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
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
// randpool.cpp - originally written and placed in the public domain by Wei Dai
// RandomPool used to follow the design of randpool in PGP 2.6.x,
// but as of version 5.5 it has been redesigned to reduce the risk
// of reusing random numbers after state rollback (which may occur
// when running in a virtual machine like VMware).
#include "pch.h"
#ifndef CRYPTOPP_IMPORTS
#include "randpool.h"
#include "aes.h"
#include "sha.h"
#include "hrtimer.h"
#include "trap.h"
// OldRandomPool
#include "mdc.h"
#include "modes.h"
#include <time.h>
NAMESPACE_BEGIN(CryptoPP)
RandomPool::RandomPool()
: m_pCipher(new AES::Encryption), m_keySet(false)
{
std::memset(m_key, 0, m_key.SizeInBytes());
std::memset(m_seed, 0, m_seed.SizeInBytes());
}
void RandomPool::IncorporateEntropy(const byte *input, size_t length)
{
SHA256 hash;
hash.Update(m_key, 32);
hash.Update(input, length);
hash.Final(m_key);
m_keySet = false;
}
void RandomPool::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
{
if (size > 0)
{
if (!m_keySet)
m_pCipher->SetKey(m_key, 32);
CRYPTOPP_COMPILE_ASSERT(sizeof(TimerWord) <= 16);
CRYPTOPP_COMPILE_ASSERT(sizeof(time_t) <= 8);
Timer timer;
TimerWord tw = timer.GetCurrentTimerValue();
*(TimerWord *)(void*)m_seed.data() += tw;
time_t t = time(NULLPTR);
// UBsan finding: signed integer overflow: 1876017710 + 1446085457 cannot be represented in type 'long int'
// *(time_t *)(m_seed.data()+8) += t;
word64 tt1 = 0, tt2 = (word64)t;
std::memcpy(&tt1, m_seed.data()+8, 8);
std::memcpy(m_seed.data()+8, &(tt2 += tt1), 8);
// Wipe the intermediates
*((volatile TimerWord*)&tw) = 0;
*((volatile word64*)&tt1) = 0;
*((volatile word64*)&tt2) = 0;
do
{
m_pCipher->ProcessBlock(m_seed);
size_t len = UnsignedMin(16, size);
target.ChannelPut(channel, m_seed, len);
size -= len;
} while (size > 0);
}
}
// OldRandomPool is provided for backwards compatibility for a migration path
typedef MDC<SHA1> OldRandomPoolCipher;
OldRandomPool::OldRandomPool(unsigned int poolSize)
: pool(poolSize), key(OldRandomPoolCipher::DEFAULT_KEYLENGTH), addPos(0), getPos(poolSize)
{
CRYPTOPP_ASSERT(poolSize > key.size());
std::memset(pool, 0, poolSize);
std::memset(key, 0, key.size());
}
void OldRandomPool::IncorporateEntropy(const byte *input, size_t length)
{
size_t t;
while (length > (t = pool.size() - addPos))
{
xorbuf(pool+addPos, input, t);
input += t;
length -= t;
Stir();
}
if (length)
{
xorbuf(pool+addPos, input, length);
addPos += length;
getPos = pool.size(); // Force stir on get
}
}
// GenerateWord32 is overridden and provides Crypto++ 5.4 behavior.
// Taken from RandomNumberGenerator::GenerateWord32 in cryptlib.cpp.
word32 OldRandomPool::GenerateWord32 (word32 min, word32 max)
{
const word32 range = max-min;
const unsigned int maxBytes = BytePrecision(range);
const unsigned int maxBits = BitPrecision(range);
word32 value;
do
{
value = 0;
for (unsigned int i=0; i<maxBytes; i++)
value = (value << 8) | GenerateByte();
value = Crop(value, maxBits);
} while (value > range);
return value+min;
}
void OldRandomPool::Stir()
{
CFB_Mode<OldRandomPoolCipher>::Encryption cipher;
for (int i=0; i<2; i++)
{
cipher.SetKeyWithIV(key, key.size(), pool.end()-cipher.IVSize());
cipher.ProcessString(pool, pool.size());
std::memcpy(key, pool, key.size());
}
addPos = 0;
getPos = key.size();
}
void OldRandomPool::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
{
while (size > 0)
{
if (getPos == pool.size())
Stir();
size_t t = UnsignedMin(pool.size() - getPos, size);
target.ChannelPut(channel, pool+getPos, t);
size -= t;
getPos += t;
}
}
byte OldRandomPool::GenerateByte()
{
if (getPos == pool.size())
Stir();
return pool[getPos++];
}
void OldRandomPool::GenerateBlock(byte *outString, size_t size)
{
ArraySink sink(outString, size);
GenerateIntoBufferedTransformation(sink, DEFAULT_CHANNEL, size);
}
NAMESPACE_END
#endif
|
