nextcloud-desktop/src/libsync/clientsideencryption.cpp

#include "clientsideencryption.h"
#include "account.h"
#include "capabilities.h"
#include "networkjobs.h"
#include "clientsideencryptionjobs.h"
#include "theme.h"
#include "creds/abstractcredentials.h"

#include <openssl/rsa.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/engine.h>

#include <map>

#include <cstdio>

#include <QDebug>
#include <QLoggingCategory>
#include <QFileInfo>
#include <QDir>
#include <QJsonObject>
#include <QXmlStreamReader>
#include <QXmlStreamNamespaceDeclaration>
#include <QStack>
#include <QInputDialog>
#include <QLineEdit>

#include <keychain.h>

#include "wordlist.h"

QDebug operator<<(QDebug out, const std::string& str)
{
    out << QString::fromStdString(str);
    return out;
}

using namespace QKeychain;

namespace OCC
{

Q_LOGGING_CATEGORY(lcCse, "sync.clientsideencryption", QtInfoMsg)

QString baseUrl(){
    return QStringLiteral("ocs/v2.php/apps/end_to_end_encryption/api/v1/");
}

QString baseDirectory() {
    return QDir::homePath() + QStringLiteral("/.nextcloud-keys/");
}

namespace {
    void handleErrors(void)
    {
        ERR_print_errors_fp(stdout); // This line is not printing anything.
        fflush(stdout);
    }
}

class EncryptionHelper {
public:
    using Password = QByteArray;
    using Salt = QByteArray;

    static QByteArray generateRandom(int size);
    static QPair<Password, Salt> generatePassword(const QString &wordlist);
    static QByteArray encryptPrivateKey(
            const QByteArray& key,
            const QByteArray& privateKey
    );
    static QByteArray decryptPrivateKey(
            const QByteArray& key,
            const QByteArray& data
    );
    static QByteArray encryptStringSymmetric(
            const QByteArray& key,
            const QByteArray& data
    );
    static QByteArray decryptStringSymmetric(
            const QByteArray& key,
            const QByteArray& data
    );
    static QByteArray encryptStringAsymmetric(
            EVP_PKEY *publicKey,
            const QByteArray& data
    );
    static QByteArray BIO2ByteArray(BIO *b);
};

QByteArray EncryptionHelper::generateRandom(int size) {
    unsigned char *tmp = (unsigned char *)malloc(sizeof(unsigned char) * size);

    int ret = RAND_bytes(tmp, size);
    if (ret != 1) {
        qCInfo(lcCse()) << "Random byte generation failed!";
        // Error out?
    }

    QByteArray result((const char *)tmp, size);
    free(tmp);

    return result;
}

QPair<EncryptionHelper::Password, EncryptionHelper::Salt> EncryptionHelper::generatePassword(const QString& wordlist) {
    qCInfo(lcCse()) << "Start encryption key generation!";

    // TODO generate salt
    const unsigned char *_salt = (unsigned char *)"$4$YmBjm3hk$Qb74D5IUYwghUmzsMqeNFx5z0/8$";
    const int saltLen = 40;

    QByteArray salt((const char *)_salt, saltLen);

    const int iterationCount = 1024;
    const int keyStrength = 256;
    const int keyLength = keyStrength/8;

    unsigned char secretKey[keyLength];

    int ret = PKCS5_PBKDF2_HMAC_SHA1(
        wordlist.toLocal8Bit().constData(),     // const char *password,
        wordlist.size(),                        // int password length,
        (const unsigned char *)salt.constData(),                       // const unsigned char *salt,
        salt.size(),                            // int saltlen,
        iterationCount,                         // int iterations,
        keyLength,                              // int keylen,
        secretKey                               // unsigned char *out
    );

    if (ret != 1) {
        qCInfo(lcCse()) << "Failed to generate encryption key";
        // Error out?
    }

    qCInfo(lcCse()) << "Encryption key generated!";

    QByteArray password((const char *)secretKey, keyLength);
    return {password, salt};
}

QByteArray EncryptionHelper::encryptPrivateKey(
        const QByteArray& key,
        const QByteArray& privateKey
        ) {

    QByteArray iv = generateRandom(12);

    EVP_CIPHER_CTX *ctx;
    /* Create and initialise the context */
    if(!(ctx = EVP_CIPHER_CTX_new())) {
        qCInfo(lcCse()) << "Error creating cipher";
        handleErrors();
    }

    /* Initialise the decryption operation. */
    if(!EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL)) {
        qCInfo(lcCse()) << "Error initializing context with aes_256";
        handleErrors();
    }

    // No padding
    EVP_CIPHER_CTX_set_padding(ctx, 0);

    /* Set IV length. */
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv.size(), NULL)) {
        qCInfo(lcCse()) << "Error setting iv length";
        handleErrors();
    }

    /* Initialise key and IV */
    if(!EVP_EncryptInit_ex(ctx, NULL, NULL, (unsigned char *)key.constData(), (unsigned char *)iv.constData())) {
        qCInfo(lcCse()) << "Error initialising key and iv";
        handleErrors();
    }

    // We write the base64 encoded private key
    QByteArray privateKeyB64 = privateKey.toBase64();

    // Make sure we have enough room in the cipher text
    unsigned char *ctext = (unsigned char *)malloc(sizeof(unsigned char) * (privateKeyB64.size() + 32));

    // Do the actual encryption
    int len = 0;
    if(!EVP_EncryptUpdate(ctx, ctext, &len, (unsigned char *)privateKeyB64.constData(), privateKeyB64.size())) {
        qCInfo(lcCse()) << "Error encrypting";
        handleErrors();
    }

    int clen = len;

    /* Finalise the encryption. Normally ciphertext bytes may be written at
     * this stage, but this does not occur in GCM mode
     */
    if(1 != EVP_EncryptFinal_ex(ctx, ctext + len, &len)) {
        qCInfo(lcCse()) << "Error finalizing encryption";
        handleErrors();
    }
    clen += len;

    /* Get the tag */
    unsigned char *tag = (unsigned char *)calloc(sizeof(unsigned char), 16);
    if(1 != EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, 16, tag)) {
        qCInfo(lcCse()) << "Error getting the tag";
        handleErrors();
    }

    QByteArray cipherTXT((char *)ctext, clen);
    cipherTXT.append((char *)tag, 16);

    QByteArray result = cipherTXT.toBase64();
    result += "fA==";
    result += iv.toBase64();

    return result;
}

QByteArray EncryptionHelper::decryptPrivateKey(const QByteArray& key, const QByteArray& data) {
    qCInfo(lcCse()) << "decryptStringSymmetric key: " << key;
    qCInfo(lcCse()) << "decryptStringSymmetric data: " << data;

    int sep = data.indexOf("fA==");
    qCInfo(lcCse()) << "sep at" << sep;

    QByteArray cipherTXT64 = data.left(sep);
    QByteArray ivB64 = data.right(data.size() - sep - 4);

    qCInfo(lcCse()) << "decryptStringSymmetric cipherTXT: " << cipherTXT64;
    qCInfo(lcCse()) << "decryptStringSymmetric IV: " << ivB64;

    QByteArray cipherTXT = QByteArray::fromBase64(cipherTXT64);
    QByteArray iv = QByteArray::fromBase64(ivB64);

    QByteArray tag = cipherTXT.right(16);
    cipherTXT.chop(16);

    // Init
    EVP_CIPHER_CTX *ctx;

    /* Create and initialise the context */
    if(!(ctx = EVP_CIPHER_CTX_new())) {
        qCInfo(lcCse()) << "Error creating cipher";
        return QByteArray();
    }

    /* Initialise the decryption operation. */
    if(!EVP_DecryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL)) {
        qCInfo(lcCse()) << "Error initialising context with aes 256";
        EVP_CIPHER_CTX_free(ctx);
        return QByteArray();
    }

    /* Set IV length. Not necessary if this is 12 bytes (96 bits) */
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv.size(), NULL)) {
        qCInfo(lcCse()) << "Error setting IV size";
        EVP_CIPHER_CTX_free(ctx);
        return QByteArray();
    }

    /* Initialise key and IV */
    if(!EVP_DecryptInit_ex(ctx, NULL, NULL, (unsigned char *)key.constData(), (unsigned char *)iv.constData())) {
        qCInfo(lcCse()) << "Error initialising key and iv";
        EVP_CIPHER_CTX_free(ctx);
        return QByteArray();
    }

    unsigned char *ptext = (unsigned char *)calloc(cipherTXT.size() + 16, sizeof(unsigned char));
    int plen;

    /* Provide the message to be decrypted, and obtain the plaintext output.
     * EVP_DecryptUpdate can be called multiple times if necessary
     */
    if(!EVP_DecryptUpdate(ctx, ptext, &plen, (unsigned char *)cipherTXT.constData(), cipherTXT.size())) {
        qCInfo(lcCse()) << "Could not decrypt";
        EVP_CIPHER_CTX_free(ctx);
        free(ptext);
        return QByteArray();
    }

    /* Set expected tag value. Works in OpenSSL 1.0.1d and later */
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, tag.size(), (unsigned char *)tag.constData())) {
        qCInfo(lcCse()) << "Could not set tag";
        EVP_CIPHER_CTX_free(ctx);
        free(ptext);
        return QByteArray();
    }

    /* Finalise the decryption. A positive return value indicates success,
     * anything else is a failure - the plaintext is not trustworthy.
     */
    int len = plen;
    if (EVP_DecryptFinal_ex(ctx, ptext + plen, &len) == 0) {
        qCInfo(lcCse()) << "Tag did not match!";
        EVP_CIPHER_CTX_free(ctx);
        free(ptext);
        return QByteArray();
    }

    QByteArray result((char *)ptext, plen);

    free(ptext);
    EVP_CIPHER_CTX_free(ctx);

    return QByteArray::fromBase64(result);
}

QByteArray EncryptionHelper::decryptStringSymmetric(const QByteArray& key, const QByteArray& data) {
    qCInfo(lcCse()) << "decryptStringSymmetric key: " << key;
    qCInfo(lcCse()) << "decryptStringSymmetric data: " << data;

    int sep = data.indexOf("fA==");
    qCInfo(lcCse()) << "sep at" << sep;

    QByteArray cipherTXT64 = data.left(sep);
    QByteArray ivB64 = data.right(data.size() - sep - 4);

    qCInfo(lcCse()) << "decryptStringSymmetric cipherTXT: " << cipherTXT64;
    qCInfo(lcCse()) << "decryptStringSymmetric IV: " << ivB64;

    QByteArray cipherTXT = QByteArray::fromBase64(cipherTXT64);
    QByteArray iv = QByteArray::fromBase64(ivB64);

    QByteArray tag = cipherTXT.right(16);
    cipherTXT.chop(16);

    // Init
    EVP_CIPHER_CTX *ctx;

    /* Create and initialise the context */
    if(!(ctx = EVP_CIPHER_CTX_new())) {
        qCInfo(lcCse()) << "Error creating cipher";
        return QByteArray();
    }

    /* Initialise the decryption operation. */
    if(!EVP_DecryptInit_ex(ctx, EVP_aes_128_gcm(), NULL, NULL, NULL)) {
        qCInfo(lcCse()) << "Error initialising context with aes 128";
        EVP_CIPHER_CTX_free(ctx);
        return QByteArray();
    }

    /* Set IV length. Not necessary if this is 12 bytes (96 bits) */
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv.size(), NULL)) {
        qCInfo(lcCse()) << "Error setting IV size";
        EVP_CIPHER_CTX_free(ctx);
        return QByteArray();
    }

    /* Initialise key and IV */
    if(!EVP_DecryptInit_ex(ctx, NULL, NULL, (unsigned char *)key.constData(), (unsigned char *)iv.constData())) {
        qCInfo(lcCse()) << "Error initialising key and iv";
        EVP_CIPHER_CTX_free(ctx);
        return QByteArray();
    }

    unsigned char *ptext = (unsigned char *)calloc(cipherTXT.size() + 16, sizeof(unsigned char));
    int plen;

    /* Provide the message to be decrypted, and obtain the plaintext output.
     * EVP_DecryptUpdate can be called multiple times if necessary
     */
    if(!EVP_DecryptUpdate(ctx, ptext, &plen, (unsigned char *)cipherTXT.constData(), cipherTXT.size())) {
        qCInfo(lcCse()) << "Could not decrypt";
        EVP_CIPHER_CTX_free(ctx);
        free(ptext);
        return QByteArray();
    }

    /* Set expected tag value. Works in OpenSSL 1.0.1d and later */
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, tag.size(), (unsigned char *)tag.constData())) {
        qCInfo(lcCse()) << "Could not set tag";
        EVP_CIPHER_CTX_free(ctx);
        free(ptext);
        return QByteArray();
    }

    /* Finalise the decryption. A positive return value indicates success,
     * anything else is a failure - the plaintext is not trustworthy.
     */
    int len = plen;
    if (EVP_DecryptFinal_ex(ctx, ptext + plen, &len) == 0) {
        qCInfo(lcCse()) << "Tag did not match!";
        EVP_CIPHER_CTX_free(ctx);
        free(ptext);
        return QByteArray();
    }

    QByteArray result((char *)ptext, plen);

    free(ptext);
    EVP_CIPHER_CTX_free(ctx);

    return QByteArray();
}

QByteArray EncryptionHelper::encryptStringSymmetric(const QByteArray& key, const QByteArray& data) {
    QByteArray iv = generateRandom(16);

    EVP_CIPHER_CTX *ctx;
    /* Create and initialise the context */
    if(!(ctx = EVP_CIPHER_CTX_new())) {
        qCInfo(lcCse()) << "Error creating cipher";
        handleErrors();
    }

    /* Initialise the decryption operation. */
    if(!EVP_EncryptInit_ex(ctx, EVP_aes_128_gcm(), NULL, NULL, NULL)) {
        qCInfo(lcCse()) << "Error initializing context with aes_128";
        handleErrors();
    }

    // No padding
    EVP_CIPHER_CTX_set_padding(ctx, 0);

    /* Set IV length. */
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv.size(), NULL)) {
        qCInfo(lcCse()) << "Error setting iv length";
        handleErrors();
    }

    /* Initialise key and IV */
    if(!EVP_EncryptInit_ex(ctx, NULL, NULL, (unsigned char *)key.constData(), (unsigned char *)iv.constData())) {
        qCInfo(lcCse()) << "Error initialising key and iv";
        handleErrors();
    }

    // We write the data base64 encoded
    QByteArray dataB64 = data.toBase64();

    // Make sure we have enough room in the cipher text
    unsigned char *ctext = (unsigned char *)malloc(sizeof(unsigned char) * (dataB64.size() + 16));

    // Do the actual encryption
    int len = 0;
    if(!EVP_EncryptUpdate(ctx, ctext, &len, (unsigned char *)dataB64.constData(), dataB64.size())) {
        qCInfo(lcCse()) << "Error encrypting";
        handleErrors();
    }

    int clen = len;

    /* Finalise the encryption. Normally ciphertext bytes may be written at
     * this stage, but this does not occur in GCM mode
     */
    if(1 != EVP_EncryptFinal_ex(ctx, ctext + len, &len)) {
        qCInfo(lcCse()) << "Error finalizing encryption";
        handleErrors();
    }
    clen += len;

    /* Get the tag */
    unsigned char *tag = (unsigned char *)calloc(sizeof(unsigned char), 16);
    if(1 != EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, 16, tag)) {
        qCInfo(lcCse()) << "Error getting the tag";
        handleErrors();
    }

    QByteArray cipherTXT((char *)ctext, clen);
    cipherTXT.append((char *)tag, 16);

    QByteArray result = cipherTXT.toBase64();
    result += "fA==";
    result += iv.toBase64();

    return result;
}

QByteArray EncryptionHelper::encryptStringAsymmetric(EVP_PKEY *publicKey, const QByteArray& data) {
    int err = -1;

    auto ctx = EVP_PKEY_CTX_new(publicKey, ENGINE_get_default_RSA());
    if (!ctx) {
        qCInfo(lcCse()) << "Could not initialize the pkey context.";
        exit(1);
    }

    if (EVP_PKEY_encrypt_init(ctx) != 1) {
        qCInfo(lcCse()) << "Error initilaizing the encryption.";
        exit(1);
    }

    if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_OAEP_PADDING) <= 0) {
        qCInfo(lcCse()) << "Error setting the encryption padding.";
        exit(1);
    }

    if (EVP_PKEY_CTX_set_rsa_oaep_md(ctx, EVP_sha256()) <= 0) {
        qCInfo(lcCse()) << "Error setting OAEP SHA 256";
        exit(1);
    }

    if (EVP_PKEY_CTX_set_rsa_mgf1_md(ctx, EVP_sha256()) <= 0) {
        qCInfo(lcCse()) << "Error setting MGF1 padding";
        exit(1);
    }

    size_t outLen = 0;
    if (EVP_PKEY_encrypt(ctx, NULL, &outLen, (unsigned char *)data.constData(), data.size()) != 1) {
        qCInfo(lcCse()) << "Error retrieving the size of the encrypted data";
        exit(1);
    } else {
        qCInfo(lcCse()) << "Encrption Length:" << outLen;
    }

    unsigned char *out = (uchar*) OPENSSL_malloc(outLen);
    if (!out) {
        qCInfo(lcCse()) << "Error requesting memory for the encrypted contents";
        exit(1);
    }

    if (EVP_PKEY_encrypt(ctx, out, &outLen, (unsigned char *)data.constData(), data.size()) != 1) {
        qCInfo(lcCse()) << "Could not encrypt key." << err;
        exit(1);
    }

    // Transform the encrypted data into base64.
    QByteArray raw((const char*) out, outLen);
    qCInfo(lcCse()) << raw.toBase64();
    return raw.toBase64();
}

QByteArray EncryptionHelper::BIO2ByteArray(BIO *b) {
    int pending = BIO_ctrl_pending(b);
    char *tmp = (char *)calloc(pending+1, sizeof(char));
    BIO_read(b, tmp, pending);

    QByteArray res(tmp, pending);
    free(tmp);

    return res;
}

ClientSideEncryption::ClientSideEncryption()
{
}

void ClientSideEncryption::setAccount(AccountPtr account)
{
    _account = account;
}

void ClientSideEncryption::initialize()
{
    qCInfo(lcCse()) << "Initializing";
    if (!_account->capabilities().clientSideEncryptionAvaliable()) {
        qCInfo(lcCse()) << "No Client side encryption avaliable on server.";
        emit initializationFinished();
    }

    fetchFromKeyChain();
}

void ClientSideEncryption::fetchFromKeyChain() {
    const QString kck = AbstractCredentials::keychainKey(
                _account->url().toString(),
                _account->credentials()->user() + "_e2e-certificate",
                _account->id()
    );

    ReadPasswordJob *job = new ReadPasswordJob(Theme::instance()->appName());
    job->setInsecureFallback(false);
    job->setKey(kck);
    connect(job, &ReadPasswordJob::finished, this, &ClientSideEncryption::publicKeyFetched);
    job->start();
}

void ClientSideEncryption::publicKeyFetched(Job *incoming) {
    ReadPasswordJob *readJob = static_cast<ReadPasswordJob *>(incoming);

    // Error or no valid public key error out
    if (readJob->error() != NoError || readJob->binaryData().length() == 0) {
        getPublicKeyFromServer();
        return;
    }

    _certificate = QSslCertificate(readJob->binaryData(), QSsl::Pem);

    if (_certificate.isNull()) {
        getPublicKeyFromServer();
        return;
    }

    _publicKey = _certificate.publicKey();

    qCInfo(lcCse()) << "Public key fetched from keychain";

    const QString kck = AbstractCredentials::keychainKey(
                _account->url().toString(),
                _account->credentials()->user() + "_e2e-private",
                _account->id()
    );

    ReadPasswordJob *job = new ReadPasswordJob(Theme::instance()->appName());
    job->setInsecureFallback(false);
    job->setKey(kck);
    connect(job, &ReadPasswordJob::finished, this, &ClientSideEncryption::privateKeyFetched);
    job->start();
}

void ClientSideEncryption::privateKeyFetched(Job *incoming) {
    ReadPasswordJob *readJob = static_cast<ReadPasswordJob *>(incoming);

    // Error or no valid public key error out
    if (readJob->error() != NoError || readJob->binaryData().length() == 0) {
        _certificate = QSslCertificate();
        _publicKey = QSslKey();
        getPublicKeyFromServer();
        return;
    }

    _privateKey = QSslKey(readJob->binaryData(), QSsl::Rsa, QSsl::Pem, QSsl::PrivateKey);

    if (_privateKey.isNull()) {
        getPrivateKeyFromServer();
        return;
    }

    qCInfo(lcCse()) << "Private key fetched from keychain";

    const QString kck = AbstractCredentials::keychainKey(
                _account->url().toString(),
                _account->credentials()->user() + "_e2e-mnemonic",
                _account->id()
    );

    ReadPasswordJob *job = new ReadPasswordJob(Theme::instance()->appName());
    job->setInsecureFallback(false);
    job->setKey(kck);
    connect(job, &ReadPasswordJob::finished, this, &ClientSideEncryption::mnemonicKeyFetched);
    job->start();
}

void ClientSideEncryption::mnemonicKeyFetched(QKeychain::Job *incoming) {
    ReadPasswordJob *readJob = static_cast<ReadPasswordJob *>(incoming);

    // Error or no valid public key error out
    if (readJob->error() != NoError || readJob->textData().length() == 0) {
        _certificate = QSslCertificate();
        _publicKey = QSslKey();
        _privateKey = QSslKey();
        getPublicKeyFromServer();
        return;
    }

    _mnemonic = readJob->textData();

    qCInfo(lcCse()) << "Mnemonic key fetched from keychain";

    emit initializationFinished();
}

void ClientSideEncryption::writePrivateKey() {
    const QString kck = AbstractCredentials::keychainKey(
                _account->url().toString(),
                _account->credentials()->user() + "_e2e-private",
                _account->id()
    );

    WritePasswordJob *job = new WritePasswordJob(Theme::instance()->appName());
    job->setInsecureFallback(false);
    job->setKey(kck);
    job->setBinaryData(_privateKey.toPem());
    connect(job, &WritePasswordJob::finished, [this](Job *incoming) {
        Q_UNUSED(incoming);
        qCInfo(lcCse()) << "Private key stored in keychain";
    });
    job->start();
}

void ClientSideEncryption::writeCertificate() {
    const QString kck = AbstractCredentials::keychainKey(
                _account->url().toString(),
                _account->credentials()->user() + "_e2e-certificate",
                _account->id()
    );

    WritePasswordJob *job = new WritePasswordJob(Theme::instance()->appName());
    job->setInsecureFallback(false);
    job->setKey(kck);
    job->setBinaryData(_certificate.toPem());
    connect(job, &WritePasswordJob::finished, [this](Job *incoming) {
        Q_UNUSED(incoming);
        qCInfo(lcCse()) << "Certificate stored in keychain";
    });
    job->start();
}

void ClientSideEncryption::writeMnemonic() {
    const QString kck = AbstractCredentials::keychainKey(
                _account->url().toString(),
                _account->credentials()->user() + "_e2e-mnemonic",
                _account->id()
    );

    WritePasswordJob *job = new WritePasswordJob(Theme::instance()->appName());
    job->setInsecureFallback(false);
    job->setKey(kck);
    job->setTextData(_mnemonic);
    connect(job, &WritePasswordJob::finished, [this](Job *incoming) {
        Q_UNUSED(incoming);
        qCInfo(lcCse()) << "Mnemonic stored in keychain";
    });
    job->start();
}


QString publicKeyPath(AccountPtr account)
{
    return baseDirectory() + account->displayName() + ".pub";
}

QString privateKeyPath(AccountPtr account)
{
    return baseDirectory() + account->displayName() + ".rsa";
}

bool ClientSideEncryption::hasPrivateKey() const
{
    return QFileInfo(privateKeyPath(_account)).exists();
}

bool ClientSideEncryption::hasPublicKey() const
{
    return QFileInfo(publicKeyPath(_account)).exists();
}

void ClientSideEncryption::generateKeyPair()
{
    // AES/GCM/NoPadding,
    // metadataKeys with RSA/ECB/OAEPWithSHA-256AndMGF1Padding
    qCInfo(lcCse()) << "No public key, generating a pair.";
    const int rsaKeyLen = 2048;

    EVP_PKEY *localKeyPair = nullptr;

    // Init RSA
    EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_RSA, NULL);

    if(EVP_PKEY_keygen_init(ctx) <= 0) {
        qCInfo(lcCse()) << "Couldn't initialize the key generator";
        return;
    }

    if(EVP_PKEY_CTX_set_rsa_keygen_bits(ctx, rsaKeyLen) <= 0) {
        qCInfo(lcCse()) << "Couldn't initialize the key generator bits";
        return;
    }

    if(EVP_PKEY_keygen(ctx, &localKeyPair) <= 0) {
        qCInfo(lcCse()) << "Could not generate the key";
        return;
    }
    EVP_PKEY_CTX_free(ctx);
    qCInfo(lcCse()) << "Key correctly generated";
    qCInfo(lcCse()) << "Storing keys locally";

    BIO *privKey = BIO_new(BIO_s_mem());
    if (PEM_write_bio_PrivateKey(privKey, localKeyPair, NULL, NULL, 0, NULL, NULL) <= 0) {
        qCInfo(lcCse()) << "Could not read private key from bio.";
        return;
    }
    QByteArray key = EncryptionHelper::BIO2ByteArray(privKey);
    _privateKey = QSslKey(key, QSsl::Rsa, QSsl::Pem, QSsl::PrivateKey);

    qCInfo(lcCse()) << "Keys generated correctly, sending to server.";
    generateCSR(localKeyPair);
}

void ClientSideEncryption::generateCSR(EVP_PKEY *keyPair)
{
    // OpenSSL expects const char.
    auto cnArray = _account->davUser().toLocal8Bit();
    qCInfo(lcCse()) << "Getting the following array for the account Id" << cnArray;

    auto certParams = std::map<const char *, const char*>{
      {"C", "DE"},
      {"ST", "Baden-Wuerttemberg"},
      {"L", "Stuttgart"},
      {"O","Nextcloud"},
      {"CN", cnArray.constData()}
    };

    int             ret = 0;
    int             nVersion = 1;

    X509_REQ *x509_req = nullptr;
    SignPublicKeyApiJob *job = nullptr;

    // 2. set version of x509 req
    x509_req = X509_REQ_new();
    ret = X509_REQ_set_version(x509_req, nVersion);

    // 3. set subject of x509 req
    auto x509_name = X509_REQ_get_subject_name(x509_req);

    using ucharp = const unsigned char *;
    for(const auto& v : certParams) {
        ret = X509_NAME_add_entry_by_txt(x509_name, v.first,  MBSTRING_ASC, (ucharp) v.second, -1, -1, 0);
        if (ret != 1) {
            qCInfo(lcCse()) << "Error Generating the Certificate while adding" << v.first << v.second;
            X509_REQ_free(x509_req);
            return;
        }
    }

    ret = X509_REQ_set_pubkey(x509_req, keyPair);
    if (ret != 1){
        qCInfo(lcCse()) << "Error setting the public key on the csr";
        X509_REQ_free(x509_req);
        return;
    }

    ret = X509_REQ_sign(x509_req, keyPair, EVP_sha1());    // return x509_req->signature->length
    if (ret <= 0){
        qCInfo(lcCse()) << "Error setting the public key on the csr";
        X509_REQ_free(x509_req);
        return;
    }

    BIO *out = BIO_new(BIO_s_mem());
    ret = PEM_write_bio_X509_REQ(out, x509_req);
    QByteArray output = EncryptionHelper::BIO2ByteArray(out);
    BIO_free(out);
    EVP_PKEY_free(keyPair);

    qCInfo(lcCse()) << "Returning the certificate";
    qCInfo(lcCse()) << output;

    job = new SignPublicKeyApiJob(_account, baseUrl() + "public-key", this);
    job->setCsr(output);

    connect(job, &SignPublicKeyApiJob::jsonReceived, [this](const QJsonDocument& json, int retCode) {
        if (retCode == 200) {
            QString cert = json.object().value("ocs").toObject().value("data").toObject().value("public-key").toString();
            _certificate = QSslCertificate(cert.toLocal8Bit(), QSsl::Pem);
            qCInfo(lcCse()) << "Certificate saved, Encrypting Private Key.";
            encryptPrivateKey();
        }
        qCInfo(lcCse()) << retCode;
    });
    job->start();
}

void ClientSideEncryption::setTokenForFolder(const QByteArray& folderId, const QByteArray& token)
{
	_folder2token[folderId] = token;
}

QByteArray ClientSideEncryption::tokenForFolder(const QByteArray& folderId) const
{
	Q_ASSERT(_folder2token.contains(folderId));
	return _folder2token[folderId];
}

void ClientSideEncryption::encryptPrivateKey()
{
    QStringList list = WordList::getRandomWords(12);
    _mnemonic = list.join(' ');
    qCInfo(lcCse()) << "mnemonic Generated:" << _mnemonic;

    QString passPhrase = list.join(QString());
    qCInfo(lcCse()) << "Passphrase Generated:" << passPhrase;

    /*TODO: C++17: auto [secretKey, salt]. */
    auto secretKey = EncryptionHelper::generatePassword(passPhrase);
    auto cryptedText = EncryptionHelper::encryptPrivateKey(secretKey.first, _privateKey.toPem());

    // Send private key to the server
	auto job = new StorePrivateKeyApiJob(_account, baseUrl() + "private-key", this);
    job->setPrivateKey(cryptedText);
	connect(job, &StorePrivateKeyApiJob::jsonReceived, [this](const QJsonDocument& doc, int retCode) {
		Q_UNUSED(doc);
		switch(retCode) {
			case 200:
                qCInfo(lcCse()) << "Private key stored encrypted on server.";
                writePrivateKey();
                writeCertificate();
                writeMnemonic();
				emit initializationFinished();
				break;
			default:
				qCInfo(lcCse()) << "Store private key failed, return code:" << retCode;
		}
	});
	job->start();
}

void ClientSideEncryption::decryptPrivateKey(const QByteArray &key) {
    QString msg = tr("Please enter your end to end encryption passphrase:<br>"
                     "<br>"
                     "User: %2<br>"
                     "Account: %3<br>")
                      .arg(Utility::escape(_account->credentials()->user()),
                           Utility::escape(_account->displayName()));

    QInputDialog dialog;
    dialog.setWindowTitle(tr("Enter E2E passphrase"));
    dialog.setLabelText(msg);
    dialog.setTextEchoMode(QLineEdit::Normal);

    QString prev;

    while(true) {
        if (!prev.isEmpty()) {
            dialog.setTextValue(prev);
        }
        bool ok = dialog.exec();
        if (ok) {
            qCInfo(lcCse()) << "Got mnemonic:" << dialog.textValue();
            prev = dialog.textValue();

            _mnemonic = prev;
            QString mnemonic = prev.split(" ").join(QString());
            qCInfo(lcCse()) << "mnemonic:" << mnemonic;
            auto pass = EncryptionHelper::generatePassword(mnemonic);
            qCInfo(lcCse()) << "Generated key:" << pass.first;

            QByteArray privateKey = EncryptionHelper::decryptPrivateKey(pass.first, key);
            _privateKey = QSslKey(privateKey, QSsl::Rsa, QSsl::Pem, QSsl::PrivateKey);

            qCInfo(lcCse()) << "Private key: " << _privateKey.toPem();

            if (!_privateKey.isNull()) {
                writePrivateKey();
                writeCertificate();
                writeMnemonic();
                break;
            }
        } else {
            _mnemonic = QString();
            _privateKey = QSslKey();
            qCInfo(lcCse()) << "Cancelled";
            break;
        }
    }

    emit initializationFinished();
}

void ClientSideEncryption::getPrivateKeyFromServer()
{
    qCInfo(lcCse()) << "Retrieving private key from server";
    auto job = new JsonApiJob(_account, baseUrl() + "private-key", this);
    connect(job, &JsonApiJob::jsonReceived, [this](const QJsonDocument& doc, int retCode) {
            if (retCode == 200) {
                QString key = doc.object()["ocs"].toObject()["data"].toObject()["private-key"].toString();
                qCInfo(lcCse()) << key;
                qCInfo(lcCse()) << "Found private key, lets decrypt it!";
                decryptPrivateKey(key.toLocal8Bit());
            } else if (retCode == 404) {
                qCInfo(lcCse()) << "No private key on the server: setup is incomplete.";
            } else {
                qCInfo(lcCse()) << "Error while requesting public key: " << retCode;
            }
    });
    job->start();
}

void ClientSideEncryption::getPublicKeyFromServer()
{
    qCInfo(lcCse()) << "Retrieving public key from server";
    auto job = new JsonApiJob(_account, baseUrl() + "public-key", this);
    connect(job, &JsonApiJob::jsonReceived, [this](const QJsonDocument& doc, int retCode) {
            if (retCode == 200) {
                QString publicKey = doc.object()["ocs"].toObject()["data"].toObject()["public-keys"].toObject()[_account->davUser()].toString();
                _certificate = QSslCertificate(publicKey.toLocal8Bit(), QSsl::Pem);
                _publicKey = _certificate.publicKey();
                qCInfo(lcCse()) << publicKey;
                qCInfo(lcCse()) << "Found Public key, requesting Private Key.";
                getPrivateKeyFromServer();
            } else if (retCode == 404) {
                qCInfo(lcCse()) << "No public key on the server";
                generateKeyPair();
            } else {
                qCInfo(lcCse()) << "Error while requesting public key: " << retCode;
            }
    });
    job->start();
}

void ClientSideEncryption::fetchFolderEncryptedStatus() {
	_refreshingEncryptionStatus = true;
	auto getEncryptedStatus = new GetFolderEncryptStatusJob(_account, QString());
	connect(getEncryptedStatus, &GetFolderEncryptStatusJob::encryptStatusReceived,
					this, &ClientSideEncryption::folderEncryptedStatusFetched);
	connect(getEncryptedStatus, &GetFolderEncryptStatusJob::encryptStatusError,
					this, &ClientSideEncryption::folderEncryptedStatusError);
	getEncryptedStatus->start();
}

void ClientSideEncryption::folderEncryptedStatusFetched(const QMap<QString, bool>& result)
{
	_refreshingEncryptionStatus = false;
	_folder2encryptedStatus = result;
	qDebug() << "Retrieved correctly the encrypted status of the folders." << result;
}

void ClientSideEncryption::folderEncryptedStatusError(int error)
{
	_refreshingEncryptionStatus = false;
	qDebug() << "Failed to retrieve the status of the folders." << error;
}



//TODO: Create an actuall encryption here.
auto metadataKeyEnc(const QByteArray& data) -> QByteArray
{
    return data;
}

auto metadataKeyDec(const QByteArray& data) -> QByteArray
{
    return data;
}

FolderMetadata::FolderMetadata(AccountPtr account, const QByteArray& metadata) : _account(account), _metadata(metadata)
{
    if (metadata.isEmpty()) {
        qCInfo(lcCse()) << "Setupping Empty Metadata";
        setupEmptyMetadata();
    } else {
        qCInfo(lcCse()) << "Setting up existing metadata";
        setupExistingMetadata();
    }
}

void FolderMetadata::setupExistingMetadata()
{
  /* This is the json response from the server, it contains two extra objects that we are *not* interested.
  * ocs and data.
  */
  std::string byteArray(_metadata.constData(), _metadata.length());
  nlohmann::json j = nlohmann::json::parse(byteArray);

  // The metadata is being retrieved as a string stored in a json.
  // This *seems* to be broken - the strung us nit base64 encoded,
  // I'm currently unsure if this is error on my side or in the server implementation.
  // And because inside of the meta-data there's an object called metadata, without '-'
  // make it really different.
  auto meta_Data = nlohmann::json::parse(j["ocs"]["data"]["meta-data"].get<std::string>());

  qDebug() << "######################################333";
  qDebug() << " EXisting Metadata";
  qDebug() << _metadata;
  qDebug() << meta_Data.dump(4);
  for (nlohmann::json::iterator it = meta_Data.begin(); it != meta_Data.end(); ++it) {
    std::cout << it.key() << " : " << it.value() << std::endl;
  }
  qDebug() << "##########################################";

  // This is the encrypted metadata string.
  std::string encrypted_metadata_keys = meta_Data["metadata"]["metadataKeys"];
  std::string decrypted_metadata_keys = decryptMetadataKeys(encrypted_metadata_keys);
  qDebug() << encrypted_metadata_keys;
  qDebug() << decrypted_metadata_keys;

}

// RSA/ECB/OAEPWithSHA-256AndMGF1Padding using private / public key.
QByteArray FolderMetadata::encryptMetadataKeys(const nlohmann::json& metadataKeys) const {

    BIO *publicKeyBio = BIO_new(BIO_s_mem());
    QByteArray publicKeyPem = _account->e2e()->_publicKey.toPem();
    BIO_write(publicKeyBio, publicKeyPem.constData(), publicKeyPem.size());

    EVP_PKEY *publicKey = PEM_read_bio_PUBKEY(publicKeyBio, NULL, NULL, NULL);

    auto data = QByteArray::fromStdString(metadataKeys.dump());
    auto ret = EncryptionHelper::encryptStringAsymmetric(publicKey, data);

    EVP_PKEY_free(publicKey);

    return ret;
}

std::string FolderMetadata::decryptMetadataKeys(const std::string& encryptedMetadata) const
{
    qCInfo(lcCse()) << "Starting to decrypt the metadata key";
    unsigned char *out = nullptr;
    size_t outlen = 0;
    int err = -1;

    BIO *privateKeyBio = BIO_new(BIO_s_mem());
    QByteArray privateKeyPem = _account->e2e()->_privateKey.toPem();
    BIO_write(privateKeyBio, privateKeyPem.constData(), privateKeyPem.size());
    EVP_PKEY *key = PEM_read_bio_PrivateKey(privateKeyBio, NULL, NULL, NULL);

    if (!key) {
        qCInfo(lcCse()) << "Error reading private key";
    }

    // Data is base64 encoded.
    qCInfo(lcCse()) << "encryptedMetadata" << encryptedMetadata;
    auto raw = QByteArray(encryptedMetadata.c_str(), encryptedMetadata.length());
    auto b64d = QByteArray::fromBase64(raw);
    auto in = (unsigned char *) b64d.constData();
    size_t inlen = b64d.length();

    qCInfo(lcCse()) << "Encrypted metadata length: " << inlen;

    /* NB: assumes key in, inlen are already set up
    * and that key is an RSA private key
    */
    auto ctx = EVP_PKEY_CTX_new(key, nullptr);
    if (!ctx) {
        qCInfo(lcCse()) << "Could not create the PKEY context.";
        exit(1);
    }

    err = EVP_PKEY_decrypt_init(ctx);
    if (err <= 0) {
        qCInfo(lcCse()) << "Could not init the decryption of the metadata";
        exit(1);
    }

    err = EVP_PKEY_CTX_set_rsa_padding(ctx, 1); //TODO: Make this a class variable.
    if (err <= 0) {
        qCInfo(lcCse()) << "Could not set the RSA padding";
        exit(1);
    }

    err = EVP_PKEY_decrypt(ctx, NULL, &outlen, in, inlen);
    if (err <= 0) {
        qCInfo(lcCse()) << "Could not determine the buffer length";
        exit(1);
    } else {
        qCInfo(lcCse()) << "Size of output is: " << outlen;
    }

    out = (unsigned char *) OPENSSL_malloc(outlen);
    if (!out) {
        qCInfo(lcCse()) << "Could not alloc space for the decrypted metadata";
        exit(1);
    }

    err = EVP_PKEY_decrypt(ctx, out, &outlen, in, inlen);
    if (err <= 0) {
        qCInfo(lcCse()) << "Could not decrypt the metadata";
        exit(1);
    }

    qCInfo(lcCse()) << "Metadata decrypted successfully";
    const auto ret = std::string((char*) out, outlen);

    return ret;
}

// AES/GCM/NoPadding (128 bit key size)
QByteArray FolderMetadata::encryptJsonObject(const nlohmann::json& obj, const QByteArray pass) const {
    auto data = QByteArray::fromStdString(obj.dump());
    return EncryptionHelper::encryptStringSymmetric(pass, data);
}

std::string FolderMetadata::decryptJsonObject(const std::string& encryptedMetadata, const std::string& pass) const
{
    // Jesus, should I encrypt here in 128kb chunks?
    // perhaps.

    // Data is base64 encoded.
    // TODO: Transform this bit into a function to remove duplicated code.
    qCInfo(lcCse()) << "encryptedMetadata" << encryptedMetadata;
    auto raw = QByteArray(encryptedMetadata.c_str(), encryptedMetadata.length());
    auto b64d = QByteArray::fromBase64(raw);
    auto in = (unsigned char *) b64d.constData();
    // The tag is appended but it is not part of the cipher text
    size_t inlen = b64d.length() - 16;
    auto tag = in + inlen;

    EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
    if (!ctx) {
        qCInfo(lcCse()) << "Coult not create decryptioncontext, aborting.";
        exit(1);
    }

    /* Initialise the decryption operation. */
    if(!EVP_DecryptInit_ex(ctx, EVP_aes_128_gcm(), NULL, NULL, NULL)) {
        qCInfo(lcCse()) << "Error initialializing the decryption, aborting.";
        exit(1);
    }

    EVP_CIPHER_CTX_set_padding(ctx, 0);

    unsigned char *iv = (unsigned char *)"0123456789012345";
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, 16, NULL)) {
        qCInfo(lcCse()) << "Could not set IV length, aborting.";
        exit(1);
    }

    auto key = (const unsigned char*) pass.c_str();
    int err = EVP_DecryptInit_ex(ctx, NULL, NULL, key, iv);
    if (err != 1) {
        qCInfo(lcCse()) << "Error setting the key and iv, aborting.";
        exit(1);
    }

    int outlen = 0;

    /*
     * Max outlen is inlen + blocksize (16 bytes)
     */
    auto out = (unsigned char *) OPENSSL_malloc(inlen + 16);
    err = EVP_DecryptUpdate(ctx, out, &outlen, in, inlen);
    if (err != 1) {
        qCInfo(lcCse()) << "Error decrypting the json blob, aborting.";
        exit(1);
    }
    qCInfo(lcCse()) << "currently decrypted" << std::string( (char*) out, outlen);
    qCInfo(lcCse()) << "Current decrypt  length" << outlen;

    /* Set expected tag value. Works in OpenSSL 1.0.1d and later */
    if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, 16, tag)) {
        qCInfo(lcCse()) << "Error setting the tag, aborting.";
        exit(1);
    }

    qCInfo(lcCse()) << "Tag: " << tag;

    int f_len = outlen;
    err = EVP_DecryptFinal_ex(ctx, out + outlen, &f_len);
    if (err != 1) {
        qCInfo(lcCse()) << "Error finalyzing the decryption, aborting.";
        exit(1);
    }

    qCInfo(lcCse()) << "Decryption finalized.";
    const auto ret = std::string((char*) out, outlen);
    return ret;
}

void FolderMetadata::setupEmptyMetadata() {
    using namespace nlohmann;
    QByteArray newMetadataPass = EncryptionHelper::generateRandom(16);
    qCInfo(lcCse()) << "Key Generated for the Metadata" << newMetadataPass;

    json metadataKeyObj = {"0", newMetadataPass.toStdString()};
    json recepient = {"recipient", {}};

    auto b64String = encryptMetadataKeys(metadataKeyObj);
    qCInfo(lcCse()) << "ENCRYPTED METADATA KEY" << b64String;
    auto db64String = decryptMetadataKeys(std::string(b64String.constData(), b64String.size()));
    qCInfo(lcCse()) << "DECRYPTED METADATA KEY" << b64String;
    auto sharingEncrypted = encryptJsonObject(recepient, newMetadataPass);

    json m = {
        {"metadata", {
            {"metadataKeys", b64String.toStdString()},
            {"sharing", sharingEncrypted.toStdString()},
            {"version",1}
        }},
            {"files", {
        }}
    };

    _metadata = QByteArray::fromStdString(m.dump());
}

QByteArray FolderMetadata::encryptedMetadata() {
	return _metadata;
}




bool ClientSideEncryption::isFolderEncrypted(const QString& path) {
  auto it = _folder2encryptedStatus.find(path);
  if (it == _folder2encryptedStatus.end())
    return false;
  return (*it);
}

}