diff options
| -rw-r--r-- | cryptography/hazmat/backends/openssl/backend.py | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/cryptography/hazmat/backends/openssl/backend.py b/cryptography/hazmat/backends/openssl/backend.py index beec5864..5d2fddc1 100644 --- a/cryptography/hazmat/backends/openssl/backend.py +++ b/cryptography/hazmat/backends/openssl/backend.py @@ -16,6 +16,7 @@ from __future__ import absolute_import, division, print_function import collections import itertools import warnings +from contextlib import contextmanager import six @@ -1012,6 +1013,15 @@ class Backend(object): ) return curve_nid + @contextmanager + def _bn_ctx_manager(self): + bn_ctx = self._lib.BN_CTX_new() + assert bn_ctx != self._ffi.NULL + bn_ctx = self._ffi.gc(bn_ctx, self._lib.BN_CTX_free) + self._lib.BN_CTX_start(bn_ctx) + yield bn_ctx + self._lib.BN_CTX_end(bn_ctx) + def _ec_key_set_public_key_affine_coordinates(self, ctx, x, y): """ This is a port of EC_KEY_set_public_key_affine_coordinates that was @@ -1029,10 +1039,6 @@ class Backend(object): nid_two_field = self._lib.OBJ_sn2nid(b"characteristic-two-field") assert nid_two_field != self._lib.NID_undef - bn_ctx = self._lib.BN_CTX_new() - assert bn_ctx != self._ffi.NULL - bn_ctx = self._ffi.gc(bn_ctx, self._lib.BN_CTX_free) - group = self._lib.EC_KEY_get0_group(ctx) assert group != self._ffi.NULL @@ -1055,9 +1061,7 @@ class Backend(object): assert set_func and get_func - try: - self._lib.BN_CTX_start(bn_ctx) - + with self._bn_ctx_manager() as bn_ctx: check_x = self._lib.BN_CTX_get(bn_ctx) check_y = self._lib.BN_CTX_get(bn_ctx) @@ -1071,8 +1075,6 @@ class Backend(object): self._lib.BN_cmp(bn_x, check_x) == 0 and self._lib.BN_cmp(bn_y, check_y) == 0 ) - finally: - self._lib.BN_CTX_end(bn_ctx) res = self._lib.EC_KEY_set_public_key(ctx, point) assert res == 1 |