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/*
* Random Number Generator
* (C) 1999-2008,2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/rng.h>
#include <botan/auto_rng.h>
#include <botan/entropy_src.h>
#include <botan/loadstor.h>
#include <botan/internal/os_utils.h>
#if defined(BOTAN_HAS_HMAC_DRBG)
#include <botan/hmac_drbg.h>
#endif
#if defined(BOTAN_HAS_HMAC_RNG)
#include <botan/hmac_rng.h>
#endif
namespace Botan {
size_t RandomNumberGenerator::reseed(size_t bits_to_collect)
{
return this->reseed_with_timeout(bits_to_collect,
BOTAN_RNG_RESEED_DEFAULT_TIMEOUT);
}
size_t RandomNumberGenerator::reseed_with_timeout(size_t bits_to_collect,
std::chrono::milliseconds timeout)
{
return this->reseed_with_sources(Entropy_Sources::global_sources(),
bits_to_collect,
timeout);
}
size_t RandomNumberGenerator::reseed_with_sources(Entropy_Sources& srcs,
size_t poll_bits,
std::chrono::milliseconds poll_timeout)
{
return srcs.poll(*this, poll_bits, poll_timeout);
}
Stateful_RNG::Stateful_RNG(size_t max_output_before_reseed) : m_max_output_before_reseed(max_output_before_reseed)
{
}
void Stateful_RNG::clear()
{
m_successful_initialization = false;
m_bytes_since_reseed = 0;
m_last_pid = 0;
}
size_t Stateful_RNG::reseed_with_sources(Entropy_Sources& srcs,
size_t poll_bits,
std::chrono::milliseconds poll_timeout)
{
size_t bits_collected = RandomNumberGenerator::reseed_with_sources(srcs, poll_bits, poll_timeout);
if(bits_collected >= poll_bits)
{
m_successful_initialization = true;
m_bytes_since_reseed = 0;
}
return bits_collected;
}
void Stateful_RNG::reseed_check(size_t bytes_requested)
{
const bool fork_detected = (m_last_pid > 0) && (OS::get_process_id() != m_last_pid);
m_bytes_since_reseed += bytes_requested;
m_last_pid = OS::get_process_id();
if(!is_seeded() || fork_detected)
{
this->reseed(BOTAN_RNG_RESEED_POLL_BITS);
}
else if(m_max_output_before_reseed > 0 && m_bytes_since_reseed >= m_max_output_before_reseed)
{
this->reseed_with_timeout(BOTAN_RNG_RESEED_POLL_BITS,
BOTAN_RNG_AUTO_RESEED_TIMEOUT);
}
if(!is_seeded())
{
throw PRNG_Unseeded(name());
}
}
void Stateful_RNG::initialize_with(const byte input[], size_t len)
{
add_entropy(input, len);
m_successful_initialization = true;
}
bool Stateful_RNG::is_seeded() const
{
return m_successful_initialization;
}
RandomNumberGenerator* RandomNumberGenerator::make_rng()
{
return new AutoSeeded_RNG;
}
AutoSeeded_RNG::AutoSeeded_RNG(size_t max_output_before_reseed)
{
m_rng.reset(new BOTAN_AUTO_RNG_DRBG(BOTAN_AUTO_RNG_HASH, max_output_before_reseed));
size_t bits = m_rng->reseed(BOTAN_AUTO_RNG_ENTROPY_TARGET);
if(!m_rng->is_seeded())
{
throw Exception("AutoSeeded_RNG failed to gather enough entropy only got " +
std::to_string(bits) + " bits");
}
}
void AutoSeeded_RNG::randomize(byte output[], size_t output_len)
{
/*
Form additional input which is provided to the PRNG implementation
to paramaterize the KDF output.
*/
byte additional_input[24] = { 0 };
store_le(OS::get_system_timestamp_ns(), additional_input);
store_le(OS::get_processor_timestamp(), additional_input + 8);
store_le(OS::get_process_id(), additional_input + 16);
store_le(m_counter++, additional_input + 20);
randomize_with_input(output, output_len, additional_input, sizeof(additional_input));
}
void AutoSeeded_RNG::randomize_with_input(byte output[], size_t output_len,
const byte ad[], size_t ad_len)
{
m_rng->randomize_with_input(output, output_len, ad, ad_len);
}
}
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