source: trunk/src/network/ssl/qsslsocket.cpp@ 561

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//#define QSSLSOCKET_DEBUG

/*!
    \class QSslSocket
    \brief The QSslSocket class provides an SSL encrypted socket for both
    clients and servers.
    \since 4.3

    \reentrant
    \ingroup network
    \ingroup ssl
    \inmodule QtNetwork

    QSslSocket establishes a secure, encrypted TCP connection you can
    use for transmitting encrypted data. It can operate in both client
    and server mode, and it supports modern SSL protocols, including
    SSLv3 and TLSv1. By default, QSslSocket uses SSLv3, but you can
    change the SSL protocol by calling setProtocol() as long as you do
    it before the handshake has started.

    SSL encryption operates on top of the existing TCP stream after
    the socket enters the ConnectedState. There are two simple ways to
    establish a secure connection using QSslSocket: With an immediate
    SSL handshake, or with a delayed SSL handshake occurring after the
    connection has been established in unencrypted mode.

    The most common way to use QSslSocket is to construct an object
    and start a secure connection by calling connectToHostEncrypted().
    This method starts an immediate SSL handshake once the connection
    has been established.

    \snippet doc/src/snippets/code/src_network_ssl_qsslsocket.cpp 0

    As with a plain QTcpSocket, QSslSocket enters the HostLookupState,
    ConnectingState, and finally the ConnectedState, if the connection
    is successful. The handshake then starts automatically, and if it
    succeeds, the encrypted() signal is emitted to indicate the socket
    has entered the encrypted state and is ready for use.

    Note that data can be written to the socket immediately after the
    return from connectToHostEncrypted() (i.e., before the encrypted()
    signal is emitted). The data is queued in QSslSocket until after
    the encrypted() signal is emitted.

    An example of using the delayed SSL handshake to secure an
    existing connection is the case where an SSL server secures an
    incoming connection. Suppose you create an SSL server class as a
    subclass of QTcpServer. You would override
    QTcpServer::incomingConnection() with something like the example
    below, which first constructs an instance of QSslSocket and then
    calls setSocketDescriptor() to set the new socket's descriptor to
    the existing one passed in. It then initiates the SSL handshake
    by calling startServerEncryption().

    \snippet doc/src/snippets/code/src_network_ssl_qsslsocket.cpp 1

    If an error occurs, QSslSocket emits the sslErrors() signal. In this
    case, if no action is taken to ignore the error(s), the connection
    is dropped. To continue, despite the occurrence of an error, you
    can call ignoreSslErrors(), either from within this slot after the
    error occurs, or any time after construction of the QSslSocket and
    before the connection is attempted. This will allow QSslSocket to
    ignore the errors it encounters when establishing the identity of
    the peer. Ignoring errors during an SSL handshake should be used
    with caution, since a fundamental characteristic of secure
    connections is that they should be established with a successful
    handshake.

    Once encrypted, you use QSslSocket as a regular QTcpSocket. When
    readyRead() is emitted, you can call read(), canReadLine() and
    readLine(), or getChar() to read decrypted data from QSslSocket's
    internal buffer, and you can call write() or putChar() to write
    data back to the peer. QSslSocket will automatically encrypt the
    written data for you, and emit encryptedBytesWritten() once
    the data has been written to the peer.

    As a convenience, QSslSocket supports QTcpSocket's blocking
    functions waitForConnected(), waitForReadyRead(),
    waitForBytesWritten(), and waitForDisconnected(). It also provides
    waitForEncrypted(), which will block the calling thread until an
    encrypted connection has been established.

    \snippet doc/src/snippets/code/src_network_ssl_qsslsocket.cpp 2

    QSslSocket provides an extensive, easy-to-use API for handling
    cryptographic ciphers, private keys, and local, peer, and
    Certification Authority (CA) certificates. It also provides an API
    for handling errors that occur during the handshake phase.

    The following features can also be customized:

    \list
    \o The socket's cryptographic cipher suite can be customized before
    the handshake phase with setCiphers() and setDefaultCiphers().
    \o The socket's local certificate and private key can be customized
    before the handshake phase with setLocalCertificate() and
    setPrivateKey().
    \o The CA certificate database can be extended and customized with
    addCaCertificate(), addCaCertificates(), setCaCertificates(),
    addDefaultCaCertificate(), addDefaultCaCertificates(), and
    setDefaultCaCertificates().
    \endlist

    For more information about ciphers and certificates, refer to QSslCipher and
    QSslCertificate.

    This product includes software developed by the OpenSSL Project
    for use in the OpenSSL Toolkit (\l{http://www.openssl.org/}).

    \note Be aware of the difference between the bytesWritten() signal and
    the encryptedBytesWritten() signal. For a QTcpSocket, bytesWritten()
    will get emitted as soon as data has been written to the TCP socket.
    For a QSslSocket, bytesWritten() will get emitted when the data
    is being encrypted and encryptedBytesWritten()
    will get emitted as soon as data has been written to the TCP socket.

    \sa QSslCertificate, QSslCipher, QSslError
*/

/*!
    \enum QSslSocket::SslMode

    Describes the connection modes available for QSslSocket.

    \value UnencryptedMode The socket is unencrypted. Its
    behavior is identical to QTcpSocket.

    \value SslClientMode The socket is a client-side SSL socket.
    It is either alreayd encrypted, or it is in the SSL handshake
    phase (see QSslSocket::isEncrypted()).

    \value SslServerMode The socket is a server-side SSL socket.
    It is either already encrypted, or it is in the SSL handshake
    phase (see QSslSocket::isEncrypted()).
*/

/*!
    \enum QSslSocket::PeerVerifyMode
    \since 4.4

    Describes the peer verification modes for QSslSocket. The default mode is
    AutoVerifyPeer, which selects an appropriate mode depending on the
    socket's QSocket::SslMode.

    \value VerifyNone QSslSocket will not request a certificate from the
    peer. You can set this mode if you are not interested in the identity of
    the other side of the connection. The connection will still be encrypted,
    and your socket will still send its local certificate to the peer if it's
    requested.

    \value QueryPeer QSslSocket will request a certificate from the peer, but
    does not require this certificate to be valid. This is useful when you
    want to display peer certificate details to the user without affecting the
    actual SSL handshake. This mode is the default for servers.

    \value VerifyPeer QSslSocket will request a certificate from the peer
    during the SSL handshake phase, and requires that this certificate is
    valid. On failure, QSslSocket will emit the QSslSocket::sslErrors()
    signal. This mode is the default for clients.

    \value AutoVerifyPeer QSslSocket will automaticaly use QueryPeer for
    server sockets and VerifyPeer for client sockets.

    \sa QSslSocket::peerVerifyMode()
*/

/*!
    \fn QSslSocket::encrypted()

    This signal is emitted when QSslSocket enters encrypted mode. After this
    signal has been emitted, QSslSocket::isEncrypted() will return true, and
    all further transmissions on the socket will be encrypted.

    \sa QSslSocket::connectToHostEncrypted(), QSslSocket::isEncrypted()
*/

/*!
    \fn QSslSocket::modeChanged(QSslSocket::SslMode mode)

    This signal is emitted when QSslSocket changes from \l
    QSslSocket::UnencryptedMode to either \l QSslSocket::SslClientMode or \l
    QSslSocket::SslServerMode. \a mode is the new mode.

    \sa QSslSocket::mode()
*/

/*!
    \fn QSslSocket::encryptedBytesWritten(qint64 written)
    \since 4.4

    This signal is emitted when QSslSocket writes its encrypted data to the
    network. The \a written parameter contains the number of bytes that were
    successfully written.

    \sa QIODevice::bytesWritten()
*/

/*!
    \fn void QSslSocket::peerVerifyError(const QSslError &error)
    \since 4.4

    QSslSocket can emit this signal several times during the SSL handshake,
    before encryption has been established, to indicate that an error has
    occurred while establishing the identity of the peer. The \a error is
    usually an indication that QSslSocket is unable to securely identify the
    peer.

    This signal provides you with an early indication when something's wrong.
    By connecting to this signal, you can manually choose to tear down the
    connection from inside the connected slot before the handshake has
    completed. If no action is taken, QSslSocket will proceed to emitting
    QSslSocket::sslErrors().

    \sa sslErrors()
*/

/*!
    \fn void QSslSocket::sslErrors(const QList<QSslError> &errors);
    
    QSslSocket emits this signal after the SSL handshake to indicate that one
    or more errors have occurred while establishing the identity of the
    peer. The errors are usually an indication that QSslSocket is unable to
    securely identify the peer. Unless any action is taken, the connection
    will be dropped after this signal has been emitted.

    If you want to continue connecting despite the errors that have occurred,
    you must call QSslSocket::ignoreSslErrors() from inside a slot connected to
    this signal. If you need to access the error list at a later point, you
    can call sslErrors() (without arguments).

    \a errors contains one or more errors that prevent QSslSocket from
    verifying the identity of the peer.
    
    Note: You cannot use Qt::QueuedConnection when connecting to this signal,
    or calling QSslSocket::ignoreSslErrors() will have no effect.

    \sa peerVerifyError()
*/

#include "qsslcipher.h"
#include "qsslsocket.h"
#include "qsslsocket_openssl_p.h"
#include "qsslconfiguration_p.h"

#include <QtCore/qdebug.h>
#include <QtCore/qdir.h>
#include <QtCore/qdatetime.h>
#include <QtCore/qmutex.h>
#include <QtNetwork/qhostaddress.h>
#include <QtNetwork/qhostinfo.h>

QT_BEGIN_NAMESPACE

/*
   Returns the difference between msecs and elapsed. If msecs is -1,
   however, -1 is returned.
*/
static int qt_timeout_value(int msecs, int elapsed)
{
    if (msecs == -1)
        return -1;

    int timeout = msecs - elapsed;
    return timeout < 0 ? 0 : timeout;
}

class QSslSocketGlobalData
{
public:
    QSslSocketGlobalData() : config(new QSslConfigurationPrivate) {}

    QMutex mutex;
    QList<QSslCipher> supportedCiphers;
    QExplicitlySharedDataPointer<QSslConfigurationPrivate> config;
};
Q_GLOBAL_STATIC(QSslSocketGlobalData, globalData)

/*!
    Constructs a QSslSocket object. \a parent is passed to QObject's
    constructor. The new socket's \l {QSslCipher} {cipher} suite is
    set to the one returned by the static method defaultCiphers().
*/
QSslSocket::QSslSocket(QObject *parent)
    : QTcpSocket(*new QSslSocketBackendPrivate, parent)
{
    Q_D(QSslSocket);
#ifdef QSSLSOCKET_DEBUG
    qDebug() << "QSslSocket::QSslSocket(" << parent << "), this =" << (void *)this;
#endif
    d->q_ptr = this;
    d->init();
}

/*!
    Destroys the QSslSocket.
*/
QSslSocket::~QSslSocket()
{
    Q_D(QSslSocket);
#ifdef QSSLSOCKET_DEBUG
    qDebug() << "QSslSocket::~QSslSocket(), this =" << (void *)this;
#endif
    delete d->plainSocket;
    d->plainSocket = 0;
}

/*!
    Starts an encrypted connection to the device \a hostName on \a
    port, using \a mode as the \l OpenMode. This is equivalent to
    calling connectToHost() to establish the connection, followed by a
    call to startClientEncryption().

    QSslSocket first enters the HostLookupState. Then, after entering
    either the event loop or one of the waitFor...() functions, it
    enters the ConnectingState, emits connected(), and then initiates
    the SSL client handshake. At each state change, QSslSocket emits
    signal stateChanged().

    After initiating the SSL client handshake, if the identity of the
    peer can't be established, signal sslErrors() is emitted. If you
    want to ignore the errors and continue connecting, you must call
    ignoreSslErrors(), either from inside a slot function connected to
    the sslErrors() signal, or prior to entering encrypted mode. If
    ignoreSslErrors() is not called, the connection is dropped, signal
    disconnected() is emitted, and QSslSocket returns to the
    UnconnectedState.

    If the SSL handshake is successful, QSslSocket emits encrypted().

    \snippet doc/src/snippets/code/src_network_ssl_qsslsocket.cpp 3

    \bold{Note:} The example above shows that text can be written to
    the socket immediately after requesting the encrypted connection,
    before the encrypted() signal has been emitted. In such cases, the
    text is queued in the object and written to the socket \e after
    the connection is established and the encrypted() signal has been
    emitted.

    The default for \a mode is \l ReadWrite.

    If you want to create a QSslSocket on the server side of a connection, you
    should instead call startServerEncryption() upon receiving the incoming
    connection through QTcpServer.

    \sa connectToHost(), startClientEncryption(), waitForConnected(), waitForEncrypted()
*/
void QSslSocket::connectToHostEncrypted(const QString &hostName, quint16 port, OpenMode mode)
{
    Q_D(QSslSocket);
    if (d->state == ConnectedState || d->state == ConnectingState) {
        qWarning("QSslSocket::connectToHostEncrypted() called when already connecting/connected");
        return;
    }

    d->init();
    d->autoStartHandshake = true;
    d->initialized = true;

    // Note: When connecting to localhost, some platforms (e.g., HP-UX and some BSDs)
    // establish the connection immediately (i.e., first attempt).
    connectToHost(hostName, port, mode);
}

/*!
    \since 4.6
    \overload

    In addition to the original behaviour of connectToHostEncrypted,
    this overloaded method enables the usage of a different hostname 
    (\a sslPeerName) for the certificate validation instead of
    the one used for the TCP connection (\a hostName).

    \sa connectToHostEncrypted()
*/
void QSslSocket::connectToHostEncrypted(const QString &hostName, quint16 port,
                                        const QString &sslPeerName, OpenMode mode)
{
    Q_D(QSslSocket);
    if (d->state == ConnectedState || d->state == ConnectingState) {
        qWarning("QSslSocket::connectToHostEncrypted() called when already connecting/connected");
        return;
    }

    d->init();
    d->autoStartHandshake = true;
    d->initialized = true;
    d->verificationPeerName = sslPeerName;

    // Note: When connecting to localhost, some platforms (e.g., HP-UX and some BSDs)
    // establish the connection immediately (i.e., first attempt).
    connectToHost(hostName, port, mode);
}

/*!
    Initializes QSslSocket with the native socket descriptor \a
    socketDescriptor. Returns true if \a socketDescriptor is accepted
    as a valid socket descriptor; otherwise returns false.
    The socket is opened in the mode specified by \a openMode, and
    enters the socket state specified by \a state.

    \bold{Note:} It is not possible to initialize two sockets with the same
    native socket descriptor.

    \sa socketDescriptor()
*/
bool QSslSocket::setSocketDescriptor(int socketDescriptor, SocketState state, OpenMode openMode)
{
    Q_D(QSslSocket);
#ifdef QSSLSOCKET_DEBUG
    qDebug() << "QSslSocket::setSocketDescriptor(" << socketDescriptor << ','
             << state << ',' << openMode << ')';
#endif
    if (!d->plainSocket)
        d->createPlainSocket(openMode);
    bool retVal = d->plainSocket->setSocketDescriptor(socketDescriptor, state, openMode);
    d->cachedSocketDescriptor = d->plainSocket->socketDescriptor();
    setSocketError(d->plainSocket->error());
    setSocketState(state);
    setOpenMode(openMode);
    setLocalPort(d->plainSocket->localPort());
    setLocalAddress(d->plainSocket->localAddress());
    setPeerPort(d->plainSocket->peerPort());
    setPeerAddress(d->plainSocket->peerAddress());
    setPeerName(d->plainSocket->peerName());
    return retVal;
}

/*!
    \since 4.6
    Sets the given \a option to the value described by \a value.

    \sa socketOption()
*/
void QSslSocket::setSocketOption(QAbstractSocket::SocketOption option, const QVariant &value)
{
    Q_D(QSslSocket);
    if (d->plainSocket)
        d->plainSocket->setSocketOption(option, value);
}

/*!
    \since 4.6
    Returns the value of the \a option option.

    \sa setSocketOption()
*/
QVariant QSslSocket::socketOption(QAbstractSocket::SocketOption option)
{
    Q_D(QSslSocket);
    if (d->plainSocket)
        return d->plainSocket->socketOption(option);
    else
        return QVariant();
}

/*!
    Returns the current mode for the socket; either UnencryptedMode, where
    QSslSocket behaves identially to QTcpSocket, or one of SslClientMode or
    SslServerMode, where the client is either negotiating or in encrypted
    mode.

    When the mode changes, QSslSocket emits modeChanged()

    \sa SslMode
*/
QSslSocket::SslMode QSslSocket::mode() const
{
    Q_D(const QSslSocket);
    return d->mode;
}

/*!
    Returns true if the socket is encrypted; otherwise, false is returned.

    An encrypted socket encrypts all data that is written by calling write()
    or putChar() before the data is written to the network, and decrypts all
    incoming data as the data is received from the network, before you call
    read(), readLine() or getChar().

    QSslSocket emits encrypted() when it enters encrypted mode.

    You can call sessionCipher() to find which cryptographic cipher is used to
    encrypt and decrypt your data.

    \sa mode()
*/
bool QSslSocket::isEncrypted() const
{
    Q_D(const QSslSocket);
    return d->connectionEncrypted;
}

/*!
    Returns the socket's SSL protocol. By default, \l QSsl::SslV3 is used.

    \sa setProtocol()
*/
QSsl::SslProtocol QSslSocket::protocol() const
{
    Q_D(const QSslSocket);
    return d->configuration.protocol;
}

/*!
    Sets the socket's SSL protocol to \a protocol. This will affect the next
    initiated handshake; calling this function on an already-encrypted socket
    will not affect the socket's protocol.
*/
void QSslSocket::setProtocol(QSsl::SslProtocol protocol)
{
    Q_D(QSslSocket);
    d->configuration.protocol = protocol;
}

/*!
    \since 4.4

    Returns the socket's verify mode. This mode mode decides whether
    QSslSocket should request a certificate from the peer (i.e., the client
    requests a certificate from the server, or a server requesting a
    certificate from the client), and whether it should require that this
    certificate is valid.

    The default mode is AutoVerifyPeer, which tells QSslSocket to use
    VerifyPeer for clients, QueryPeer for clients.

    \sa setPeerVerifyMode(), peerVerifyDepth(), mode()
*/
QSslSocket::PeerVerifyMode QSslSocket::peerVerifyMode() const
{
    Q_D(const QSslSocket);
    return d->configuration.peerVerifyMode;
}

/*!
    \since 4.4

    Sets the socket's verify mode to \a mode. This mode decides whether
    QSslSocket should request a certificate from the peer (i.e., the client
    requests a certificate from the server, or a server requesting a
    certificate from the client), and whether it should require that this
    certificate is valid.

    The default mode is AutoVerifyPeer, which tells QSslSocket to use
    VerifyPeer for clients, QueryPeer for clients.