Add the ability to prefer the cipher preferences specified by the server.

Currently the cipher preferred by the client will always be used for SSL
connections. This change makes it so that by default the ciphers
specified by the server will be used (like the Apache SSLHonorCipherOrder
option). This behavior can be disabled using a new SslOption.

[ChangeLog][QtNetwork][QSslSocket] QSslSocket will now default to using
the cipher preferences of the server socket when used as an SSL server.
This can be disabled using the QSslConfiguration.

Change-Id: I2d16d10145cf88a7412f30ef960d87024777de1c
Reviewed-by: Peter Hartmann <peter-qt@hartmann.tk>

1 files changed, 85 insertions, 7 deletions

diff --git a/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp b/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
index f4d3555531..d95f2fa546 100644
--- a/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
+++ b/tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp
@@ -170,6 +170,9 @@ private slots:
     void protocol();
     void protocolServerSide_data();
     void protocolServerSide();
+#ifndef QT_NO_OPENSSL
+    void serverCipherPreferences();
+#endif // QT_NO_OPENSSL
     void setCaCertificates();
     void setLocalCertificate();
     void localCertificateChain();
@@ -1063,6 +1066,7 @@ public:
               const QString &certFile = SRCDIR "certs/fluke.cert",
               const QString &interFile = QString())
         : socket(0),
+          config(QSslConfiguration::defaultConfiguration()),
           ignoreSslErrors(true),
           peerVerifyMode(QSslSocket::AutoVerifyPeer),
           protocol(QSsl::TlsV1_0),
@@ -1071,6 +1075,7 @@ public:
           m_interFile(interFile)
           { }
     QSslSocket *socket;
+    QSslConfiguration config;
     QString addCaCertificates;
     bool ignoreSslErrors;
     QSslSocket::PeerVerifyMode peerVerifyMode;
@@ -1084,6 +1089,7 @@ protected:
     void incomingConnection(qintptr socketDescriptor)
     {
         socket = new QSslSocket(this);
+        socket->setSslConfiguration(config);
         socket->setPeerVerifyMode(peerVerifyMode);
         socket->setProtocol(protocol);
         if (ignoreSslErrors)
@@ -1254,6 +1260,78 @@ void tst_QSslSocket::protocolServerSide()
     QCOMPARE(client->isEncrypted(), works);
 }
 
+#ifndef QT_NO_OPENSSL
+
+void tst_QSslSocket::serverCipherPreferences()
+{
+    if (!QSslSocket::supportsSsl()) {
+        qWarning("SSL not supported, skipping test");
+        return;
+    }
+
+    QFETCH_GLOBAL(bool, setProxy);
+    if (setProxy)
+        return;
+
+    // First using the default (server preference)
+    {
+        SslServer server;
+        server.ciphers = QString("AES128-SHA:AES256-SHA");
+        QVERIFY(server.listen());
+
+        QEventLoop loop;
+        QTimer::singleShot(5000, &loop, SLOT(quit()));
+
+        QSslSocketPtr client(new QSslSocket);
+        socket = client.data();
+        socket->setCiphers("AES256-SHA:AES128-SHA");
+
+        // upon SSL wrong version error, error will be triggered, not sslErrors
+        connect(socket, SIGNAL(error(QAbstractSocket::SocketError)), &loop, SLOT(quit()));
+        connect(socket, SIGNAL(sslErrors(QList<QSslError>)), this, SLOT(ignoreErrorSlot()));
+        connect(socket, SIGNAL(encrypted()), &loop, SLOT(quit()));
+
+        client->connectToHostEncrypted(QHostAddress(QHostAddress::LocalHost).toString(), server.serverPort());
+
+        loop.exec();
+
+        QVERIFY(client->isEncrypted());
+        QCOMPARE(client->sessionCipher().name(), QString("AES128-SHA"));
+    }
+
+    {
+        // Now using the client preferences
+        SslServer server;
+        QSslConfiguration config = QSslConfiguration::defaultConfiguration();
+        config.setSslOption(QSsl::SslOptionDisableServerCipherPreference, true);
+        server.config = config;
+        server.ciphers = QString("AES128-SHA:AES256-SHA");
+        QVERIFY(server.listen());
+
+        QEventLoop loop;
+        QTimer::singleShot(5000, &loop, SLOT(quit()));
+
+        QSslSocketPtr client(new QSslSocket);
+        socket = client.data();
+        socket->setCiphers("AES256-SHA:AES128-SHA");
+
+        // upon SSL wrong version error, error will be triggered, not sslErrors
+        connect(socket, SIGNAL(error(QAbstractSocket::SocketError)), &loop, SLOT(quit()));
+        connect(socket, SIGNAL(sslErrors(QList<QSslError>)), this, SLOT(ignoreErrorSlot()));
+        connect(socket, SIGNAL(encrypted()), &loop, SLOT(quit()));
+
+        client->connectToHostEncrypted(QHostAddress(QHostAddress::LocalHost).toString(), server.serverPort());
+
+        loop.exec();
+
+        QVERIFY(client->isEncrypted());
+        QCOMPARE(client->sessionCipher().name(), QString("AES256-SHA"));
+    }
+}
+
+#endif // QT_NO_OPENSSL
+
+
 void tst_QSslSocket::setCaCertificates()
 {
     if (!QSslSocket::supportsSsl())
@@ -2354,28 +2432,28 @@ void tst_QSslSocket::sslOptions()
 #ifdef SSL_OP_NO_COMPRESSION
     QCOMPARE(QSslSocketBackendPrivate::setupOpenSslOptions(QSsl::SecureProtocols,
                                                            QSslConfigurationPrivate::defaultSslOptions),
-             long(SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_NO_COMPRESSION));
+             long(SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_NO_COMPRESSION|SSL_OP_CIPHER_SERVER_PREFERENCE));
 #else
     QCOMPARE(QSslSocketBackendPrivate::setupOpenSslOptions(QSsl::SecureProtocols,
                                                            QSslConfigurationPrivate::defaultSslOptions),
-             long(SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3));
+             long(SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_CIPHER_SERVER_PREFERENCE));
 #endif
 
     QCOMPARE(QSslSocketBackendPrivate::setupOpenSslOptions(QSsl::SecureProtocols,
                                                            QSsl::SslOptionDisableEmptyFragments
                                                            |QSsl::SslOptionDisableLegacyRenegotiation),
-             long(SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3));
+             long(SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_CIPHER_SERVER_PREFERENCE));
 
 #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
     QCOMPARE(QSslSocketBackendPrivate::setupOpenSslOptions(QSsl::SecureProtocols,
                                                            QSsl::SslOptionDisableEmptyFragments),
-             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)));
+             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION|SSL_OP_CIPHER_SERVER_PREFERENCE)));
 #endif
 
 #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
     QCOMPARE(QSslSocketBackendPrivate::setupOpenSslOptions(QSsl::SecureProtocols,
                                                            QSsl::SslOptionDisableLegacyRenegotiation),
-             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3) & ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS));
+             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_CIPHER_SERVER_PREFERENCE) & ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS));
 #endif
 
 #ifdef SSL_OP_NO_TICKET
@@ -2383,7 +2461,7 @@ void tst_QSslSocket::sslOptions()
                                                            QSsl::SslOptionDisableEmptyFragments
                                                            |QSsl::SslOptionDisableLegacyRenegotiation
                                                            |QSsl::SslOptionDisableSessionTickets),
-             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_NO_TICKET)));
+             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_NO_TICKET|SSL_OP_CIPHER_SERVER_PREFERENCE)));
 #endif
 
 #ifdef SSL_OP_NO_TICKET
@@ -2393,7 +2471,7 @@ void tst_QSslSocket::sslOptions()
                                                            |QSsl::SslOptionDisableLegacyRenegotiation
                                                            |QSsl::SslOptionDisableSessionTickets
                                                            |QSsl::SslOptionDisableCompression),
-             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_NO_TICKET|SSL_OP_NO_COMPRESSION)));
+             long((SSL_OP_ALL|SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3|SSL_OP_NO_TICKET|SSL_OP_NO_COMPRESSION|SSL_OP_CIPHER_SERVER_PREFERENCE)));
 #endif
 #endif
 }