seed_material_test.cc (7479B)
1 // Copyright 2017 The Abseil Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #include "absl/random/internal/seed_material.h" 16 17 #include <bitset> 18 #include <cstdint> 19 #include <cstdlib> 20 #include <cstring> 21 #include <random> 22 #include <vector> 23 24 #include "gmock/gmock.h" 25 #include "gtest/gtest.h" 26 #include "absl/types/span.h" 27 28 #ifdef __ANDROID__ 29 // Android assert messages only go to system log, so death tests cannot inspect 30 // the message for matching. 31 #define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \ 32 EXPECT_DEATH_IF_SUPPORTED(statement, ".*") 33 #else 34 #define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \ 35 EXPECT_DEATH_IF_SUPPORTED(statement, regex) 36 #endif 37 38 namespace { 39 40 using testing::Each; 41 using testing::ElementsAre; 42 using testing::Eq; 43 using testing::Ne; 44 using testing::Pointwise; 45 46 TEST(SeedBitsToBlocks, VerifyCases) { 47 EXPECT_EQ(0, absl::random_internal::SeedBitsToBlocks(0)); 48 EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(1)); 49 EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(31)); 50 EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(32)); 51 EXPECT_EQ(2, absl::random_internal::SeedBitsToBlocks(33)); 52 EXPECT_EQ(4, absl::random_internal::SeedBitsToBlocks(127)); 53 EXPECT_EQ(4, absl::random_internal::SeedBitsToBlocks(128)); 54 EXPECT_EQ(5, absl::random_internal::SeedBitsToBlocks(129)); 55 } 56 57 TEST(ReadSeedMaterialFromOSEntropy, SuccessiveReadsAreDistinct) { 58 constexpr size_t kSeedMaterialSize = 64; 59 uint32_t seed_material_1[kSeedMaterialSize] = {}; 60 uint32_t seed_material_2[kSeedMaterialSize] = {}; 61 62 EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy( 63 absl::Span<uint32_t>(seed_material_1, kSeedMaterialSize))); 64 EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy( 65 absl::Span<uint32_t>(seed_material_2, kSeedMaterialSize))); 66 67 EXPECT_THAT(seed_material_1, Pointwise(Ne(), seed_material_2)); 68 } 69 70 TEST(ReadSeedMaterialFromOSEntropy, ReadZeroBytesIsNoOp) { 71 uint32_t seed_material[32] = {}; 72 std::memset(seed_material, 0xAA, sizeof(seed_material)); 73 EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy( 74 absl::Span<uint32_t>(seed_material, 0))); 75 76 EXPECT_THAT(seed_material, Each(Eq(0xAAAAAAAA))); 77 } 78 79 TEST(ReadSeedMaterialFromOSEntropy, NullPtrVectorArgument) { 80 #ifdef NDEBUG 81 EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromOSEntropy( 82 absl::Span<uint32_t>(nullptr, 32))); 83 #else 84 bool result; 85 ABSL_EXPECT_DEATH_IF_SUPPORTED( 86 result = absl::random_internal::ReadSeedMaterialFromOSEntropy( 87 absl::Span<uint32_t>(nullptr, 32)), 88 "!= nullptr"); 89 (void)result; // suppress unused-variable warning 90 #endif 91 } 92 93 TEST(ReadSeedMaterialFromURBG, SeedMaterialEqualsVariateSequence) { 94 // Two default-constructed instances of std::mt19937_64 are guaranteed to 95 // produce equal variate-sequences. 96 std::mt19937 urbg_1; 97 std::mt19937 urbg_2; 98 constexpr size_t kSeedMaterialSize = 1024; 99 uint32_t seed_material[kSeedMaterialSize] = {}; 100 101 EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromURBG( 102 &urbg_1, absl::Span<uint32_t>(seed_material, kSeedMaterialSize))); 103 for (uint32_t seed : seed_material) { 104 EXPECT_EQ(seed, urbg_2()); 105 } 106 } 107 108 TEST(ReadSeedMaterialFromURBG, ReadZeroBytesIsNoOp) { 109 std::mt19937_64 urbg; 110 uint32_t seed_material[32]; 111 std::memset(seed_material, 0xAA, sizeof(seed_material)); 112 EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromURBG( 113 &urbg, absl::Span<uint32_t>(seed_material, 0))); 114 115 EXPECT_THAT(seed_material, Each(Eq(0xAAAAAAAA))); 116 } 117 118 TEST(ReadSeedMaterialFromURBG, NullUrbgArgument) { 119 constexpr size_t kSeedMaterialSize = 32; 120 uint32_t seed_material[kSeedMaterialSize]; 121 #ifdef NDEBUG 122 EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromURBG<std::mt19937_64>( 123 nullptr, absl::Span<uint32_t>(seed_material, kSeedMaterialSize))); 124 #else 125 bool result; 126 ABSL_EXPECT_DEATH_IF_SUPPORTED( 127 result = absl::random_internal::ReadSeedMaterialFromURBG<std::mt19937_64>( 128 nullptr, absl::Span<uint32_t>(seed_material, kSeedMaterialSize)), 129 "!= nullptr"); 130 (void)result; // suppress unused-variable warning 131 #endif 132 } 133 134 TEST(ReadSeedMaterialFromURBG, NullPtrVectorArgument) { 135 std::mt19937_64 urbg; 136 #ifdef NDEBUG 137 EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromURBG( 138 &urbg, absl::Span<uint32_t>(nullptr, 32))); 139 #else 140 bool result; 141 ABSL_EXPECT_DEATH_IF_SUPPORTED( 142 result = absl::random_internal::ReadSeedMaterialFromURBG( 143 &urbg, absl::Span<uint32_t>(nullptr, 32)), 144 "!= nullptr"); 145 (void)result; // suppress unused-variable warning 146 #endif 147 } 148 149 // The avalanche effect is a desirable cryptographic property of hashes in which 150 // changing a single bit in the input causes each bit of the output to be 151 // changed with probability near 50%. 152 // 153 // https://en.wikipedia.org/wiki/Avalanche_effect 154 155 TEST(MixSequenceIntoSeedMaterial, AvalancheEffectTestOneBitLong) { 156 std::vector<uint32_t> seed_material = {1, 2, 3, 4, 5, 6, 7, 8}; 157 158 // For every 32-bit number with exactly one bit set, verify the avalanche 159 // effect holds. In order to reduce flakiness of tests, accept values 160 // anywhere in the range of 30%-70%. 161 for (uint32_t v = 1; v != 0; v <<= 1) { 162 std::vector<uint32_t> seed_material_copy = seed_material; 163 absl::random_internal::MixIntoSeedMaterial( 164 absl::Span<uint32_t>(&v, 1), 165 absl::Span<uint32_t>(seed_material_copy.data(), 166 seed_material_copy.size())); 167 168 uint32_t changed_bits = 0; 169 for (size_t i = 0; i < seed_material.size(); i++) { 170 std::bitset<sizeof(uint32_t) * 8> bitset(seed_material[i] ^ 171 seed_material_copy[i]); 172 changed_bits += bitset.count(); 173 } 174 175 EXPECT_LE(changed_bits, 0.7 * sizeof(uint32_t) * 8 * seed_material.size()); 176 EXPECT_GE(changed_bits, 0.3 * sizeof(uint32_t) * 8 * seed_material.size()); 177 } 178 } 179 180 TEST(MixSequenceIntoSeedMaterial, AvalancheEffectTestOneBitShort) { 181 std::vector<uint32_t> seed_material = {1}; 182 183 // For every 32-bit number with exactly one bit set, verify the avalanche 184 // effect holds. In order to reduce flakiness of tests, accept values 185 // anywhere in the range of 30%-70%. 186 for (uint32_t v = 1; v != 0; v <<= 1) { 187 std::vector<uint32_t> seed_material_copy = seed_material; 188 absl::random_internal::MixIntoSeedMaterial( 189 absl::Span<uint32_t>(&v, 1), 190 absl::Span<uint32_t>(seed_material_copy.data(), 191 seed_material_copy.size())); 192 193 uint32_t changed_bits = 0; 194 for (size_t i = 0; i < seed_material.size(); i++) { 195 std::bitset<sizeof(uint32_t) * 8> bitset(seed_material[i] ^ 196 seed_material_copy[i]); 197 changed_bits += bitset.count(); 198 } 199 200 EXPECT_LE(changed_bits, 0.7 * sizeof(uint32_t) * 8 * seed_material.size()); 201 EXPECT_GE(changed_bits, 0.3 * sizeof(uint32_t) * 8 * seed_material.size()); 202 } 203 } 204 205 } // namespace