@ class Backend(object):
                 mode_cls,
                 mode_const
             )
-        self._register_cipher_adapter(
-            CAST5,
-            self._lib.kCCAlgorithmCAST,
-            ECB,
-            self._lib.kCCModeECB
-        )
+        for mode_cls, mode_const in [
+            (CBC, self._lib.kCCModeCBC),
+            (ECB, self._lib.kCCModeECB),
+            (CFB, self._lib.kCCModeCFB),
+            (OFB, self._lib.kCCModeOFB)
+        ]:
+            self._register_cipher_adapter(
+                CAST5,
+                self._lib.kCCAlgorithmCAST,
+                mode_cls,
+                mode_const
+            )
         self._register_cipher_adapter(
             ARC4,
             self._lib.kCCAlgorithmRC4,
diff --git a/cryptography/hazmat/backends/openssl/backend.py b/cryptography/hazmat/backends/openssl/backend.py
index 0e5e92a5..ef34cb43 100644
--- a/cryptography/hazmat/backends/openssl/backend.py
+++ b/cryptography/hazmat/backends/openssl/backend.py
@@ -153,11 +153,12 @@ class Backend(object):
                 mode_cls,
                 GetCipherByName("bf-{mode.name}")
             )
-        self.register_cipher_adapter(
-            CAST5,
-            ECB,
-            GetCipherByName("cast5-{mode.name}")
-        )
+        for mode_cls in [CBC, CFB, OFB, ECB]:
+            self.register_cipher_adapter(
+                CAST5,
+                mode_cls,
+                GetCipherByName("cast5-{mode.name}")
+            )
         self.register_cipher_adapter(
             ARC4,
             type(None),
diff --git a/tests/hazmat/primitives/test_cast5.py b/tests/hazmat/primitives/test_cast5.py
index d65a86b2..682b4496 100644
--- a/tests/hazmat/primitives/test_cast5.py
+++ b/tests/hazmat/primitives/test_cast5.py
@@ -31,7 +31,7 @@ from ...utils import load_nist_vectors
     skip_message="Does not support CAST5 ECB",
 )
 @pytest.mark.cipher
-class TestCAST5(object):
+class TestCAST5_ECB(object):
     test_ECB = generate_encrypt_test(
         load_nist_vectors,
         os.path.join("ciphers", "CAST5"),
@@ -39,3 +39,54 @@ class TestCAST5(object):
         lambda key, **kwargs: algorithms.CAST5(binascii.unhexlify((key))),
         lambda **kwargs: modes.ECB(),
     )
+
+
+@pytest.mark.supported(
+    only_if=lambda backend: backend.cipher_supported(
+        algorithms.CAST5("\x00" * 16), modes.CBC("\x00" * 8)
+    ),
+    skip_message="Does not support CAST5 CBC",
+)
+@pytest.mark.cipher
+class TestCAST5_CBC(object):
+    test_CBC = generate_encrypt_test(
+        load_nist_vectors,
+        os.path.join("ciphers", "CAST5"),
+        ["cast5-cbc.txt"],
+        lambda key, **kwargs: algorithms.CAST5(binascii.unhexlify((key))),
+        lambda iv, **kwargs: modes.CBC(binascii.unhexlify(iv))
+    )
+
+
+@pytest.mark.supported(
+    only_if=lambda backend: backend.cipher_supported(
+        algorithms.CAST5("\x00" * 16), modes.OFB("\x00" * 8)
+    ),
+    skip_message="Does not support CAST5 OFB",
+)
+@pytest.mark.cipher
+class TestCAST5_OFB(object):
+    test_OFB = generate_encrypt_test(
+        load_nist_vectors,
+        os.path.join("ciphers", "CAST5"),
+        ["cast5-ofb.txt"],
+        lambda key, **kwargs: algorithms.CAST5(binascii.unhexlify((key))),
+        lambda iv, **kwargs: modes.OFB(binascii.unhexlify(iv))
+    )
+
+
+@pytest.mark.supported(
+    only_if=lambda backend: backend.cipher_supported(
+        algorithms.CAST5("\x00" * 16), modes.CFB("\x00" * 8)
+    ),
+    skip_message="Does not support CAST5 CFB",
+)
+@pytest.mark.cipher
+class TestCAST5_CFB(object):
+    test_CFB = generate_encrypt_test(
+        load_nist_vectors,
+        os.path.join("ciphers", "CAST5"),
+        ["cast5-cfb.txt"],
+        lambda key, **kwargs: algorithms.CAST5(binascii.unhexlify((key))),
+        lambda iv, **kwargs: modes.CFB(binascii.unhexlify(iv))
+    )