Handle informational HTTP replies (1xx) for HTTP/2

Make QHttp2ProtocolHandler discard all informational (1xx) replies with
the exception of 101.

According to RFC 9110:

"A client MUST be able to parse one or more 1xx responses received
prior to a final response, even if the client does not expect one.
A user agent MAY ignore unexpected 1xx responses."

Fixes: QTBUG-121755
Change-Id: I8b8d578f23d4fbe28929f8c54b3607bcaf85405f
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Juha Vuolle <juha.vuolle@qt.io>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/network/access/qhttp2protocolhandler.cpp b/src/network/access/qhttp2protocolhandler.cpp
index 251d17b0b4..d25be851bf 100644
--- a/src/network/access/qhttp2protocolhandler.cpp
+++ b/src/network/access/qhttp2protocolhandler.cpp
@@ -1101,6 +1101,13 @@ void QHttp2ProtocolHandler::updateStream(Stream &stream, const HPack::HttpHeader
         }
     }
 
+    // Discard all informational (1xx) replies with the exception of 101.
+    // Also see RFC 9110 (Chapter 15.2)
+    if (statusCode == 100 || (102 <= statusCode && statusCode <= 199)) {
+        httpReplyPrivate->clearHttpLayerInformation();
+        return;
+    }
+
     if (QHttpNetworkReply::isHttpRedirect(statusCode) && httpRequest.isFollowRedirects()) {
         QHttpNetworkConnectionPrivate::ParseRedirectResult result =
                 m_connection->d_func()->parseRedirectResponse(httpReply);