Atmosphere/stratosphere/spl/source/spl_ctr_drbg.cpp
2021-10-10 00:14:06 -07:00

81 lines
2.7 KiB
C++

/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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 <stratosphere.hpp>
#include "spl_ctr_drbg.hpp"
namespace ams::spl {
void CtrDrbg::Update(const void *data) {
aes128ContextCreate(std::addressof(m_aes_ctx), m_key, true);
for (size_t offset = 0; offset < sizeof(m_work[1]); offset += BlockSize) {
IncrementCounter(m_counter);
aes128EncryptBlock(std::addressof(m_aes_ctx), std::addressof(m_work[1][offset]), m_counter);
}
Xor(m_work[1], data, sizeof(m_work[1]));
std::memcpy(m_key, std::addressof(m_work[1][0]), sizeof(m_key));
std::memcpy(m_counter, std::addressof(m_work[1][BlockSize]), sizeof(m_key));
}
void CtrDrbg::Initialize(const void *seed) {
std::memcpy(m_work[0], seed, sizeof(m_work[0]));
std::memset(m_key, 0, sizeof(m_key));
std::memset(m_counter, 0, sizeof(m_counter));
this->Update(m_work[0]);
m_reseed_counter = 1;
}
void CtrDrbg::Reseed(const void *seed) {
std::memcpy(m_work[0], seed, sizeof(m_work[0]));
this->Update(m_work[0]);
m_reseed_counter = 1;
}
bool CtrDrbg::GenerateRandomBytes(void *out, size_t size) {
if (size > MaxRequestSize) {
return false;
}
if (m_reseed_counter > ReseedInterval) {
return false;
}
aes128ContextCreate(std::addressof(m_aes_ctx), m_key, true);
u8 *cur_dst = reinterpret_cast<u8 *>(out);
size_t aligned_size = (size & ~(BlockSize - 1));
for (size_t offset = 0; offset < aligned_size; offset += BlockSize) {
IncrementCounter(m_counter);
aes128EncryptBlock(std::addressof(m_aes_ctx), cur_dst, m_counter);
cur_dst += BlockSize;
}
if (size > aligned_size) {
IncrementCounter(m_counter);
aes128EncryptBlock(std::addressof(m_aes_ctx), m_work[1], m_counter);
std::memcpy(cur_dst, m_work[1], size - aligned_size);
}
std::memset(m_work[0], 0, sizeof(m_work[0]));
this->Update(m_work[0]);
m_reseed_counter++;
return true;
}
}