diff options
| -rw-r--r-- | src/cryptography/hazmat/backends/openssl/rsa.py | 171 |
1 files changed, 73 insertions, 98 deletions
diff --git a/src/cryptography/hazmat/backends/openssl/rsa.py b/src/cryptography/hazmat/backends/openssl/rsa.py index 4c554be6..8bb85783 100644 --- a/src/cryptography/hazmat/backends/openssl/rsa.py +++ b/src/cryptography/hazmat/backends/openssl/rsa.py @@ -139,11 +139,11 @@ def _handle_rsa_enc_dec_error(backend, key): raise ValueError("Decryption failed.") -def _rsa_sig_determine_padding(backend, private_key, padding, algorithm): +def _rsa_sig_determine_padding(backend, key, padding, algorithm): if not isinstance(padding, AsymmetricPadding): raise TypeError("Expected provider of AsymmetricPadding.") - pkey_size = backend._lib.EVP_PKEY_size(private_key._evp_pkey) + pkey_size = backend._lib.EVP_PKEY_size(key._evp_pkey) backend.openssl_assert(pkey_size > 0) if isinstance(padding, PKCS1v15): @@ -159,7 +159,7 @@ def _rsa_sig_determine_padding(backend, private_key, padding, algorithm): # PSS signature length (salt length is checked later) if pkey_size - algorithm.digest_size - 2 < 0: raise ValueError("Digest too large for key size. Use a larger " - "key.") + "key or different digest.") if not backend._pss_mgf1_hash_supported(padding._mgf._algorithm): raise UnsupportedAlgorithm( @@ -251,6 +251,65 @@ def _rsa_sig_sign(backend, padding, padding_enum, algorithm, private_key, 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 + ) + 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) + if backend._lib.Cryptography_HAS_MGF1_MD: + # MGF1 MD is configurable in OpenSSL 1.0.1+ + 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) + ) + # 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 + # occurs. + backend.openssl_assert(res >= 0) + if res == 0: + errors = backend._consume_errors() + assert errors + raise InvalidSignature + + @utils.register_interface(AsymmetricSignatureContext) class _RSASignatureContext(object): def __init__(self, backend, private_key, padding, algorithm): @@ -284,49 +343,13 @@ class _RSAVerificationContext(object): self._backend = backend self._public_key = public_key self._signature = signature + self._padding = padding - if not isinstance(padding, AsymmetricPadding): - raise TypeError("Expected provider of AsymmetricPadding.") - - self._pkey_size = self._backend._lib.EVP_PKEY_size( - self._public_key._evp_pkey + self._padding_enum = _rsa_sig_determine_padding( + backend, public_key, padding, algorithm ) - self._backend.openssl_assert(self._pkey_size > 0) - - if isinstance(padding, PKCS1v15): - self._padding_enum = self._backend._lib.RSA_PKCS1_PADDING - elif isinstance(padding, PSS): - if not isinstance(padding._mgf, MGF1): - raise UnsupportedAlgorithm( - "Only MGF1 is supported by this backend.", - _Reasons.UNSUPPORTED_MGF - ) - - # Size of key in bytes - 2 is the maximum - # PSS signature length (salt length is checked later) - if self._pkey_size - algorithm.digest_size - 2 < 0: - raise ValueError( - "Digest too large for key size. Check that you have the " - "correct key and digest algorithm." - ) - - if not self._backend._pss_mgf1_hash_supported( - padding._mgf._algorithm - ): - raise UnsupportedAlgorithm( - "When OpenSSL is older than 1.0.1 then only SHA1 is " - "supported with MGF1.", - _Reasons.UNSUPPORTED_HASH - ) - - self._padding_enum = self._backend._lib.RSA_PKCS1_PSS_PADDING - else: - raise UnsupportedAlgorithm( - "{0} is not supported by this backend.".format(padding.name), - _Reasons.UNSUPPORTED_PADDING - ) - self._padding = padding + padding = padding self._algorithm = algorithm self._hash_ctx = hashes.Hash(self._algorithm, self._backend) @@ -334,63 +357,15 @@ class _RSAVerificationContext(object): self._hash_ctx.update(data) def verify(self): - evp_md = self._backend._lib.EVP_get_digestbyname( - self._algorithm.name.encode("ascii")) - self._backend.openssl_assert(evp_md != self._backend._ffi.NULL) - - pkey_ctx = self._backend._lib.EVP_PKEY_CTX_new( - self._public_key._evp_pkey, self._backend._ffi.NULL - ) - self._backend.openssl_assert(pkey_ctx != self._backend._ffi.NULL) - pkey_ctx = self._backend._ffi.gc(pkey_ctx, - self._backend._lib.EVP_PKEY_CTX_free) - res = self._backend._lib.EVP_PKEY_verify_init(pkey_ctx) - self._backend.openssl_assert(res == 1) - res = self._backend._lib.EVP_PKEY_CTX_set_signature_md( - pkey_ctx, evp_md) - self._backend.openssl_assert(res > 0) - - res = self._backend._lib.EVP_PKEY_CTX_set_rsa_padding( - pkey_ctx, self._padding_enum) - self._backend.openssl_assert(res > 0) - if isinstance(self._padding, PSS): - res = self._backend._lib.EVP_PKEY_CTX_set_rsa_pss_saltlen( - pkey_ctx, - _get_rsa_pss_salt_length( - self._padding, - self._public_key, - self._hash_ctx.algorithm, - ) - ) - self._backend.openssl_assert(res > 0) - if self._backend._lib.Cryptography_HAS_MGF1_MD: - # MGF1 MD is configurable in OpenSSL 1.0.1+ - mgf1_md = self._backend._lib.EVP_get_digestbyname( - self._padding._mgf._algorithm.name.encode("ascii")) - self._backend.openssl_assert( - mgf1_md != self._backend._ffi.NULL - ) - res = self._backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md( - pkey_ctx, mgf1_md - ) - self._backend.openssl_assert(res > 0) - - data_to_verify = self._hash_ctx.finalize() - res = self._backend._lib.EVP_PKEY_verify( - pkey_ctx, + return _rsa_sig_verify( + self._backend, + self._padding, + self._padding_enum, + self._algorithm, + self._public_key, self._signature, - len(self._signature), - data_to_verify, - len(data_to_verify) + self._hash_ctx.finalize() ) - # 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 - # occurs. - self._backend.openssl_assert(res >= 0) - if res == 0: - errors = self._backend._consume_errors() - assert errors - raise InvalidSignature @utils.register_interface(RSAPrivateKeyWithSerialization) |