1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
/*
* (C) 2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/stateful_rng.h>
#include <botan/internal/os_utils.h>
#include <botan/loadstor.h>
namespace Botan {
void Stateful_RNG::clear()
{
m_reseed_counter = 0;
m_last_pid = 0;
}
void Stateful_RNG::force_reseed()
{
m_reseed_counter = 0;
}
bool Stateful_RNG::is_seeded() const
{
return m_reseed_counter > 0;
}
void Stateful_RNG::initialize_with(const uint8_t input[], size_t len)
{
add_entropy(input, len);
if(8*len >= security_level())
{
m_reseed_counter = 1;
}
}
void Stateful_RNG::randomize_with_ts_input(uint8_t output[], size_t output_len)
{
uint8_t additional_input[24] = { 0 };
store_le(OS::get_system_timestamp_ns(), additional_input);
store_le(OS::get_high_resolution_clock(), additional_input + 8);
store_le(m_last_pid, additional_input + 16);
store_le(static_cast<uint32_t>(m_reseed_counter), additional_input + 20);
randomize_with_input(output, output_len, additional_input, sizeof(additional_input));
}
size_t Stateful_RNG::reseed(Entropy_Sources& srcs,
size_t poll_bits,
std::chrono::milliseconds poll_timeout)
{
size_t bits_collected = RandomNumberGenerator::reseed(srcs, poll_bits, poll_timeout);
if(bits_collected >= security_level())
{
m_reseed_counter = 1;
}
return bits_collected;
}
void Stateful_RNG::reseed_from_rng(RandomNumberGenerator& rng, size_t poll_bits)
{
RandomNumberGenerator::reseed_from_rng(rng, poll_bits);
if(poll_bits >= security_level())
{
m_reseed_counter = 1;
}
}
void Stateful_RNG::reseed_check()
{
const uint32_t cur_pid = OS::get_process_id();
const bool fork_detected = (m_last_pid > 0) && (cur_pid != m_last_pid);
if(is_seeded() == false ||
fork_detected ||
(m_reseed_interval > 0 && m_reseed_counter >= m_reseed_interval))
{
m_reseed_counter = 0;
m_last_pid = cur_pid;
if(m_underlying_rng)
{
reseed_from_rng(*m_underlying_rng, security_level());
}
if(m_entropy_sources)
{
reseed(*m_entropy_sources, security_level());
}
if(!is_seeded())
{
if(fork_detected)
throw Exception("Detected use of fork but cannot reseed DRBG");
else
throw PRNG_Unseeded(name());
}
}
else
{
BOTAN_ASSERT(m_reseed_counter != 0, "RNG is seeded");
m_reseed_counter += 1;
}
}
}
|
