add get_digest method to X509Req

src/OpenSSL/crypto.py

@@ -962,6 +962,33 @@ def verify(self, pkey):
 
         return result
 
+    def digest(self, digest_name):
+        """
+        Return the digest of the X509Req object.
+
+        :param digest_name: The name of the digest algorithm to use.
+        :type digest_name: :py:class:`bytes`
+
+        :return: The digest of the object
+        """
+        digest = _lib.EVP_get_digestbyname(_byte_string(digest_name))
+        if digest == _ffi.NULL:
+            raise ValueError("No such digest method")
+
+        result_buffer = _ffi.new("char[]", _lib.EVP_MAX_MD_SIZE)
+        result_length = _ffi.new("unsigned int[]", len(result_buffer))
+
+        digest_result = _lib.X509_REQ_digest(
+            self._req, digest, result_buffer, result_length)
+
+        if not digest_result:
+            # TODO: This is untested.
+            _raise_current_error()
+
+        return b":".join([
+            b16encode(ch).upper() for ch
+            in _ffi.buffer(result_buffer, result_length[0])])
+
 
 X509ReqType = X509Req
 

tests/test_crypto.py

@@ -128,6 +128,18 @@ def normalize_privatekey_pem(pem):
 -----END RSA PRIVATE KEY-----
 """)
 
+server_csr_pem = b("""-----BEGIN CERTIFICATE REQUEST-----
+MIIBVzCBwQIBADAYMRYwFAYDVQQDDA1sb3ZlbHkgc2VydmVyMIGfMA0GCSqGSIb3
+DQEBAQUAA4GNADCBiQKBgQC+pvhuud1dLaQQvzipdtlcTotgr5SuE2LvSx0gz/bg
+1U3u1eQ+U5eqsxaEUceaX5p5Kk+QflvW8qdjVNxQuYS5uc0gK2+OZnlIYxCf4n5G
+YGzVIx3QSBj/TAEFB2WuVinZBiCbxgL7PFM1Kpa+EwVkCAduPpSflJJPwkYGrK2M
+HQIDAQABoAAwDQYJKoZIhvcNAQEEBQADgYEAMRbqLdsXDEb4yR9KbuUqg9k90w0+
+8xPYgrNcTIrF2zTSZQKDfio6B7LBeD51fQabBNJo83+3M849Np8wN/h7ZFALiln6
+2ElkKCTQwmt/TbR3snakotqYUFw9//3PQCIq5cZfc32wim2IEyKOGBRvHqejpwbI
+yT4P3uVSsYc35vY=
+-----END CERTIFICATE REQUEST-----
+""")
+
 server_cert_pem = b("""-----BEGIN CERTIFICATE-----
 MIICKDCCAZGgAwIBAgIJAJn/HpR21r/8MA0GCSqGSIb3DQEBBQUAMFgxCzAJBgNV
 BAYTAlVTMQswCQYDVQQIEwJJTDEQMA4GA1UEBxMHQ2hpY2FnbzEQMA4GA1UEChMH
@@ -1264,6 +1276,20 @@ def test_verify_success(self):
         request.sign(pkey, GOOD_DIGEST)
         self.assertEqual(True, request.verify(pkey))
 
+    def test_digest(self):
+        """
+        :py:obj:`X509Req.digest` returns a string giving ":"-separated
+        hex-encoded words of the digest of the certificate request.
+        """
+        csr = load_certificate_request(FILETYPE_PEM, server_csr_pem)
+
+        self.assertEqual(
+            # This is MD5 instead of GOOD_DIGEST because the digest algorithm
+            # actually matters to the assertion (ie, another arbitrary, good
+            # digest will not produce the same digest).
+            csr.digest("MD5"),
+            b("FB:D9:74:AB:24:A9:80:64:96:92:C0:1B:82:3C:36:C9"))
+
 
 class X509Tests(TestCase, _PKeyInteractionTestsMixin):
     """