keepassxc/src/crypto/Random.cpp
2021-07-13 22:08:33 -04:00

83 lines
1.9 KiB
C++

/*
* Copyright (C) 2010 Felix Geyer <debfx@fobos.de>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 or (at your option)
* version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "Random.h"
#include "core/Global.h"
#include <QSharedPointer>
#include <botan/system_rng.h>
QSharedPointer<Random> Random::m_instance;
QSharedPointer<Random> Random::instance()
{
if (!m_instance) {
m_instance.reset(new Random());
}
return m_instance;
}
Random::Random()
{
#ifdef BOTAN_HAS_SYSTEM_RNG
m_rng.reset(new Botan::System_RNG);
#else
m_rng.reset(new Botan::Autoseeded_RNG);
#endif
}
QSharedPointer<Botan::RandomNumberGenerator> Random::getRng()
{
return m_rng;
}
void Random::randomize(QByteArray& ba)
{
m_rng->randomize(reinterpret_cast<uint8_t*>(ba.data()), ba.size());
}
QByteArray Random::randomArray(int len)
{
QByteArray ba(len, '\0');
randomize(ba);
return ba;
}
quint32 Random::randomUInt(quint32 limit)
{
Q_ASSERT(limit <= QUINT32_MAX);
if (limit == 0) {
return 0;
}
quint32 rand;
const quint32 ceil = QUINT32_MAX - (QUINT32_MAX % limit) - 1;
// To avoid modulo bias make sure rand is below the largest number where rand%limit==0
do {
m_rng->randomize(reinterpret_cast<uint8_t*>(&rand), 4);
} while (rand > ceil);
return (rand % limit);
}
quint32 Random::randomUIntRange(quint32 min, quint32 max)
{
return min + randomUInt(max - min);
}