QSslSocketBackendPrivate - avoid recursion while handing errors

The logic seems to be simple - if client code on error signal
tries to close TLS socket and this socket has buffered data,
it calls 'flush' and 'transmit' or even 'startHandshake' as
a result, which in turn will set and emit error again. To auto-
test this, we initiate a handshake with pre-shared key hint
on a server side and both client/server sockets incorrectly
configured (missing PSK signals). We also do early write
into the client socket to make sure it has some data
buffered by the moment we call 'close'.

Task-number: QTBUG-68089
Task-number: QTBUG-56476
Change-Id: I6ba6435bd572ad85d9209c4c81774a397081b34f
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 63 insertions, 0 deletions

diff --git a/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp b/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
index f07d3c6507..b759aed074 100644
--- a/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
+++ b/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
@@ -202,6 +202,9 @@ private slots:
     void verifyDepth();
     void disconnectFromHostWhenConnecting();
     void disconnectFromHostWhenConnected();
+#ifndef QT_NO_OPENSSL
+    void closeWhileEmittingSocketError();
+#endif
     void resetProxy();
     void ignoreSslErrorsList_data();
     void ignoreSslErrorsList();
@@ -2336,6 +2339,66 @@ void tst_QSslSocket::disconnectFromHostWhenConnected()
     QCOMPARE(socket->bytesToWrite(), qint64(0));
 }
 
+#ifndef QT_NO_OPENSSL
+
+class BrokenPskHandshake : public QTcpServer
+{
+public:
+    void socketError(QAbstractSocket::SocketError error)
+    {
+        Q_UNUSED(error);
+        QSslSocket *clientSocket = qobject_cast<QSslSocket *>(sender());
+        Q_ASSERT(clientSocket);
+        clientSocket->close();
+        QTestEventLoop::instance().exitLoop();
+    }
+private:
+
+    void incomingConnection(qintptr handle) override
+    {
+        if (!socket.setSocketDescriptor(handle))
+            return;
+
+        QSslConfiguration serverConfig(QSslConfiguration::defaultConfiguration());
+        serverConfig.setPreSharedKeyIdentityHint("abcdefghijklmnop");
+        socket.setSslConfiguration(serverConfig);
+        socket.startServerEncryption();
+    }
+
+    QSslSocket socket;
+};
+
+void tst_QSslSocket::closeWhileEmittingSocketError()
+{
+    QFETCH_GLOBAL(bool, setProxy);
+    if (setProxy)
+        return;
+
+    BrokenPskHandshake handshake;
+    if (!handshake.listen())
+        QSKIP("failed to start TLS server");
+
+    QSslSocket clientSocket;
+    QSslConfiguration clientConfig(QSslConfiguration::defaultConfiguration());
+    clientConfig.setPeerVerifyMode(QSslSocket::VerifyNone);
+    clientSocket.setSslConfiguration(clientConfig);
+
+    QSignalSpy socketErrorSpy(&clientSocket, SIGNAL(error(QAbstractSocket::SocketError)));
+    void (QSslSocket::*errorSignal)(QAbstractSocket::SocketError) = &QSslSocket::error;
+    connect(&clientSocket, errorSignal, &handshake, &BrokenPskHandshake::socketError);
+
+    clientSocket.connectToHostEncrypted(QStringLiteral("127.0.0.1"), handshake.serverPort());
+    // Make sure we have some data buffered so that close will try to flush:
+    clientSocket.write(QByteArray(1000000, Qt::Uninitialized));
+
+    QTestEventLoop::instance().enterLoopMSecs(1000);
+    QVERIFY(!QTestEventLoop::instance().timeout());
+
+    QCOMPARE(socketErrorSpy.count(), 1);
+}
+
+#endif // QT_NO_OPENSSL
+
 void tst_QSslSocket::resetProxy()
 {
 #ifndef QT_NO_NETWORKPROXY