1  // Copyright (c) 2023-present The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or https://opensource.org/license/mit.
  4  
  5  #include <blockencodings.h>
  6  #include <consensus/merkle.h>
  7  #include <consensus/validation.h>
  8  #include <primitives/block.h>
  9  #include <primitives/transaction.h>
 10  #include <test/fuzz/FuzzedDataProvider.h>
 11  #include <test/fuzz/fuzz.h>
 12  #include <test/fuzz/util.h>
 13  #include <test/fuzz/util/mempool.h>
 14  #include <test/util/setup_common.h>
 15  #include <test/util/txmempool.h>
 16  #include <txmempool.h>
 17  #include <util/check.h>
 18  #include <util/time.h>
 19  #include <util/translation.h>
 20  
 21  #include <cstddef>
 22  #include <cstdint>
 23  #include <limits>
 24  #include <memory>
 25  #include <optional>
 26  #include <set>
 27  #include <vector>
 28  
 29  namespace {
 30  const TestingSetup* g_setup;
 31  } // namespace
 32  
 33  void initialize_pdb()
 34  {
 35      static const auto testing_setup = MakeNoLogFileContext<const TestingSetup>();
 36      g_setup = testing_setup.get();
 37  }
 38  
 39  PartiallyDownloadedBlock::IsBlockMutatedFn FuzzedIsBlockMutated(bool result)
 40  {
 41      return [result](const CBlock& block, bool) {
 42          return result;
 43      };
 44  }
 45  
 46  FUZZ_TARGET(partially_downloaded_block, .init = initialize_pdb)
 47  {
 48      SeedRandomStateForTest(SeedRand::ZEROS);
 49      FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
 50      SetMockTime(ConsumeTime(fuzzed_data_provider));
 51  
 52      auto block{ConsumeDeserializable<CBlock>(fuzzed_data_provider, TX_WITH_WITNESS)};
 53      if (!block || block->vtx.size() == 0 ||
 54          block->vtx.size() >= std::numeric_limits<uint16_t>::max()) {
 55          return;
 56      }
 57  
 58      CBlockHeaderAndShortTxIDs cmpctblock{*block, fuzzed_data_provider.ConsumeIntegral<uint64_t>()};
 59  
 60      bilingual_str error;
 61      CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node), error};
 62      Assert(error.empty());
 63      PartiallyDownloadedBlock pdb{&pool};
 64  
 65      // Set of available transactions (mempool or extra_txn)
 66      std::set<uint16_t> available;
 67      // The coinbase is always available
 68      available.insert(0);
 69  
 70      std::vector<std::pair<Wtxid, CTransactionRef>> extra_txn;
 71      for (size_t i = 1; i < block->vtx.size(); ++i) {
 72          auto tx{block->vtx[i]};
 73  
 74          bool add_to_extra_txn{fuzzed_data_provider.ConsumeBool()};
 75          bool add_to_mempool{fuzzed_data_provider.ConsumeBool()};
 76  
 77          if (add_to_extra_txn) {
 78              extra_txn.emplace_back(tx->GetWitnessHash(), tx);
 79              available.insert(i);
 80          }
 81  
 82          if (add_to_mempool && !pool.exists(tx->GetHash())) {
 83              LOCK2(cs_main, pool.cs);
 84              TryAddToMempool(pool, ConsumeTxMemPoolEntry(fuzzed_data_provider, *tx));
 85              available.insert(i);
 86          }
 87      }
 88  
 89      auto init_status{pdb.InitData(cmpctblock, extra_txn)};
 90  
 91      std::vector<CTransactionRef> missing;
 92      // Whether we skipped a transaction that should be included in `missing`.
 93      // FillBlock should never return READ_STATUS_OK if that is the case.
 94      bool skipped_missing{false};
 95      for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) {
 96          // If init_status == READ_STATUS_OK then a available transaction in the
 97          // compact block (i.e. IsTxAvailable(i) == true) implies that we marked
 98          // that transaction as available above (i.e. available.contains(i)).
 99          // The reverse is not true, due to possible compact block short id
100          // collisions (i.e. available.contains(i) does not imply
101          // IsTxAvailable(i) == true).
102          if (init_status == READ_STATUS_OK) {
103              assert(!pdb.IsTxAvailable(i) || available.contains(i));
104          }
105  
106          bool skip{fuzzed_data_provider.ConsumeBool()};
107          if (!pdb.IsTxAvailable(i) && !skip) {
108              missing.push_back(block->vtx[i]);
109          }
110  
111          skipped_missing |= (!pdb.IsTxAvailable(i) && skip);
112      }
113  
114      bool segwit_active{fuzzed_data_provider.ConsumeBool()};
115  
116      // Mock IsBlockMutated
117      bool fail_block_mutated{fuzzed_data_provider.ConsumeBool()};
118      pdb.m_check_block_mutated_mock = FuzzedIsBlockMutated(fail_block_mutated);
119  
120      CBlock reconstructed_block;
121      auto fill_status{pdb.FillBlock(reconstructed_block, missing, segwit_active)};
122      switch (fill_status) {
123      case READ_STATUS_OK:
124          assert(!skipped_missing);
125          assert(!fail_block_mutated);
126          assert(block->GetHash() == reconstructed_block.GetHash());
127          break;
128      case READ_STATUS_FAILED:
129          assert(fail_block_mutated);
130          break;
131      case READ_STATUS_INVALID:
132          break;
133      }
134  }