Get a HashContext from the hmac backend like we do a CipherContext
diff --git a/cryptography/hazmat/bindings/openssl/backend.py b/cryptography/hazmat/bindings/openssl/backend.py
index 1cb886d..60d5130 100644
--- a/cryptography/hazmat/bindings/openssl/backend.py
+++ b/cryptography/hazmat/bindings/openssl/backend.py
@@ -312,44 +312,66 @@
return copied_ctx
+@interfaces.register(interfaces.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.ffi.new("HMAC_CTX *")
+ self._backend.lib.HMAC_CTX_init(ctx)
+ ctx = self._backend.ffi.gc(ctx, self._backend.lib.HMAC_CTX_cleanup)
+ evp_md = self._backend.lib.EVP_get_digestbyname(
+ algorithm.name.encode('ascii'))
+ assert evp_md != self._backend.ffi.NULL
+ res = self._backend.lib.Cryptography_HMAC_Init_ex(
+ ctx, key, len(key), evp_md, self._backend.ffi.NULL
+ )
+ assert res != 0
+
+ self._ctx = ctx
+ self._key = key
+
+ def copy(self):
+ copied_ctx = self._backend.ffi.new("HMAC_CTX *")
+ self._backend.lib.HMAC_CTX_init(copied_ctx)
+ copied_ctx = self._backend.ffi.gc(
+ copied_ctx, self._backend.lib.HMAC_CTX_cleanup
+ )
+ res = self._backend.lib.Cryptography_HMAC_CTX_copy(
+ copied_ctx, self._ctx
+ )
+ assert res != 0
+ return self.__class__(
+ self._backend, self._key, self.algorithm, ctx=copied_ctx
+ )
+
+ def update(self, data):
+ res = self._backend.lib.Cryptography_HMAC_Update(
+ self._ctx, data, len(data)
+ )
+ assert res != 0
+
+ def finalize(self):
+ buf = self._backend.ffi.new("unsigned char[]",
+ self.algorithm.digest_size)
+ buflen = self._backend.ffi.new("unsigned int *",
+ self.algorithm.digest_size)
+ res = self._backend.lib.Cryptography_HMAC_Final(self._ctx, buf, buflen)
+ assert res != 0
+ self._backend.lib.HMAC_CTX_cleanup(self._ctx)
+ return self._backend.ffi.buffer(buf)[:self.algorithm.digest_size]
+
+
class HMACs(object):
def __init__(self, backend):
super(HMACs, self).__init__()
self._backend = backend
- def create_ctx(self, key, hash_cls):
- ctx = self._backend.ffi.new("HMAC_CTX *")
- self._backend.lib.HMAC_CTX_init(ctx)
- ctx = self._backend.ffi.gc(ctx, self._backend.lib.HMAC_CTX_cleanup)
- evp_md = self._backend.lib.EVP_get_digestbyname(
- hash_cls.name.encode('ascii'))
- assert evp_md != self._backend.ffi.NULL
- res = self._backend.lib.Cryptography_HMAC_Init_ex(
- ctx, key, len(key), evp_md, self._backend.ffi.NULL
- )
- assert res != 0
- return ctx
-
- def update_ctx(self, ctx, data):
- res = self._backend.lib.Cryptography_HMAC_Update(ctx, data, len(data))
- assert res != 0
-
- def finalize_ctx(self, ctx, digest_size):
- buf = self._backend.ffi.new("unsigned char[]", digest_size)
- buflen = self._backend.ffi.new("unsigned int *", digest_size)
- res = self._backend.lib.Cryptography_HMAC_Final(ctx, buf, buflen)
- assert res != 0
- self._backend.lib.HMAC_CTX_cleanup(ctx)
- return self._backend.ffi.buffer(buf)[:digest_size]
-
- def copy_ctx(self, ctx):
- copied_ctx = self._backend.ffi.new("HMAC_CTX *")
- self._backend.lib.HMAC_CTX_init(copied_ctx)
- copied_ctx = self._backend.ffi.gc(copied_ctx,
- self._backend.lib.HMAC_CTX_cleanup)
- res = self._backend.lib.Cryptography_HMAC_CTX_copy(copied_ctx, ctx)
- assert res != 0
- return copied_ctx
+ def create_ctx(self, key, algorithm):
+ return _HMACContext(self._backend, key, algorithm)
backend = Backend()
diff --git a/cryptography/hazmat/primitives/hmac.py b/cryptography/hazmat/primitives/hmac.py
index 1457ed7..27bc0fe 100644
--- a/cryptography/hazmat/primitives/hmac.py
+++ b/cryptography/hazmat/primitives/hmac.py
@@ -40,12 +40,13 @@
def update(self, msg):
if isinstance(msg, six.text_type):
raise TypeError("Unicode-objects must be encoded before hashing")
- self._backend.hmacs.update_ctx(self._ctx, msg)
+ self._ctx.update(msg)
def copy(self):
- return self.__class__(self._key, self.algorithm, backend=self._backend,
- ctx=self._backend.hmacs.copy_ctx(self._ctx))
+ return self.__class__(
+ self._key, self.algorithm, ctx=self._ctx.copy(),
+ backend=self._backend
+ )
def finalize(self):
- return self._backend.hmacs.finalize_ctx(self._ctx,
- self.algorithm.digest_size)
+ return self._ctx.finalize()
diff --git a/tests/hazmat/primitives/test_hmac.py b/tests/hazmat/primitives/test_hmac.py
index a44838c..0f627a1 100644
--- a/tests/hazmat/primitives/test_hmac.py
+++ b/tests/hazmat/primitives/test_hmac.py
@@ -37,9 +37,10 @@
h.update(six.u("\u00FC"))
def test_copy_backend_object(self):
- pretend_hmac = pretend.stub(copy_ctx=lambda a: True)
+ pretend_hmac = pretend.stub()
pretend_backend = pretend.stub(hmacs=pretend_hmac)
- pretend_ctx = pretend.stub()
+ copied_ctx = pretend.stub()
+ pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
h = hmac.HMAC(b"key", hashes.SHA1(), backend=pretend_backend,
ctx=pretend_ctx)
assert h._backend is pretend_backend