Function AreInputsStandard

src/policy/policy.cpp:182–219

* Check transaction inputs to mitigate two * potential denial-of-service attacks: * * 1. scriptSigs with extra data stuffed into them, * not consumed by scriptPubKey (or P2SH script) * 2. P2SH scripts with a crazy number of expensive * CHECKSIG/CHECKMULTISIG operations * * Why bother? To avoid denial-of-service attacks; an attacker * can submit a standard HASH... OP_EQUAL transactio

 * Note that only the non-witness portion of the transaction is checked here.
 */
bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
{
    if (tx.IsCoinBase()) {
        return true; // Coinbases don't use vin normally
    }

    for (unsigned int i = 0; i < tx.vin.size(); i++) {
        if (tx.vin[i].m_is_pegin) {
            // This deals with p2sh in general only
            continue;
        }

        const CTxOut& prev = mapInputs.AccessCoin(tx.vin[i].prevout).out;

        std::vector<std::vector<unsigned char> > vSolutions;
        TxoutType whichType = Solver(prev.scriptPubKey, vSolutions);
        if (whichType == TxoutType::NONSTANDARD || whichType == TxoutType::WITNESS_UNKNOWN) {
            // WITNESS_UNKNOWN failures are typically also caught with a policy
            // flag in the script interpreter, but it can be helpful to catch
            // this type of NONSTANDARD transaction earlier in transaction
            // validation.
            return false;
        } else if (whichType == TxoutType::SCRIPTHASH) {
            std::vector<std::vector<unsigned char> > stack;
            // convert the scriptSig into a stack, so we can inspect the redeemScript
            if (!EvalScript(stack, tx.vin[i].scriptSig, SCRIPT_VERIFY_NONE, BaseSignatureChecker(), SigVersion::BASE))
                return false;
            if (stack.empty())
                return false;
            CScript subscript(stack.back().begin(), stack.back().end());
            if (subscript.GetSigOpCount(true) > MAX_P2SH_SIGOPS) {
                return false;
            }
        }
    }

    return true;
}

bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
{