keepassxc

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/*
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 *  Copyright (C) 2021 KeePassXC Team <team@keepassxc.org>
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 *
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 *  This program is free software: you can redistribute it and/or modify
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 *  it under the terms of the GNU General Public License as published by
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 *  the Free Software Foundation, either version 2 or (at your option)
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 *  version 3 of the License.
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 *
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 *  This program is distributed in the hope that it will be useful,
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *  GNU General Public License for more details.
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 *
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 *  You should have received a copy of the GNU General Public License
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 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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#include "OpenSSHKeyGen.h"
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#include "BinaryStream.h"
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#include "OpenSSHKey.h"
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#include "crypto/Random.h"
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#include <botan/ecdsa.h>
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#include <botan/ed25519.h>
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#include <botan/rsa.h>
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namespace OpenSSHKeyGen
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{
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    namespace
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    {
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        void bigIntToStream(const Botan::BigInt& i, BinaryStream& stream, int padding = 0)
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        {
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            QByteArray ba(i.bytes() + padding, 0);
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            i.binary_encode(reinterpret_cast<uint8_t*>(ba.data() + padding), ba.size() - padding);
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            stream.writeString(ba);
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        }
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        void vectorToStream(const std::vector<uint8_t>& v, BinaryStream& stream)
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        {
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            QByteArray ba(reinterpret_cast<const char*>(v.data()), v.size());
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            stream.writeString(ba);
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        }
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        void vectorToStream(const Botan::secure_vector<uint8_t>& v, BinaryStream& stream)
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        {
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            QByteArray ba(reinterpret_cast<const char*>(v.data()), v.size());
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            stream.writeString(ba);
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        }
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    } // namespace
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    bool generateRSA(OpenSSHKey& key, int bits)
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    {
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        auto rng = randomGen()->getRng();
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        try {
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            Botan::RSA_PrivateKey rsaKey(*rng, bits);
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            QByteArray publicData;
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            BinaryStream publicStream(&publicData);
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            // intentionally flipped n e -> e n
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            bigIntToStream(rsaKey.get_e(), publicStream);
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            bigIntToStream(rsaKey.get_n(), publicStream, 1);
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            QByteArray privateData;
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            BinaryStream privateStream(&privateData);
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            bigIntToStream(rsaKey.get_n(), privateStream, 1);
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            bigIntToStream(rsaKey.get_e(), privateStream);
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            bigIntToStream(rsaKey.get_d(), privateStream, 1);
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            bigIntToStream(rsaKey.get_c(), privateStream, 1);
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            bigIntToStream(rsaKey.get_p(), privateStream, 1);
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            bigIntToStream(rsaKey.get_q(), privateStream, 1);
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            key.setType("ssh-rsa");
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            key.setCheck(randomGen()->randomUInt(std::numeric_limits<quint32>::max() - 1) + 1);
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            key.setPublicData(publicData);
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            key.setPrivateData(privateData);
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            key.setComment("id_rsa");
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            return true;
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        } catch (std::exception& e) {
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            return false;
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        }
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    }
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    bool generateECDSA(OpenSSHKey& key, int bits)
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    {
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        auto rng = randomGen()->getRng();
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        QString group = QString("nistp%1").arg(bits);
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        try {
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            Botan::EC_Group domain(QString("secp%1r1").arg(bits).toStdString());
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            Botan::ECDSA_PrivateKey ecdsaKey(*rng, domain);
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            QByteArray publicData;
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            BinaryStream publicStream(&publicData);
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            publicStream.writeString(group);
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            vectorToStream(ecdsaKey.public_key_bits(), publicStream);
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            QByteArray privateData;
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            BinaryStream privateStream(&privateData);
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            privateStream.writeString(group);
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            vectorToStream(ecdsaKey.public_key_bits(), privateStream);
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            bigIntToStream(ecdsaKey.private_value(), privateStream, 1);
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            key.setType("ecdsa-sha2-" + group);
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            key.setCheck(randomGen()->randomUInt(std::numeric_limits<quint32>::max() - 1) + 1);
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            key.setPublicData(publicData);
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            key.setPrivateData(privateData);
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            key.setComment("id_ecdsa");
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            return true;
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        } catch (std::exception& e) {
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            return false;
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        }
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    }
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    bool generateEd25519(OpenSSHKey& key)
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    {
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        auto rng = randomGen()->getRng();
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        try {
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            Botan::Ed25519_PrivateKey ed25519Key(*rng);
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            QByteArray publicData;
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            BinaryStream publicStream(&publicData);
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            vectorToStream(ed25519Key.get_public_key(), publicStream);
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            QByteArray privateData;
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            BinaryStream privateStream(&privateData);
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            vectorToStream(ed25519Key.get_public_key(), privateStream);
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            vectorToStream(ed25519Key.get_private_key(), privateStream);
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            key.setType("ssh-ed25519");
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            key.setCheck(randomGen()->randomUInt(std::numeric_limits<quint32>::max() - 1) + 1);
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            key.setPublicData(publicData);
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            key.setPrivateData(privateData);
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            key.setComment("id_ed25519");
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            return true;
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        } catch (std::exception& e) {
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            return false;
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        }
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    }
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} // namespace OpenSSHKeyGen
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