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// Copyright (c) 2021-present 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 <chain.h>
#include <chainparams.h>
#include <coins.h>
#include <consensus/consensus.h>
#include <consensus/validation.h>
#include <node/blockstorage.h>
#include <node/utxo_snapshot.h>
#include <primitives/block.h>
#include <primitives/transaction.h>
#include <serialize.h>
#include <span.h>
#include <streams.h>
#include <sync.h>
#include <test/fuzz/FuzzedDataProvider.h>
#include <test/fuzz/fuzz.h>
#include <test/fuzz/util.h>
#include <test/util/mining.h>
#include <test/util/setup_common.h>
#include <uint256.h>
#include <util/check.h>
#include <util/fs.h>
#include <util/result.h>
#include <validation.h>
#include <cstdint>
#include <functional>
#include <ios>
#include <memory>
#include <optional>
#include <vector>
using node::SnapshotMetadata;
namespace {
const std::vector<std::shared_ptr<CBlock>>* g_chain;
TestingSetup* g_setup;
template <bool INVALID>
void initialize_chain()
{
const auto params{CreateChainParams(ArgsManager{}, ChainType::REGTEST)};
static const auto chain{CreateBlockChain(2 * COINBASE_MATURITY, *params)};
g_chain = &chain;
static const auto setup{
MakeNoLogFileContext<TestingSetup>(ChainType::REGTEST,
TestOpts{
.setup_net = false,
.setup_validation_interface = false,
.min_validation_cache = true,
}),
};
if constexpr (INVALID) {
auto& chainman{*setup->m_node.chainman};
for (const auto& block : chain) {
BlockValidationState dummy;
bool processed{chainman.ProcessNewBlockHeaders({{block->GetBlockHeader()}}, true, dummy)};
Assert(processed);
const auto* index{WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(block->GetHash()))};
Assert(index);
}
}
g_setup = setup.get();
}
template <bool INVALID>
void utxo_snapshot_fuzz(FuzzBufferType buffer)
{
FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
auto& setup{*g_setup};
bool dirty_chainman{false}; // Re-use the global chainman, but reset it when it is dirty
auto& chainman{*setup.m_node.chainman};
const auto snapshot_path = gArgs.GetDataDirNet() / "fuzzed_snapshot.dat";
Assert(!chainman.SnapshotBlockhash());
{
AutoFile outfile{fsbridge::fopen(snapshot_path, "wb")};
// Metadata
if (fuzzed_data_provider.ConsumeBool()) {
std::vector<uint8_t> metadata{ConsumeRandomLengthByteVector(fuzzed_data_provider)};
outfile << Span{metadata};
} else {
auto msg_start = chainman.GetParams().MessageStart();
int base_blockheight{fuzzed_data_provider.ConsumeIntegralInRange<int>(1, 2 * COINBASE_MATURITY)};
uint256 base_blockhash{g_chain->at(base_blockheight - 1)->GetHash()};
uint64_t m_coins_count{fuzzed_data_provider.ConsumeIntegralInRange<uint64_t>(1, 3 * COINBASE_MATURITY)};
SnapshotMetadata metadata{msg_start, base_blockhash, m_coins_count};
outfile << metadata;
}
// Coins
if (fuzzed_data_provider.ConsumeBool()) {
std::vector<uint8_t> file_data{ConsumeRandomLengthByteVector(fuzzed_data_provider)};
outfile << Span{file_data};
} else {
int height{0};
for (const auto& block : *g_chain) {
auto coinbase{block->vtx.at(0)};
outfile << coinbase->GetHash();
WriteCompactSize(outfile, 1); // number of coins for the hash
WriteCompactSize(outfile, 0); // index of coin
outfile << Coin(coinbase->vout[0], height, /*fCoinBaseIn=*/1);
height++;
}
}
if constexpr (INVALID) {
// Append an invalid coin to ensure invalidity. This error will be
// detected late in PopulateAndValidateSnapshot, and allows the
// INVALID fuzz target to reach more potential code coverage.
const auto& coinbase{g_chain->back()->vtx.back()};
outfile << coinbase->GetHash();
WriteCompactSize(outfile, 1); // number of coins for the hash
WriteCompactSize(outfile, 999); // index of coin
outfile << Coin{coinbase->vout[0], /*nHeightIn=*/999, /*fCoinBaseIn=*/0};
}
}
const auto ActivateFuzzedSnapshot{[&] {
AutoFile infile{fsbridge::fopen(snapshot_path, "rb")};
auto msg_start = chainman.GetParams().MessageStart();
SnapshotMetadata metadata{msg_start};
try {
infile >> metadata;
} catch (const std::ios_base::failure&) {
return false;
}
return !!chainman.ActivateSnapshot(infile, metadata, /*in_memory=*/true);
}};
if (fuzzed_data_provider.ConsumeBool()) {
// Consume the bool, but skip the code for the INVALID fuzz target
if constexpr (!INVALID) {
for (const auto& block : *g_chain) {
BlockValidationState dummy;
bool processed{chainman.ProcessNewBlockHeaders({{block->GetBlockHeader()}}, true, dummy)};
Assert(processed);
const auto* index{WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(block->GetHash()))};
Assert(index);
}
dirty_chainman = true;
}
}
if (ActivateFuzzedSnapshot()) {
LOCK(::cs_main);
Assert(!chainman.ActiveChainstate().m_from_snapshot_blockhash->IsNull());
Assert(*chainman.ActiveChainstate().m_from_snapshot_blockhash ==
*chainman.SnapshotBlockhash());
const auto& coinscache{chainman.ActiveChainstate().CoinsTip()};
for (const auto& block : *g_chain) {
Assert(coinscache.HaveCoin(COutPoint{block->vtx.at(0)->GetHash(), 0}));
const auto* index{chainman.m_blockman.LookupBlockIndex(block->GetHash())};
Assert(index);
Assert(index->nTx == 0);
if (index->nHeight == chainman.GetSnapshotBaseHeight()) {
auto params{chainman.GetParams().AssumeutxoForHeight(index->nHeight)};
Assert(params.has_value());
Assert(params.value().m_chain_tx_count == index->m_chain_tx_count);
} else {
Assert(index->m_chain_tx_count == 0);
}
}
Assert(g_chain->size() == coinscache.GetCacheSize());
dirty_chainman = true;
} else {
Assert(!chainman.SnapshotBlockhash());
Assert(!chainman.ActiveChainstate().m_from_snapshot_blockhash);
}
// Snapshot should refuse to load a second time regardless of validity
Assert(!ActivateFuzzedSnapshot());
if constexpr (INVALID) {
// Activating the snapshot, or any other action that makes the chainman
// "dirty" can and must not happen for the INVALID fuzz target
Assert(!dirty_chainman);
}
if (dirty_chainman) {
setup.m_node.chainman.reset();
setup.m_make_chainman();
setup.LoadVerifyActivateChainstate();
}
}
// There are two fuzz targets:
//
// The target 'utxo_snapshot', which allows valid snapshots, but is slow,
// because it has to reset the chainstate manager on almost all fuzz inputs.
// Otherwise, a dirty header tree or dirty chainstate could leak from one fuzz
// input execution into the next, which makes execution non-deterministic.
//
// The target 'utxo_snapshot_invalid', which is fast and does not require any
// expensive state to be reset.
FUZZ_TARGET(utxo_snapshot /*valid*/, .init = initialize_chain<false>) { utxo_snapshot_fuzz<false>(buffer); }
FUZZ_TARGET(utxo_snapshot_invalid, .init = initialize_chain<true>) { utxo_snapshot_fuzz<true>(buffer); }
} // namespace
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