Process curve name when loading EC keys. Fixes #1336

2 files changed, 52 insertions, 3 deletions

diff --git a/cryptography/hazmat/backends/openssl/backend.py b/cryptography/hazmat/backends/openssl/backend.py
index 0b129d1a..65fcbcb1 100644
--- a/cryptography/hazmat/backends/openssl/backend.py
+++ b/cryptography/hazmat/backends/openssl/backend.py
@@ -474,12 +474,28 @@ class Backend(object):
             assert dsa_cdata != self._ffi.NULL
             dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free)
             return _DSAPrivateKey(self, dsa_cdata)
-        elif self._lib.Cryptography_HAS_EC == 1 \
-                and type == self._lib.EVP_PKEY_EC:
+        elif (self._lib.Cryptography_HAS_EC == 1 and
+              type == self._lib.EVP_PKEY_EC):
             ec_cdata = self._lib.EVP_PKEY_get1_EC_KEY(evp_pkey)
             assert ec_cdata != self._ffi.NULL
             ec_cdata = self._ffi.gc(ec_cdata, self._lib.EC_KEY_free)
-            return _EllipticCurvePrivateKey(self, ec_cdata, None)
+            group = self._lib.EC_KEY_get0_group(ec_cdata)
+            assert group != self._ffi.NULL
+
+            nid = self._lib.EC_GROUP_get_curve_name(group)
+            assert nid != 0
+
+            curve_name = self._lib.OBJ_nid2sn(nid)
+            assert curve_name != self._ffi.NULL
+
+            sn = self._ffi.string(curve_name).decode('ascii')
+
+            curve = self._sn_to_elliptic_curve(sn)
+
+            point = self._lib.EC_POINT_new(group)
+            assert point != self._ffi.NULL
+            point = self._ffi.gc(point, self._lib.EC_POINT_free)
+            return _EllipticCurvePrivateKey(self, ec_cdata, curve)
         else:
             raise UnsupportedAlgorithm("Unsupported key type.")
 
@@ -1048,6 +1064,15 @@ class Backend(object):
             )
         return curve_nid
 
+    def _sn_to_elliptic_curve(self, sn):
+        try:
+            return ec.CURVE_TYPES[sn]()
+        except KeyError:
+            raise UnsupportedAlgorithm(
+                "{0} is not a supported elliptic curve".format(sn),
+                _Reasons.UNSUPPORTED_ELLIPTIC_CURVE
+            )
+
     @contextmanager
     def _bn_ctx_manager(self):
         bn_ctx = self._lib.BN_CTX_new()
diff --git a/cryptography/hazmat/primitives/asymmetric/ec.py b/cryptography/hazmat/primitives/asymmetric/ec.py
index 220a419c..813e2c9e 100644
--- a/cryptography/hazmat/primitives/asymmetric/ec.py
+++ b/cryptography/hazmat/primitives/asymmetric/ec.py
@@ -184,6 +184,30 @@ class SECP192R1(object):
         return 192
 
 
+CURVE_TYPES = {
+    "prime192v1": SECP192R1,
+    "prime256v1": SECP256R1,
+
+    "secp192r1": SECP192R1,
+    "secp224r1": SECP224R1,
+    "secp256r1": SECP256R1,
+    "secp384r1": SECP384R1,
+    "secp521r1": SECP521R1,
+
+    "sect163k1": SECT163K1,
+    "sect233k1": SECT233K1,
+    "sect283k1": SECT283K1,
+    "sect409k1": SECT409K1,
+    "sect571k1": SECT571K1,
+
+    "sect163r2": SECT163R2,
+    "sect233r1": SECT233R1,
+    "sect283r1": SECT283R1,
+    "sect409r1": SECT409R1,
+    "sect571r1": SECT571R1,
+}
+
+
 @utils.register_interface(interfaces.EllipticCurveSignatureAlgorithm)
 class ECDSA(object):
     def __init__(self, algorithm):