commit 5db4e5e77ee40521cd732058262e228be4430588
author Alex Gaynor <alex.gaynor@gmail.com> Mon Dec 18 10:24:17 2017 -0500
committer Paul Kehrer <paul.l.kehrer@gmail.com> Mon Dec 18 09:24:17 2017 -0600
tree 81d3dfa9f9a3066f45dbc7155f2108854561b3ca
parent 582b2b4d85c4bb902beab05fb3044d96c49c910f

Fixed #4058 -- use the thread-safe API from OpenSSL, not the danger one (#4059)

src/_cffi_src/openssl/err.py

diff --git a/src/_cffi_src/openssl/err.py b/src/_cffi_src/openssl/err.py
index 55f2470..5770429 100644
--- a/src/_cffi_src/openssl/err.py
+++ b/src/_cffi_src/openssl/err.py
@@ -231,7 +231,6 @@
 """
 
 FUNCTIONS = """
-char *ERR_error_string(unsigned long, char *);
 void ERR_error_string_n(unsigned long, char *, size_t);
 const char *ERR_lib_error_string(unsigned long);
 const char *ERR_func_error_string(unsigned long);

src/cryptography/hazmat/bindings/openssl/binding.py

diff --git a/src/cryptography/hazmat/bindings/openssl/binding.py b/src/cryptography/hazmat/bindings/openssl/binding.py
index 7790213..7d528ad 100644
--- a/src/cryptography/hazmat/bindings/openssl/binding.py
+++ b/src/cryptography/hazmat/bindings/openssl/binding.py
@@ -55,9 +55,10 @@
         errors = _consume_errors(lib)
         errors_with_text = []
         for err in errors:
-            err_text_reason = ffi.string(
-                lib.ERR_error_string(err.code, ffi.NULL)
-            )
+            buf = ffi.new("char[]", 256)
+            lib.ERR_error_string_n(err.code, buf, len(buf))
+            err_text_reason = ffi.string(buf)
+
             errors_with_text.append(
                 _OpenSSLErrorWithText(
                     err.code, err.lib, err.func, err.reason, err_text_reason

tests/hazmat/backends/test_openssl.py

diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index e430e2d..5863149 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -125,9 +125,9 @@
         assert cipher != backend._ffi.NULL
 
     def test_error_strings_loaded(self):
-        # returns a value in a static buffer
-        err = backend._lib.ERR_error_string(101183626, backend._ffi.NULL)
-        assert b"data not multiple of block length" in backend._ffi.string(err)
+        buf = backend._ffi.new("char[]", 256)
+        backend._lib.ERR_error_string_n(101183626, buf, len(buf))
+        assert b"data not multiple of block length" in backend._ffi.string(buf)
 
     def test_unknown_error_in_cipher_finalize(self):
         cipher = Cipher(AES(b"\0" * 16), CBC(b"\0" * 16), backend=backend)