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[unit test] different witness in package submission
If/when witness replacement is implemented in the future, this test case can be easily replaced with witness replacement tests.
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‎src/test/txpackage_tests.cpp‎

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@@ -327,4 +327,124 @@ BOOST_FIXTURE_TEST_CASE(package_submission_tests, TestChain100Setup)
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BOOST_CHECK(m_node.mempool->exists(GenTxid::Txid(tx_child->GetHash())));
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}
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}
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// Tests for packages containing transactions that have same-txid-different-witness equivalents in
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// the mempool.
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BOOST_FIXTURE_TEST_CASE(package_witness_swap_tests, TestChain100Setup)
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{
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LOCK(cs_main);
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// Transactions with a same-txid-different-witness transaction in the mempool should be ignored,
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// and the mempool entry's wtxid returned.
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CScript witnessScript = CScript() << OP_DROP << OP_TRUE;
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CScript scriptPubKey = GetScriptForDestination(WitnessV0ScriptHash(witnessScript));
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auto mtx_parent = CreateValidMempoolTransaction(/*input_transaction=*/ m_coinbase_txns[0], /*vout=*/ 0,
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/*input_height=*/ 0, /*input_signing_key=*/ coinbaseKey,
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/*output_destination=*/ scriptPubKey,
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/*output_amount=*/ CAmount(49 * COIN), /*submit=*/ false);
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CTransactionRef ptx_parent = MakeTransactionRef(mtx_parent);
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// Make two children with the same txid but different witnesses.
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CScriptWitness witness1;
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witness1.stack.push_back(std::vector<unsigned char>(1));
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witness1.stack.push_back(std::vector<unsigned char>(witnessScript.begin(), witnessScript.end()));
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CScriptWitness witness2(witness1);
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witness2.stack.push_back(std::vector<unsigned char>(2));
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witness2.stack.push_back(std::vector<unsigned char>(witnessScript.begin(), witnessScript.end()));
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CKey child_key;
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child_key.MakeNewKey(true);
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CScript child_locking_script = GetScriptForDestination(WitnessV0KeyHash(child_key.GetPubKey()));
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CMutableTransaction mtx_child1;
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mtx_child1.nVersion = 1;
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mtx_child1.vin.resize(1);
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mtx_child1.vin[0].prevout.hash = ptx_parent->GetHash();
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mtx_child1.vin[0].prevout.n = 0;
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mtx_child1.vin[0].scriptSig = CScript();
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mtx_child1.vin[0].scriptWitness = witness1;
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mtx_child1.vout.resize(1);
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mtx_child1.vout[0].nValue = CAmount(48 * COIN);
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mtx_child1.vout[0].scriptPubKey = child_locking_script;
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CMutableTransaction mtx_child2{mtx_child1};
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mtx_child2.vin[0].scriptWitness = witness2;
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CTransactionRef ptx_child1 = MakeTransactionRef(mtx_child1);
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CTransactionRef ptx_child2 = MakeTransactionRef(mtx_child2);
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// child1 and child2 have the same txid
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BOOST_CHECK_EQUAL(ptx_child1->GetHash(), ptx_child2->GetHash());
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// child1 and child2 have different wtxids
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BOOST_CHECK(ptx_child1->GetWitnessHash() != ptx_child2->GetWitnessHash());
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// Try submitting Package1{parent, child1} and Package2{parent, child2} where the children are
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// same-txid-different-witness.
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{
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const auto submit_witness1 = ProcessNewPackage(m_node.chainman->ActiveChainstate(), *m_node.mempool,
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{ptx_parent, ptx_child1}, /*test_accept=*/ false);
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BOOST_CHECK_MESSAGE(submit_witness1.m_state.IsValid(),
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"Package validation unexpectedly failed: " << submit_witness1.m_state.GetRejectReason());
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auto it_parent1 = submit_witness1.m_tx_results.find(ptx_parent->GetWitnessHash());
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auto it_child1 = submit_witness1.m_tx_results.find(ptx_child1->GetWitnessHash());
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BOOST_CHECK(it_parent1 != submit_witness1.m_tx_results.end());
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BOOST_CHECK_MESSAGE(it_parent1->second.m_state.IsValid(),
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"Transaction unexpectedly failed: " << it_parent1->second.m_state.GetRejectReason());
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BOOST_CHECK(it_child1 != submit_witness1.m_tx_results.end());
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BOOST_CHECK_MESSAGE(it_child1->second.m_state.IsValid(),
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"Transaction unexpectedly failed: " << it_child1->second.m_state.GetRejectReason());
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BOOST_CHECK(m_node.mempool->exists(GenTxid::Txid(ptx_parent->GetHash())));
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BOOST_CHECK(m_node.mempool->exists(GenTxid::Txid(ptx_child1->GetHash())));
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const auto submit_witness2 = ProcessNewPackage(m_node.chainman->ActiveChainstate(), *m_node.mempool,
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{ptx_parent, ptx_child2}, /*test_accept=*/ false);
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BOOST_CHECK_MESSAGE(submit_witness2.m_state.IsValid(),
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"Package validation unexpectedly failed: " << submit_witness2.m_state.GetRejectReason());
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auto it_parent2_deduped = submit_witness2.m_tx_results.find(ptx_parent->GetWitnessHash());
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auto it_child2 = submit_witness2.m_tx_results.find(ptx_child2->GetWitnessHash());
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BOOST_CHECK(it_parent2_deduped != submit_witness2.m_tx_results.end());
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BOOST_CHECK(it_parent2_deduped->second.m_result_type == MempoolAcceptResult::ResultType::MEMPOOL_ENTRY);
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BOOST_CHECK(it_child2 != submit_witness2.m_tx_results.end());
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BOOST_CHECK(it_child2->second.m_result_type == MempoolAcceptResult::ResultType::DIFFERENT_WITNESS);
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BOOST_CHECK_EQUAL(ptx_child1->GetWitnessHash(), it_child2->second.m_other_wtxid.value());
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BOOST_CHECK(m_node.mempool->exists(GenTxid::Txid(ptx_child2->GetHash())));
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BOOST_CHECK(!m_node.mempool->exists(GenTxid::Wtxid(ptx_child2->GetWitnessHash())));
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}
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// Try submitting Package1{child2, grandchild} where child2 is same-txid-different-witness as
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// the in-mempool transaction, child1. Since child1 exists in the mempool and its outputs are
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// available, child2 should be ignored and grandchild should be accepted.
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//
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// This tests a potential censorship vector in which an attacker broadcasts a competing package
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// where a parent's witness is mutated. The honest package should be accepted despite the fact
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// that we don't allow witness replacement.
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CKey grandchild_key;
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grandchild_key.MakeNewKey(true);
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CScript grandchild_locking_script = GetScriptForDestination(WitnessV0KeyHash(grandchild_key.GetPubKey()));
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auto mtx_grandchild = CreateValidMempoolTransaction(/*input_transaction=*/ ptx_child2, /* vout=*/ 0,
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/*input_height=*/ 0, /*input_signing_key=*/ child_key,
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/*output_destination=*/ grandchild_locking_script,
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/*output_amount=*/ CAmount(47 * COIN), /*submit=*/ false);
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CTransactionRef ptx_grandchild = MakeTransactionRef(mtx_grandchild);
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// We already submitted child1 above.
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{
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const auto submit_spend_ignored = ProcessNewPackage(m_node.chainman->ActiveChainstate(), *m_node.mempool,
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{ptx_child2, ptx_grandchild}, /*test_accept=*/ false);
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BOOST_CHECK_MESSAGE(submit_spend_ignored.m_state.IsValid(),
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"Package validation unexpectedly failed: " << submit_spend_ignored.m_state.GetRejectReason());
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auto it_child2_ignored = submit_spend_ignored.m_tx_results.find(ptx_child2->GetWitnessHash());
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auto it_grandchild = submit_spend_ignored.m_tx_results.find(ptx_grandchild->GetWitnessHash());
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BOOST_CHECK(it_child2_ignored != submit_spend_ignored.m_tx_results.end());
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BOOST_CHECK(it_child2_ignored->second.m_result_type == MempoolAcceptResult::ResultType::DIFFERENT_WITNESS);
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BOOST_CHECK(it_grandchild != submit_spend_ignored.m_tx_results.end());
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BOOST_CHECK(it_grandchild->second.m_result_type == MempoolAcceptResult::ResultType::VALID);
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BOOST_CHECK(m_node.mempool->exists(GenTxid::Txid(ptx_child2->GetHash())));
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BOOST_CHECK(!m_node.mempool->exists(GenTxid::Wtxid(ptx_child2->GetWitnessHash())));
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BOOST_CHECK(m_node.mempool->exists(GenTxid::Wtxid(ptx_grandchild->GetWitnessHash())));
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}
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}
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BOOST_AUTO_TEST_SUITE_END()

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