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Atmosphere/libraries/libstratosphere/source/crypto/crypto_csrng.os.generic.cpp

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1.9 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/impl/spl_ctr_drbg.hpp"
#include <sys/random.h>
namespace ams::crypto {
namespace {
using Drbg = ::ams::spl::impl::CtrDrbg<crypto::AesEncryptor128, crypto::AesEncryptor128::KeySize, false>;
constinit util::TypedStorage<Drbg> g_drbg = {};
bool InitializeCsrng() {
u8 seed[Drbg::SeedSize];
AMS_ABORT_UNLESS(::getentropy(seed, sizeof(seed)) == 0);
util::ConstructAt(g_drbg);
util::GetReference(g_drbg).Initialize(seed, sizeof(seed), nullptr, 0, nullptr, 0);
return true;
}
}
void GenerateCryptographicallyRandomBytes(void *dst, size_t dst_size) {
AMS_FUNCTION_LOCAL_STATIC(bool, s_initialized, InitializeCsrng());
AMS_ABORT_UNLESS(s_initialized);
AMS_ASSERT(dst_size <= Drbg::RequestSizeMax);
if (!util::GetReference(g_drbg).Generate(dst, dst_size, nullptr, 0)) {
/* Reseed, if needed. */
{
u8 seed[Drbg::SeedSize];
AMS_ABORT_UNLESS(::getentropy(seed, sizeof(seed)) == 0);
util::GetReference(g_drbg).Reseed(seed, sizeof(seed), nullptr, 0);
}
util::GetReference(g_drbg).Generate(dst, dst_size, nullptr, 0);
}
}
}