validation_block_tests.cpp

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// Copyright (c) 2018-2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#include <boost/test/unit_test.hpp>
 
#include <chainparams.h>
#include <consensus/merkle.h>
#include <consensus/validation.h>
#include <miner.h>
#include <pow.h>
#include <random.h>
#include <script/standard.h>
#include <test/util/script.h>
#include <test/util/setup_common.h>
#include <util/time.h>
#include <validation.h>
#include <validationinterface.h>
 
#include <thread>
 
namespace validation_block_tests {
struct MinerTestingSetup : public RegTestingSetup {
    std::shared_ptr<CBlock> Block(const uint256& prev_hash);
    std::shared_ptr<const CBlock> GoodBlock(const uint256& prev_hash);
    std::shared_ptr<const CBlock> BadBlock(const uint256& prev_hash);
    std::shared_ptr<CBlock> FinalizeBlock(std::shared_ptr<CBlock> pblock);
    void BuildChain(const uint256& root, int height, const unsigned int invalid_rate, const unsigned int branch_rate, const unsigned int max_size, std::vector<std::shared_ptr<const CBlock>>& blocks);
};
} // namespace validation_block_tests
 
BOOST_FIXTURE_TEST_SUITE(validation_block_tests, MinerTestingSetup)
 
struct TestSubscriber final : public CValidationInterface {
    uint256 m_expected_tip;
 
    explicit TestSubscriber(uint256 tip) : m_expected_tip(tip) {}
 
    void UpdatedBlockTip(const CBlockIndex* pindexNew, const CBlockIndex* pindexFork, bool fInitialDownload) override
    {
        BOOST_CHECK_EQUAL(m_expected_tip, pindexNew->GetBlockHash());
    }
 
    void BlockConnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* pindex) override
    {
        BOOST_CHECK_EQUAL(m_expected_tip, block->hashPrevBlock);
        BOOST_CHECK_EQUAL(m_expected_tip, pindex->pprev->GetBlockHash());
 
        m_expected_tip = block->GetHash();
    }
 
    void BlockDisconnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* pindex) override
    {
        BOOST_CHECK_EQUAL(m_expected_tip, block->GetHash());
        BOOST_CHECK_EQUAL(m_expected_tip, pindex->GetBlockHash());
 
        m_expected_tip = block->hashPrevBlock;
    }
};
 
std::shared_ptr<CBlock> MinerTestingSetup::Block(const uint256& prev_hash)
{
    static int i = 0;
    static uint64_t time = Params().GenesisBlock().nTime;
 
    auto ptemplate = BlockAssembler(m_node.chainman->ActiveChainstate(), *m_node.mempool, Params()).CreateNewBlock(CScript{} << i++ << OP_TRUE);
    auto pblock = std::make_shared<CBlock>(ptemplate->block);
    pblock->hashPrevBlock = prev_hash;
    pblock->nTime = ++time;
 
    // Make the coinbase transaction with two outputs:
    // One zero-value one that has a unique pubkey to make sure that blocks at the same height can have a different hash
    // Another one that has the coinbase reward in a P2WSH with OP_TRUE as witness program to make it easy to spend
    CMutableTransaction txCoinbase(*pblock->vtx[0]);
    txCoinbase.vout.resize(2);
    txCoinbase.vout[1].scriptPubKey = P2WSH_OP_TRUE;
    txCoinbase.vout[1].nValue = txCoinbase.vout[0].nValue;
    txCoinbase.vout[0].nValue = 0;
    txCoinbase.vin[0].scriptWitness.SetNull();
    // Always pad with OP_0 at the end to avoid bad-cb-length error
    txCoinbase.vin[0].scriptSig = CScript{} << WITH_LOCK(::cs_main, return m_node.chainman->m_blockman.LookupBlockIndex(prev_hash)->nHeight + 1) << OP_0;
    pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
 
    return pblock;
}
 
std::shared_ptr<CBlock> MinerTestingSetup::FinalizeBlock(std::shared_ptr<CBlock> pblock)
{
    const CBlockIndex* prev_block{WITH_LOCK(::cs_main, return m_node.chainman->m_blockman.LookupBlockIndex(pblock->hashPrevBlock))};
    GenerateCoinbaseCommitment(*pblock, prev_block, Params().GetConsensus());
 
    pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
 
    while (!CheckProofOfWork(pblock->GetHash(), pblock->nBits, Params().GetConsensus())) {
        ++(pblock->nNonce);
    }
 
    // submit block header, so that miner can get the block height from the
    // global state and the node has the topology of the chain
    BlockValidationState ignored;
    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({pblock->GetBlockHeader()}, ignored, Params()));
 
    return pblock;
}
 
// construct a valid block
std::shared_ptr<const CBlock> MinerTestingSetup::GoodBlock(const uint256& prev_hash)
{
    return FinalizeBlock(Block(prev_hash));
}
 
// construct an invalid block (but with a valid header)
std::shared_ptr<const CBlock> MinerTestingSetup::BadBlock(const uint256& prev_hash)
{
    auto pblock = Block(prev_hash);
 
    CMutableTransaction coinbase_spend;
    coinbase_spend.vin.push_back(CTxIn(COutPoint(pblock->vtx[0]->GetHash(), 0), CScript(), 0));
    coinbase_spend.vout.push_back(pblock->vtx[0]->vout[0]);
 
    CTransactionRef tx = MakeTransactionRef(coinbase_spend);
    pblock->vtx.push_back(tx);
 
    auto ret = FinalizeBlock(pblock);
    return ret;
}
 
void MinerTestingSetup::BuildChain(const uint256& root, int height, const unsigned int invalid_rate, const unsigned int branch_rate, const unsigned int max_size, std::vector<std::shared_ptr<const CBlock>>& blocks)
{
    if (height <= 0 || blocks.size() >= max_size) return;
 
    bool gen_invalid = InsecureRandRange(100) < invalid_rate;
    bool gen_fork = InsecureRandRange(100) < branch_rate;
 
    const std::shared_ptr<const CBlock> pblock = gen_invalid ? BadBlock(root) : GoodBlock(root);
    blocks.push_back(pblock);
    if (!gen_invalid) {
        BuildChain(pblock->GetHash(), height - 1, invalid_rate, branch_rate, max_size, blocks);
    }
 
    if (gen_fork) {
        blocks.push_back(GoodBlock(root));
        BuildChain(blocks.back()->GetHash(), height - 1, invalid_rate, branch_rate, max_size, blocks);
    }
}
 
BOOST_AUTO_TEST_CASE(processnewblock_signals_ordering)
{
    // build a large-ish chain that's likely to have some forks
    std::vector<std::shared_ptr<const CBlock>> blocks;
    while (blocks.size() < 50) {
        blocks.clear();
        BuildChain(Params().GenesisBlock().GetHash(), 100, 15, 10, 500, blocks);
    }
 
    bool ignored;
    // Connect the genesis block and drain any outstanding events
    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlock(Params(), std::make_shared<CBlock>(Params().GenesisBlock()), true, &ignored));
    SyncWithValidationInterfaceQueue();
 
    // subscribe to events (this subscriber will validate event ordering)
    const CBlockIndex* initial_tip = nullptr;
    {
        LOCK(cs_main);
        initial_tip = m_node.chainman->ActiveChain().Tip();
    }
    auto sub = std::make_shared<TestSubscriber>(initial_tip->GetBlockHash());
    RegisterSharedValidationInterface(sub);
 
    // create a bunch of threads that repeatedly process a block generated above at random
    // this will create parallelism and randomness inside validation - the ValidationInterface
    // will subscribe to events generated during block validation and assert on ordering invariance
    std::vector<std::thread> threads;
    for (int i = 0; i < 10; i++) {
        threads.emplace_back([&]() {
            bool ignored;
            FastRandomContext insecure;
            for (int i = 0; i < 1000; i++) {
                auto block = blocks[insecure.randrange(blocks.size() - 1)];
                Assert(m_node.chainman)->ProcessNewBlock(Params(), block, true, &ignored);
            }
 
            // to make sure that eventually we process the full chain - do it here
            for (auto block : blocks) {
                if (block->vtx.size() == 1) {
                    bool processed = Assert(m_node.chainman)->ProcessNewBlock(Params(), block, true, &ignored);
                    assert(processed);
                }
            }
        });
    }
 
    for (auto& t : threads) {
        t.join();
    }
    SyncWithValidationInterfaceQueue();
 
    UnregisterSharedValidationInterface(sub);
 
    LOCK(cs_main);
    BOOST_CHECK_EQUAL(sub->m_expected_tip, m_node.chainman->ActiveChain().Tip()->GetBlockHash());
}
 
BOOST_AUTO_TEST_CASE(mempool_locks_reorg)
{
    bool ignored;
    auto ProcessBlock = [&](std::shared_ptr<const CBlock> block) -> bool {
        return Assert(m_node.chainman)->ProcessNewBlock(Params(), block, /* fForceProcessing */ true, /* fNewBlock */ &ignored);
    };
 
    // Process all mined blocks
    BOOST_REQUIRE(ProcessBlock(std::make_shared<CBlock>(Params().GenesisBlock())));
    auto last_mined = GoodBlock(Params().GenesisBlock().GetHash());
    BOOST_REQUIRE(ProcessBlock(last_mined));
 
    // Run the test multiple times
    for (int test_runs = 3; test_runs > 0; --test_runs) {
        BOOST_CHECK_EQUAL(last_mined->GetHash(), m_node.chainman->ActiveChain().Tip()->GetBlockHash());
 
        // Later on split from here
        const uint256 split_hash{last_mined->hashPrevBlock};
 
        // Create a bunch of transactions to spend the miner rewards of the
        // most recent blocks
        std::vector<CTransactionRef> txs;
        for (int num_txs = 22; num_txs > 0; --num_txs) {
            CMutableTransaction mtx;
            mtx.vin.push_back(CTxIn{COutPoint{last_mined->vtx[0]->GetHash(), 1}, CScript{}});
            mtx.vin[0].scriptWitness.stack.push_back(WITNESS_STACK_ELEM_OP_TRUE);
            mtx.vout.push_back(last_mined->vtx[0]->vout[1]);
            mtx.vout[0].nValue -= 1000;
            txs.push_back(MakeTransactionRef(mtx));
 
            last_mined = GoodBlock(last_mined->GetHash());
            BOOST_REQUIRE(ProcessBlock(last_mined));
        }
 
        // Mature the inputs of the txs
        for (int j = COINBASE_MATURITY; j > 0; --j) {
            last_mined = GoodBlock(last_mined->GetHash());
            BOOST_REQUIRE(ProcessBlock(last_mined));
        }
 
        // Mine a reorg (and hold it back) before adding the txs to the mempool
        const uint256 tip_init{last_mined->GetHash()};
 
        std::vector<std::shared_ptr<const CBlock>> reorg;
        last_mined = GoodBlock(split_hash);
        reorg.push_back(last_mined);
        for (size_t j = COINBASE_MATURITY + txs.size() + 1; j > 0; --j) {
            last_mined = GoodBlock(last_mined->GetHash());
            reorg.push_back(last_mined);
        }
 
        // Add the txs to the tx pool
        {
            LOCK(cs_main);
            for (const auto& tx : txs) {
                const MempoolAcceptResult result = AcceptToMemoryPool(m_node.chainman->ActiveChainstate(), *m_node.mempool, tx, false /* bypass_limits */);
                BOOST_REQUIRE(result.m_result_type == MempoolAcceptResult::ResultType::VALID);
            }
        }
 
        // Check that all txs are in the pool
        {
            LOCK(m_node.mempool->cs);
            BOOST_CHECK_EQUAL(m_node.mempool->mapTx.size(), txs.size());
        }
 
        // Run a thread that simulates an RPC caller that is polling while
        // validation is doing a reorg
        std::thread rpc_thread{[&]() {
            // This thread is checking that the mempool either contains all of
            // the transactions invalidated by the reorg, or none of them, and
            // not some intermediate amount.
            while (true) {
                LOCK(m_node.mempool->cs);
                if (m_node.mempool->mapTx.size() == 0) {
                    // We are done with the reorg
                    break;
                }
                // Internally, we might be in the middle of the reorg, but
                // externally the reorg to the most-proof-of-work chain should
                // be atomic. So the caller assumes that the returned mempool
                // is consistent. That is, it has all txs that were there
                // before the reorg.
                assert(m_node.mempool->mapTx.size() == txs.size());
                continue;
            }
            LOCK(cs_main);
            // We are done with the reorg, so the tip must have changed
            assert(tip_init != m_node.chainman->ActiveChain().Tip()->GetBlockHash());
        }};
 
        // Submit the reorg in this thread to invalidate and remove the txs from the tx pool
        for (const auto& b : reorg) {
            ProcessBlock(b);
        }
        // Check that the reorg was eventually successful
        BOOST_CHECK_EQUAL(last_mined->GetHash(), m_node.chainman->ActiveChain().Tip()->GetBlockHash());
 
        // We can join the other thread, which returns when the reorg was successful
        rpc_thread.join();
    }
}
 
BOOST_AUTO_TEST_CASE(witness_commitment_index)
{
    CScript pubKey;
    pubKey << 1 << OP_TRUE;
    auto ptemplate = BlockAssembler(m_node.chainman->ActiveChainstate(), *m_node.mempool, Params()).CreateNewBlock(pubKey);
    CBlock pblock = ptemplate->block;
 
    CTxOut witness;
    witness.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT);
    witness.scriptPubKey[0] = OP_RETURN;
    witness.scriptPubKey[1] = 0x24;
    witness.scriptPubKey[2] = 0xaa;
    witness.scriptPubKey[3] = 0x21;
    witness.scriptPubKey[4] = 0xa9;
    witness.scriptPubKey[5] = 0xed;
 
    // A witness larger than the minimum size is still valid
    CTxOut min_plus_one = witness;
    min_plus_one.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT + 1);
 
    CTxOut invalid = witness;
    invalid.scriptPubKey[0] = OP_VERIFY;
 
    CMutableTransaction txCoinbase(*pblock.vtx[0]);
    txCoinbase.vout.resize(4);
    txCoinbase.vout[0] = witness;
    txCoinbase.vout[1] = witness;
    txCoinbase.vout[2] = min_plus_one;
    txCoinbase.vout[3] = invalid;
    pblock.vtx[0] = MakeTransactionRef(std::move(txCoinbase));
 
    BOOST_CHECK_EQUAL(GetWitnessCommitmentIndex(pblock), 2);
}
BOOST_AUTO_TEST_SUITE_END()