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>

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);

tests/auto/network/access/http2/http2srv.cpp

@@ -84,6 +84,12 @@ Http2Server::~Http2Server()
 {
 }
 
+void Http2Server::setInformationalStatusCode(int code)
+{
+    if (code == 100 || (102 <= code && code <= 199))
+        informationalStatusCode = code;
+}
+
 void Http2Server::enablePushPromise(bool pushEnabled, const QByteArray &path)
 {
     pushPromiseEnabled = pushEnabled;
@@ -837,6 +843,25 @@ void Http2Server::sendResponse(quint32 streamID, bool emptyBody)
         // Now we'll continue with _normal_ response.
     }
 
+    // Create a header with an informational status code and some random header
+    // fields. The setter ensures that the value is 100 or is between 102 and 199
+    // (inclusive) if set - otherwise it is 0
+
+    if (informationalStatusCode > 0) {
+        writer.start(FrameType::HEADERS, FrameFlag::END_HEADERS, streamID);
+
+        HttpHeader informationalHeader;
+        informationalHeader.push_back({":status", QByteArray::number(informationalStatusCode)});
+        informationalHeader.push_back(HeaderField("a_random_header_field", "it_will_be_dropped"));
+        informationalHeader.push_back(HeaderField("another_random_header_field", "drop_this_too"));
+
+        HPack::BitOStream ostream(writer.outboundFrame().buffer);
+        const bool result = encoder.encodeResponse(ostream, informationalHeader);
+        Q_ASSERT(result);
+
+        writer.writeHEADERS(*socket, maxFrameSize);
+    }
+
     writer.start(FrameType::HEADERS, FrameFlag::END_HEADERS, streamID);
     if (emptyBody)
         writer.addFlag(FrameFlag::END_STREAM);

tests/auto/network/access/http2/http2srv.h

@@ -58,6 +58,8 @@ public:
     ~Http2Server();
 
 
+    // To send responses with status code 1xx
+    void setInformationalStatusCode(int code);
     // To be called before server started:
     void enablePushPromise(bool enabled, const QByteArray &path = QByteArray());
     void setResponseBody(const QByteArray &body);
@@ -210,6 +212,7 @@ private:
     int redirectCount = 0;
 
     bool sendTrailingHEADERS = false;
+    int informationalStatusCode = 0;
 protected slots:
     void ignoreErrorSlot();
 };

tests/auto/network/access/http2/tst_http2.cpp

@@ -72,6 +72,8 @@ private slots:
     void defaultQnamHttp2Configuration();
     void singleRequest_data();
     void singleRequest();
+    void informationalRequest_data();
+    void informationalRequest();
     void multipleRequests();
     void flowControlClientSide();
     void flowControlServerSide();
@@ -300,6 +302,70 @@ void tst_Http2::singleRequest()
 #endif // QT_CONFIG(ssl)
 }
 
+void tst_Http2::informationalRequest_data()
+{
+    QTest::addColumn<int>("statusCode");
+
+    // 'Clear text' that should always work, either via the protocol upgrade
+    // or as direct.
+    QTest::addRow("statusCode-100") << 100;
+    QTest::addRow("statusCode-125") << 125;
+    QTest::addRow("statusCode-150") << 150;
+    QTest::addRow("statusCode-175") << 175;
+}
+
+void tst_Http2::informationalRequest()
+{
+    clearHTTP2State();
+
+    serverPort = 0;
+    nRequests = 1;
+
+    ServerPtr srv(newServer(defaultServerSettings, defaultConnectionType()));
+
+    QFETCH(const int, statusCode);
+    srv->setInformationalStatusCode(statusCode);
+
+    QMetaObject::invokeMethod(srv.data(), "startServer", Qt::QueuedConnection);
+    runEventLoop();
+
+    QVERIFY(serverPort != 0);
+
+    auto url = requestUrl(defaultConnectionType());
+    url.setPath("/index.html");
+
+    QNetworkRequest request(url);
+    request.setAttribute(QNetworkRequest::Http2CleartextAllowedAttribute, true);
+
+    auto reply = manager->get(request);
+
+    connect(reply, &QNetworkReply::finished, this, &tst_Http2::replyFinished);
+    // Since we're using self-signed certificates,
+    // ignore SSL errors:
+    reply->ignoreSslErrors();
+
+    runEventLoop();
+    STOP_ON_FAILURE
+
+    QCOMPARE(nRequests, 0);
+    QVERIFY(prefaceOK);
+    QVERIFY(serverGotSettingsACK);
+
+    QCOMPARE(reply->error(), QNetworkReply::NoError);
+    QVERIFY(reply->isFinished());
+
+    const QVariant code(reply->attribute(QNetworkRequest::HttpStatusCodeAttribute));
+
+    // We are discarding informational headers if the status code is in the range of
+    // 102-199 or if it is 100. As these header fields were part of  the informational
+    // header used for this test case, we should not see them at this point and the
+    // status code should be 200.
+
+    QCOMPARE(code.value<int>(), 200);
+    QVERIFY(!reply->hasRawHeader("a_random_header_field"));
+    QVERIFY(!reply->hasRawHeader("another_random_header_field"));
+}
+
 void tst_Http2::multipleRequests()
 {
     clearHTTP2State();