Fix for leaking memory in EllipticCurvePublicNumbers.public_key() (#3732)

* Test for leaking memory in EllipticCurvePublicNumbers.public_key()

* Fix the memory leak

As far as I can tell, from spelunking in the OpenSSL source (as you do), EC_KEY_set_public_key_affine_coordinates doesn't take ownership of "x" or "y". https://github.com/openssl/openssl/blob/master/crypto/ec/ecp_smpl.c#L362-L420 is the place in the source I found that actually uses "x" and "y".

* Unused imports

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/hazmat/backends/test_openssl_memleak.py b/tests/hazmat/backends/test_openssl_memleak.py
index 53c41375..e58090a9 100644
--- a/tests/hazmat/backends/test_openssl_memleak.py
+++ b/tests/hazmat/backends/test_openssl_memleak.py
@@ -189,3 +189,22 @@ class TestOpenSSLMemoryLeaks(object):
 
             cert.extensions
         """), [path])
+
+    def test_ec_public_numbers_public_key(self):
+        assert_no_memory_leaks(textwrap.dedent("""
+        def func():
+            from cryptography.hazmat.backends.openssl import backend
+            from cryptography.hazmat.primitives.asymmetric import ec
+
+            ec.EllipticCurvePublicNumbers(
+                curve=ec.SECP384R1(),
+                x=int(
+                    '10036914308591746758780165503819213553101287571902957054148542'
+                    '504671046744460374996612408381962208627004841444205030'
+                ),
+                y=int(
+                    '17337335659928075994560513699823544906448896792102247714689323'
+                    '575406618073069185107088229463828921069465902299522926'
+                )
+            ).public_key(backend)
+        """))