Merge bitcoin/bitcoin#28472: Remove MemPoolAccept::m_limits to avoid mutating it in package evaluation

ee589d4466 Add regression test for m_limit mutation (Greg Sanders)
275579d8c1 Remove MemPoolAccept::m_limits, only have local copies for carveouts (Greg Sanders)

Pull request description:

  Without remoing it, if we ever call `PreChecks()` multiple times for any reason during any one `MempoolAccept`, subsequent invocations may have incorrect limits, allowing longer/larger chains than should be allowed.

  Currently this is only an issue with `submitpackage`, so this is not exposed on mainnet.

ACKs for top commit:
  achow101:
    ACK ee589d4466
  glozow:
    ACK ee589d4466, nits can be ignored
  ariard:
    Code Review ACK ee589d446

Tree-SHA512: 14cf8edc73e014220def82563f5fb4192d1c2c111829712abf16340bfbfd9a85e2148d723af6fd4995d503dd67232b48dcf8b1711668d25b5aee5eab1bdb578c
This commit is contained in:
Andrew Chow
2023-09-20 07:43:01 -04:00
4 changed files with 68 additions and 18 deletions

View File

@@ -433,8 +433,7 @@ public:
m_pool(mempool),
m_view(&m_dummy),
m_viewmempool(&active_chainstate.CoinsTip(), m_pool),
m_active_chainstate(active_chainstate),
m_limits{m_pool.m_limits}
m_active_chainstate(active_chainstate)
{
}
@@ -684,8 +683,6 @@ private:
Chainstate& m_active_chainstate;
CTxMemPool::Limits m_limits;
/** Whether the transaction(s) would replace any mempool transactions. If so, RBF rules apply. */
bool m_rbf{false};
};
@@ -874,6 +871,11 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
if (!bypass_limits && !args.m_package_feerates && !CheckFeeRate(ws.m_vsize, ws.m_modified_fees, state)) return false;
ws.m_iters_conflicting = m_pool.GetIterSet(ws.m_conflicts);
// Note that these modifications are only applicable to single transaction scenarios;
// carve-outs and package RBF are disabled for multi-transaction evaluations.
CTxMemPool::Limits maybe_rbf_limits = m_pool.m_limits;
// Calculate in-mempool ancestors, up to a limit.
if (ws.m_conflicts.size() == 1) {
// In general, when we receive an RBF transaction with mempool conflicts, we want to know whether we
@@ -906,11 +908,11 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
assert(ws.m_iters_conflicting.size() == 1);
CTxMemPool::txiter conflict = *ws.m_iters_conflicting.begin();
m_limits.descendant_count += 1;
m_limits.descendant_size_vbytes += conflict->GetSizeWithDescendants();
maybe_rbf_limits.descendant_count += 1;
maybe_rbf_limits.descendant_size_vbytes += conflict->GetSizeWithDescendants();
}
auto ancestors{m_pool.CalculateMemPoolAncestors(*entry, m_limits)};
auto ancestors{m_pool.CalculateMemPoolAncestors(*entry, maybe_rbf_limits)};
if (!ancestors) {
// If CalculateMemPoolAncestors fails second time, we want the original error string.
// Contracting/payment channels CPFP carve-out:
@@ -926,9 +928,9 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
// this, see https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html
CTxMemPool::Limits cpfp_carve_out_limits{
.ancestor_count = 2,
.ancestor_size_vbytes = m_limits.ancestor_size_vbytes,
.descendant_count = m_limits.descendant_count + 1,
.descendant_size_vbytes = m_limits.descendant_size_vbytes + EXTRA_DESCENDANT_TX_SIZE_LIMIT,
.ancestor_size_vbytes = maybe_rbf_limits.ancestor_size_vbytes,
.descendant_count = maybe_rbf_limits.descendant_count + 1,
.descendant_size_vbytes = maybe_rbf_limits.descendant_size_vbytes + EXTRA_DESCENDANT_TX_SIZE_LIMIT,
};
const auto error_message{util::ErrorString(ancestors).original};
if (ws.m_vsize > EXTRA_DESCENDANT_TX_SIZE_LIMIT) {
@@ -1011,7 +1013,7 @@ bool MemPoolAccept::PackageMempoolChecks(const std::vector<CTransactionRef>& txn
{ return !m_pool.exists(GenTxid::Txid(tx->GetHash()));}));
std::string err_string;
if (!m_pool.CheckPackageLimits(txns, m_limits, err_string)) {
if (!m_pool.CheckPackageLimits(txns, err_string)) {
// This is a package-wide error, separate from an individual transaction error.
return package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-mempool-limits", err_string);
}
@@ -1166,7 +1168,7 @@ bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>&
// Re-calculate mempool ancestors to call addUnchecked(). They may have changed since the
// last calculation done in PreChecks, since package ancestors have already been submitted.
{
auto ancestors{m_pool.CalculateMemPoolAncestors(*ws.m_entry, m_limits)};
auto ancestors{m_pool.CalculateMemPoolAncestors(*ws.m_entry, m_pool.m_limits)};
if(!ancestors) {
results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state));
// Since PreChecks() and PackageMempoolChecks() both enforce limits, this should never fail.