bpo-37440: Enable TLS 1.3 post-handshake auth in http.client (GH-14448)
Post-handshake authentication is required for conditional client cert authentication with TLS 1.3.
https://bugs.python.org/issue37440
diff --git a/Lib/http/client.py b/Lib/http/client.py
index 82908eb..f61267e 100644
--- a/Lib/http/client.py
+++ b/Lib/http/client.py
@@ -1358,6 +1358,9 @@
self.cert_file = cert_file
if context is None:
context = ssl._create_default_https_context()
+ # enable PHA for TLS 1.3 connections if available
+ if context.post_handshake_auth is not None:
+ context.post_handshake_auth = True
will_verify = context.verify_mode != ssl.CERT_NONE
if check_hostname is None:
check_hostname = context.check_hostname
@@ -1366,6 +1369,10 @@
"either CERT_OPTIONAL or CERT_REQUIRED")
if key_file or cert_file:
context.load_cert_chain(cert_file, key_file)
+ # cert and key file means the user wants to authenticate.
+ # enable TLS 1.3 PHA implicitly even for custom contexts.
+ if context.post_handshake_auth is not None:
+ context.post_handshake_auth = True
self._context = context
if check_hostname is not None:
self._context.check_hostname = check_hostname