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[refactor] Cleanup merkle root checks

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This commit is contained in:
dergoegge 2024-02-22 11:27:49 +00:00
parent 95bddb930a
commit e7669e1343
1 changed files with 41 additions and 14 deletions
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55
src/validation.cpp
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@ -3642,35 +3642,59 @@ static bool CheckBlockHeader(const CBlockHeader& block, BlockValidationState& st
static bool CheckMerkleRoot(const CBlock& block, BlockValidationState& state)
{
bool mutated;
uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated);
if (block.hashMerkleRoot != hashMerkleRoot2)
return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-txnmrklroot", "hashMerkleRoot mismatch");
uint256 merkle_root = BlockMerkleRoot(block, &mutated);
if (block.hashMerkleRoot != merkle_root) {
return state.Invalid(
/*result=*/BlockValidationResult::BLOCK_MUTATED,
/*reject_reason=*/"bad-txnmrklroot",
/*debug_message=*/"hashMerkleRoot mismatch");
}
// Check for merkle tree malleability (CVE-2012-2459): repeating sequences
// of transactions in a block without affecting the merkle root of a block,
// while still invalidating it.
if (mutated)
return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-txns-duplicate", "duplicate transaction");
if (mutated) {
return state.Invalid(
/*result=*/BlockValidationResult::BLOCK_MUTATED,
/*reject_reason=*/"bad-txns-duplicate",
/*debug_message=*/"duplicate transaction");
}
return true;
}
/** CheckWitnessMalleation performs checks for block malleation with regard to
* its witnesses.
*
* Note: If the witness commitment is expected (i.e. `expect_witness_commitment
* = true`), then the block is required to have at least one transaction and the
* first transaction needs to have at least one input. */
static bool CheckWitnessMalleation(const CBlock& block, bool expect_witness_commitment, BlockValidationState& state)
{
if (expect_witness_commitment) {
int commitpos = GetWitnessCommitmentIndex(block);
if (commitpos != NO_WITNESS_COMMITMENT) {
bool malleated = false;
uint256 hashWitness = BlockWitnessMerkleRoot(block, &malleated);
assert(!block.vtx.empty() && !block.vtx[0]->vin.empty());
const auto& witness_stack{block.vtx[0]->vin[0].scriptWitness.stack};
if (witness_stack.size() != 1 || witness_stack[0].size() != 32) {
return state.Invalid(
/*result=*/BlockValidationResult::BLOCK_MUTATED,
/*reject_reason=*/"bad-witness-nonce-size",
/*debug_message=*/strprintf("%s : invalid witness reserved value size", __func__));
}
// The malleation check is ignored; as the transaction tree itself
// already does not permit it, it is impossible to trigger in the
// witness tree.
if (block.vtx[0]->vin[0].scriptWitness.stack.size() != 1 || block.vtx[0]->vin[0].scriptWitness.stack[0].size() != 32) {
return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-witness-nonce-size", strprintf("%s : invalid witness reserved value size", __func__));
}
CHash256().Write(hashWitness).Write(block.vtx[0]->vin[0].scriptWitness.stack[0]).Finalize(hashWitness);
if (memcmp(hashWitness.begin(), &block.vtx[0]->vout[commitpos].scriptPubKey[6], 32)) {
return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-witness-merkle-match", strprintf("%s : witness merkle commitment mismatch", __func__));
uint256 hash_witness = BlockWitnessMerkleRoot(block, /*mutated=*/nullptr);
CHash256().Write(hash_witness).Write(witness_stack[0]).Finalize(hash_witness);
if (memcmp(hash_witness.begin(), &block.vtx[0]->vout[commitpos].scriptPubKey[6], 32)) {
return state.Invalid(
/*result=*/BlockValidationResult::BLOCK_MUTATED,
/*reject_reason=*/"bad-witness-merkle-match",
/*debug_message=*/strprintf("%s : witness merkle commitment mismatch", __func__));
}
return true;
@ -3680,7 +3704,10 @@ static bool CheckWitnessMalleation(const CBlock& block, bool expect_witness_comm
// No witness data is allowed in blocks that don't commit to witness data, as this would otherwise leave room for spam
for (const auto& tx : block.vtx) {
if (tx->HasWitness()) {
return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "unexpected-witness", strprintf("%s : unexpected witness data found", __func__));
return state.Invalid(
/*result=*/BlockValidationResult::BLOCK_MUTATED,
/*reject_reason=*/"unexpected-witness",
/*debug_message=*/strprintf("%s : unexpected witness data found", __func__));
}
}