add 0001-clear-openssl-errors-before-initialising-random-engi.patch

debian/changelog

@@ -1,3 +1,9 @@
+python-cryptography (1.7.1-3~bpo8+1.1) UNRELEASED; urgency=medium
+
+  * add 0001-clear-openssl-errors-before-initialising-random-engi.patch
+
+ -- Frederic Peters <fpeters@debian.org>  Thu, 29 Mar 2018 10:51:02 +0200
+
 python-cryptography (1.7.1-3~bpo8+1) jessie-backports; urgency=medium
 
   * Rebuild for jessie-backports.

debian/patches/0001-clear-openssl-errors-before-initialising-random-engi.patch

@@ -0,0 +1,30 @@
+From d07949c3f24471317e027931c51e01e34495ee4f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20P=C3=A9ters?= <fpeters@entrouvert.com>
+Date: Thu, 29 Mar 2018 10:43:28 +0200
+Subject: [PATCH] clear openssl errors before initialising random engine
+
+---
+ src/cryptography/hazmat/bindings/openssl/binding.py | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/src/cryptography/hazmat/bindings/openssl/binding.py b/src/cryptography/hazmat/bindings/openssl/binding.py
+index 39750ab..096faf5 100644
+--- a/src/cryptography/hazmat/bindings/openssl/binding.py
++++ b/src/cryptography/hazmat/bindings/openssl/binding.py
+@@ -111,7 +111,12 @@ class Binding(object):
+ 
+     @classmethod
+     def _register_osrandom_engine(cls):
+-        _openssl_assert(cls.lib, cls.lib.ERR_peek_error() == 0)
++        # Clear any errors extant in the queue before we start. In many
++        # scenarios other things may be interacting with OpenSSL in the same
++        # process space and it has proven untenable to assume that they will
++        # reliably clear the error queue. Once we clear it here we will
++        # error on any subsequent unexpected item in the stack.
++        cls.lib.ERR_clear_error()
+         cls._osrandom_engine_id = cls.lib.Cryptography_osrandom_engine_id
+         cls._osrandom_engine_name = cls.lib.Cryptography_osrandom_engine_name
+         result = cls.lib.Cryptography_add_osrandom_engine()
+-- 
+2.16.3
+

debian/patches/series

@@ -1,2 +1,3 @@
 0001-add-memory-limit-check-for-scrypt.patch
 0002-fix-compilation-on-1.1.0f-3603.patch
+0001-clear-openssl-errors-before-initialising-random-engi.patch