120 lines
3.2 KiB
C++
120 lines
3.2 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#include "td/utils/Random.h"
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#include "td/utils/logging.h"
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#include "td/utils/port/thread_local.h"
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#if TD_HAVE_OPENSSL
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#include <openssl/rand.h>
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#endif
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#include <array>
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#include <cstring>
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#include <limits>
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#include <random>
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namespace td {
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#if TD_HAVE_OPENSSL
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namespace {
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constexpr size_t secure_bytes_buffer_size = 512;
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}
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void Random::secure_bytes(MutableSlice dest) {
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Random::secure_bytes(dest.ubegin(), dest.size());
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}
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void Random::secure_bytes(unsigned char *ptr, size_t size) {
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constexpr size_t buf_size = secure_bytes_buffer_size;
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static TD_THREAD_LOCAL unsigned char *buf; // static zero-initialized
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static TD_THREAD_LOCAL size_t buf_pos;
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if (init_thread_local<unsigned char[]>(buf, buf_size)) {
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buf_pos = buf_size;
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}
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auto ready = min(size, buf_size - buf_pos);
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if (ready != 0) {
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std::memcpy(ptr, buf + buf_pos, ready);
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buf_pos += ready;
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ptr += ready;
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size -= ready;
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if (size == 0) {
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return;
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}
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}
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if (size < buf_size) {
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int err = RAND_bytes(buf, static_cast<int>(buf_size));
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// TODO: it CAN fail
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LOG_IF(FATAL, err != 1);
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buf_pos = size;
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std::memcpy(ptr, buf, size);
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return;
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}
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CHECK(size <= static_cast<size_t>(std::numeric_limits<int>::max()));
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int err = RAND_bytes(ptr, static_cast<int>(size));
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// TODO: it CAN fail
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LOG_IF(FATAL, err != 1);
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}
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int32 Random::secure_int32() {
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int32 res = 0;
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secure_bytes(reinterpret_cast<unsigned char *>(&res), sizeof(int32));
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return res;
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}
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int64 Random::secure_int64() {
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int64 res = 0;
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secure_bytes(reinterpret_cast<unsigned char *>(&res), sizeof(int64));
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return res;
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}
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void Random::add_seed(Slice bytes, double entropy) {
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RAND_add(bytes.data(), static_cast<int>(bytes.size()), entropy);
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// drain all secure_bytes buffer
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std::array<char, secure_bytes_buffer_size> buf;
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secure_bytes(MutableSlice(buf.data(), buf.size()));
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}
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#endif
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static unsigned int rand_device_helper() {
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static TD_THREAD_LOCAL std::random_device *rd;
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init_thread_local<std::random_device>(rd);
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return (*rd)();
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}
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uint32 Random::fast_uint32() {
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static TD_THREAD_LOCAL std::mt19937 *gen;
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if (!gen) {
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auto &rg = rand_device_helper;
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std::seed_seq seq{rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg()};
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init_thread_local<std::mt19937>(gen, seq);
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}
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return static_cast<uint32>((*gen)());
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}
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uint64 Random::fast_uint64() {
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static TD_THREAD_LOCAL std::mt19937_64 *gen;
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if (!gen) {
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auto &rg = rand_device_helper;
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std::seed_seq seq{rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg(), rg()};
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init_thread_local<std::mt19937_64>(gen, seq);
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}
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return static_cast<uint64>((*gen)());
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}
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int Random::fast(int min, int max) {
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if (min == std::numeric_limits<int>::min() && max == std::numeric_limits<int>::max()) {
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// to prevent integer overflow and division by zero
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min++;
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}
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CHECK(min <= max);
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return static_cast<int>(min + fast_uint32() % (max - min + 1)); // TODO signed_cast
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}
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} // namespace td
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