refactor rsa signature/verification logic to remove duplication (#3903)
diff --git a/src/cryptography/hazmat/backends/openssl/rsa.py b/src/cryptography/hazmat/backends/openssl/rsa.py
index 05b4e9d..1b6ebfd 100644
--- a/src/cryptography/hazmat/backends/openssl/rsa.py
+++ b/src/cryptography/hazmat/backends/openssl/rsa.py
@@ -187,47 +187,40 @@
return padding_enum
-def _rsa_sig_sign(backend, padding, padding_enum, algorithm, private_key,
- data):
- evp_md = backend._lib.EVP_get_digestbyname(
- algorithm.name.encode("ascii"))
+def _rsa_sig_setup(backend, padding, algorithm, key, data, init_func):
+ padding_enum = _rsa_sig_determine_padding(backend, key, padding, algorithm)
+ evp_md = backend._lib.EVP_get_digestbyname(algorithm.name.encode("ascii"))
backend.openssl_assert(evp_md != backend._ffi.NULL)
-
- pkey_ctx = backend._lib.EVP_PKEY_CTX_new(
- private_key._evp_pkey, backend._ffi.NULL
- )
+ pkey_ctx = backend._lib.EVP_PKEY_CTX_new(key._evp_pkey, backend._ffi.NULL)
backend.openssl_assert(pkey_ctx != backend._ffi.NULL)
pkey_ctx = backend._ffi.gc(pkey_ctx, backend._lib.EVP_PKEY_CTX_free)
- res = backend._lib.EVP_PKEY_sign_init(pkey_ctx)
+ res = init_func(pkey_ctx)
backend.openssl_assert(res == 1)
- res = backend._lib.EVP_PKEY_CTX_set_signature_md(
- pkey_ctx, evp_md)
+ res = backend._lib.EVP_PKEY_CTX_set_signature_md(pkey_ctx, evp_md)
backend.openssl_assert(res > 0)
-
- res = backend._lib.EVP_PKEY_CTX_set_rsa_padding(
- pkey_ctx, padding_enum)
+ res = backend._lib.EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, padding_enum)
backend.openssl_assert(res > 0)
if isinstance(padding, PSS):
res = backend._lib.EVP_PKEY_CTX_set_rsa_pss_saltlen(
- pkey_ctx,
- _get_rsa_pss_salt_length(
- padding,
- private_key,
- algorithm,
- )
+ pkey_ctx, _get_rsa_pss_salt_length(padding, key, algorithm)
)
backend.openssl_assert(res > 0)
mgf1_md = backend._lib.EVP_get_digestbyname(
- padding._mgf._algorithm.name.encode("ascii"))
- backend.openssl_assert(
- mgf1_md != backend._ffi.NULL
+ padding._mgf._algorithm.name.encode("ascii")
)
- res = backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md(
- pkey_ctx, mgf1_md
- )
+ backend.openssl_assert(mgf1_md != backend._ffi.NULL)
+ res = backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1_md)
backend.openssl_assert(res > 0)
+ return pkey_ctx
+
+
+def _rsa_sig_sign(backend, padding, algorithm, private_key, data):
+ pkey_ctx = _rsa_sig_setup(
+ backend, padding, algorithm, private_key, data,
+ backend._lib.EVP_PKEY_sign_init
+ )
buflen = backend._ffi.new("size_t *")
res = backend._lib.EVP_PKEY_sign(
pkey_ctx,
@@ -258,52 +251,13 @@
return backend._ffi.buffer(buf)[:]
-def _rsa_sig_verify(backend, padding, padding_enum, algorithm, public_key,
- signature, data):
- evp_md = backend._lib.EVP_get_digestbyname(
- algorithm.name.encode("ascii"))
- backend.openssl_assert(evp_md != backend._ffi.NULL)
-
- pkey_ctx = backend._lib.EVP_PKEY_CTX_new(
- public_key._evp_pkey, backend._ffi.NULL
+def _rsa_sig_verify(backend, padding, algorithm, public_key, signature, data):
+ pkey_ctx = _rsa_sig_setup(
+ backend, padding, algorithm, public_key, data,
+ backend._lib.EVP_PKEY_verify_init
)
- backend.openssl_assert(pkey_ctx != backend._ffi.NULL)
- pkey_ctx = backend._ffi.gc(pkey_ctx, backend._lib.EVP_PKEY_CTX_free)
- res = backend._lib.EVP_PKEY_verify_init(pkey_ctx)
- backend.openssl_assert(res == 1)
- res = backend._lib.EVP_PKEY_CTX_set_signature_md(
- pkey_ctx, evp_md)
- backend.openssl_assert(res > 0)
-
- res = backend._lib.EVP_PKEY_CTX_set_rsa_padding(
- pkey_ctx, padding_enum)
- backend.openssl_assert(res > 0)
- if isinstance(padding, PSS):
- res = backend._lib.EVP_PKEY_CTX_set_rsa_pss_saltlen(
- pkey_ctx,
- _get_rsa_pss_salt_length(
- padding,
- public_key,
- algorithm,
- )
- )
- backend.openssl_assert(res > 0)
- mgf1_md = backend._lib.EVP_get_digestbyname(
- padding._mgf._algorithm.name.encode("ascii"))
- backend.openssl_assert(
- mgf1_md != backend._ffi.NULL
- )
- res = backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md(
- pkey_ctx, mgf1_md
- )
- backend.openssl_assert(res > 0)
-
res = backend._lib.EVP_PKEY_verify(
- pkey_ctx,
- signature,
- len(signature),
- data,
- len(data)
+ pkey_ctx, signature, len(signature), data, len(data)
)
# The previous call can return negative numbers in the event of an
# error. This is not a signature failure but we need to fail if it
@@ -321,9 +275,10 @@
self._backend = backend
self._private_key = private_key
- self._padding_enum = _rsa_sig_determine_padding(
- backend, private_key, padding, algorithm
- )
+ # We now call _rsa_sig_determine_padding in _rsa_sig_setup. However
+ # we need to make a pointless call to it here so we maintain the
+ # API of erroring on init with this context if the values are invalid.
+ _rsa_sig_determine_padding(backend, private_key, padding, algorithm)
self._padding = padding
self._algorithm = algorithm
self._hash_ctx = hashes.Hash(self._algorithm, self._backend)
@@ -335,7 +290,6 @@
return _rsa_sig_sign(
self._backend,
self._padding,
- self._padding_enum,
self._algorithm,
self._private_key,
self._hash_ctx.finalize()
@@ -349,10 +303,10 @@
self._public_key = public_key
self._signature = signature
self._padding = padding
-
- self._padding_enum = _rsa_sig_determine_padding(
- backend, public_key, padding, algorithm
- )
+ # We now call _rsa_sig_determine_padding in _rsa_sig_setup. However
+ # we need to make a pointless call to it here so we maintain the
+ # API of erroring on init with this context if the values are invalid.
+ _rsa_sig_determine_padding(backend, public_key, padding, algorithm)
padding = padding
self._algorithm = algorithm
@@ -365,7 +319,6 @@
return _rsa_sig_verify(
self._backend,
self._padding,
- self._padding_enum,
self._algorithm,
self._public_key,
self._signature,
@@ -456,16 +409,10 @@
)
def sign(self, data, padding, algorithm):
- padding_enum = _rsa_sig_determine_padding(
- self._backend, self, padding, algorithm
- )
data, algorithm = _calculate_digest_and_algorithm(
self._backend, data, algorithm
)
- return _rsa_sig_sign(
- self._backend, padding, padding_enum,
- algorithm, self, data
- )
+ return _rsa_sig_sign(self._backend, padding, algorithm, self, data)
@utils.register_interface(RSAPublicKeyWithSerialization)
@@ -521,13 +468,9 @@
)
def verify(self, signature, data, padding, algorithm):
- padding_enum = _rsa_sig_determine_padding(
- self._backend, self, padding, algorithm
- )
data, algorithm = _calculate_digest_and_algorithm(
self._backend, data, algorithm
)
return _rsa_sig_verify(
- self._backend, padding, padding_enum, algorithm, self,
- signature, data
+ self._backend, padding, algorithm, self, signature, data
)