src/OpenSSL/crypto.py: support SM2 sign with OpenSSL 1.1.1x

In openssl 1.1.1 docs/man3/EVP_PKEY_set1_RSA.pod
(https://github.com/openssl/openssl/blob/OpenSSL_1_1_1/doc/man3/EVP_PKEY_set1_RSA.pod)
The EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2) API is possible to convert it to using
SM2 algorithms After loading an ECC key.

Besides, pyca/cryptography support to export `The EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2) API`
in pyca/cryptography@c28bfb3 .

So in pyopenssl, we can support SM2 sign with OpenSSL 1.1.1x and pyca/cryptography.

Signed-off-by: YiLin.Li <YiLin.Li@linux.alibaba.com>

src/OpenSSL/crypto.py

@@ -97,6 +97,9 @@
 TYPE_DH: int = _lib.EVP_PKEY_DH
 TYPE_EC: int = _lib.EVP_PKEY_EC
 
+NID_sm2 = 1172
+EVP_PKEY_SM2 = NID_sm2
+
 
 class Error(Exception):
     """
@@ -3104,6 +3107,22 @@ def sign(pkey: PKey, data: Union[str, bytes], digest: str) -> bytes:
     if digest_obj == _ffi.NULL:
         raise ValueError("No such digest method")
 
+    if (
+        _lib.OPENSSL_VERSION_NUMBER < 0x30000000
+        and _lib.EVP_PKEY_id(pkey._pkey) == _lib.EVP_PKEY_EC
+    ):
+        if (
+            _lib.EC_GROUP_get_curve_name(
+                _lib.EC_KEY_get0_group(_lib.EVP_PKEY_get1_EC_KEY(pkey._pkey))
+            )
+            == NID_sm2
+        ):
+            if hasattr(_lib, "EVP_PKEY_set_alias_type"):
+                _lib.EVP_PKEY_set_alias_type(pkey._pkey, EVP_PKEY_SM2)
+            else:
+                print("The SM2 Signing isn't enable in current OpenSSL 1.1.x")
+                return b""
+
     md_ctx = _lib.EVP_MD_CTX_new()
     md_ctx = _ffi.gc(md_ctx, _lib.EVP_MD_CTX_free)
 

tests/test_crypto.py

@@ -787,6 +787,15 @@ def normalize_privatekey_pem(pem):
 Td8GMrwKz0557OxxtKN6uVVy4ACFMqEw0zN/KJI1vxc9
 -----END CERTIFICATE-----"""
 
+sm2_root_key_pem = b"""-----BEGIN EC PARAMETERS-----
+BggqgRzPVQGCLQ==
+-----END EC PARAMETERS-----
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEII/sRQnfpXCVx5kjmRbPp7KGgwJlOCx0kBX2Tr2lXrM2oAoGCCqBHM9V
+AYItoUQDQgAEkZX7gPPNGa0uwJMjTCBgVxlTD2krqPL1rZg2z9HLg3wnH06IxQ8r
+3su/VOmyoYBLBYcEjI7GSzvBy6ynX1ZDwA==
+-----END EC PRIVATE KEY-----"""
+
 rsa_p_not_prime_pem = """
 -----BEGIN RSA PRIVATE KEY-----
 MBsCAQACAS0CAQcCAQACAQ8CAQMCAQACAQACAQA=
@@ -4397,6 +4406,20 @@ def test_sign_verify_ecdsa(self):
         sig = sign(priv_key, content, "sha256")
         verify(cert, sig, content, "sha256")
 
+    def test_sign_sm2(self):
+        """
+        `sign` generates a SM2 cryptographic signature
+        """
+        content = (
+            b"It was a bright cold day in April, and the clocks were striking "
+            b"thirteen. Winston Smith, his chin nuzzled into his breast in an "
+            b"effort to escape the vile wind, slipped quickly through the "
+            b"glass doors of Victory Mansions, though not quickly enough to "
+            b"prevent a swirl of gritty dust from entering along with him."
+        )
+        priv_key = load_privatekey(FILETYPE_PEM, sm2_root_key_pem)
+        _ = sign(priv_key, content, "sm3")
+
     def test_sign_nulls(self):
         """
         `sign` produces a signature for a string with embedded nulls.