exam_timer_teacher/utils/qjsonwebtoken.cpp

// The MIT License(MIT)
// Copyright(c) <2016> <Juan Gonzalez Burgos>
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files(the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and / or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions :
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#include "qjsonwebtoken.h"

#include <QDebug>

QJsonWebToken::QJsonWebToken()
{
    // create the header with default algorithm
    setAlgorithmStr("HS256");
    m_jdocPayload = QJsonDocument::fromJson("{}");
    // default for random generation
    m_intRandLength = 10;
    m_strRandAlphanum = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
}

QJsonWebToken::QJsonWebToken(const QJsonWebToken &other)
{
    this->m_jdocHeader = other.m_jdocHeader;
    this->m_jdocPayload = other.m_jdocPayload;
    this->m_byteSignature = other.m_byteSignature;
    this->m_strSecret = other.m_strSecret;
    this->m_strAlgorithm = other.m_strAlgorithm;
    this->m_strPayload = other.m_strPayload;
    this->m_strHeader = other.m_strHeader;
    this->m_byteAllData = other.m_byteAllData;
}

QJsonDocument QJsonWebToken::getHeaderJDoc() const
{
    return m_jdocHeader;
}

QString QJsonWebToken::getHeaderQStr() const
{
    return m_strHeader;
}

bool QJsonWebToken::setHeaderJDoc(const QJsonDocument &jdocHeader)
{
    if (jdocHeader.isEmpty() || jdocHeader.isNull() || !jdocHeader.isObject()) {
        return false;
    }

    // check if supported algorithm
    QString strAlgorithm = jdocHeader.object().value("alg").toString("");
    if (!isAlgorithmSupported(strAlgorithm)) {
        return false;
    }

    m_jdocHeader = jdocHeader;

    m_strHeader = jdocHeader.toJson(QJsonDocument::Compact);

    // set also new algorithm
    m_strAlgorithm = strAlgorithm;

    return true;
}

bool QJsonWebToken::setHeaderQStr(const QString &strHeader)
{
    QJsonParseError error;
    QJsonDocument tmpHeader = QJsonDocument::fromJson(strHeader.toUtf8(), &error);

    // validate and set header
    if (error.error != QJsonParseError::NoError || !setHeaderJDoc(tmpHeader)) {
        return false;
    }
    m_strHeader = strHeader;

    return true;
}

QJsonDocument QJsonWebToken::getPayloadJDoc() const
{
    return m_jdocPayload;
}

QString QJsonWebToken::getPayloadQStr() const
{
    return m_strPayload;
}

bool QJsonWebToken::setPayloadJDoc(const QJsonDocument &jdocPayload)
{
    if (jdocPayload.isEmpty() || jdocPayload.isNull() || !jdocPayload.isObject()) {
        return false;
    }

    m_jdocPayload = jdocPayload;

    m_strPayload = jdocPayload.toJson(QJsonDocument::Compact);

    return true;
}

bool QJsonWebToken::setPayloadQStr(const QString &strPayload)
{
    QJsonParseError error;
    QJsonDocument tmpPayload = QJsonDocument::fromJson(strPayload.toUtf8(), &error);

    // validate and set payload
    if (error.error != QJsonParseError::NoError || !setPayloadJDoc(tmpPayload)) {
        return false;
    }
    m_strPayload = strPayload;
    return true;
}

QByteArray QJsonWebToken::getSignature()
{
    // recalculate
    // get header in compact mode and base64 encoded
    QByteArray byteHeaderBase64 = getHeaderQStr().toUtf8().toBase64(
        QByteArray::Base64UrlEncoding | QByteArray::OmitTrailingEquals);
    // get payload in compact mode and base64 encoded
    QByteArray bytePayloadBase64 = getPayloadQStr().toUtf8().toBase64(
        QByteArray::Base64UrlEncoding | QByteArray::OmitTrailingEquals);
    // calculate signature based on chosen algorithm and secret
    m_byteAllData = byteHeaderBase64 + "." + bytePayloadBase64;
    //    qDebug()<<"m: " << m_byteAllData;
    if (m_strAlgorithm.compare("HS256", Qt::CaseSensitive) == 0) // HMAC using SHA-256 hash algorithm
    {
        m_byteSignature = QMessageAuthenticationCode::hash(m_byteAllData,
                                                           m_strSecret.toUtf8(),
                                                           QCryptographicHash::Sha256);
    } else if (m_strAlgorithm.compare("HS384", Qt::CaseSensitive)
               == 0) // HMAC using SHA-384 hash algorithm
    {
        m_byteSignature = QMessageAuthenticationCode::hash(m_byteAllData,
                                                           m_strSecret.toUtf8(),
                                                           QCryptographicHash::Sha384);
    } else if (m_strAlgorithm.compare("HS512", Qt::CaseSensitive)
               == 0) // HMAC using SHA-512 hash algorithm
    {
        m_byteSignature = QMessageAuthenticationCode::hash(m_byteAllData,
                                                           m_strSecret.toUtf8(),
                                                           QCryptographicHash::Sha512);
    }
    // TODO : support other algorithms
    else {
        m_byteSignature = QByteArray();
    }
    // return recalculated
    return m_byteSignature;
}

QByteArray QJsonWebToken::getSignatureBase64()
{
    // note we return through getSignature() to force recalculation
    return getSignature().toBase64(QByteArray::Base64UrlEncoding | QByteArray::OmitTrailingEquals);
}

QString QJsonWebToken::getSecret() const
{
    return m_strSecret;
}

bool QJsonWebToken::setSecret(const QString &strSecret)
{
    if (strSecret.isEmpty() || strSecret.isNull()) {
        return false;
    }

    m_strSecret = strSecret;

    return true;
}

void QJsonWebToken::setRandomSecret()
{
    m_strSecret.resize(m_intRandLength);
    for (int i = 0; i < m_intRandLength; ++i) {
        m_strSecret[i] = m_strRandAlphanum.at(rand() % (m_strRandAlphanum.length() - 1));
    }
}

QString QJsonWebToken::getAlgorithmStr() const
{
    return m_strAlgorithm;
}

bool QJsonWebToken::setAlgorithmStr(const QString &strAlgorithm)
{
    // check if supported algorithm
    if (!isAlgorithmSupported(strAlgorithm)) {
        return false;
    }
    // set algorithm
    m_strAlgorithm = strAlgorithm;
    // modify header

    m_strHeader = QByteArray("{\"typ\": \"JWT\", \"alg\" : \"") + m_strAlgorithm.toUtf8()
                  + QByteArray("\"}");
    m_jdocHeader = QJsonDocument::fromJson(m_strHeader.toUtf8());

    return true;
}

QString QJsonWebToken::getToken()
{
    // important to execute first to update m_byteAllData which contains header + "." + payload in base64
    QByteArray byteSignatureBase64 = this->getSignatureBase64();
    // compose token and return it
    return m_byteAllData + "." + byteSignatureBase64;
}

bool QJsonWebToken::setToken(const QString &strToken)
{
    // assume base64 encoded at first, if not try decoding
    bool isBase64Encoded = true;
    QStringList listJwtParts = strToken.split(".");
    // check correct size
    if (listJwtParts.count() != 3) {
        return false;
    }
    // check all parts are valid using another instance,
    // so we dont overwrite this instance in case of error
    QJsonWebToken tempTokenObj;
    if (!tempTokenObj.setHeaderQStr(
            QByteArray::fromBase64(listJwtParts.at(0).toUtf8(), QByteArray::Base64UrlEncoding))
        || !tempTokenObj.setPayloadQStr(
            QByteArray::fromBase64(listJwtParts.at(1).toUtf8(), QByteArray::Base64UrlEncoding))) {
        // try unencoded
        if (!tempTokenObj.setHeaderQStr(listJwtParts.at(0))
            || !tempTokenObj.setPayloadQStr(listJwtParts.at(1))) {
            return false;
        } else {
            isBase64Encoded = false;
        }
    }
    // set parts on this instance
    setHeaderQStr(tempTokenObj.getHeaderQStr());
    setPayloadQStr(tempTokenObj.getPayloadQStr());
    if (isBase64Encoded) { // unencode
        m_byteSignature = QByteArray::fromBase64(listJwtParts.at(2).toUtf8(),
                                                 QByteArray::Base64UrlEncoding);
    } else {
        m_byteSignature = listJwtParts.at(2).toUtf8();
    }
    // allData not valid anymore
    m_byteAllData.clear();
    // success
    return true;
}

QString QJsonWebToken::getRandAlphanum() const
{
    return m_strRandAlphanum;
}

void QJsonWebToken::setRandAlphanum(const QString &strRandAlphanum)
{
    if (strRandAlphanum.isNull()) {
        return;
    }
    m_strRandAlphanum = strRandAlphanum;
}

int QJsonWebToken::getRandLength() const
{
    return m_intRandLength;
}

void QJsonWebToken::setRandLength(const int &intRandLength)
{
    if (intRandLength < 0 || intRandLength > 1e6) {
        return;
    }
    m_intRandLength = intRandLength;
}

bool QJsonWebToken::isValid() const
{
    // calculate token on other instance,
    // so we dont overwrite this instance's signature
    QJsonWebToken tempTokenObj = *this;
    if (m_byteSignature != tempTokenObj.getSignature()) {
        return false;
    }
    return true;
}

QJsonWebToken QJsonWebToken::fromTokenAndSecret(const QString &strToken, const QString &srtSecret)
{
    QJsonWebToken tempTokenObj;
    // set Token
    tempTokenObj.setToken(strToken);
    // set Secret
    tempTokenObj.setSecret(srtSecret);
    // return
    return tempTokenObj;
}

void QJsonWebToken::appendClaim(const QString &strClaimType, const QString &strValue)
{
    // have to make a copy of the json object, modify the copy and then put it back, sigh
    QJsonObject jObj = m_jdocPayload.object();
    jObj.insert(strClaimType, strValue);
    m_jdocPayload = QJsonDocument(jObj);

    m_strPayload = QJsonDocument(jObj).toJson(QJsonDocument::Compact);
}

void QJsonWebToken::removeClaim(const QString &strClaimType)
{
    // have to make a copy of the json object, modify the copy and then put it back, sigh
    QJsonObject jObj = m_jdocPayload.object();
    jObj.remove(strClaimType);
    m_jdocPayload = QJsonDocument(jObj);
    m_strPayload = QJsonDocument(jObj).toJson(QJsonDocument::Compact);
}

QString QJsonWebToken::claim(const QString &strClaimType)
{
    QJsonObject jObj = m_jdocPayload.object();

    return jObj[strClaimType].toString();
}

bool QJsonWebToken::isAlgorithmSupported(const QString &strAlgorithm)
{
    // TODO : support other algorithms
    if (strAlgorithm.compare("HS256", Qt::CaseSensitive) != 0 && // HMAC using SHA-256 hash algorithm
        strAlgorithm.compare("HS384", Qt::CaseSensitive) != 0 && // HMAC using SHA-384 hash algorithm
        strAlgorithm.compare("HS512", Qt::CaseSensitive) != 0 /*&& // HMAC using SHA-512 hash algorithm
		strAlgorithm.compare("RS256", Qt::CaseSensitive) != 0 && // RSA using SHA-256 hash algorithm
		strAlgorithm.compare("RS384", Qt::CaseSensitive) != 0 && // RSA using SHA-384 hash algorithm
		strAlgorithm.compare("RS512", Qt::CaseSensitive) != 0 && // RSA using SHA-512 hash algorithm
		strAlgorithm.compare("ES256", Qt::CaseSensitive) != 0 && // ECDSA using P-256 curve and SHA-256 hash algorithm
		strAlgorithm.compare("ES384", Qt::CaseSensitive) != 0 && // ECDSA using P-384 curve and SHA-384 hash algorithm
		strAlgorithm.compare("ES512", Qt::CaseSensitive) != 0*/)  // ECDSA using P-521 curve and SHA-512 hash algorithm
    {
        return false;
    }
    return true;
}

QStringList QJsonWebToken::supportedAlgorithms()
{
    // TODO : support other algorithms
    return QStringList() << "HS256"
                         << "HS384"
                         << "HS512";
}