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#include <qauthenticator.h>
#include <qauthenticator_p.h>
#include <qdebug.h>
#include <qhash.h>
#include <qbytearray.h>
#include <qcryptographichash.h>
#include <qiodevice.h>
#include <qdatastream.h>
#include <qendian.h>
#include <qstring.h>
#include <qdatetime.h>
#include <qrandom.h>

#ifdef Q_OS_WIN
#include <qmutex.h>
#include <rpc.h>
#endif

#if QT_CONFIG(sspi) // SSPI
#define SECURITY_WIN32 1
#include <security.h>
#elif QT_CONFIG(gssapi) // GSSAPI
#if defined(Q_OS_DARWIN)
#include <GSS/GSS.h>
#else
#include <gssapi/gssapi.h>
#endif // Q_OS_DARWIN
#endif // Q_CONFIG(sspi)

QT_BEGIN_NAMESPACE

static QByteArray qNtlmPhase1();
static QByteArray qNtlmPhase3(QAuthenticatorPrivate *ctx, const QByteArray& phase2data);
#if QT_CONFIG(sspi) // SSPI
static bool q_SSPI_library_load();
static QByteArray qSspiStartup(QAuthenticatorPrivate *ctx, QAuthenticatorPrivate::Method method,
                               const QString& host);
static QByteArray qSspiContinue(QAuthenticatorPrivate *ctx, QAuthenticatorPrivate::Method method,
                                const QString& host, const QByteArray& challenge = QByteArray());
#elif QT_CONFIG(gssapi) // GSSAPI
static QByteArray qGssapiStartup(QAuthenticatorPrivate *ctx, const QString& host);
static QByteArray qGssapiContinue(QAuthenticatorPrivate *ctx,
                                  const QByteArray& challenge = QByteArray());
#endif // gssapi

/*!
  \class QAuthenticator
  \brief The QAuthenticator class provides an authentication object.
  \since 4.3

  \reentrant
  \ingroup network
  \inmodule QtNetwork

  The QAuthenticator class is usually used in the
  \l{QNetworkAccessManager::}{authenticationRequired()} and
  \l{QNetworkAccessManager::}{proxyAuthenticationRequired()} signals of QNetworkAccessManager and
  QAbstractSocket. The class provides a way to pass back the required
  authentication information to the socket when accessing services that
  require authentication.

  QAuthenticator supports the following authentication methods:
  \list
    \li Basic
    \li NTLM version 2
    \li Digest-MD5
    \li SPNEGO/Negotiate
  \endlist

  \target qauthenticator-options
  \section1 Options

  In addition to the username and password required for authentication, a
  QAuthenticator object can also contain additional options. The
  options() function can be used to query incoming options sent by
  the server; the setOption() function can
  be used to set outgoing options, to be processed by the authenticator
  calculation. The options accepted and provided depend on the authentication
  type (see method()).

  The following tables list known incoming options as well as accepted
  outgoing options. The list of incoming options is not exhaustive, since
  servers may include additional information at any time. The list of
  outgoing options is exhaustive, however, and no unknown options will be
  treated or sent back to the server.

  \section2 Basic

  \table
    \header \li Option \li Direction \li Type \li Description
    \row \li \tt{realm} \li Incoming \li QString \li Contains the realm of the authentication, the same as realm()
  \endtable

  The Basic authentication mechanism supports no outgoing options.

  \section2 NTLM version 2

  The NTLM authentication mechanism currently supports no incoming or outgoing options.
  On Windows, if no \a user has been set, domain\\user credentials will be searched for on the
  local system to enable Single-Sign-On functionality.

  \section2 Digest-MD5

  \table
    \header \li Option \li Direction \li Type \li Description
    \row \li \tt{realm} \li Incoming \li QString \li Contains the realm of the authentication, the same as realm()
  \endtable

  The Digest-MD5 authentication mechanism supports no outgoing options.

  \section2 SPNEGO/Negotiate

  This authentication mechanism currently supports no incoming or outgoing options.

  \sa QSslSocket
*/


/*!
  Constructs an empty authentication object.
*/
QAuthenticator::QAuthenticator()
    : d(nullptr)
{
}

/*!
  Destructs the object.
*/
QAuthenticator::~QAuthenticator()
{
    if (d)
        delete d;
}

/*!
    Constructs a copy of \a other.
*/
QAuthenticator::QAuthenticator(const QAuthenticator &other)
    : d(nullptr)
{
    if (other.d)
        *this = other;
}

/*!
    Assigns the contents of \a other to this authenticator.
*/
QAuthenticator &QAuthenticator::operator=(const QAuthenticator &other)
{
    if (d == other.d)
        return *this;

    // Do not share the d since challange reponse/based changes
    // could corrupt the internal store and different network requests
    // can utilize different types of proxies.
    detach();
    if (other.d) {
        d->user = other.d->user;
        d->userDomain = other.d->userDomain;
        d->workstation = other.d->workstation;
        d->extractedUser = other.d->extractedUser;
        d->password = other.d->password;
        d->realm = other.d->realm;
        d->method = other.d->method;
        d->options = other.d->options;
    } else if (d->phase == QAuthenticatorPrivate::Start) {
        delete d;
        d = nullptr;
    }
    return *this;
}

/*!
    Returns \c true if this authenticator is identical to \a other; otherwise
    returns \c false.
*/
bool QAuthenticator::operator==(const QAuthenticator &other) const
{
    if (d == other.d)
        return true;
    if (!d || !other.d)
        return false;
    return d->user == other.d->user
        && d->password == other.d->password
        && d->realm == other.d->realm
        && d->method == other.d->method
        && d->options == other.d->options;
}

/*!
    \fn bool QAuthenticator::operator!=(const QAuthenticator &other) const

    Returns \c true if this authenticator is different from \a other; otherwise
    returns \c false.
*/

/*!
  Returns the user used for authentication.
*/
QString QAuthenticator::user() const
{
    return d ? d->user : QString();
}

/*!
  Sets the \a user used for authentication.

  \sa QNetworkAccessManager::authenticationRequired()
*/
void QAuthenticator::setUser(const QString &user)
{
    detach();
    d->user = user;
    d->updateCredentials();
}

/*!
  Returns the password used for authentication.
*/
QString QAuthenticator::password() const
{
    return d ? d->password : QString();
}

/*!
  Sets the \a password used for authentication.

  \sa QNetworkAccessManager::authenticationRequired()
*/
void QAuthenticator::setPassword(const QString &password)
{
    detach();
    d->password = password;
}

/*!
  \internal
*/
void QAuthenticator::detach()
{
    if (!d) {
        d = new QAuthenticatorPrivate;
        return;
    }

    if (d->phase == QAuthenticatorPrivate::Done)
        d->phase = QAuthenticatorPrivate::Start;
}

/*!
  Returns the realm requiring authentication.
*/
QString QAuthenticator::realm() const
{
    return d ? d->realm : QString();
}

/*!
  \internal
*/
void QAuthenticator::setRealm(const QString &realm)
{
    detach();
    d->realm = realm;
}

/*!
    \since 4.7
    Returns the value related to option \a opt if it was set by the server.
    See the \l{QAuthenticator#qauthenticator-options}{Options section} for
    more information on incoming options.
    If option \a opt isn't found, an invalid QVariant will be returned.

    \sa options(), {QAuthenticator#qauthenticator-options}{QAuthenticator options}
*/
QVariant QAuthenticator::option(const QString &opt) const
{
    return d ? d->options.value(opt) : QVariant();
}

/*!
    \since 4.7
    Returns all incoming options set in this QAuthenticator object by parsing
    the server reply. See the \l{QAuthenticator#qauthenticator-options}{Options section}
    for more information on incoming options.

    \sa option(), {QAuthenticator#qauthenticator-options}{QAuthenticator options}
*/
QVariantHash QAuthenticator::options() const
{
    return d ? d->options : QVariantHash();
}

/*!
    \since 4.7

    Sets the outgoing option \a opt to value \a value.
    See the \l{QAuthenticator#qauthenticator-options}{Options section} for more information on outgoing options.

    \sa options(), option(), {QAuthenticator#qauthenticator-options}{QAuthenticator options}
*/
void QAuthenticator::setOption(const QString &opt, const QVariant &value)
{
    detach();
    d->options.insert(opt, value);
}


/*!
    Returns \c true if the object has not been initialized. Returns
    \c false if non-const member functions have been called, or
    the content was constructed or copied from another initialized
    QAuthenticator object.
*/
bool QAuthenticator::isNull() const
{
    return !d;
}

#if QT_CONFIG(sspi) // SSPI
class QSSPIWindowsHandles
{
public:
    CredHandle credHandle;
    CtxtHandle ctxHandle;
};
#elif QT_CONFIG(gssapi) // GSSAPI
class QGssApiHandles
{
public:
    gss_ctx_id_t gssCtx = nullptr;
    gss_name_t targetName;
};
#endif // gssapi


QAuthenticatorPrivate::QAuthenticatorPrivate()
    : method(None)
    , hasFailed(false)
    , phase(Start)
    , nonceCount(0)
{
    cnonce = QCryptographicHash::hash(QByteArray::number(QRandomGenerator::system()->generate64(), 16),
                                      QCryptographicHash::Md5).toHex();
    nonceCount = 0;
}

QAuthenticatorPrivate::~QAuthenticatorPrivate() = default;

void QAuthenticatorPrivate::updateCredentials()
{
    int separatorPosn = 0;

    switch (method) {
    case QAuthenticatorPrivate::Ntlm:
        if ((separatorPosn = user.indexOf(QLatin1String("\\"))) != -1) {
            //domain name is present
            realm.clear();
            userDomain = user.left(separatorPosn);
            extractedUser = user.mid(separatorPosn + 1);
        } else {
            extractedUser = user;
            realm.clear();
            userDomain.clear();
        }
        break;
    default:
        userDomain.clear();
        break;
    }
}

void QAuthenticatorPrivate::parseHttpResponse(const QList<QPair<QByteArray, QByteArray> > &values, bool isProxy)
{
    const char *search = isProxy ? "proxy-authenticate" : "www-authenticate";

    method = None;
    /*
      Fun from the HTTP 1.1 specs, that we currently ignore:

      User agents are advised to take special care in parsing the WWW-
      Authenticate field value as it might contain more than one challenge,
      or if more than one WWW-Authenticate header field is provided, the
      contents of a challenge itself can contain a comma-separated list of
      authentication parameters.
    */

    QByteArray headerVal;
    for (int i = 0; i < values.size(); ++i) {
        const QPair<QByteArray, QByteArray> &current = values.at(i);
        if (current.first.compare(search, Qt::CaseInsensitive) != 0)
            continue;
        QByteArray str = current.second.toLower();
        if (method < Basic && str.startsWith("basic")) {
            method = Basic;
            headerVal = current.second.mid(6);
        } else if (method < Ntlm && str.startsWith("ntlm")) {
            method = Ntlm;
            headerVal = current.second.mid(5);
        } else if (method < DigestMd5 && str.startsWith("digest")) {
            method = DigestMd5;
            headerVal = current.second.mid(7);
        } else if (method < Negotiate && str.startsWith("negotiate")) {
            method = Negotiate;
            headerVal = current.second.mid(10);
        }
    }

    // Reparse credentials since we know the method now
    updateCredentials();
    challenge = headerVal.trimmed();
    QHash<QByteArray, QByteArray> options = parseDigestAuthenticationChallenge(challenge);

    switch(method) {
    case Basic:
        this->options[QLatin1String("realm")] = realm = QString::fromLatin1(options.value("realm"));
        if (user.isEmpty() && password.isEmpty())
            phase = Done;
        break;
    case Ntlm:
    case Negotiate:
        // work is done in calculateResponse()
        break;
    case DigestMd5: {
        this->options[QLatin1String("realm")] = realm = QString::fromLatin1(options.value("realm"));
        if (options.value("stale").compare("true", Qt::CaseInsensitive) == 0) {
            phase = Start;
            nonceCount = 0;
        }
        if (user.isEmpty() && password.isEmpty())
            phase = Done;
        break;
    }
    default:
        realm.clear();
        challenge = QByteArray();
        phase = Invalid;
    }
}

QByteArray QAuthenticatorPrivate::calculateResponse(const QByteArray &requestMethod, const QByteArray &path, const QString& host)
{
#if !QT_CONFIG(sspi) && !QT_CONFIG(gssapi)
    Q_UNUSED(host);
#endif
    QByteArray response;
    const char* methodString = nullptr;
    switch(method) {
    case QAuthenticatorPrivate::None:
        methodString = "";
        phase = Done;
        break;
    case QAuthenticatorPrivate::Basic:
        methodString = "Basic";
        response = user.toLatin1() + ':' + password.toLatin1();
        response = response.toBase64();
        phase = Done;
        break;
    case QAuthenticatorPrivate::DigestMd5:
        methodString = "Digest";
        response = digestMd5Response(challenge, requestMethod, path);
        phase = Done;
        break;
    case QAuthenticatorPrivate::Ntlm:
        methodString = "NTLM";
        if (challenge.isEmpty()) {
#if QT_CONFIG(sspi) // SSPI
            QByteArray phase1Token;
            if (user.isEmpty()) { // Only pull from system if no user was specified in authenticator
                phase1Token = qSspiStartup(this, method, host);
            } else if (!q_SSPI_library_load()) {
                // Since we're not running qSspiStartup we have to make sure the library is loaded
                qWarning("Failed to load the SSPI libraries");
                return "";
            }
            if (!phase1Token.isEmpty()) {
                response = phase1Token.toBase64();
                phase = Phase2;
            } else
#endif
            {
                response = qNtlmPhase1().toBase64();
                if (user.isEmpty())
                    phase = Done;
                else
                    phase = Phase2;
            }
        } else {
#if QT_CONFIG(sspi) // SSPI
            QByteArray phase3Token;
            if (sspiWindowsHandles)
                phase3Token = qSspiContinue(this, method, host, QByteArray::fromBase64(challenge));
            if (!phase3Token.isEmpty()) {
                response = phase3Token.toBase64();
                phase = Done;
            } else
#endif
            {
                response = qNtlmPhase3(this, QByteArray::fromBase64(challenge)).toBase64();
                phase = Done;
            }
            challenge = "";
        }

        break;
    case QAuthenticatorPrivate::Negotiate:
        methodString = "Negotiate";
        if (challenge.isEmpty()) {
            QByteArray phase1Token;
#if QT_CONFIG(sspi) // SSPI
            phase1Token = qSspiStartup(this, method, host);
#elif QT_CONFIG(gssapi) // GSSAPI
            phase1Token = qGssapiStartup(this, host);
#endif

            if (!phase1Token.isEmpty()) {
                response = phase1Token.toBase64();
                phase = Phase2;
            } else {
                phase = Done;
            }
        } else {
            QByteArray phase3Token;
#if QT_CONFIG(sspi) // SSPI
            phase3Token = qSspiContinue(this, method, host, QByteArray::fromBase64(challenge));
#elif QT_CONFIG(gssapi) // GSSAPI
            phase3Token = qGssapiContinue(this, QByteArray::fromBase64(challenge));
#endif
            if (!phase3Token.isEmpty()) {
                response = phase3Token.toBase64();
                phase = Done;
                challenge = "";
            }
        }

        break;
    }

    return QByteArray::fromRawData(methodString, qstrlen(methodString)) + ' ' + response;
}


// ---------------------------- Digest Md5 code ----------------------------------------

QHash<QByteArray, QByteArray> QAuthenticatorPrivate::parseDigestAuthenticationChallenge(const QByteArray &challenge)
{
    QHash<QByteArray, QByteArray> options;
    // parse the challenge
    const char *d = challenge.constData();
    const char *end = d + challenge.length();
    while (d < end) {
        while (d < end && (*d == ' ' || *d == '\n' || *d == '\r'))
            ++d;
        const char *start = d;
        while (d < end && *d != '=')
            ++d;
        QByteArray key = QByteArray(start, d - start);
        ++d;
        if (d >= end)
            break;
        bool quote = (*d == '"');
        if (quote)
            ++d;
        if (d >= end)
            break;
        start = d;
        QByteArray value;
        while (d < end) {
            bool backslash = false;
            if (*d == '\\' && d < end - 1) {
                ++d;
                backslash = true;
            }
            if (!backslash) {
                if (quote) {
                    if (*d == '"')
                        break;
                } else {
                    if (*d == ',')
                        break;
                }
            }
            value += *d;
            ++d;
        }
        while (d < end && *d != ',')
            ++d;
        ++d;
        options[key] = value;
    }

    QByteArray qop = options.value("qop");
    if (!qop.isEmpty()) {
        QList<QByteArray> qopoptions = qop.split(',');
        if (!qopoptions.contains("auth"))
            return QHash<QByteArray, QByteArray>();
        // #### can't do auth-int currently
//         if (qop.contains("auth-int"))
//             qop = "auth-int";
//         else if (qop.contains("auth"))
//             qop = "auth";
//         else
//             qop = QByteArray();
        options["qop"] = "auth";
    }

    return options;
}

/*
  Digest MD5 implementation

  Code taken from RFC 2617

  Currently we don't support the full SASL authentication mechanism (which includes cyphers)
*/


/* calculate request-digest/response-digest as per HTTP Digest spec */
static QByteArray digestMd5ResponseHelper(
    const QByteArray &alg,
    const QByteArray &userName,
    const QByteArray &realm,
    const QByteArray &password,
    const QByteArray &nonce,       /* nonce from server */
    const QByteArray &nonceCount,  /* 8 hex digits */
    const QByteArray &cNonce,      /* client nonce */
    const QByteArray &qop,         /* qop-value: "", "auth", "auth-int" */
    const QByteArray &method,      /* method from the request */
    const QByteArray &digestUri,   /* requested URL */
    const QByteArray &hEntity       /* H(entity body) if qop="auth-int" */
    )
{
    QCryptographicHash hash(QCryptographicHash::Md5);
    hash.addData(userName);
    hash.addData(":", 1);
    hash.addData(realm);
    hash.addData(":", 1);
    hash.addData(password);
    QByteArray ha1 = hash.result();
    if (alg.compare("md5-sess", Qt::CaseInsensitive) == 0) {
        hash.reset();
        // RFC 2617 contains an error, it was:
        // hash.addData(ha1);
        // but according to the errata page at http://www.rfc-editor.org/errata_list.php, ID 1649, it
        // must be the following line:
        hash.addData(ha1.toHex());
        hash.addData(":", 1);
        hash.addData(nonce);
        hash.addData(":", 1);
        hash.addData(cNonce);
        ha1 = hash.result();
    };
    ha1 = ha1.toHex();

    // calculate H(A2)
    hash.reset();
    hash.addData(method);
    hash.addData(":", 1);
    hash.addData(digestUri);
    if (qop.compare("auth-int", Qt::CaseInsensitive) == 0) {
        hash.addData(":", 1);
        hash.addData(hEntity);
    }
    QByteArray ha2hex = hash.result().toHex();

    // calculate response
    hash.reset();
    hash.addData(ha1);
    hash.addData(":", 1);
    hash.addData(nonce);
    hash.addData(":", 1);
    if (!qop.isNull()) {
        hash.addData(nonceCount);
        hash.addData(":", 1);
        hash.addData(cNonce);
        hash.addData(":", 1);
        hash.addData(qop);
        hash.addData(":", 1);
    }
    hash.addData(ha2hex);
    return hash.result().toHex();
}

QByteArray QAuthenticatorPrivate::digestMd5Response(const QByteArray &challenge, const QByteArray &method, const QByteArray &path)
{
    QHash<QByteArray,QByteArray> options = parseDigestAuthenticationChallenge(challenge);

    ++nonceCount;
    QByteArray nonceCountString = QByteArray::number(nonceCount, 16);
    while (nonceCountString.length() < 8)
        nonceCountString.prepend('0');

    QByteArray nonce = options.value("nonce");
    QByteArray opaque = options.value("opaque");
    QByteArray qop = options.value("qop");

//    qDebug() << "calculating digest: method=" << method << "path=" << path;
    QByteArray response = digestMd5ResponseHelper(options.value("algorithm"), user.toLatin1(),
                                              realm.toLatin1(), password.toLatin1(),
                                              nonce, nonceCountString,
                                              cnonce, qop, method,
                                              path, QByteArray());


    QByteArray credentials;
    credentials += "username=\"" + user.toLatin1() + "\", ";
    credentials += "realm=\"" + realm.toLatin1() + "\", ";
    credentials += "nonce=\"" + nonce + "\", ";
    credentials += "uri=\"" + path + "\", ";
    if (!opaque.isEmpty())
        credentials += "opaque=\"" + opaque + "\", ";
    credentials += "response=\"" + response + '"';
    if (!options.value("algorithm").isEmpty())
        credentials += ", algorithm=" + options.value("algorithm");
    if (!options.value("qop").isEmpty()) {
        credentials += ", qop=" + qop + ", ";
        credentials += "nc=" + nonceCountString + ", ";
        credentials += "cnonce=\"" + cnonce + '"';
    }

    return credentials;
}

// ---------------------------- End of Digest Md5 code ---------------------------------


// ---------------------------- NTLM code ----------------------------------------------

/*
 * NTLM message flags.
 *
 * Copyright (c) 2004 Andrey Panin <pazke@donpac.ru>
 *
 * This software is released under the MIT license.
 */

/*
 * Indicates that Unicode strings are supported for use in security
 * buffer data.
 */
#define NTLMSSP_NEGOTIATE_UNICODE 0x00000001

/*
 * Indicates that OEM strings are supported for use in security buffer data.
 */
#define NTLMSSP_NEGOTIATE_OEM 0x00000002

/*
 * Requests that the server's authentication realm be included in the
 * Type 2 message.
 */
#define NTLMSSP_REQUEST_TARGET 0x00000004

/*
 * Specifies that authenticated communication between the client and server
 * should carry a digital signature (message integrity).
 */
#define NTLMSSP_NEGOTIATE_SIGN 0x00000010

/*
 * Specifies that authenticated communication between the client and server
 * should be encrypted (message confidentiality).
 */
#define NTLMSSP_NEGOTIATE_SEAL 0x00000020

/*
 * Indicates that datagram authentication is being used.
 */
#define NTLMSSP_NEGOTIATE_DATAGRAM 0x00000040

/*
 * Indicates that the LAN Manager session key should be
 * used for signing and sealing authenticated communications.
 */
#define NTLMSSP_NEGOTIATE_LM_KEY 0x00000080

/*
 * Indicates that NTLM authentication is being used.
 */
#define NTLMSSP_NEGOTIATE_NTLM 0x00000200

/*
 * Sent by the client in the Type 1 message to indicate that the name of the
 * domain in which the client workstation has membership is included in the
 * message. This is used by the server to determine whether the client is
 * eligible for local authentication.
 */
#define NTLMSSP_NEGOTIATE_DOMAIN_SUPPLIED 0x00001000

/*
 * Sent by the client in the Type 1 message to indicate that the client
 * workstation's name is included in the message. This is used by the server
 * to determine whether the client is eligible for local authentication.
 */
#define NTLMSSP_NEGOTIATE_WORKSTATION_SUPPLIED 0x00002000

/*
 * Sent by the server to indicate that the server and client are on the same
 * machine. Implies that the client may use the established local credentials
 * for authentication instead of calculating a response to the challenge.
 */
#define NTLMSSP_NEGOTIATE_LOCAL_CALL 0x00004000

/*
 * Indicates that authenticated communication between the client and server
 * should be signed with a "dummy" signature.
 */
#define NTLMSSP_NEGOTIATE_ALWAYS_SIGN 0x00008000

/*
 * Sent by the server in the Type 2 message to indicate that the target
 * authentication realm is a domain.
 */
#define NTLMSSP_TARGET_TYPE_DOMAIN 0x00010000

/*
 * Sent by the server in the Type 2 message to indicate that the target
 * authentication realm is a server.
 */
#define NTLMSSP_TARGET_TYPE_SERVER 0x00020000

/*
 * Sent by the server in the Type 2 message to indicate that the target
 * authentication realm is a share. Presumably, this is for share-level
 * authentication. Usage is unclear.
 */
#define NTLMSSP_TARGET_TYPE_SHARE 0x00040000

/*
 * Indicates that the NTLM2 signing and sealing scheme should be used for
 * protecting authenticated communications. Note that this refers to a
 * particular session security scheme, and is not related to the use of
 * NTLMv2 authentication.
 */
#define NTLMSSP_NEGOTIATE_NTLM2 0x00080000

/*
 * Sent by the server in the Type 2 message to indicate that it is including
 * a Target Information block in the message. The Target Information block
 * is used in the calculation of the NTLMv2 response.
 */
#define NTLMSSP_NEGOTIATE_TARGET_INFO 0x00800000

/*
 * Indicates that 128-bit encryption is supported.
 */
#define NTLMSSP_NEGOTIATE_128 0x20000000

/*
 * Indicates that the client will provide an encrypted master session key in
 * the "Session Key" field of the Type 3 message. This is used in signing and
 * sealing, and is RC4-encrypted using the previous session key as the
 * encryption key.
 */
#define NTLMSSP_NEGOTIATE_KEY_EXCHANGE 0x40000000

/*
 * Indicates that 56-bit encryption is supported.
 */
#define NTLMSSP_NEGOTIATE_56 0x80000000

/*
 * AvId values
 */
#define AVTIMESTAMP 7


//************************Global variables***************************

const int blockSize = 64; //As per RFC2104 Block-size is 512 bits
const quint8 respversion = 1;
const quint8 hirespversion = 1;

/* usage:
   // fill up ctx with what we know.
   QByteArray response = qNtlmPhase1(ctx);
   // send response (b64 encoded??)
   // get response from server (b64 decode?)
   Phase2Block pb;
   qNtlmDecodePhase2(response, pb);
   response = qNtlmPhase3(ctx, pb);
   // send response (b64 encoded??)
*/

/*
   TODO:
    - Fix unicode handling
    - add v2 handling
*/

class QNtlmBuffer {
public:
    QNtlmBuffer() : len(0), maxLen(0), offset(0) {}
    quint16 len;
    quint16 maxLen;
    quint32 offset;
    enum { Size = 8 };
};

class QNtlmPhase1BlockBase
{
public:
    char magic[8];
    quint32 type;
    quint32 flags;
    QNtlmBuffer domain;
    QNtlmBuffer workstation;
    enum { Size = 32 };
};

// ################# check paddings
class QNtlmPhase2BlockBase
{
public:
    char magic[8];
    quint32 type;
    QNtlmBuffer targetName;
    quint32 flags;
    unsigned char challenge[8];
    quint32 context[2];
    QNtlmBuffer targetInfo;
    enum { Size = 48 };
};

class QNtlmPhase3BlockBase {
public:
    char magic[8];
    quint32 type;
    QNtlmBuffer lmResponse;
    QNtlmBuffer ntlmResponse;
    QNtlmBuffer domain;
    QNtlmBuffer user;
    QNtlmBuffer workstation;
    QNtlmBuffer sessionKey;
    quint32 flags;
    enum { Size = 64 };
};

static void qStreamNtlmBuffer(QDataStream& ds, const QByteArray& s)
{
    ds.writeRawData(s.constData(), s.size());
}


static void qStreamNtlmString(QDataStream& ds, const QString& s, bool unicode)
{
    if (!unicode) {
        qStreamNtlmBuffer(ds, s.toLatin1());
        return;
    }
    const ushort *d = s.utf16();
    for (int i = 0; i < s.length(); ++i)
        ds << d[i];
}


static int qEncodeNtlmBuffer(QNtlmBuffer& buf, int offset, const QByteArray& s)
{
    buf.len = s.size();
    buf.maxLen = buf.len;
    buf.offset = (offset + 1) & ~1;
    return buf.offset + buf.len;
}


static int qEncodeNtlmString(QNtlmBuffer& buf, int offset, const QString& s, bool unicode)
{
    if (!unicode)
        return qEncodeNtlmBuffer(buf, offset, s.toLatin1());
    buf.len = 2 * s.length();
    buf.maxLen = buf.len;
    buf.offset = (offset + 1) & ~1;
    return buf.offset + buf.len;
}


static QDataStream& operator<<(QDataStream& s, const QNtlmBuffer& b)
{
    s << b.len << b.maxLen << b.offset;
    return s;
}

static QDataStream& operator>>(QDataStream& s, QNtlmBuffer& b)
{
    s >> b.len >> b.maxLen >> b.offset;
    return s;
}


class QNtlmPhase1Block : public QNtlmPhase1BlockBase
{  // request
public:
    QNtlmPhase1Block() {
        qstrncpy(magic, "NTLMSSP", 8);
        type = 1;
        flags = NTLMSSP_NEGOTIATE_UNICODE | NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_REQUEST_TARGET | NTLMSSP_NEGOTIATE_ALWAYS_SIGN | NTLMSSP_NEGOTIATE_NTLM2;
    }

    // extracted
    QString domainStr, workstationStr;
};


class QNtlmPhase2Block : public QNtlmPhase2BlockBase
{  // challenge
public:
    QNtlmPhase2Block() {
        magic[0] = 0;
        type = 0xffffffff;
    }

    // extracted
    QString targetNameStr, targetInfoStr;
    QByteArray targetInfoBuff;
};


class QNtlmPhase3Block : public QNtlmPhase3BlockBase {  // response
public:
    QNtlmPhase3Block() {
        qstrncpy(magic, "NTLMSSP", 8);
        type = 3;
        flags = NTLMSSP_NEGOTIATE_UNICODE | NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_TARGET_INFO;
    }

    // extracted
    QByteArray lmResponseBuf, ntlmResponseBuf;
    QString domainStr, userStr, workstationStr, sessionKeyStr;
    QByteArray v2Hash;
};


static QDataStream& operator<<(QDataStream& s, const QNtlmPhase1Block& b) {
    bool unicode = (b.flags & NTLMSSP_NEGOTIATE_UNICODE);

    s.writeRawData(b.magic, sizeof(b.magic));
    s << b.type;
    s << b.flags;
    s << b.domain;
    s << b.workstation;
    if (!b.domainStr.isEmpty())
        qStreamNtlmString(s, b.domainStr, unicode);
    if (!b.workstationStr.isEmpty())
        qStreamNtlmString(s, b.workstationStr, unicode);
    return s;
}


static QDataStream& operator<<(QDataStream& s, const QNtlmPhase3Block& b) {
    bool unicode = (b.flags & NTLMSSP_NEGOTIATE_UNICODE);
    s.writeRawData(b.magic, sizeof(b.magic));
    s << b.type;
    s << b.lmResponse;
    s << b.ntlmResponse;
    s << b.domain;
    s << b.user;
    s << b.workstation;
    s << b.sessionKey;
    s << b.flags;

    if (!b.domainStr.isEmpty())
        qStreamNtlmString(s, b.domainStr, unicode);

    qStreamNtlmString(s, b.userStr, unicode);

    if (!b.workstationStr.isEmpty())
        qStreamNtlmString(s, b.workstationStr, unicode);

    // Send auth info
    qStreamNtlmBuffer(s, b.lmResponseBuf);
    qStreamNtlmBuffer(s, b.ntlmResponseBuf);


    return s;
}


static QByteArray qNtlmPhase1()
{
    QByteArray rc;
    QDataStream ds(&rc, QIODevice::WriteOnly);
    ds.setByteOrder(QDataStream::LittleEndian);
    QNtlmPhase1Block pb;
    ds << pb;
    return rc;
}


static QByteArray qStringAsUcs2Le(const QString& src)
{
    QByteArray rc(2*src.length(), 0);
    const unsigned short *s = src.utf16();
    unsigned short *d = (unsigned short*)rc.data();
    for (int i = 0; i < src.length(); ++i) {
        d[i] = qToLittleEndian(s[i]);
    }
    return rc;
}


static QString qStringFromUcs2Le(QByteArray src)
{
    Q_ASSERT(src.size() % 2 == 0);
    unsigned short *d = (unsigned short*)src.data();
    for (int i = 0; i < src.length() / 2; ++i) {
        d[i] = qFromLittleEndian(d[i]);
    }
    return QString((const QChar *)src.data(), src.size()/2);
}


/*********************************************************************
* Function Name: qEncodeHmacMd5
* Params:
*    key:   Type - QByteArray
*         - It is the Authentication key
*    message:   Type - QByteArray
*         - This is the actual message which will be encoded
*           using HMacMd5 hash algorithm
*
* Return Value:
*    hmacDigest:   Type - QByteArray
*
* Description:
*    This function will be used to encode the input message using
*    HMacMd5 hash algorithm.
*
*    As per the RFC2104 the HMacMd5 algorithm can be specified
*        ---------------------------------------
*         MD5(K XOR opad, MD5(K XOR ipad, text))
*        ---------------------------------------
*
*********************************************************************/
QByteArray qEncodeHmacMd5(QByteArray &key, const QByteArray &message)
{
    Q_ASSERT_X(!(message.isEmpty()),"qEncodeHmacMd5", "Empty message check");
    Q_ASSERT_X(!(key.isEmpty()),"qEncodeHmacMd5", "Empty key check");

    QCryptographicHash hash(QCryptographicHash::Md5);
    QByteArray hMsg;

    QByteArray iKeyPad(blockSize, 0x36);
    QByteArray oKeyPad(blockSize, 0x5c);

    hash.reset();
    // Adjust the key length to blockSize

    if(blockSize < key.length()) {
        hash.addData(key);
        key = hash.result(); //MD5 will always return 16 bytes length output
    }

    //Key will be <= 16 or 20 bytes as hash function (MD5 or SHA hash algorithms)
    //key size can be max of Block size only
    key = key.leftJustified(blockSize,0,true);

    //iKeyPad, oKeyPad and key are all of same size "blockSize"

    //xor of iKeyPad with Key and store the result into iKeyPad
    for(int i = 0; i<key.size();i++) {
        iKeyPad[i] = key[i]^iKeyPad[i];
    }

    //xor of oKeyPad with Key and store the result into oKeyPad
    for(int i = 0; i<key.size();i++) {
        oKeyPad[i] = key[i]^oKeyPad[i];
    }

    iKeyPad.append(message); // (K0 xor ipad) || text

    hash.reset();
    hash.addData(iKeyPad);
    hMsg = hash.result();
                    //Digest gen after pass-1: H((K0 xor ipad)||text)

    QByteArray hmacDigest;
    oKeyPad.append(hMsg);
    hash.reset();
    hash.addData(oKeyPad);
    hmacDigest = hash.result();
                    // H((K0 xor opad )|| H((K0 xor ipad) || text))

    /*hmacDigest should not be less than half the length of the HMAC output
      (to match the birthday attack bound) and not less than 80 bits
      (a suitable lower bound on the number of bits that need to be
      predicted by an attacker).
      Refer RFC 2104 for more details on truncation part */

    /*MD5 hash always returns 16 byte digest only and HMAC-MD5 spec
      (RFC 2104) also says digest length should be 16 bytes*/
    return hmacDigest;
}

static QByteArray qCreatev2Hash(const QAuthenticatorPrivate *ctx,
                                QNtlmPhase3Block *phase3)
{
    Q_ASSERT(phase3 != nullptr);
    // since v2 Hash is need for both NTLMv2 and LMv2 it is calculated
    // only once and stored and reused
    if(phase3->v2Hash.size() == 0) {
        QCryptographicHash md4(QCryptographicHash::Md4);
        QByteArray passUnicode = qStringAsUcs2Le(ctx->password);
        md4.addData(passUnicode.data(), passUnicode.size());

        QByteArray hashKey = md4.result();
        Q_ASSERT(hashKey.size() == 16);
        // Assuming the user and domain is always unicode in challenge
        QByteArray message =
                qStringAsUcs2Le(ctx->extractedUser.toUpper()) +
                qStringAsUcs2Le(phase3->domainStr);

        phase3->v2Hash = qEncodeHmacMd5(hashKey, message);
    }
    return phase3->v2Hash;
}

static QByteArray clientChallenge(const QAuthenticatorPrivate *ctx)
{
    Q_ASSERT(ctx->cnonce.size() >= 8);
    QByteArray clientCh = ctx->cnonce.right(8);
    return clientCh;
}

// caller has to ensure a valid targetInfoBuff
static QByteArray qExtractServerTime(const QByteArray& targetInfoBuff)
{
    QByteArray timeArray;
    QDataStream ds(targetInfoBuff);
    ds.setByteOrder(QDataStream::LittleEndian);

    quint16 avId;
    quint16 avLen;

    ds >> avId;
    ds >> avLen;
    while(avId != 0) {
        if(avId == AVTIMESTAMP) {
            timeArray.resize(avLen);
            //avLen size of QByteArray is allocated
            ds.readRawData(timeArray.data(), avLen);
            break;
        }
        ds.skipRawData(avLen);
        ds >> avId;
        ds >> avLen;
    }
    return timeArray;
}

static QByteArray qEncodeNtlmv2Response(const QAuthenticatorPrivate *ctx,
                                        const QNtlmPhase2Block& ch,
                                        QNtlmPhase3Block *phase3)
{
    Q_ASSERT(phase3 != nullptr);
    // return value stored in phase3
    qCreatev2Hash(ctx, phase3);

    QByteArray temp;
    QDataStream ds(&temp, QIODevice::WriteOnly);
    ds.setByteOrder(QDataStream::LittleEndian);

    ds << respversion;
    ds << hirespversion;

    //Reserved
    QByteArray reserved1(6, 0);
    ds.writeRawData(reserved1.constData(), reserved1.size());

    quint64 time = 0;
    QByteArray timeArray;

    if(ch.targetInfo.len)
    {
        timeArray = qExtractServerTime(ch.targetInfoBuff);
    }

    //if server sends time, use it instead of current time
    if(timeArray.size()) {
        ds.writeRawData(timeArray.constData(), timeArray.size());
    } else {
        // number of seconds between 1601 and the epoch (1970)
        // 369 years, 89 leap years
        // ((369 * 365) + 89) * 24 * 3600 = 11644473600
        time = QDateTime::currentSecsSinceEpoch() + 11644473600;

        // represented as 100 nano seconds
        time = time * Q_UINT64_C(10000000);
        ds << time;
    }

    //8 byte client challenge
    QByteArray clientCh = clientChallenge(ctx);
    ds.writeRawData(clientCh.constData(), clientCh.size());

    //Reserved
    QByteArray reserved2(4, 0);
    ds.writeRawData(reserved2.constData(), reserved2.size());

    if (ch.targetInfo.len > 0) {
        ds.writeRawData(ch.targetInfoBuff.constData(),
                        ch.targetInfoBuff.size());
    }

    //Reserved
    QByteArray reserved3(4, 0);
    ds.writeRawData(reserved3.constData(), reserved3.size());

    QByteArray message((const char*)ch.challenge, sizeof(ch.challenge));
    message.append(temp);

    QByteArray ntChallengeResp = qEncodeHmacMd5(phase3->v2Hash, message);
    ntChallengeResp.append(temp);

    return ntChallengeResp;
}

static QByteArray qEncodeLmv2Response(const QAuthenticatorPrivate *ctx,
                                      const QNtlmPhase2Block& ch,
                                      QNtlmPhase3Block *phase3)
{
    Q_ASSERT(phase3 != nullptr);
    // return value stored in phase3
    qCreatev2Hash(ctx, phase3);

    QByteArray message((const char*)ch.challenge, sizeof(ch.challenge));
    QByteArray clientCh = clientChallenge(ctx);

    message.append(clientCh);

    QByteArray lmChallengeResp = qEncodeHmacMd5(phase3->v2Hash, message);
    lmChallengeResp.append(clientCh);

    return lmChallengeResp;
}

static bool qNtlmDecodePhase2(const QByteArray& data, QNtlmPhase2Block& ch)
{
    Q_ASSERT(QNtlmPhase2BlockBase::Size == sizeof(QNtlmPhase2BlockBase));
    if (data.size() < QNtlmPhase2BlockBase::Size)
        return false;


    QDataStream ds(data);
    ds.setByteOrder(QDataStream::LittleEndian);
    if (ds.readRawData(ch.magic, 8) < 8)
        return false;
    if (strncmp(ch.magic, "NTLMSSP", 8) != 0)
        return false;

    ds >> ch.type;
    if (ch.type != 2)
        return false;

    ds >> ch.targetName;
    ds >> ch.flags;
    if (ds.readRawData((char *)ch.challenge, 8) < 8)
        return false;
    ds >> ch.context[0] >> ch.context[1];
    ds >> ch.targetInfo;

    if (ch.targetName.len > 0) {
        if (ch.targetName.len + ch.targetName.offset > (unsigned)data.size())
            return false;

        ch.targetNameStr = qStringFromUcs2Le(data.mid(ch.targetName.offset, ch.targetName.len));
    }

    if (ch.targetInfo.len > 0) {
        if (ch.targetInfo.len + ch.targetInfo.offset > (unsigned)data.size())
            return false;

        ch.targetInfoBuff = data.mid(ch.targetInfo.offset, ch.targetInfo.len);
    }

    return true;
}


static QByteArray qNtlmPhase3(QAuthenticatorPrivate *ctx, const QByteArray& phase2data)
{
    QNtlmPhase2Block ch;
    if (!qNtlmDecodePhase2(phase2data, ch))
        return QByteArray();

    QByteArray rc;
    QDataStream ds(&rc, QIODevice::WriteOnly);
    ds.setByteOrder(QDataStream::LittleEndian);
    QNtlmPhase3Block pb;

    // set NTLMv2
    if (ch.flags & NTLMSSP_NEGOTIATE_NTLM2)
        pb.flags |= NTLMSSP_NEGOTIATE_NTLM2;

    // set Always Sign
    if (ch.flags & NTLMSSP_NEGOTIATE_ALWAYS_SIGN)
        pb.flags |= NTLMSSP_NEGOTIATE_ALWAYS_SIGN;

    bool unicode = ch.flags & NTLMSSP_NEGOTIATE_UNICODE;

    if (unicode)
        pb.flags |= NTLMSSP_NEGOTIATE_UNICODE;
    else
        pb.flags |= NTLMSSP_NEGOTIATE_OEM;


    int offset = QNtlmPhase3BlockBase::Size;
    Q_ASSERT(QNtlmPhase3BlockBase::Size == sizeof(QNtlmPhase3BlockBase));

    // for kerberos style user@domain logins, NTLM domain string should be left empty
    if (ctx->userDomain.isEmpty() && !ctx->extractedUser.contains(QLatin1Char('@'))) {
        offset = qEncodeNtlmString(pb.domain, offset, ch.targetNameStr, unicode);
        pb.domainStr = ch.targetNameStr;
    } else {
        offset = qEncodeNtlmString(pb.domain, offset, ctx->userDomain, unicode);
        pb.domainStr = ctx->userDomain;
    }

    offset = qEncodeNtlmString(pb.user, offset, ctx->extractedUser, unicode);
    pb.userStr = ctx->extractedUser;

    offset = qEncodeNtlmString(pb.workstation, offset, ctx->workstation, unicode);
    pb.workstationStr = ctx->workstation;

    // Get LM response
    if (ch.targetInfo.len > 0) {
        pb.lmResponseBuf = QByteArray();
    } else {
        pb.lmResponseBuf = qEncodeLmv2Response(ctx, ch, &pb);
    }
    offset = qEncodeNtlmBuffer(pb.lmResponse, offset, pb.lmResponseBuf);

    // Get NTLM response
    pb.ntlmResponseBuf = qEncodeNtlmv2Response(ctx, ch, &pb);
    offset = qEncodeNtlmBuffer(pb.ntlmResponse, offset, pb.ntlmResponseBuf);


    // Encode and send
    ds << pb;

    return rc;
}

// ---------------------------- End of NTLM code ---------------------------------------

#if QT_CONFIG(sspi) // SSPI
// ---------------------------- SSPI code ----------------------------------------------
// See http://davenport.sourceforge.net/ntlm.html
// and libcurl http_ntlm.c

// Handle of secur32.dll
static HMODULE securityDLLHandle = nullptr;
// Pointer to SSPI dispatch table
static PSecurityFunctionTable pSecurityFunctionTable = nullptr;

static bool q_SSPI_library_load()
{
    static QBasicMutex mutex;
    QMutexLocker l(&mutex);

    // Initialize security interface
    if (pSecurityFunctionTable == nullptr) {
        securityDLLHandle = LoadLibrary(L"secur32.dll");
        if (securityDLLHandle != nullptr) {
            INIT_SECURITY_INTERFACE pInitSecurityInterface =
                reinterpret_cast<INIT_SECURITY_INTERFACE>(
                    reinterpret_cast<QFunctionPointer>(GetProcAddress(securityDLLHandle, "InitSecurityInterfaceW")));
            if (pInitSecurityInterface != nullptr)
                pSecurityFunctionTable = pInitSecurityInterface();
        }
    }

    if (pSecurityFunctionTable == nullptr)
        return false;

    return true;
}

static QByteArray qSspiStartup(QAuthenticatorPrivate *ctx, QAuthenticatorPrivate::Method method,
                               const QString& host)
{
    if (!q_SSPI_library_load())
        return QByteArray();

    TimeStamp expiry; // For Windows 9x compatibility of SSPI calls

    if (!ctx->sspiWindowsHandles)
        ctx->sspiWindowsHandles.reset(new QSSPIWindowsHandles);
    memset(&ctx->sspiWindowsHandles->credHandle, 0, sizeof(CredHandle));

    // Acquire our credentials handle
    SECURITY_STATUS secStatus = pSecurityFunctionTable->AcquireCredentialsHandle(
                nullptr,
                (SEC_WCHAR*)(method == QAuthenticatorPrivate::Negotiate ? L"Negotiate" : L"NTLM"),
                SECPKG_CRED_OUTBOUND, nullptr, nullptr, nullptr, nullptr,
                &ctx->sspiWindowsHandles->credHandle, &expiry
    );
    if (secStatus != SEC_E_OK) {
        ctx->sspiWindowsHandles.reset(nullptr);
        return QByteArray();
    }

    return qSspiContinue(ctx, method, host);
}

static QByteArray qSspiContinue(QAuthenticatorPrivate *ctx, QAuthenticatorPrivate::Method method,
                                  const QString &host, const QByteArray &challenge)
{
    QByteArray result;
    SecBuffer challengeBuf;
    SecBuffer responseBuf;
    SecBufferDesc challengeDesc;
    SecBufferDesc responseDesc;
    unsigned long attrs;
    TimeStamp expiry; // For Windows 9x compatibility of SSPI calls

    if (!challenge.isEmpty())
    {
        // Setup the challenge "input" security buffer
        challengeDesc.ulVersion = SECBUFFER_VERSION;
        challengeDesc.cBuffers  = 1;
        challengeDesc.pBuffers  = &challengeBuf;
        challengeBuf.BufferType = SECBUFFER_TOKEN;
        challengeBuf.pvBuffer   = (PVOID)(challenge.data());
        challengeBuf.cbBuffer   = challenge.length();
    }

    // Setup the response "output" security buffer
    responseDesc.ulVersion = SECBUFFER_VERSION;
    responseDesc.cBuffers  = 1;
    responseDesc.pBuffers  = &responseBuf;
    responseBuf.BufferType = SECBUFFER_TOKEN;
    responseBuf.pvBuffer   = nullptr;
    responseBuf.cbBuffer   = 0;

    // Calculate target (SPN for Negotiate, empty for NTLM)
    std::wstring targetNameW = (method == QAuthenticatorPrivate::Negotiate
                                ? QLatin1String("HTTP/") + host : QString()).toStdWString();

    // Generate our challenge-response message
    SECURITY_STATUS secStatus = pSecurityFunctionTable->InitializeSecurityContext(
                &ctx->sspiWindowsHandles->credHandle,
                !challenge.isEmpty() ? &ctx->sspiWindowsHandles->ctxHandle : nullptr,
                const_cast<wchar_t*>(targetNameW.data()),
                ISC_REQ_ALLOCATE_MEMORY,
                0, SECURITY_NATIVE_DREP,
                !challenge.isEmpty() ? &challengeDesc : nullptr,
                0, &ctx->sspiWindowsHandles->ctxHandle,
                &responseDesc, &attrs,
                &expiry
    );

    if (secStatus == SEC_I_COMPLETE_NEEDED || secStatus == SEC_I_COMPLETE_AND_CONTINUE) {
        secStatus = pSecurityFunctionTable->CompleteAuthToken(&ctx->sspiWindowsHandles->ctxHandle,
                                                              &responseDesc);
    }

    if (secStatus != SEC_I_COMPLETE_AND_CONTINUE && secStatus != SEC_I_CONTINUE_NEEDED) {
        pSecurityFunctionTable->FreeCredentialsHandle(&ctx->sspiWindowsHandles->credHandle);
        pSecurityFunctionTable->DeleteSecurityContext(&ctx->sspiWindowsHandles->ctxHandle);
        ctx->sspiWindowsHandles.reset(nullptr);
    }

    result = QByteArray((const char*)responseBuf.pvBuffer, responseBuf.cbBuffer);
    pSecurityFunctionTable->FreeContextBuffer(responseBuf.pvBuffer);

    return result;
}

// ---------------------------- End of SSPI code ---------------------------------------

#elif QT_CONFIG(gssapi) // GSSAPI

// ---------------------------- GSSAPI code ----------------------------------------------
// See postgres src/interfaces/libpq/fe-auth.c

// Fetch all errors of a specific type
static void q_GSSAPI_error_int(const char *message, OM_uint32 stat, int type)
{
    OM_uint32 minStat, msgCtx = 0;
    gss_buffer_desc msg;

    do {
        gss_display_status(&minStat, stat, type, GSS_C_NO_OID, &msgCtx, &msg);
        qDebug() << message << ": " << reinterpret_cast<const char*>(msg.value);
        gss_release_buffer(&minStat, &msg);
    } while (msgCtx);
}

// GSSAPI errors contain two parts; extract both
static void q_GSSAPI_error(const char *message, OM_uint32 majStat, OM_uint32 minStat)
{
    // Fetch major error codes
    q_GSSAPI_error_int(message, majStat, GSS_C_GSS_CODE);

    // Add the minor codes as well
    q_GSSAPI_error_int(message, minStat, GSS_C_MECH_CODE);
}

// Send initial GSS authentication token
static QByteArray qGssapiStartup(QAuthenticatorPrivate *ctx, const QString &host)
{
    OM_uint32 majStat, minStat;

    if (!ctx->gssApiHandles)
        ctx->gssApiHandles.reset(new QGssApiHandles);

    // Convert target name to internal form
    QByteArray serviceName = QStringLiteral("HTTPS@%1").arg(host).toLocal8Bit();
    gss_buffer_desc nameDesc = {static_cast<std::size_t>(serviceName.size()), serviceName.data()};

    majStat = gss_import_name(&minStat, &nameDesc,
                              GSS_C_NT_HOSTBASED_SERVICE, &ctx->gssApiHandles->targetName);

    if (majStat != GSS_S_COMPLETE) {
        q_GSSAPI_error("gss_import_name error", majStat, minStat);
        ctx->gssApiHandles.reset(nullptr);
        return QByteArray();
    }

    // Call qGssapiContinue with GSS_C_NO_CONTEXT to get initial packet
    ctx->gssApiHandles->gssCtx = GSS_C_NO_CONTEXT;
    return qGssapiContinue(ctx);
}

// Continue GSS authentication with next token as needed
static QByteArray qGssapiContinue(QAuthenticatorPrivate *ctx, const QByteArray& challenge)
{
    OM_uint32 majStat, minStat, ignored;
    QByteArray result;
    gss_buffer_desc inBuf = {0, nullptr}; // GSS input token
    gss_buffer_desc outBuf; // GSS output token

    if (!challenge.isEmpty()) {
        inBuf.value = const_cast<char*>(challenge.data());
        inBuf.length = challenge.length();
    }

    majStat = gss_init_sec_context(&minStat,
                                   GSS_C_NO_CREDENTIAL,
                                   &ctx->gssApiHandles->gssCtx,
                                   ctx->gssApiHandles->targetName,
                                   GSS_C_NO_OID,
                                   GSS_C_MUTUAL_FLAG,
                                   0,
                                   GSS_C_NO_CHANNEL_BINDINGS,
                                   challenge.isEmpty() ? GSS_C_NO_BUFFER : &inBuf,
                                   nullptr,
                                   &outBuf,
                                   nullptr,
                                   nullptr);

    if (outBuf.length != 0)
        result = QByteArray(reinterpret_cast<const char*>(outBuf.value), outBuf.length);
    gss_release_buffer(&ignored, &outBuf);

    if (majStat != GSS_S_COMPLETE && majStat != GSS_S_CONTINUE_NEEDED) {
        q_GSSAPI_error("gss_init_sec_context error", majStat, minStat);
        gss_release_name(&ignored, &ctx->gssApiHandles->targetName);
        if (ctx->gssApiHandles->gssCtx)
            gss_delete_sec_context(&ignored, &ctx->gssApiHandles->gssCtx, GSS_C_NO_BUFFER);
        ctx->gssApiHandles.reset(nullptr);
    }

    if (majStat == GSS_S_COMPLETE) {
        gss_release_name(&ignored, &ctx->gssApiHandles->targetName);
        ctx->gssApiHandles.reset(nullptr);
    }

    return result;
}

// ---------------------------- End of GSSAPI code ----------------------------------------------

#endif // gssapi

QT_END_NAMESPACE