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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/random/internal/seed_material.h"
#include <bitset>
#include <cstdlib>
#include <cstring>
#include <random>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#ifdef __ANDROID__
// Android assert messages only go to system log, so death tests cannot inspect
// the message for matching.
#define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
EXPECT_DEATH_IF_SUPPORTED(statement, ".*")
#else
#define ABSL_EXPECT_DEATH_IF_SUPPORTED EXPECT_DEATH_IF_SUPPORTED
#endif
namespace {
using testing::Each;
using testing::ElementsAre;
using testing::Eq;
using testing::Ne;
using testing::Pointwise;
TEST(SeedBitsToBlocks, VerifyCases) {
EXPECT_EQ(0, absl::random_internal::SeedBitsToBlocks(0));
EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(1));
EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(31));
EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(32));
EXPECT_EQ(2, absl::random_internal::SeedBitsToBlocks(33));
EXPECT_EQ(4, absl::random_internal::SeedBitsToBlocks(127));
EXPECT_EQ(4, absl::random_internal::SeedBitsToBlocks(128));
EXPECT_EQ(5, absl::random_internal::SeedBitsToBlocks(129));
}
TEST(ReadSeedMaterialFromOSEntropy, SuccessiveReadsAreDistinct) {
constexpr size_t kSeedMaterialSize = 64;
uint32_t seed_material_1[kSeedMaterialSize] = {};
uint32_t seed_material_2[kSeedMaterialSize] = {};
EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
absl::Span<uint32_t>(seed_material_1, kSeedMaterialSize)));
EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
absl::Span<uint32_t>(seed_material_2, kSeedMaterialSize)));
EXPECT_THAT(seed_material_1, Pointwise(Ne(), seed_material_2));
}
TEST(ReadSeedMaterialFromOSEntropy, ReadZeroBytesIsNoOp) {
uint32_t seed_material[32] = {};
std::memset(seed_material, 0xAA, sizeof(seed_material));
EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
absl::Span<uint32_t>(seed_material, 0)));
EXPECT_THAT(seed_material, Each(Eq(0xAAAAAAAA)));
}
TEST(ReadSeedMaterialFromOSEntropy, NullPtrVectorArgument) {
#ifdef NDEBUG
EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
absl::Span<uint32_t>(nullptr, 32)));
#else
bool result;
ABSL_EXPECT_DEATH_IF_SUPPORTED(
result = absl::random_internal::ReadSeedMaterialFromOSEntropy(
absl::Span<uint32_t>(nullptr, 32)),
"!= nullptr");
(void)result; // suppress unused-variable warning
#endif
}
TEST(ReadSeedMaterialFromURBG, SeedMaterialEqualsVariateSequence) {
// Two default-constructed instances of std::mt19937_64 are guaranteed to
// produce equal variate-sequences.
std::mt19937 urbg_1;
std::mt19937 urbg_2;
constexpr size_t kSeedMaterialSize = 1024;
uint32_t seed_material[kSeedMaterialSize] = {};
EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromURBG(
&urbg_1, absl::Span<uint32_t>(seed_material, kSeedMaterialSize)));
for (uint32_t seed : seed_material) {
EXPECT_EQ(seed, urbg_2());
}
}
TEST(ReadSeedMaterialFromURBG, ReadZeroBytesIsNoOp) {
std::mt19937_64 urbg;
uint32_t seed_material[32];
std::memset(seed_material, 0xAA, sizeof(seed_material));
EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromURBG(
&urbg, absl::Span<uint32_t>(seed_material, 0)));
EXPECT_THAT(seed_material, Each(Eq(0xAAAAAAAA)));
}
TEST(ReadSeedMaterialFromURBG, NullUrbgArgument) {
constexpr size_t kSeedMaterialSize = 32;
uint32_t seed_material[kSeedMaterialSize];
#ifdef NDEBUG
EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromURBG<std::mt19937_64>(
nullptr, absl::Span<uint32_t>(seed_material, kSeedMaterialSize)));
#else
bool result;
ABSL_EXPECT_DEATH_IF_SUPPORTED(
result = absl::random_internal::ReadSeedMaterialFromURBG<std::mt19937_64>(
nullptr, absl::Span<uint32_t>(seed_material, kSeedMaterialSize)),
"!= nullptr");
(void)result; // suppress unused-variable warning
#endif
}
TEST(ReadSeedMaterialFromURBG, NullPtrVectorArgument) {
std::mt19937_64 urbg;
#ifdef NDEBUG
EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromURBG(
&urbg, absl::Span<uint32_t>(nullptr, 32)));
#else
bool result;
ABSL_EXPECT_DEATH_IF_SUPPORTED(
result = absl::random_internal::ReadSeedMaterialFromURBG(
&urbg, absl::Span<uint32_t>(nullptr, 32)),
"!= nullptr");
(void)result; // suppress unused-variable warning
#endif
}
// The avalanche effect is a desirable cryptographic property of hashes in which
// changing a single bit in the input causes each bit of the output to be
// changed with probability near 50%.
//
// https://en.wikipedia.org/wiki/Avalanche_effect
TEST(MixSequenceIntoSeedMaterial, AvalancheEffectTestOneBitLong) {
std::vector<uint32_t> seed_material = {1, 2, 3, 4, 5, 6, 7, 8};
// For every 32-bit number with exactly one bit set, verify the avalanche
// effect holds. In order to reduce flakiness of tests, accept values
// anywhere in the range of 30%-70%.
for (uint32_t v = 1; v != 0; v <<= 1) {
std::vector<uint32_t> seed_material_copy = seed_material;
absl::random_internal::MixIntoSeedMaterial(
absl::Span<uint32_t>(&v, 1),
absl::Span<uint32_t>(seed_material_copy.data(),
seed_material_copy.size()));
uint32_t changed_bits = 0;
for (size_t i = 0; i < seed_material.size(); i++) {
std::bitset<sizeof(uint32_t) * 8> bitset(seed_material[i] ^
seed_material_copy[i]);
changed_bits += bitset.count();
}
EXPECT_LE(changed_bits, 0.7 * sizeof(uint32_t) * 8 * seed_material.size());
EXPECT_GE(changed_bits, 0.3 * sizeof(uint32_t) * 8 * seed_material.size());
}
}
TEST(MixSequenceIntoSeedMaterial, AvalancheEffectTestOneBitShort) {
std::vector<uint32_t> seed_material = {1};
// For every 32-bit number with exactly one bit set, verify the avalanche
// effect holds. In order to reduce flakiness of tests, accept values
// anywhere in the range of 30%-70%.
for (uint32_t v = 1; v != 0; v <<= 1) {
std::vector<uint32_t> seed_material_copy = seed_material;
absl::random_internal::MixIntoSeedMaterial(
absl::Span<uint32_t>(&v, 1),
absl::Span<uint32_t>(seed_material_copy.data(),
seed_material_copy.size()));
uint32_t changed_bits = 0;
for (size_t i = 0; i < seed_material.size(); i++) {
std::bitset<sizeof(uint32_t) * 8> bitset(seed_material[i] ^
seed_material_copy[i]);
changed_bits += bitset.count();
}
EXPECT_LE(changed_bits, 0.7 * sizeof(uint32_t) * 8 * seed_material.size());
EXPECT_GE(changed_bits, 0.3 * sizeof(uint32_t) * 8 * seed_material.size());
}
}
} // namespace
|
