X509 distinguished name parsing support in the OpenSSL backend

2 files changed, 135 insertions, 0 deletions

diff --git a/src/cryptography/hazmat/backends/openssl/x509.py b/src/cryptography/hazmat/backends/openssl/x509.py
index 66c99c9f..e27d32f8 100644
--- a/src/cryptography/hazmat/backends/openssl/x509.py
+++ b/src/cryptography/hazmat/backends/openssl/x509.py
@@ -91,3 +91,45 @@ class _Certificate(object):
             )
         ).decode("ascii")
         return datetime.datetime.strptime(time, "%Y%m%d%H%M%SZ")
+
+    @property
+    def issuer(self):
+        issuer = self._backend._lib.X509_get_issuer_name(self._x509)
+        assert issuer != self._backend._ffi.NULL
+        return self._build_x509_name(issuer)
+
+    @property
+    def subject(self):
+        subject = self._backend._lib.X509_get_subject_name(self._x509)
+        assert subject != self._backend._ffi.NULL
+        return self._build_x509_name(subject)
+
+    def _build_x509_name(self, x509_name):
+        count = self._backend._lib.X509_NAME_entry_count(x509_name)
+        attributes = []
+        for x in range(0, count):
+            entry = self._backend._lib.X509_NAME_get_entry(x509_name, x)
+            obj = self._backend._lib.X509_NAME_ENTRY_get_object(entry)
+            assert obj != self._backend._ffi.NULL
+            data = self._backend._lib.X509_NAME_ENTRY_get_data(entry)
+            assert data != self._backend._ffi.NULL
+            buf = self._backend._ffi.new("unsigned char **")
+            res = self._backend._lib.ASN1_STRING_to_UTF8(buf, data)
+            assert buf[0] != self._backend._ffi.NULL
+            buf = self._backend._ffi.gc(
+                buf, lambda buf: self._backend._lib.OPENSSL_free(buf[0])
+            )
+            value = self._backend._ffi.buffer(buf[0], res)[:].decode('utf8')
+            buf_len = 50
+            buf = self._backend._ffi.new("char[]", buf_len)
+            res = self._backend._lib.OBJ_obj2txt(buf, buf_len, obj, 1)
+            assert res > 0
+            oid = self._backend._ffi.buffer(buf, res)[:].decode()
+
+            attributes.append(
+                x509.NameAttribute(
+                    x509.ObjectIdentifier(oid), value
+                )
+            )
+
+        return x509.Name(attributes)
diff --git a/src/cryptography/x509.py b/src/cryptography/x509.py
index 71062588..2371b36c 100644
--- a/src/cryptography/x509.py
+++ b/src/cryptography/x509.py
@@ -104,6 +104,87 @@ class ObjectIdentifier(object):
     dotted_string = utils.read_only_property("_dotted_string")
 
 
+class Name(object):
+    def __init__(self, attributes):
+        self._attributes = attributes
+
+    def _filter_attr_list(self, oid):
+        return [i for i in self._attributes if i.oid == oid]
+
+    @property
+    def common_name(self):
+        return self._filter_attr_list(OID_COMMON_NAME)
+
+    @property
+    def country_name(self):
+        return self._filter_attr_list(OID_COUNTRY_NAME)
+
+    @property
+    def locality_name(self):
+        return self._filter_attr_list(OID_LOCALITY_NAME)
+
+    @property
+    def state_or_province_name(self):
+        return self._filter_attr_list(OID_STATE_OR_PROVINCE_NAME)
+
+    @property
+    def organization_name(self):
+        return self._filter_attr_list(OID_ORGANIZATION_NAME)
+
+    @property
+    def organizational_unit_name(self):
+        return self._filter_attr_list(OID_ORGANIZATIONAL_UNIT_NAME)
+
+    @property
+    def serial_number(self):
+        return self._filter_attr_list(OID_SERIAL_NUMBER)
+
+    @property
+    def surname(self):
+        return self._filter_attr_list(OID_SURNAME)
+
+    @property
+    def given_name(self):
+        return self._filter_attr_list(OID_GIVEN_NAME)
+
+    @property
+    def title(self):
+        return self._filter_attr_list(OID_TITLE)
+
+    @property
+    def generation_qualifier(self):
+        return self._filter_attr_list(OID_GENERATION_QUALIFIER)
+
+    @property
+    def dn_qualifier(self):
+        return self._filter_attr_list(OID_DN_QUALIFIER)
+
+    @property
+    def pseudonym(self):
+        return self._filter_attr_list(OID_PSEUDONYM)
+
+    @property
+    def domain_component(self):
+        return self._filter_attr_list(OID_DOMAIN_COMPONENT)
+
+    @property
+    def email_address(self):
+        return self._filter_attr_list(OID_EMAIL_ADDRESS)
+
+    @property
+    def attributes(self):
+        return self._attributes[:]
+
+    def __eq__(self, other):
+        if not isinstance(other, Name):
+            return NotImplemented
+
+        return self.attributes == other.attributes
+
+    def __ne__(self, other):
+        return not self == other
+
+
 OID_COMMON_NAME = ObjectIdentifier("2.5.4.3")
 OID_COUNTRY_NAME = ObjectIdentifier("2.5.4.6")
 OID_LOCALITY_NAME = ObjectIdentifier("2.5.4.7")
@@ -158,3 +239,15 @@ class Certificate(object):
         """
         Not after time (represented as UTC datetime)
         """
+
+    @abc.abstractproperty
+    def issuer(self):
+        """
+        Returns the issuer name object.
+        """
+
+    @abc.abstractproperty
+    def subject(self):
+        """
+        Returns the subject name object.
+        """