[Python-checkins] [3.8] bpo-43789: OpenSSL 3.0.0 Don't call passwd callback again in error case (GH-25303) (GH-25306)

[tiran]

https://github.com/python/cpython/commit/a28398e9c60848fc291c83dac44e5212694fb0b2
commit: a28398e9c60848fc291c83dac44e5212694fb0b2
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: tiran <christian at python.org>
date: 2021-04-09T16:51:25+02:00
summary:

[3.8] bpo-43789: OpenSSL 3.0.0 Don't call passwd callback again in error case (GH-25303) (GH-25306)

(cherry picked from commit d3b73f32ef7c693a6ae8c54eb0e62df3b5315caf)

Co-authored-by: Christian Heimes <christian at python.org>

files:
A Misc/NEWS.d/next/Library/2021-04-09-14-08-03.bpo-43789.eaHlAm.rst
M Modules/_ssl.c

diff --git a/Misc/NEWS.d/next/Library/2021-04-09-14-08-03.bpo-43789.eaHlAm.rst b/Misc/NEWS.d/next/Library/2021-04-09-14-08-03.bpo-43789.eaHlAm.rst
new file mode 100644
index 0000000000000..1c0852946214d
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-04-09-14-08-03.bpo-43789.eaHlAm.rst
@@ -0,0 +1,2 @@
+OpenSSL 3.0.0: Don't call the password callback function a second time when
+first call has signaled an error condition.
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index bc98375379b54..58d9f86489c4c 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -3933,6 +3933,13 @@ _password_callback(char *buf, int size, int rwflag, void *userdata)
 
     PySSL_END_ALLOW_THREADS_S(pw_info->thread_state);
 
+    if (pw_info->error) {
+        /* already failed previously. OpenSSL 3.0.0-alpha14 invokes the
+         * callback multiple times which can lead to fatal Python error in
+         * exception check. */
+        goto error;
+    }
+
     if (pw_info->callable) {
         fn_ret = _PyObject_CallNoArg(pw_info->callable);
         if (!fn_ret) {