Fix OIDC login regression (#17031)

Requests may require a User-Agent header, and the change in #16972
accidentally removed it, resulting in requests getting rejected causing
login to fail.

2 files changed, 8 insertions, 0 deletions

diff --git a/changelog.d/17031.feature b/changelog.d/17031.feature
new file mode 100644

index 0000000000..0f28cbbcd6
--- /dev/null
+++ b/changelog.d/17031.feature
@@ -0,0 +1 @@
+OIDC: try to JWT decode userinfo response if JSON parsing failed.
diff --git a/synapse/http/client.py b/synapse/http/client.py

index 08a8634dae..4718517c97 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -390,6 +390,13 @@ class BaseHttpClient:
                         cooperator=self._cooperator,
                     )
 
+                # Always make sure we add a user agent to the request
+                if headers is None:
+                    headers = Headers()
+
+                if not headers.hasHeader("User-Agent"):
+                    headers.addRawHeader("User-Agent", self.user_agent)
+
                 request_deferred: defer.Deferred = treq.request(
                     method,
                     uri,