qtransportauth_qws.cpp

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#include "qtransportauth_qws.h"
#include "qtransportauth_qws_p.h"

#ifndef QT_NO_SXE

#include "../../3rdparty/md5/md5.h"
#include "../../3rdparty/md5/md5.cpp"
#include "qwsutils_qws.h"
#include "qwssocket_qws.h"
#include "qwscommand_qws_p.h"
#include "qwindowsystem_qws.h"
#include "qbuffer.h"
#include "qthread.h"
#include "qabstractsocket.h"
#include "qlibraryinfo.h"
#include "qfile.h"
#include "qdebug.h"
#include <private/qcore_unix_p.h> // overrides QT_OPEN

#include <syslog.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>

#include <QtCore/qcache.h>

#define BUF_SIZE 512

QT_BEGIN_NAMESPACE

Q_GUI_EXPORT void *guaranteed_memset(void *v,int c,size_t n)
{
    volatile char *p = (char *)v; while (n--) *p++=c; return v;
}

static int hmac_md5(
        unsigned char*  text,         /* pointer to data stream */
        int             text_length,  /* length of data stream */
        const unsigned char*  key,    /* pointer to authentication key */
        int             key_length,   /* length of authentication key */
        unsigned char * digest        /* caller digest to be filled in */
        );



#define KEY_CACHE_SIZE 30

const char * const errorStrings[] = {
    "pending identity verification",
    "message too small to carry auth data",
    "cache miss on connection oriented transport",
    "no magic bytes on message",
    "key not found for prog id",
    "authorization key match failed",
    "key out of date"
};

const char *QTransportAuth::errorString( const Data &d )
{
    if (( d.status & ErrMask ) == Success )
        return "success";
    int e = d.status & ErrMask;
    if ( e > OutOfDate )
        return "unknown";
    return errorStrings[e];
}

SxeRegistryLocker::SxeRegistryLocker( QObject *reg )
    : m_success( false )
    , m_reg( 0 )
{
    if ( reg )
        if ( !QMetaObject::invokeMethod( reg, "lockManifest", Q_RETURN_ARG(bool, m_success) ))
            m_success = false;
    m_reg = reg;
}

SxeRegistryLocker::~SxeRegistryLocker()
{
    if ( m_success )
        QMetaObject::invokeMethod( m_reg, "unlockManifest" );
}


QTransportAuthPrivate::QTransportAuthPrivate()
    : keyInitialised(false)
    , m_packageRegistry( 0 )
{
}

QTransportAuthPrivate::~QTransportAuthPrivate()
{
}

QTransportAuth::QTransportAuth() : QObject(*new QTransportAuthPrivate)
{
    // qDebug( "creating transport auth" );
}

QTransportAuth::~QTransportAuth()
{
    // qDebug( "deleting transport auth" );
}

void QTransportAuth::setProcessKey( const char *authdata )
{
    Q_D(QTransportAuth);
    ::memcpy(&d->authKey, authdata, sizeof(struct AuthCookie));
    QFile proc_key( QLatin1String("/proc/self/lids_key") );
    // where proc key exists use that instead
    if ( proc_key.open( QIODevice::ReadOnly ))
    {
        qint64 kb = proc_key.read( (char*)&d->authKey.key, QSXE_KEY_LEN );
#ifdef QTRANSPORTAUTH_DEBUG
        qDebug( "Using %li bytes of /proc/%i/lids_key\n", (long int)kb, getpid() );
#else
        Q_UNUSED( kb );
#endif
    }
    d->keyInitialised = true;
}


void QTransportAuth::setProcessKey( const char *key, const char *prog )
{
    Q_UNUSED(prog);
    setProcessKey( key );
#ifdef QTRANSPORTAUTH_DEBUG
    char displaybuf[QSXE_KEY_LEN*2+1];
    hexstring( displaybuf, (const unsigned char *)key, QSXE_KEY_LEN );
    qDebug() << "key" << displaybuf << "set";
#endif
}

void QTransportAuth::registerPolicyReceiver( QObject *pr )
{
    // not every policy receiver needs setup - no error if this fails
    QMetaObject::invokeMethod( pr, "setupPolicyCheck" );

    connect( this, SIGNAL(policyCheck(QTransportAuth::Data&,QString)),
             pr, SLOT(policyCheck(QTransportAuth::Data&,QString)), Qt::DirectConnection );
}

void QTransportAuth::unregisterPolicyReceiver( QObject *pr )
{
    disconnect( pr );
    // not every policy receiver needs tear down - no error if this fails
    QMetaObject::invokeMethod( pr, "teardownPolicyCheck" );
}

QTransportAuth::Data *QTransportAuth::connectTransport( unsigned char properties, int descriptor )
{
    Data *data = new Data(properties, descriptor);
    data->status = Pending;
    return data;
}

inline bool QTransportAuth::Data::trusted() const
{
    return (bool)(properties & Trusted);
}

inline void QTransportAuth::Data::setTrusted( bool t )
{
    properties = t ? properties | Trusted : properties & ~Trusted;
}

inline bool QTransportAuth::Data::connection() const
{
    return (bool)(properties & Connection);
}

inline void QTransportAuth::Data::setConnection( bool t )
{
    properties = t ? properties | Connection : properties & ~Connection;
}

QTransportAuth *QTransportAuth::getInstance()
{
    static QTransportAuth theInstance;

    return &theInstance;
}

void QTransportAuth::setKeyFilePath( const QString &path )
{
    Q_D(QTransportAuth);
    d->m_keyFilePath = path;
}

QString QTransportAuth::keyFilePath() const
{
    Q_D(const QTransportAuth);
    return d->m_keyFilePath;
}

void QTransportAuth::setLogFilePath( const QString &path )
{
    Q_D(QTransportAuth);
    d->m_logFilePath = path;
}

QString QTransportAuth::logFilePath() const
{
    Q_D(const QTransportAuth);
    return d->m_logFilePath;
}

void QTransportAuth::setPackageRegistry( QObject *registry )
{
    Q_D(QTransportAuth);
    d->m_packageRegistry = registry;
}

bool QTransportAuth::isDiscoveryMode() const
{
#if defined(SXE_DISCOVERY)
    static bool checked = false;
    static bool yesItIs = false;

    if ( checked ) return yesItIs;

    yesItIs = ( getenv( "SXE_DISCOVERY_MODE" ) != 0 );
    if ( yesItIs )
    {
        qWarning("SXE Discovery mode on, ALLOWING ALL requests and logging to %s",
                 qPrintable(logFilePath()));
        QFile::remove( logFilePath() );
    }
    checked = true;
    return yesItIs;
#else
    return false;
#endif
}

QIODevice *QTransportAuth::passThroughByClient( QWSClient *client ) const
{
    Q_D(const QTransportAuth);

    if ( client == 0 ) return 0;
    if ( d->buffersByClient.contains( client ))
    {
        return d->buffersByClient[client];
    }
    // qWarning( "buffer not found for client %p", client );
    return 0;
}

QAuthDevice *QTransportAuth::recvBuf( QTransportAuth::Data *data, QIODevice *iod )
{
    return new QAuthDevice( iod, data, QAuthDevice::Receive );
}

QAuthDevice *QTransportAuth::authBuf( QTransportAuth::Data *data, QIODevice *iod )
{
    return new QAuthDevice( iod, data, QAuthDevice::Send );
}

const unsigned char *QTransportAuth::getClientKey( unsigned char progId )
{
    Q_D(QTransportAuth);
    return d->getClientKey( progId );
}

void QTransportAuth::invalidateClientKeyCache()
{
    Q_D(QTransportAuth);
    d->invalidateClientKeyCache();
}

QMutex *QTransportAuth::getKeyFileMutex()
{
    Q_D(QTransportAuth);
    return &d->keyfileMutex;
}

/*
   \internal
   Respond to the destroyed(QObject*) signal of the QAuthDevice's
   client object and remove it from the buffersByClient lookup hash.
*/
void QTransportAuth::bufferDestroyed( QObject *cli )
{
    Q_D(QTransportAuth);
    if ( cli == NULL ) return;

    if ( d->buffersByClient.contains( cli ))
    {
        d->buffersByClient.remove( cli );
        // qDebug( "@@@@@@@ client %p removed @@@@@@@@@", cli );
    }
    // qDebug( "           client count %d", d->buffersByClient.count() );
}

bool QTransportAuth::authorizeRequest( QTransportAuth::Data &d, const QString &request )
{
    bool isAuthorized = true;

    if ( !request.isEmpty() && request != QLatin1String("Unknown") )
    {
        d.status &= QTransportAuth::ErrMask;  // clear the status
        emit policyCheck( d, request );
        isAuthorized = (( d.status & QTransportAuth::StatusMask ) == QTransportAuth::Allow );
    }
#if defined(SXE_DISCOVERY)
    if (isDiscoveryMode()) {
#ifndef QT_NO_TEXTSTREAM
        if (!logFilePath().isEmpty()) {
            QFile log( logFilePath() );
            if (!log.open(QIODevice::WriteOnly | QIODevice::Append)) {
                qWarning("Could not write to log in discovery mode: %s",
                         qPrintable(logFilePath()));
            } else {
                QTextStream ts( &log );
                ts << d.progId << '\t' << ( isAuthorized ? "Allow" : "Deny" ) << '\t' << request << endl;
            }
        }
#endif
        isAuthorized = true;
    }
#endif
    if ( !isAuthorized )
    {
        qWarning( "%s - denied: for Program Id %u [PID %d]"
                , qPrintable(request), d.progId, d.processId );

        char linkTarget[BUF_SIZE]="";
        char exeLink[BUF_SIZE]="";
        char cmdlinePath[BUF_SIZE]="";
        char cmdline[BUF_SIZE]="";

        //get executable from /proc/pid/exe
        snprintf( exeLink, BUF_SIZE, "/proc/%d/exe", d.processId );
        if ( -1 == ::readlink( exeLink, linkTarget, BUF_SIZE - 1 ) )
        {
            qWarning( "SXE:- Error encountered in retrieving executable link target from /proc/%u/exe : %s",
                d.processId, strerror(errno) );
            snprintf( linkTarget, BUF_SIZE, "%s", linkTarget );
        }

        //get cmdline from proc/pid/cmdline
        snprintf( cmdlinePath, BUF_SIZE, "/proc/%d/cmdline", d.processId );
        int  cmdlineFd = QT_OPEN( cmdlinePath, O_RDONLY );
        if ( cmdlineFd == -1 )
        {
            qWarning( "SXE:- Error encountered in opening /proc/%u/cmdline: %s",
                d.processId, strerror(errno) );
            snprintf( cmdline, BUF_SIZE, "%s", "Unknown" );
        }
        else
        {
            if ( -1 == QT_READ(cmdlineFd, cmdline, BUF_SIZE - 1 ) )
            {
                qWarning( "SXE:- Error encountered in reading /proc/%u/cmdline : %s",
                    d.processId, strerror(errno) );
                snprintf( cmdline, BUF_SIZE, "%s", "Unknown" );
            }
            QT_CLOSE( cmdlineFd );
        }

        syslog( LOG_ERR | LOG_LOCAL6, "%s // PID:%u // ProgId:%u // Exe:%s // Request:%s // Cmdline:%s",
                "<SXE Breach>", d.processId, d.progId, linkTarget, qPrintable(request), cmdline);
    }

    return isAuthorized;
}

inline bool __fileOpen( QFile *f )
{
#ifdef QTRANSPORTAUTH_DEBUG
    if ( f->open( QIODevice::ReadOnly ))
    {
        qDebug( "Opened file: %s\n", qPrintable( f->fileName() ));
        return true;
    }
    else
    {
        qWarning( "Could not open file: %s\n", qPrintable( f->fileName() ));
        return false;
    }
#else
    return ( f->open( QIODevice::ReadOnly ));
#endif
}

const unsigned char *QTransportAuthPrivate::getClientKey(unsigned char progId)
{
    int manifestMatchCount = 0;
    struct IdBlock mr;
    int total_size = 0;
    char *result = 0;
    char *result_ptr;
    int keysFound = 0;
    bool foundKey;
    int keysRead = 0;
    struct usr_key_entry keys_list[128];

    if ( keyCache.contains( progId ))
        return (const unsigned char *)keyCache[progId];

    SxeRegistryLocker rlock( m_packageRegistry );

    // ### Qt 4.3: this is hacky - see documentation for setKeyFilePath
    QString manifestPath = m_keyFilePath + QLatin1String("/manifest");
    QString actualKeyPath = QLatin1String("/proc/lids/keys");
    bool noFailOnKeyMissing = true;
    if ( !QFile::exists( actualKeyPath )) {
        actualKeyPath = m_keyFilePath + QLatin1String( "/" QSXE_KEYFILE );
    }
    QFile kf( actualKeyPath );
    QFile mn( manifestPath );
    if ( !__fileOpen( &mn ))
        goto key_not_found;
    // first find how much storage is needed
    while ( mn.read( (char*)&mr, sizeof(struct IdBlock)) > 0 )
        if ( mr.progId == progId )
            manifestMatchCount++;
    if ( manifestMatchCount == 0 )
        goto key_not_found;
    if ( !__fileOpen( &kf ))
    {
        noFailOnKeyMissing = false;
        goto key_not_found;
    }
    total_size = 2 * QSXE_MAGIC_BYTES + manifestMatchCount * QSXE_KEY_LEN;
    result = (char*)malloc( total_size );
    Q_CHECK_PTR( result );
    mn.seek( 0 );
    result_ptr = result;
    /* reading whole key array in is much more efficient, 99% case is this loop only
       executes once, should not have more than 128 keyed items */
    while (( keysRead = kf.read( (char*)keys_list, sizeof(struct usr_key_entry)*128 )) > 0 )
    {
        /* qDebug("PID %d: getClientKey() - read %d bytes = %d keys from %s", getpid(), keysRead,
                keysRead/sizeof(struct usr_key_entry), qPrintable(actualKeyPath)); */
        keysRead /= sizeof(struct usr_key_entry);
        while ( mn.read( (char*)&mr, sizeof(struct IdBlock)) > 0 )
        {
            if ( mr.progId == progId )
            {
                foundKey = false;
                for ( int i = 0; i < keysRead; ++i )
                {
                    /* if ( i == 0 )
                        qDebug() << "         pid" << getpid() << "looking for device"  << (dev_t)mr.device << "inode" << (ino_t)mr.inode;
                    qDebug() << "         pid" << getpid() << "trying device" <<  keys_list[i].dev << "inode" <<  keys_list[i].ino; */
                    if ( keys_list[i].ino == (ino_t)mr.inode && keys_list[i].dev == (dev_t)mr.device )
                    {
                        memcpy( result_ptr, keys_list[i].key, QSXE_KEY_LEN );
                        result_ptr += QSXE_KEY_LEN;
                        foundKey = true;
                        break;
                    }
                }
                if ( foundKey )
                {
                    keysFound++;
                    if ( keysFound == manifestMatchCount )
                        break;
                }
            }
        }
    }
    if ( result_ptr == result ) // nothing found!
        goto key_not_found;
    // 2 x magic bytes sentinel at end of sequence
    for ( int i = 0; i < 2; ++i )
        for ( int j = 0; j < QSXE_MAGIC_BYTES; ++j )
            *result_ptr++ = magic[j];
    keyCache.insert( progId, result, total_size / 10 );
    /* qDebug( "PID %d : Found %d client keys for prog %u", getpid(), keysFound, progId ); */
    goto success_out;

key_not_found:
    if ( noFailOnKeyMissing )  // return an "empty" set of keys in this case
    {
        if ( result == 0 )
        {
            result = (char*)malloc( 2 * QSXE_MAGIC_BYTES );
            Q_CHECK_PTR( result );
        }
        result_ptr = result;
        for ( int i = 0; i < 2; ++i )
            for ( int j = 0; j < QSXE_MAGIC_BYTES; ++j )
                *result_ptr++ = magic[j];
        return (unsigned char *)result;
    }
    qWarning( "PID %d : Not found client key for prog %u", getpid(), progId );
    if ( result )
    {
        free( result );
        result = 0;
    }
success_out:
    if ( mn.isOpen() )
        mn.close();
    if ( kf.isOpen() )
        kf.close();
    return (unsigned char *)result;
}

void QTransportAuthPrivate::invalidateClientKeyCache()
{
    keyfileMutex.lock();
    keyCache.clear();
    keyfileMutex.unlock();
}



RequestAnalyzer::RequestAnalyzer()
    : moreData( false )
    , dataSize( 0 )
{
}

RequestAnalyzer::~RequestAnalyzer()
{
}

QString RequestAnalyzer::analyze( QByteArray *msgQueue )
{
#ifdef Q_WS_QWS
    dataSize = 0;
    moreData = false;
    QBuffer cmdBuf( msgQueue );
    cmdBuf.open( QIODevice::ReadOnly | QIODevice::Unbuffered );
    QWSCommand::Type command_type = (QWSCommand::Type)(qws_read_uint( &cmdBuf ));
    QWSCommand *command = QWSCommand::factory(command_type);
    // if NULL, factory will have already printed warning for bogus
    // command_type just purge the bad stuff and attempt to recover
    if ( command == NULL )
    {
        *msgQueue = msgQueue->mid( sizeof(int) );
        return QString();
    }
    QString request = QLatin1String(qws_getCommandTypeString(command_type));
#ifndef QT_NO_COP
    if ( !command->read( &cmdBuf ))
    {
        // not all command arrived yet - come back later
        delete command;
        moreData = true;
        return QString();
    }
    if ( command_type == QWSCommand::QCopSend )
    {
        QWSQCopSendCommand *sendCommand = static_cast<QWSQCopSendCommand*>(command);
        request += QString::fromLatin1("/QCop/%1/%2").arg( sendCommand->channel ).arg( sendCommand->message );
    }
    if ( command_type == QWSCommand::QCopRegisterChannel )
    {
        QWSQCopRegisterChannelCommand *registerCommand = static_cast<QWSQCopRegisterChannelCommand*>(command);
        request += QString::fromLatin1("/QCop/RegisterChannel/%1").arg( registerCommand->channel );
    }
#endif
    dataSize = QWS_PROTOCOL_ITEM_SIZE( *command );
    delete command;
    return request;
#else
    Q_UNUSED(msgQueue);
    return QString();
#endif
}


QAuthDevice::QAuthDevice( QIODevice *parent, QTransportAuth::Data *data, AuthDirection dir )
    : QIODevice( parent )
    , d( data )
    , way( dir )
    , m_target( parent )
    , m_client( 0 )
    , m_bytesAvailable( 0 )
    , m_skipWritten( 0 )
    , analyzer( 0 )
{
    if ( dir == Receive ) // server side
    {
        connect( m_target, SIGNAL(readyRead()),
                this, SLOT(recvReadyRead()));
    } else {
        connect( m_target, SIGNAL(readyRead()),
                this, SIGNAL(readyRead()));
    }
    connect( m_target, SIGNAL(bytesWritten(qint64)),
            this, SLOT(targetBytesWritten(qint64)) );
    open( QIODevice::ReadWrite | QIODevice::Unbuffered );
}

QAuthDevice::~QAuthDevice()
{
    if ( analyzer )
        delete analyzer;
    delete d;
}

void QAuthDevice::setClient( QObject *cli )
{
    m_client = cli;
    QTransportAuth::getInstance()->d_func()->buffersByClient[cli] = this;
    QObject::connect( cli, SIGNAL(destroyed(QObject*)),
            QTransportAuth::getInstance(), SLOT(bufferDestroyed(QObject*)) );
    // qDebug( "@@@@@@@@@@@@ client set %p @@@@@@@@@", cli );
    // qDebug( "           client count %d", QTransportAuth::getInstance()->d_func()->buffersByClient.count() );
}

QObject *QAuthDevice::client() const
{
    return m_client;
}

/*
  \fn void QAuthDevice::authViolation(QTransportAuth::Data &)

  This signal is emitted if an authorization failure is generated, as
  described in checkAuth();

  \sa checkAuth()
*/


/*
  \fn void QAuthDevice::policyCheck(QTransportAuth::Data &transport, const QString &request )

  This signal is emitted when a transport successfully delivers a request
  and gives the opportunity to either deny or accept the request.

  This signal must be connected in the same thread, ie it cannot be queued.

  As soon as all handlers connected to this signal are processed the Allow or
  Deny state on the \a transport is checked, and the request is allowed or denied
  accordingly.

  \sa checkAuth()
*/

qint64 QAuthDevice::writeData(const char *data, qint64 len)
{
    if ( way == Receive )  // server
        return m_target->write( data, len );
    // client
#ifdef QTRANSPORTAUTH_DEBUG
    char displaybuf[1024];
#endif
    char header[QSXE_HEADER_LEN];
    ::memset( header, 0, QSXE_HEADER_LEN );
    qint64 bytes = 0;
    if ( QTransportAuth::getInstance()->authToMessage( *d, header, data, len ))
    {
        m_target->write( header, QSXE_HEADER_LEN );
#ifdef QTRANSPORTAUTH_DEBUG
        hexstring( displaybuf, (const unsigned char *)header, QSXE_HEADER_LEN );
        qDebug( "%d QAuthDevice::writeData - CLIENT: Header written: %s", getpid(), displaybuf );
#endif
        m_skipWritten += QSXE_HEADER_LEN;
    }
    m_target->write( data, len );
    bytes += len;
#ifdef QTRANSPORTAUTH_DEBUG
    int bytesToDisplay = bytes;
    const unsigned char *dataptr = (const unsigned char *)data;
    while ( bytesToDisplay > 0 )
    {
        int amt = bytes < 500 ? bytes : 500;
        hexstring( displaybuf, dataptr, amt );
        qDebug( "%d QAuthDevice::writeData - CLIENT: %s", getpid(), bytes > 0 ? displaybuf : "(null)" );
        dataptr += 500;
        bytesToDisplay -= 500;
    }
#endif
    if ( m_target->inherits( "QAbstractSocket" ))
        static_cast<QAbstractSocket*>(m_target)->flush();
    return bytes;
}

qint64 QAuthDevice::readData( char *data, qint64 maxSize )
{
    if ( way == Send )  // client
        return m_target->read( data, maxSize );
    if ( msgQueue.size() == 0 )
        return 0;
#ifdef QTRANSPORTAUTH_DEBUG
    char displaybuf[1024];
    hexstring( displaybuf, reinterpret_cast<const unsigned char *>(msgQueue.constData()),
            msgQueue.size() > 500 ? 500 : msgQueue.size() );
    qDebug() << getpid() << "QAuthDevice::readData() buffered/requested/avail"
            << msgQueue.size() << maxSize << m_bytesAvailable << displaybuf;
#endif
    Q_ASSERT( m_bytesAvailable <= msgQueue.size() );
    qint64 bytes = ( maxSize > m_bytesAvailable ) ? m_bytesAvailable : maxSize;
    ::memcpy( data, msgQueue.constData(), bytes );
    msgQueue = msgQueue.mid( bytes );
    m_bytesAvailable -= bytes;
    return bytes;
}

void QAuthDevice::recvReadyRead()
{
    qint64 bytes = m_target->bytesAvailable();
    if ( bytes <= 0 ) return;
    open( QIODevice::ReadWrite | QIODevice::Unbuffered );
    QUnixSocket *usock = static_cast<QUnixSocket*>(m_target);
    QUnixSocketMessage msg = usock->read();
    msgQueue.append( msg.bytes() );
    d->processId = msg.processId();
    // if "fragmented" packet 1/2 way through start of a command, ie
    // in the QWS msg type, cant do anything, come back later when
    // there's more of the packet
    if ( msgQueue.size() < (int)sizeof(int) )
    {
        // qDebug() << "returning: msg size too small" << msgQueue.size();
        return;
    }
#ifdef QTRANSPORTAUTH_DEBUG
    char displaybuf[1024];
    hexstring( displaybuf, reinterpret_cast<const unsigned char *>(msgQueue.constData()),
            msgQueue.size() > 500 ? 500 : msgQueue.size() );
    qDebug( "%d ***** SERVER read %lli bytes - msg %s", getpid(), bytes, displaybuf );
#endif

    bool bufHasMessages = msgQueue.size() >= (int)sizeof(int);
    while ( bufHasMessages )
    {
        unsigned char saveStatus = d->status;
        if (( d->status & QTransportAuth::ErrMask ) == QTransportAuth::NoSuchKey )
        {
            QTransportAuth::getInstance()->authorizeRequest( *d, QLatin1String("NoSuchKey") );
            break;
        }
        if ( !QTransportAuth::getInstance()->authFromMessage( *d, msgQueue, msgQueue.size() ))
        {
            // not all arrived yet?  come back later
            if (( d->status & QTransportAuth::ErrMask ) == QTransportAuth::TooSmall )
            {
                d->status = saveStatus;
                return;
            }
        }
        if (( d->status & QTransportAuth::ErrMask ) == QTransportAuth::NoMagic )
        {
            // no msg auth header, don't change the success status for connections
            if ( d->connection() )
                d->status = saveStatus;
        }
        else
        {
            // msg auth header detected and auth determined, remove hdr
            msgQueue = msgQueue.mid( QSXE_HEADER_LEN );
        }
        if ( !authorizeMessage() )
            break;
        bufHasMessages = msgQueue.size() >= (int)sizeof(int);
    }
}

void QAuthDevice::targetBytesWritten( qint64 bytes )
{
    if ( m_skipWritten >= bytes ) {
        m_skipWritten -= bytes;
        bytes = 0;
    } else if ( m_skipWritten > 0 ) {
        bytes -= m_skipWritten;
        m_skipWritten = 0;
    }
    if ( bytes > 0 ) {
        emit bytesWritten( bytes );
    }
}

bool QAuthDevice::authorizeMessage()
{
    if ( analyzer == NULL )
        analyzer = new RequestAnalyzer();
    QString request = (*analyzer)( &msgQueue );
    if ( analyzer->requireMoreData() )
        return false;
    bool isAuthorized = true;

    if ( !request.isEmpty() && request != QLatin1String("Unknown") )
    {
        isAuthorized = QTransportAuth::getInstance()->authorizeRequest( *d, request );
    }

    bool moreToProcess = ( msgQueue.size() - analyzer->bytesAnalyzed() ) > (int)sizeof(int);
    if ( isAuthorized )
    {
#ifdef QTRANSPORTAUTH_DEBUG
        qDebug() << getpid() << "SERVER authorized: releasing" << analyzer->bytesAnalyzed() << "byte command" << request;
#endif
        m_bytesAvailable = analyzer->bytesAnalyzed();
        emit QIODevice::readyRead();
        return moreToProcess;
    }
    else
    {
        msgQueue = msgQueue.mid( analyzer->bytesAnalyzed() );
    }

    return true;
}

void QAuthDevice::setRequestAnalyzer( RequestAnalyzer *ra )
{
    Q_ASSERT( ra );
    if ( analyzer )
        delete analyzer;
    analyzer = ra;
}

bool QTransportAuth::authToMessage( QTransportAuth::Data &d, char *hdr, const char *msg, int msgLen )
{
    // qDebug( "authToMessage(): prog id %u", d.progId );
    // only authorize connection oriented transports once, unless key has changed
    if ( d.connection() && ((d.status & QTransportAuth::ErrMask) != QTransportAuth::Pending) &&
        d_func()->authKey.progId == d.progId )
        return false;
    d.progId = d_func()->authKey.progId;
    // If Unix socket credentials are being used the key wont be set
    if ( !d_func()->keyInitialised )
        return false;
    unsigned char digest[QSXE_KEY_LEN];
    char *msgPtr = hdr;
    // magic always goes on the beginning
    for ( int m = 0; m < QSXE_MAGIC_BYTES; ++m )
        *msgPtr++ = magic[m];
    hdr[ QSXE_LEN_IDX ] = (unsigned char)msgLen;
    if ( !d.trusted())
    {
        // Use HMAC
        int rc = hmac_md5( (unsigned char *)msg, msgLen, d_func()->authKey.key, QSXE_KEY_LEN, digest );
        if ( rc == -1 )
            return false;
        memcpy( hdr + QSXE_KEY_IDX, digest, QSXE_KEY_LEN );
    }
    else
    {
        memcpy( hdr + QSXE_KEY_IDX, d_func()->authKey.key, QSXE_KEY_LEN );
    }

    hdr[ QSXE_PROG_IDX ] = d_func()->authKey.progId;

#ifdef QTRANSPORTAUTH_DEBUG
    char keydisplay[QSXE_KEY_LEN*2+1];
    hexstring( keydisplay, d_func()->authKey.key, QSXE_KEY_LEN );

    qDebug( "%d CLIENT Auth to message %s against prog id %u and key %s\n",
            getpid(), msg, d_func()->authKey.progId, keydisplay );
#endif

    // TODO implement sequence to prevent replay attack, not required
    // for trusted transports
    hdr[ QSXE_SEQ_IDX ] = 1;  // dummy sequence

    d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::Success;
    return true;
}


bool QTransportAuth::authFromMessage( QTransportAuth::Data &d, const char *msg, int msgLen )
{
    if ( msgLen < QSXE_MAGIC_BYTES )
    {
        d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::TooSmall;
        return false;
    }
    // if no magic bytes, exit straight away
    int m;
    const unsigned char *mptr = reinterpret_cast<const unsigned char *>(msg);
    for ( m = 0; m < QSXE_MAGIC_BYTES; ++m )
    {
        if ( *mptr++ != magic[m] )
        {
            d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::NoMagic;
            return false;
        }
    }

    if ( msgLen < AUTH_SPACE(1) )
    {
        d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::TooSmall;
        return false;
    }

    // At this point we know the header is at least long enough to contain valid auth
    // data, however the data may be spoofed.  If it is not verified then the status will
    // be set to uncertified so the spoofed data will not be relied on.  However we want to
    // know the program id which is being reported (even if it might be spoofed) for
    // policy debugging purposes.  So set it here, rather than after verification.
    d.progId = msg[QSXE_PROG_IDX];

#ifdef QTRANSPORTAUTH_DEBUG
    char authhdr[QSXE_HEADER_LEN*2+1];
    hexstring( authhdr, reinterpret_cast<const unsigned char *>(msg), QSXE_HEADER_LEN );
    qDebug( "%d SERVER authFromMessage(): message header is %s",
            getpid(), authhdr );
#endif

    unsigned char authLen = (unsigned char)(msg[ QSXE_LEN_IDX ]);

    if ( msgLen < AUTH_SPACE(authLen) )
    {
        d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::TooSmall;
        return false;
    }

    bool isCached = d_func()->keyCache.contains( d.progId );
    const unsigned char *clientKey = d_func()->getClientKey( d.progId );
    if ( clientKey == NULL )
    {
        d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::NoSuchKey;
        return false;
    }

#ifdef QTRANSPORTAUTH_DEBUG
    char keydisplay[QSXE_KEY_LEN*2+1];
    hexstring( keydisplay, clientKey, QSXE_KEY_LEN );
    qDebug( "\t\tauthFromMessage(): message %s against prog id %u and key %s\n",
            AUTH_DATA(msg), ((unsigned int)d.progId), keydisplay );
#endif

    const unsigned char *auth_tok;
    unsigned char digest[QSXE_KEY_LEN];
    bool multi_tok = false;

    bool need_to_recheck=false;
    do
    {
        if ( !d.trusted())
        {
            hmac_md5( AUTH_DATA(msg), authLen, clientKey, QSXE_KEY_LEN, digest );
            auth_tok = digest;
        }
        else
        {
            auth_tok = clientKey;
            multi_tok = true;  // 1 or more keys are in the clientKey
        }
        while( true )
        {
            if ( memcmp( auth_tok, magic, QSXE_MAGIC_BYTES ) == 0
                    && memcmp( auth_tok + QSXE_MAGIC_BYTES, magic, QSXE_MAGIC_BYTES ) == 0 )
                break;
            if ( memcmp( msg + QSXE_KEY_IDX, auth_tok, QSXE_KEY_LEN ) == 0 )
            {
                d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::Success;
                return true;
            }
            if ( !multi_tok )
                break;
            auth_tok += QSXE_KEY_LEN;
        }
        //the keys cached on d.progId may not contain the binary key because the cache entry was made
        //before the binary had first started, must search for client key again.
        if ( isCached )
        {
            d_func()->keyCache.remove(d.progId);
            isCached = false;

#ifdef QTRANSPORTAUTH_DEBUG
            qDebug() << "QTransportAuth::authFromMessage(): key not found in set of keys cached"
                     << "against prog Id =" << d.progId << ". Re-obtaining client key. ";
#endif
            clientKey = d_func()->getClientKey( d.progId );
            if ( clientKey == NULL )
            {
                d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::NoSuchKey;
                return false;
            }
            need_to_recheck = true;
        }
        else
        {
            need_to_recheck = false;
        }
    } while( need_to_recheck );

    d.status = ( d.status & QTransportAuth::StatusMask ) | QTransportAuth::FailMatch;
    qWarning() << "QTransportAuth::authFromMessage():failed authentication";
    FAREnforcer::getInstance()->logAuthAttempt( QDateTime::currentDateTime() );
    emit authViolation( d );
    return false;
}


#ifdef QTRANSPORTAUTH_DEBUG

void hexstring( char *buf, const unsigned char* key, size_t key_len )
{
    unsigned int i, p;
    for ( i = 0, p = 0; i < key_len; i++, p+=2 )
    {
        unsigned char lo_nibble = key[i] & 0x0f;
        unsigned char hi_nibble = key[i] >> 4;
        buf[p] = (int)hi_nibble > 9 ? hi_nibble-10 + 'A' : hi_nibble + '0';
        buf[p+1] = (int)lo_nibble > 9 ? lo_nibble-10 + 'A' : lo_nibble + '0';
    }
    buf[p] = '\0';
}
#endif

/*
  HMAC MD5 as listed in RFC 2104

  This code is taken from:

      http://www.faqs.org/rfcs/rfc2104.html

  with the allowance for keys other than length 16 removed, but otherwise
  a straight cut-and-paste.

  The HMAC_MD5 transform looks like:

  \snippet doc/src/snippets/code/src.gui.embedded.qtransportauth_qws.cpp 5

  \list
    <li> where K is an n byte key
    <li> ipad is the byte 0x36 repeated 64 times
    <li> opad is the byte 0x5c repeated 64 times
    <li> and text is the data being protected
  \endlist

  Hardware is available with accelerated implementations of HMAC-MD5 and
  HMAC-SHA1.  Where this hardware is available, this routine should be
  replaced with a call into the accelerated version.
*/

static int hmac_md5(
        unsigned char*  text,         /* pointer to data stream */
        int             text_length,  /* length of data stream */
        const unsigned char*  key,    /* pointer to authentication key */
        int             key_length,   /* length of authentication key */
        unsigned char * digest        /* caller digest to be filled in */
        )
{
        MD5Context context;
        unsigned char k_ipad[65];    /* inner padding - * key XORd with ipad */
        unsigned char k_opad[65];    /* outer padding - * key XORd with opad */
        int i;

        /* in this implementation key_length == 16 */
        if ( key_length != 16 )
        {
            fprintf( stderr, "Key length was %d - must be 16 bytes", key_length );
            return 0;
        }

        /* start out by storing key in pads */
        memset( k_ipad, 0, sizeof k_ipad );
        memset( k_opad, 0, sizeof k_opad );
        memcpy( k_ipad, key, key_length );
        memcpy( k_opad, key, key_length );

        /* XOR key with ipad and opad values */
        for (i=0; i<64; i++) {
                k_ipad[i] ^= 0x36;
                k_opad[i] ^= 0x5c;
        }

        /* perform inner MD5 */
        MD5Init(&context);                   /* init context for 1st pass */
        MD5Update(&context, k_ipad, 64);     /* start with inner pad */
        MD5Update(&context, text, text_length); /* then text of datagram */
        MD5Final(&context, digest);          /* finish up 1st pass */

        /* perform outer MD5 */
        MD5Init(&context);                   /* init context for 2nd pass */
        MD5Update(&context, k_opad, 64);     /* start with outer pad */
        MD5Update(&context, digest, 16);     /* then results of 1st * hash */
        MD5Final(&context, digest);          /* finish up 2nd pass */
        return 1;
}


const int FAREnforcer::minutelyRate = 4; //allowed number of false authentication attempts per minute
const QString FAREnforcer::FARMessage = QLatin1String("FAR_Exceeded");
const QString FAREnforcer::SxeTag = QLatin1String("<SXE Breach>");
const int FAREnforcer::minute = 60;

FAREnforcer::FAREnforcer():authAttempts()
{
    QDateTime nullDateTime = QDateTime();
    for (int i = 0; i < minutelyRate; i++ )
        authAttempts << nullDateTime;
}


FAREnforcer *FAREnforcer::getInstance()
{
    static FAREnforcer theInstance;
    return &theInstance;
}

void FAREnforcer::logAuthAttempt( QDateTime time )
{
    QDateTime dt =  authAttempts.takeFirst();

    authAttempts.append( time );
    if ( dt.secsTo( authAttempts.last() ) <= minute )
    {
#if defined(SXE_DISCOVERY)
        if ( QTransportAuth::getInstance()->isDiscoveryMode() ) {
            static QBasicAtomicInt reported = Q_BASIC_ATOMIC_INITIALIZER(0);
            if ( reported.testAndSetRelaxed(0,1) ) {
#ifndef QT_NO_TEXTSTREAM
                QString logFilePath = QTransportAuth::getInstance()->logFilePath();
                if ( !logFilePath.isEmpty() ) {
                      QFile log( logFilePath );
                    if ( !log.open(QIODevice::WriteOnly | QIODevice::Append) ) {
                        qWarning("Could not write to log in discovery mode: %s",
                                 qPrintable(logFilePath) );
                    } else {
                        QTextStream ts( &log );
                        ts << "\t\tWarning: False Authentication Rate of " <<  minutelyRate << "\n"
                           << "\t\tserver connections/authentications per minute has been exceeded,\n"
                           << "\t\tno further warnings will be issued\n";
                    }
                }
            }
#endif
            reset();
            return;
        }
#endif
        syslog( LOG_ERR | LOG_LOCAL6, "%s %s",
                qPrintable( FAREnforcer::SxeTag ),
                qPrintable( FAREnforcer::FARMessage ) );
        reset();
    }
}

void FAREnforcer::reset()
{
    QDateTime nullDateTime = QDateTime();
    for (int i = 0; i < minutelyRate; i++ )
        authAttempts[i] = nullDateTime;
}

QT_END_NAMESPACE

#include "moc_qtransportauth_qws_p.cpp"

#endif // QT_NO_SXE