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refactor: untangle assumevalid decision branches

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Flatten nested conditionals into a linear gating sequence for readability and precise logging. No functional change, TODOs are addressed in next commit
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Lőrinc
2025-09-14 14:40:45 -07:00
parent 9bc298556c
commit f2ea6f04e7
1 changed files with 30 additions and 21 deletions
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51
src/validation.cpp
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@@ -2424,33 +2424,42 @@ bool Chainstate::ConnectBlock(const CBlock& block, BlockValidationState& state,
}
bool fScriptChecks = true;
if (!m_chainman.AssumedValidBlock().IsNull()) {
if (m_chainman.AssumedValidBlock().IsNull()) {
// TODO
} else {
constexpr int64_t TWO_WEEKS_IN_SECONDS{60 * 60 * 24 * 7 * 2};
// We've been configured with the hash of a block which has been externally verified to have a valid history.
// A suitable default value is included with the software and updated from time to time. Because validity
// relative to a piece of software is an objective fact these defaults can be easily reviewed.
// This setting doesn't force the selection of any particular chain but makes validating some faster by
// effectively caching the result of part of the verification.
BlockMap::const_iterator it{m_blockman.m_block_index.find(m_chainman.AssumedValidBlock())};
if (it != m_blockman.m_block_index.end()) {
if (it->second.GetAncestor(pindex->nHeight) == pindex &&
m_chainman.m_best_header->GetAncestor(pindex->nHeight) == pindex &&
m_chainman.m_best_header->nChainWork >= m_chainman.MinimumChainWork()) {
// This block is a member of the assumed verified chain and an ancestor of the best header.
// Script verification is skipped when connecting blocks under the
// assumevalid block. Assuming the assumevalid block is valid this
// is safe because block merkle hashes are still computed and checked,
// Of course, if an assumed valid block is invalid due to false scriptSigs
// this optimization would allow an invalid chain to be accepted.
// The equivalent time check discourages hash power from extorting the network via DOS attack
// into accepting an invalid block through telling users they must manually set assumevalid.
// Requiring a software change or burying the invalid block, regardless of the setting, makes
// it hard to hide the implication of the demand. This also avoids having release candidates
// that are hardly doing any signature verification at all in testing without having to
// artificially set the default assumed verified block further back.
// The test against the minimum chain work prevents the skipping when denied access to any chain at
// least as good as the expected chain.
fScriptChecks = (GetBlockProofEquivalentTime(*m_chainman.m_best_header, *pindex, *m_chainman.m_best_header, params.GetConsensus()) <= 60 * 60 * 24 * 7 * 2);
}
if (it == m_blockman.m_block_index.end()) {
// TODO
} else if (it->second.GetAncestor(pindex->nHeight) != pindex) {
// TODO
} else if (m_chainman.m_best_header->GetAncestor(pindex->nHeight) != pindex) {
// TODO
} else if (m_chainman.m_best_header->nChainWork < m_chainman.MinimumChainWork()) {
// TODO
} else if (GetBlockProofEquivalentTime(*m_chainman.m_best_header, *pindex, *m_chainman.m_best_header, params.GetConsensus()) <= TWO_WEEKS_IN_SECONDS) {
// TODO
} else {
// This block is a member of the assumed verified chain and an ancestor of the best header.
// Script verification is skipped when connecting blocks under the
// assumevalid block. Assuming the assumevalid block is valid this
// is safe because block merkle hashes are still computed and checked,
// Of course, if an assumed valid block is invalid due to false scriptSigs
// this optimization would allow an invalid chain to be accepted.
// The equivalent time check discourages hash power from extorting the network via DOS attack
// into accepting an invalid block through telling users they must manually set assumevalid.
// Requiring a software change or burying the invalid block, regardless of the setting, makes
// it hard to hide the implication of the demand. This also avoids having release candidates
// that are hardly doing any signature verification at all in testing without having to
// artificially set the default assumed verified block further back.
// The test against the minimum chain work prevents the skipping when denied access to any chain at
// least as good as the expected chain.
fScriptChecks = false;
}
}