Refs #4833 -- try testing with a similar cert

src/cryptography/hazmat/backends/openssl/decode_asn1.py

@@ -259,7 +259,9 @@ def parse(self, backend, x509_obj):
 
 def _decode_certificate_policies(backend, cp):
     cp = backend._ffi.cast("Cryptography_STACK_OF_POLICYINFO *", cp)
-    cp = backend._ffi.gc(cp, backend._lib.CERTIFICATEPOLICIES_free)
+    cp = backend._ffi.gc(cp, lambda x: backend._lib.sk_POLICYINFO_pop_free(
+        x, backend._ffi.addressof(backend._lib._original_lib, "POLICYINFO_free")
+    ))
 
     num = backend._lib.sk_POLICYINFO_num(cp)
     certificate_policies = []

tests/hazmat/backends/test_openssl_memleak.py

@@ -22,15 +22,16 @@
 def main(argv):
     import gc
     import json
+    import traceback
 
     import cffi
 
     from cryptography.hazmat.bindings._openssl import ffi, lib
 
     heap = {}
 
-    BACKTRACE_ENABLED = False
-    if BACKTRACE_ENABLED:
+    C_BACKTRACE_ENABLED = False
+    if C_BACKTRACE_ENABLED:
         backtrace_ffi = cffi.FFI()
         backtrace_ffi.cdef('''
             int backtrace(void **, int);
@@ -54,10 +55,10 @@ def symbolize_backtrace(trace):
             return stack
     else:
         def backtrace():
-            return None
+            return traceback.format_stack()
 
         def symbolize_backtrace(trace):
-            return None
+            return trace
 
     @ffi.callback("void *(size_t, const char *, int)")
     def malloc(size, path, line):
@@ -210,7 +211,7 @@ class TestOpenSSLMemoryLeaks(object):
     @pytest.mark.parametrize("path", [
         "x509/PKITS_data/certs/ValidcRLIssuerTest28EE.crt",
     ])
-    def test_x509_certificate_extensions(self, path):
+    def test_der_x509_certificate_extensions(self, path):
         assert_no_memory_leaks(textwrap.dedent("""
         def func(path):
             from cryptography import x509
@@ -226,6 +227,25 @@ def func(path):
             cert.extensions
         """), [path])
 
+    @pytest.mark.parametrize("path", [
+        "x509/cryptography.io.pem",
+    ])
+    def test_pem_x509_certificate_extensions(self, path):
+        assert_no_memory_leaks(textwrap.dedent("""
+        def func(path):
+            from cryptography import x509
+            from cryptography.hazmat.backends.openssl import backend
+
+            import cryptography_vectors
+
+            with cryptography_vectors.open_vector_file(path, "rb") as f:
+                cert = x509.load_pem_x509_certificate(
+                    f.read(), backend
+                )
+
+            cert.extensions
+        """), [path])
+
     def test_x509_csr_extensions(self):
         assert_no_memory_leaks(textwrap.dedent("""
         def func():