keepassxc/src/crypto/Random.cpp
2015-09-12 13:55:50 +02:00

99 lines
2.1 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 <gcrypt.h>
#include "core/Global.h"
#include "crypto/Crypto.h"
class RandomBackendGcrypt : public RandomBackend
{
public:
void randomize(void* data, int len) override;
};
Random* Random::m_instance(nullptr);
void Random::randomize(QByteArray& ba)
{
m_backend->randomize(ba.data(), ba.size());
}
QByteArray Random::randomArray(int len)
{
QByteArray ba;
ba.resize(len);
randomize(ba);
return ba;
}
quint32 Random::randomUInt(quint32 limit)
{
Q_ASSERT(limit != 0);
Q_ASSERT(limit <= QUINT32_MAX);
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_backend->randomize(&rand, 4);
} while (rand > ceil);
return (rand % limit);
}
quint32 Random::randomUIntRange(quint32 min, quint32 max)
{
return min + randomUInt(max - min);
}
Random* Random::instance()
{
if (!m_instance) {
m_instance = new Random(new RandomBackendGcrypt());
}
return m_instance;
}
void Random::createWithBackend(RandomBackend* backend)
{
Q_ASSERT(backend);
Q_ASSERT(!m_instance);
m_instance = new Random(backend);
}
Random::Random(RandomBackend* backend)
: m_backend(backend)
{
}
void RandomBackendGcrypt::randomize(void* data, int len)
{
Q_ASSERT(Crypto::initalized());
gcry_randomize(data, len, GCRY_STRONG_RANDOM);
}