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author | Suhas Daftuar <sdaftuar@gmail.com> | 2022-05-25 10:16:56 -0400 |
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committer | Suhas Daftuar <sdaftuar@gmail.com> | 2022-08-23 11:34:10 -0400 |
commit | 1d4cfa4272cf2c8b980cc8762c1ff2220d3e8d51 (patch) | |
tree | 4d1338b17702e4ed0998ece0f00f2d4b8b9ba062 /src/test | |
parent | 2bd9aa5a44b88c866c4d98f8a7bf7154049cba31 (diff) | |
download | bitcoin-1d4cfa4272cf2c8b980cc8762c1ff2220d3e8d51.tar.xz |
Add function to validate difficulty changes
The rule against difficulty adjustments changing by more than a factor of 4 can
be helpful for anti-DoS measures in contexts where we lack a full headers
chain, so expose this functionality separately and in the narrow case where we
only know the height, new value, and old value.
Includes fuzz test by Martin Zumsande.
Diffstat (limited to 'src/test')
-rw-r--r-- | src/test/fuzz/pow.cpp | 37 | ||||
-rw-r--r-- | src/test/pow_tests.cpp | 27 |
2 files changed, 60 insertions, 4 deletions
diff --git a/src/test/fuzz/pow.cpp b/src/test/fuzz/pow.cpp index 0004d82d66..507ce57ec0 100644 --- a/src/test/fuzz/pow.cpp +++ b/src/test/fuzz/pow.cpp @@ -83,3 +83,40 @@ FUZZ_TARGET_INIT(pow, initialize_pow) } } } + + +FUZZ_TARGET_INIT(pow_transition, initialize_pow) +{ + FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size()); + const Consensus::Params& consensus_params{Params().GetConsensus()}; + std::vector<std::unique_ptr<CBlockIndex>> blocks; + + const uint32_t old_time{fuzzed_data_provider.ConsumeIntegral<uint32_t>()}; + const uint32_t new_time{fuzzed_data_provider.ConsumeIntegral<uint32_t>()}; + const int32_t version{fuzzed_data_provider.ConsumeIntegral<int32_t>()}; + uint32_t nbits{fuzzed_data_provider.ConsumeIntegral<uint32_t>()}; + + const arith_uint256 pow_limit = UintToArith256(consensus_params.powLimit); + arith_uint256 old_target; + old_target.SetCompact(nbits); + if (old_target > pow_limit) { + nbits = pow_limit.GetCompact(); + } + // Create one difficulty adjustment period worth of headers + for (int height = 0; height < consensus_params.DifficultyAdjustmentInterval(); ++height) { + CBlockHeader header; + header.nVersion = version; + header.nTime = old_time; + header.nBits = nbits; + if (height == consensus_params.DifficultyAdjustmentInterval() - 1) { + header.nTime = new_time; + } + auto current_block{std::make_unique<CBlockIndex>(header)}; + current_block->pprev = blocks.empty() ? nullptr : blocks.back().get(); + current_block->nHeight = height; + blocks.emplace_back(std::move(current_block)).get(); + } + auto last_block{blocks.back().get()}; + unsigned int new_nbits{GetNextWorkRequired(last_block, nullptr, consensus_params)}; + Assert(PermittedDifficultyTransition(consensus_params, last_block->nHeight + 1, last_block->nBits, new_nbits)); +} diff --git a/src/test/pow_tests.cpp b/src/test/pow_tests.cpp index 2f43ae52f7..3695ea9d16 100644 --- a/src/test/pow_tests.cpp +++ b/src/test/pow_tests.cpp @@ -20,7 +20,14 @@ BOOST_AUTO_TEST_CASE(get_next_work) pindexLast.nHeight = 32255; pindexLast.nTime = 1262152739; // Block #32255 pindexLast.nBits = 0x1d00ffff; - BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), 0x1d00d86aU); + + // Here (and below): expected_nbits is calculated in + // CalculateNextWorkRequired(); redoing the calculation here would be just + // reimplementing the same code that is written in pow.cpp. Rather than + // copy that code, we just hardcode the expected result. + unsigned int expected_nbits = 0x1d00d86aU; + BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), expected_nbits); + BOOST_CHECK(PermittedDifficultyTransition(chainParams->GetConsensus(), pindexLast.nHeight+1, pindexLast.nBits, expected_nbits)); } /* Test the constraint on the upper bound for next work */ @@ -32,7 +39,9 @@ BOOST_AUTO_TEST_CASE(get_next_work_pow_limit) pindexLast.nHeight = 2015; pindexLast.nTime = 1233061996; // Block #2015 pindexLast.nBits = 0x1d00ffff; - BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), 0x1d00ffffU); + unsigned int expected_nbits = 0x1d00ffffU; + BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), expected_nbits); + BOOST_CHECK(PermittedDifficultyTransition(chainParams->GetConsensus(), pindexLast.nHeight+1, pindexLast.nBits, expected_nbits)); } /* Test the constraint on the lower bound for actual time taken */ @@ -44,7 +53,12 @@ BOOST_AUTO_TEST_CASE(get_next_work_lower_limit_actual) pindexLast.nHeight = 68543; pindexLast.nTime = 1279297671; // Block #68543 pindexLast.nBits = 0x1c05a3f4; - BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), 0x1c0168fdU); + unsigned int expected_nbits = 0x1c0168fdU; + BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), expected_nbits); + BOOST_CHECK(PermittedDifficultyTransition(chainParams->GetConsensus(), pindexLast.nHeight+1, pindexLast.nBits, expected_nbits)); + // Test that reducing nbits further would not be a PermittedDifficultyTransition. + unsigned int invalid_nbits = expected_nbits-1; + BOOST_CHECK(!PermittedDifficultyTransition(chainParams->GetConsensus(), pindexLast.nHeight+1, pindexLast.nBits, invalid_nbits)); } /* Test the constraint on the upper bound for actual time taken */ @@ -56,7 +70,12 @@ BOOST_AUTO_TEST_CASE(get_next_work_upper_limit_actual) pindexLast.nHeight = 46367; pindexLast.nTime = 1269211443; // Block #46367 pindexLast.nBits = 0x1c387f6f; - BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), 0x1d00e1fdU); + unsigned int expected_nbits = 0x1d00e1fdU; + BOOST_CHECK_EQUAL(CalculateNextWorkRequired(&pindexLast, nLastRetargetTime, chainParams->GetConsensus()), expected_nbits); + BOOST_CHECK(PermittedDifficultyTransition(chainParams->GetConsensus(), pindexLast.nHeight+1, pindexLast.nBits, expected_nbits)); + // Test that increasing nbits further would not be a PermittedDifficultyTransition. + unsigned int invalid_nbits = expected_nbits+1; + BOOST_CHECK(!PermittedDifficultyTransition(chainParams->GetConsensus(), pindexLast.nHeight+1, pindexLast.nBits, invalid_nbits)); } BOOST_AUTO_TEST_CASE(CheckProofOfWork_test_negative_target) |