qauthenticator.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include <qauthenticator.h>
#include <qauthenticator_p.h>
#include <qdebug.h>
#include <qloggingcategory.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>
#include <QtNetwork/qhttpheaders.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
 
using namespace Qt::StringLiterals;
 
Q_DECLARE_LOGGING_CATEGORY(lcAuthenticator);
Q_LOGGING_CATEGORY(lcAuthenticator, "qt.network.authenticator");
 
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,
                               QStringView host);
static QByteArray qSspiContinue(QAuthenticatorPrivate *ctx, QAuthenticatorPrivate::Method method,
                                QStringView host, QByteArrayView challenge = {});
#elif QT_CONFIG(gssapi) // GSSAPI
static bool qGssapiTestGetCredentials(QStringView host);
static QByteArray qGssapiStartup(QAuthenticatorPrivate *ctx, QStringView host);
static QByteArray qGssapiContinue(QAuthenticatorPrivate *ctx, QByteArrayView challenge = {});
#endif // gssapi
 
QAuthenticator::QAuthenticator()
    : d(nullptr)
{
}
 
QAuthenticator::~QAuthenticator()
{
    if (d)
        delete d;
}
 
QAuthenticator::QAuthenticator(const QAuthenticator &other)
    : d(nullptr)
{
    if (other.d)
        *this = other;
}
 
QAuthenticator &QAuthenticator::operator=(const QAuthenticator &other)
{
    if (d == other.d)
        return *this;
 
    // Do not share the d since challenge response/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;
}
 
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;
}
 
QString QAuthenticator::user() const
{
    return d ? d->user : QString();
}
 
void QAuthenticator::setUser(const QString &user)
{
    if (!d || d->user != user) {
        detach();
        d->user = user;
        d->updateCredentials();
    }
}
 
QString QAuthenticator::password() const
{
    return d ? d->password : QString();
}
 
void QAuthenticator::setPassword(const QString &password)
{
    if (!d || d->password != password) {
        detach();
        d->password = password;
    }
}
 
void QAuthenticator::detach()
{
    if (!d) {
        d = new QAuthenticatorPrivate;
        return;
    }
 
    if (d->phase == QAuthenticatorPrivate::Done)
        d->phase = QAuthenticatorPrivate::Start;
}
 
QString QAuthenticator::realm() const
{
    return d ? d->realm : QString();
}
 
void QAuthenticator::setRealm(const QString &realm)
{
    if (!d || d->realm != realm) {
        detach();
        d->realm = realm;
    }
}
 
QVariant QAuthenticator::option(const QString &opt) const
{
    return d ? d->options.value(opt) : QVariant();
}
 
QVariantHash QAuthenticator::options() const
{
    return d ? d->options : QVariantHash();
}
 
void QAuthenticator::setOption(const QString &opt, const QVariant &value)
{
    if (option(opt) != value) {
        detach();
        d->options.insert(opt, value);
    }
}
 
 
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("\\"_L1)) != -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;
    }
}
 
bool QAuthenticatorPrivate::isMethodSupported(QByteArrayView method)
{
    Q_ASSERT(!method.startsWith(' ')); // This should be trimmed during parsing
    auto separator = method.indexOf(' ');
    if (separator != -1)
        method = method.first(separator);
    const auto isSupported = [method](QByteArrayView reference) {
        return method.compare(reference, Qt::CaseInsensitive) == 0;
    };
    static const char methods[][10] = {
        "basic",
        "ntlm",
        "digest",
#if QT_CONFIG(sspi) || QT_CONFIG(gssapi)
        "negotiate",
#endif
    };
    return std::any_of(methods, methods + std::size(methods), isSupported);
}
 
static bool verifyDigestMD5(QByteArrayView value)
{
    auto opts = QAuthenticatorPrivate::parseDigestAuthenticationChallenge(value);
    if (auto it = opts.constFind("algorithm"); it != opts.cend()) {
        QByteArray alg = it.value();
        if (alg.size() < 3)
            return false;
        // Just compare the first 3 characters, that way we match other subvariants as well, such as
        // "MD5-sess"
        auto view = QByteArrayView(alg).first(3);
        return view.compare("MD5", Qt::CaseInsensitive) == 0;
    }
    return true; // assume it's ok if algorithm is not specified
}
 
void QAuthenticatorPrivate::parseHttpResponse(const QHttpHeaders &headers,
                                              bool isProxy, QStringView host)
{
#if !QT_CONFIG(gssapi)
    Q_UNUSED(host);
#endif
    const auto search = isProxy ? QHttpHeaders::WellKnownHeader::ProxyAuthenticate
                                : QHttpHeaders::WellKnownHeader::WWWAuthenticate;
 
    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.
    */
 
    QByteArrayView headerVal;
    for (const auto &current : headers.values(search)) {
        const QLatin1StringView str(current);
        if (method < Basic && str.startsWith("basic"_L1, Qt::CaseInsensitive)) {
            method = Basic;
            headerVal = QByteArrayView(current).mid(6);
        } else if (method < Ntlm && str.startsWith("ntlm"_L1, Qt::CaseInsensitive)) {
            method = Ntlm;
            headerVal = QByteArrayView(current).mid(5);
        } else if (method < DigestMd5 && str.startsWith("digest"_L1, Qt::CaseInsensitive)) {
            // Make sure the algorithm is actually MD5 before committing to it:
            if (!verifyDigestMD5(QByteArrayView(current).sliced(7)))
                continue;
 
            method = DigestMd5;
            headerVal = QByteArrayView(current).mid(7);
        } else if (method < Negotiate && str.startsWith("negotiate"_L1, Qt::CaseInsensitive)) {
#if QT_CONFIG(sspi) || QT_CONFIG(gssapi) // if it's not supported then we shouldn't try to use it
#if QT_CONFIG(gssapi)
            // For GSSAPI there needs to be a KDC set up for the host (afaict).
            // So let's only conditionally use it if we can fetch the credentials.
            // Sadly it's a bit slow because it requires a DNS lookup.
            if (!qGssapiTestGetCredentials(host))
                continue;
#endif
            method = Negotiate;
            headerVal = QByteArrayView(current).mid(10);
#endif
        }
    }
 
    // Reparse credentials since we know the method now
    updateCredentials();
    challenge = headerVal.trimmed().toByteArray();
    QHash<QByteArray, QByteArray> options = parseDigestAuthenticationChallenge(challenge);
 
    // Sets phase to Start if this updates our realm and sets the two locations where we store
    // realm
    auto privSetRealm = [this](QString newRealm) {
        if (newRealm != realm) {
            if (phase == Done)
                phase = Start;
            realm = newRealm;
            this->options["realm"_L1] = realm;
        }
    };
 
    switch(method) {
    case Basic:
        privSetRealm(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: {
        privSetRealm(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(QByteArrayView requestMethod,
                                                    QByteArrayView path, QStringView host)
{
#if !QT_CONFIG(sspi) && !QT_CONFIG(gssapi)
    Q_UNUSED(host);
#endif
    QByteArray response;
    QByteArrayView methodString;
    switch(method) {
    case QAuthenticatorPrivate::None:
        phase = Done;
        break;
    case QAuthenticatorPrivate::Basic:
        methodString = "Basic";
        response = (user + ':'_L1 + password).toLatin1().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;
                return "";
            }
        } else {
            QByteArray phase3Token;
#if QT_CONFIG(sspi) // SSPI
            if (sspiWindowsHandles)
                phase3Token = qSspiContinue(this, method, host, QByteArray::fromBase64(challenge));
#elif QT_CONFIG(gssapi) // GSSAPI
            if (gssApiHandles)
                phase3Token = qGssapiContinue(this, QByteArray::fromBase64(challenge));
#endif
            if (!phase3Token.isEmpty()) {
                response = phase3Token.toBase64();
                phase = Done;
                challenge = "";
            } else {
                phase = Done;
                return "";
            }
        }
 
        break;
    }
 
    return methodString + ' ' + response;
}
 
 
// ---------------------------- Digest Md5 code ----------------------------------------
 
static bool containsAuth(QByteArrayView data)
{
    for (auto element : QLatin1StringView(data).tokenize(','_L1)) {
        if (element == "auth"_L1)
            return true;
    }
    return false;
}
 
QHash<QByteArray, QByteArray>
QAuthenticatorPrivate::parseDigestAuthenticationChallenge(QByteArrayView challenge)
{
    QHash<QByteArray, QByteArray> options;
    // parse the challenge
    const char *d = challenge.data();
    const char *end = d + challenge.size();
    while (d < end) {
        while (d < end && (*d == ' ' || *d == '\n' || *d == '\r'))
            ++d;
        const char *start = d;
        while (d < end && *d != '=')
            ++d;
        QByteArrayView key = QByteArrayView(start, d - start);
        ++d;
        if (d >= end)
            break;
        bool quote = (*d == '"');
        if (quote)
            ++d;
        if (d >= end)
            break;
        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.toByteArray()] = std::move(value);
    }
 
    QByteArray qop = options.value("qop");
    if (!qop.isEmpty()) {
        if (!containsAuth(qop))
            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(
    QByteArrayView alg,
    QByteArrayView userName,
    QByteArrayView realm,
    QByteArrayView password,
    QByteArrayView nonce,       /* nonce from server */
    QByteArrayView nonceCount,  /* 8 hex digits */
    QByteArrayView cNonce,      /* client nonce */
    QByteArrayView qop,         /* qop-value: "", "auth", "auth-int" */
    QByteArrayView method,      /* method from the request */
    QByteArrayView digestUri,   /* requested URL */
    QByteArrayView hEntity       /* H(entity body) if qop="auth-int" */
    )
{
    QCryptographicHash hash(QCryptographicHash::Md5);
    hash.addData(userName);
    hash.addData(":");
    hash.addData(realm);
    hash.addData(":");
    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(":");
        hash.addData(nonce);
        hash.addData(":");
        hash.addData(cNonce);
        ha1 = hash.result();
    };
    ha1 = ha1.toHex();
 
    // calculate H(A2)
    hash.reset();
    hash.addData(method);
    hash.addData(":");
    hash.addData(digestUri);
    if (qop.compare("auth-int", Qt::CaseInsensitive) == 0) {
        hash.addData(":");
        hash.addData(hEntity);
    }
    QByteArray ha2hex = hash.result().toHex();
 
    // calculate response
    hash.reset();
    hash.addData(ha1);
    hash.addData(":");
    hash.addData(nonce);
    hash.addData(":");
    if (!qop.isNull()) {
        hash.addData(nonceCount);
        hash.addData(":");
        hash.addData(cNonce);
        hash.addData(":");
        hash.addData(qop);
        hash.addData(":");
    }
    hash.addData(ha2hex);
    return hash.result().toHex();
}
 
QByteArray QAuthenticatorPrivate::digestMd5Response(QByteArrayView challenge, QByteArrayView method,
                                                    QByteArrayView path)
{
    QHash<QByteArray,QByteArray> options = parseDigestAuthenticationChallenge(challenge);
 
    ++nonceCount;
    QByteArray nonceCountString = QByteArray::number(nonceCount, 16);
    while (nonceCountString.size() < 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;
    }
 
    for (QChar ch : s)
        ds << quint16(ch.unicode());
}
 
 
 
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.size();
    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.size(), 0);
    unsigned short *d = (unsigned short*)rc.data();
    for (QChar ch : src)
        *d++ = qToLittleEndian(quint16(ch.unicode()));
 
    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.size() / 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, QByteArrayView message)
{
    Q_ASSERT_X(!(message.isEmpty()),"qEncodeHmacMd5", "Empty message check");
    Q_ASSERT_X(!(key.isEmpty()),"qEncodeHmacMd5", "Empty key check");
 
    QCryptographicHash hash(QCryptographicHash::Md5);
 
    QByteArray iKeyPad(blockSize, 0x36);
    QByteArray oKeyPad(blockSize, 0x5c);
 
    hash.reset();
    // Adjust the key length to blockSize
 
    if (blockSize < key.size()) {
        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);
    QByteArrayView hMsg = hash.resultView();
                    //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);
 
        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 (qsizetype(ch.targetName.len + ch.targetName.offset) > 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(u'@')) {
        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
 
// Pointer to SSPI dispatch table
static PSecurityFunctionTableW pSecurityFunctionTable = nullptr;
 
static bool q_SSPI_library_load()
{
    Q_CONSTINIT static QBasicMutex mutex;
    QMutexLocker l(&mutex);
 
    if (pSecurityFunctionTable == nullptr)
        pSecurityFunctionTable = InitSecurityInterfaceW();
 
    if (pSecurityFunctionTable == nullptr)
        return false;
 
    return true;
}
 
static QByteArray qSspiStartup(QAuthenticatorPrivate *ctx, QAuthenticatorPrivate::Method method,
                               QStringView 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);
    SecInvalidateHandle(&ctx->sspiWindowsHandles->credHandle);
    SecInvalidateHandle(&ctx->sspiWindowsHandles->ctxHandle);
 
    SEC_WINNT_AUTH_IDENTITY auth;
    auth.Flags = SEC_WINNT_AUTH_IDENTITY_UNICODE;
    bool useAuth = false;
    if (method == QAuthenticatorPrivate::Negotiate && !ctx->user.isEmpty()) {
        auth.Domain = const_cast<ushort *>(reinterpret_cast<const ushort *>(ctx->userDomain.constData()));
        auth.DomainLength = ctx->userDomain.size();
        auth.User = const_cast<ushort *>(reinterpret_cast<const ushort *>(ctx->user.constData()));
        auth.UserLength = ctx->user.size();
        auth.Password = const_cast<ushort *>(reinterpret_cast<const ushort *>(ctx->password.constData()));
        auth.PasswordLength = ctx->password.size();
        useAuth = true;
    }
 
    // Acquire our credentials handle
    SECURITY_STATUS secStatus = pSecurityFunctionTable->AcquireCredentialsHandle(
            nullptr,
            (SEC_WCHAR *)(method == QAuthenticatorPrivate::Negotiate ? L"Negotiate" : L"NTLM"),
            SECPKG_CRED_OUTBOUND, nullptr, useAuth ? &auth : 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,
                                QStringView host, QByteArrayView 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)
    QString targetName = ctx->options.value("spn"_L1).toString();
    if (targetName.isEmpty())
        targetName = "HTTP/"_L1 + host;
    const std::wstring targetNameW = (method == QAuthenticatorPrivate::Negotiate
                                      ? targetName : 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);
        qCDebug(lcAuthenticator) << 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);
}
 
static gss_name_t qGSsapiGetServiceName(QStringView host)
{
    QByteArray serviceName = "HTTPS@" + host.toLocal8Bit();
    gss_buffer_desc nameDesc = {static_cast<std::size_t>(serviceName.size()), serviceName.data()};
 
    gss_name_t importedName;
    OM_uint32 minStat;
    OM_uint32 majStat = gss_import_name(&minStat, &nameDesc,
                              GSS_C_NT_HOSTBASED_SERVICE, &importedName);
 
    if (majStat != GSS_S_COMPLETE) {
        q_GSSAPI_error("gss_import_name error", majStat, minStat);
        return nullptr;
    }
    return importedName;
}
 
// Send initial GSS authentication token
static QByteArray qGssapiStartup(QAuthenticatorPrivate *ctx, QStringView host)
{
    if (!ctx->gssApiHandles)
        ctx->gssApiHandles.reset(new QGssApiHandles);
 
    // Convert target name to internal form
    gss_name_t name = qGSsapiGetServiceName(host);
    if (name == nullptr) {
        ctx->gssApiHandles.reset(nullptr);
        return QByteArray();
    }
    ctx->gssApiHandles->targetName = name;
 
    // 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, QByteArrayView 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.size();
    }
 
    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;
}
 
static bool qGssapiTestGetCredentials(QStringView host)
{
    gss_name_t serviceName = qGSsapiGetServiceName(host);
    if (!serviceName)
        return false; // Something was wrong with the service name, so skip this
    OM_uint32 minStat;
    gss_cred_id_t cred;
    OM_uint32 majStat = gss_acquire_cred(&minStat, serviceName, GSS_C_INDEFINITE,
                                         GSS_C_NO_OID_SET, GSS_C_INITIATE, &cred, nullptr,
                                         nullptr);
 
    OM_uint32 ignored;
    gss_release_name(&ignored, &serviceName);
    gss_release_cred(&ignored, &cred);
 
    if (majStat != GSS_S_COMPLETE) {
        q_GSSAPI_error("gss_acquire_cred", majStat, minStat);
        return false;
    }
    return true;
}
 
// ---------------------------- End of GSSAPI code ----------------------------------------------
 
#endif // gssapi
 
QT_END_NAMESPACE