Merge pull request #1723 from public/strict-bn-int

Stricter asserts on _bn_to_int and _int_to_bn

1 files changed, 2 insertions, 0 deletions

diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
index de653032..27d5e353 100644
--- a/src/cryptography/hazmat/backends/openssl/backend.py
+++ b/src/cryptography/hazmat/backends/openssl/backend.py
@@ -320,6 +320,7 @@ class Backend(object):
         )
 
     def _bn_to_int(self, bn):
+        assert bn != self._ffi.NULL
         if six.PY3:
             # Python 3 has constant time from_bytes, so use that.
 
@@ -346,6 +347,7 @@ class Backend(object):
         ownership of the object). Be sure to register it for GC if it will
         be discarded after use.
         """
+        assert bn is None or bn != self._ffi.NULL
 
         if bn is None:
             bn = self._ffi.NULL