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secure_random: add_seed flushes all buffered random

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GitOrigin-RevId: 408dea74532e882d1f42126999b7394a46cebfd1
This commit is contained in:
Arseny Smirnov 2018-11-16 16:41:53 +04:00
parent be92820691
commit b6e8be94c6
1 changed files with 10 additions and 3 deletions
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13
tdutils/td/utils/Random.cpp
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@ -27,13 +27,22 @@ constexpr size_t secure_bytes_buffer_size = 512;
void Random::secure_bytes(MutableSlice dest) {
Random::secure_bytes(dest.ubegin(), dest.size());
}
namespace {
std::atomic<int64> random_seed_generation{0};
}
void Random::secure_bytes(unsigned char *ptr, size_t size) {
constexpr size_t buf_size = secure_bytes_buffer_size;
static TD_THREAD_LOCAL unsigned char *buf; // static zero-initialized
static TD_THREAD_LOCAL size_t buf_pos;
static TD_THREAD_LOCAL int64 generation;
if (init_thread_local<unsigned char[]>(buf, buf_size)) {
buf_pos = buf_size;
generation = 0;
}
if (generation != random_seed_generation.load(std::memory_order_relaxed)) {
generation = random_seed_generation.load(std::memory_order_acquire);
buf_pos = buf_size;
}
auto ready = min(size, buf_size - buf_pos);
@ -75,9 +84,7 @@ int64 Random::secure_int64() {
void Random::add_seed(Slice bytes, double entropy) {
RAND_add(bytes.data(), static_cast<int>(bytes.size()), entropy);
// drain all secure_bytes buffer
std::array<char, secure_bytes_buffer_size> buf;
secure_bytes(MutableSlice(buf.data(), buf.size()));
random_seed_generation++;
}
#endif