revm_handler/

pre_execution.rs

//! Handles related to the main function of the EVM.
//!
//! They handle initial setup of the EVM, call loop and the final return of the EVM

use crate::{EvmTr, PrecompileProvider};
use bytecode::Bytecode;
use context_interface::{
    journaled_state::{account::JournaledAccountTr, JournalTr},
    result::InvalidTransaction,
    transaction::{AccessListItemTr, AuthorizationTr, Transaction, TransactionType},
    Block, Cfg, ContextTr, Database,
};
use core::cmp::Ordering;
use interpreter::InitialAndFloorGas;
use primitives::{hardfork::SpecId, AddressMap, HashSet, StorageKey, U256};
use state::AccountInfo;

/// Loads and warms accounts for execution, including precompiles and access list.
pub fn load_accounts<
    EVM: EvmTr<Precompiles: PrecompileProvider<EVM::Context>>,
    ERROR: From<<<EVM::Context as ContextTr>::Db as Database>::Error>,
>(
    evm: &mut EVM,
) -> Result<(), ERROR> {
    let (context, precompiles) = evm.ctx_precompiles();

    let gen_spec = context.cfg().spec();
    let spec = gen_spec.clone().into();
    // sets eth spec id in journal
    context.journal_mut().set_spec_id(spec);
    let precompiles_changed = precompiles.set_spec(gen_spec);
    let empty_warmed_precompiles = context.journal_mut().precompile_addresses().is_empty();

    if precompiles_changed || empty_warmed_precompiles {
        // load new precompile addresses into journal.
        // When precompiles addresses are changed we reset the warmed hashmap to those new addresses.
        context
            .journal_mut()
            .warm_precompiles(precompiles.warm_addresses());
    }

    // Load coinbase
    // EIP-3651: Warm COINBASE. Starts the `COINBASE` address warm
    if spec.is_enabled_in(SpecId::SHANGHAI) {
        let coinbase = context.block().beneficiary();
        context.journal_mut().warm_coinbase_account(coinbase);
    }

    // Load access list
    let (tx, journal) = context.tx_journal_mut();
    // legacy is only tx type that does not have access list.
    if tx.tx_type() != TransactionType::Legacy {
        if let Some(access_list) = tx.access_list() {
            let mut map: AddressMap<HashSet<StorageKey>> = AddressMap::default();
            for item in access_list {
                map.entry(*item.address())
                    .or_default()
                    .extend(item.storage_slots().map(|key| U256::from_be_bytes(key.0)));
            }
            journal.warm_access_list(map);
        }
    }

    Ok(())
}

/// Validates caller account nonce and code according to EIP-3607.
#[inline]
pub fn validate_account_nonce_and_code_with_components(
    caller_info: &AccountInfo,
    tx: impl Transaction,
    cfg: impl Cfg,
) -> Result<(), InvalidTransaction> {
    validate_account_nonce_and_code(
        caller_info,
        tx.nonce(),
        cfg.is_eip3607_disabled(),
        cfg.is_nonce_check_disabled(),
    )
}

/// Validates caller account nonce and code according to EIP-3607.
#[inline]
pub fn validate_account_nonce_and_code(
    caller_info: &AccountInfo,
    tx_nonce: u64,
    is_eip3607_disabled: bool,
    is_nonce_check_disabled: bool,
) -> Result<(), InvalidTransaction> {
    // EIP-3607: Reject transactions from senders with deployed code
    // This EIP is introduced after london but there was no collision in past
    // so we can leave it enabled always
    if !is_eip3607_disabled {
        let bytecode = match caller_info.code.as_ref() {
            Some(code) => code,
            None => &Bytecode::default(),
        };
        // Allow EOAs whose code is a valid delegation designation,
        // i.e. 0xef0100 || address, to continue to originate transactions.
        if !bytecode.is_empty() && !bytecode.is_eip7702() {
            return Err(InvalidTransaction::RejectCallerWithCode);
        }
    }

    // Check that the transaction's nonce is correct
    if !is_nonce_check_disabled {
        let tx = tx_nonce;
        let state = caller_info.nonce;
        if tx == u64::MAX && state == u64::MAX {
            return Err(InvalidTransaction::NonceOverflowInTransaction);
        }
        match tx.cmp(&state) {
            Ordering::Greater => {
                return Err(InvalidTransaction::NonceTooHigh { tx, state });
            }
            Ordering::Less => {
                return Err(InvalidTransaction::NonceTooLow { tx, state });
            }
            _ => {}
        }
    }
    Ok(())
}

/// Check maximum possible fee and deduct the effective fee.
///
/// Returns new balance.
#[inline]
pub fn calculate_caller_fee(
    balance: U256,
    tx: impl Transaction,
    block: impl Block,
    cfg: impl Cfg,
) -> Result<U256, InvalidTransaction> {
    // If fee charge is disabled, return the balance as-is without deducting fees.
    // This is useful for `eth_call` and similar simulation scenarios.
    if cfg.is_fee_charge_disabled() {
        return Ok(balance);
    }

    let basefee = block.basefee() as u128;
    let blob_price = block.blob_gasprice().unwrap_or_default();
    let is_balance_check_disabled = cfg.is_balance_check_disabled();

    if !is_balance_check_disabled {
        tx.ensure_enough_balance(balance)?;
    }

    let effective_balance_spending = tx
        .effective_balance_spending(basefee, blob_price)
        .expect("effective balance is always smaller than max balance so it can't overflow");

    let gas_balance_spending = effective_balance_spending - tx.value();

    // new balance
    let mut new_balance = balance.saturating_sub(gas_balance_spending);

    if is_balance_check_disabled {
        // Make sure the caller's balance is at least the value of the transaction.
        new_balance = new_balance.max(tx.value());
    }

    Ok(new_balance)
}

/// Validates caller state and deducts transaction costs from the caller's balance.
#[inline]
pub fn validate_against_state_and_deduct_caller<
    CTX: ContextTr,
    ERROR: From<InvalidTransaction> + From<<CTX::Db as Database>::Error>,
>(
    context: &mut CTX,
) -> Result<(), ERROR> {
    let (block, tx, cfg, journal, _, _) = context.all_mut();

    // Load caller's account.
    let mut caller = journal.load_account_with_code_mut(tx.caller())?.data;

    validate_account_nonce_and_code_with_components(&caller.account().info, tx, cfg)?;

    let new_balance = calculate_caller_fee(*caller.balance(), tx, block, cfg)?;

    caller.set_balance(new_balance);
    if tx.kind().is_call() {
        caller.bump_nonce();
    }
    Ok(())
}

/// Apply EIP-7702 auth list and return number gas refund on already created accounts.
///
/// Note that this function will do nothing if the transaction type is not EIP-7702.
/// If you need to apply auth list for other transaction types, use [`apply_auth_list`] function.
///
/// Internally uses [`apply_auth_list`] function.
#[inline]
pub fn apply_eip7702_auth_list<
    CTX: ContextTr,
    ERROR: From<InvalidTransaction> + From<<CTX::Db as Database>::Error>,
>(
    context: &mut CTX,
    init_and_floor_gas: &mut InitialAndFloorGas,
) -> Result<u64, ERROR> {
    let chain_id = context.cfg().chain_id();
    let is_eip8037 = context.cfg().is_amsterdam_eip8037_enabled();
    let (tx, journal) = context.tx_journal_mut();

    // Return if not EIP-7702 transaction.
    if tx.tx_type() != TransactionType::Eip7702 {
        return Ok(0);
    }
    let (number_of_refunded_accounts, number_of_refunded_bytecodes) =
        apply_auth_list::<_, ERROR>(chain_id, tx.authorization_list(), journal, is_eip8037)?;

    let params = context.cfg().gas_params();

    // EIP-8037: Split per-auth refund into state and regular components. The
    // state portion is credited back to the reservoir by reducing
    // `initial_state_gas` (which is what `initial_gas_and_reservoir` deducts
    // from the reservoir). The regular portion is returned and routed through
    // the standard refund counter, subject to the 1/5 cap.
    if is_eip8037 {
        init_and_floor_gas.state_refund += params
            .tx_eip7702_state_refund(number_of_refunded_accounts, number_of_refunded_bytecodes);
    }

    let regular_gas_refund = params
        .tx_eip7702_auth_refund_regular()
        .saturating_mul(number_of_refunded_accounts);

    Ok(regular_gas_refund)
}

/// Apply EIP-7702 style auth list and return number gas refund on already created accounts.
///
/// It is more granular function from [`apply_eip7702_auth_list`] function as it takes only the list, journal and chain id.
///
/// The `refund_per_auth` parameter specifies the gas refund per existing account authorization.
/// By default this is `PER_EMPTY_ACCOUNT_COST - PER_AUTH_BASE_COST` (25000 - 12500 = 12500),
/// but can be configured via [`GasParams::tx_eip7702_auth_refund`](context_interface::cfg::gas_params::GasParams::tx_eip7702_auth_refund).
///
/// Return number of refunded account and number of refunded bytecodes (Delegation length is already fixed).
#[inline]
pub fn apply_auth_list<
    JOURNAL: JournalTr,
    ERROR: From<InvalidTransaction> + From<<JOURNAL::Database as Database>::Error>,
>(
    chain_id: u64,
    auth_list: impl Iterator<Item = impl AuthorizationTr>,
    journal: &mut JOURNAL,
    is_eip8037: bool,
) -> Result<(u64, u64), ERROR> {
    let mut refunded_accounts = 0;
    let mut refunded_bytecodes = 0;
    // EIP-8037: a rejected authorization had its full pessimistic intrinsic cost
    // charged (regular ACCOUNT_WRITE plus per-account NEW_ACCOUNT and per-bytecode
    // AUTH_BASE state gas), none of which is needed, so all of it is refunded.
    // Counting both refund slots credits the regular ACCOUNT_WRITE and both
    // state-gas portions. Before EIP-8037 rejected authorizations refund nothing.
    macro_rules! reject {
        () => {{
            if is_eip8037 {
                refunded_accounts += 1;
                refunded_bytecodes += 1;
            }
            continue;
        }};
    }
    for authorization in auth_list {
        // 1. Verify the chain id is either 0 or the chain's current ID.
        let auth_chain_id = authorization.chain_id();
        if !auth_chain_id.is_zero() && auth_chain_id != U256::from(chain_id) {
            reject!();
        }

        // 2. Verify the `nonce` is less than `2**64 - 1`.
        if authorization.nonce() == u64::MAX {
            reject!();
        }

        // recover authority and authorized addresses.
        // 3. `authority = ecrecover(keccak(MAGIC || rlp([chain_id, address, nonce])), y_parity, r, s]`
        let Some(authority) = authorization.authority() else {
            reject!();
        };

        // warm authority account and check nonce.
        // 4. Add `authority` to `accessed_addresses` (as defined in [EIP-2929](./eip-2929.md).)
        let mut authority_acc = journal.load_account_with_code_mut(authority)?;
        let authority_acc_info = &authority_acc.account().info;

        // 5. Verify the code of `authority` is either empty or already delegated.
        if let Some(bytecode) = &authority_acc_info.code {
            // if it is not empty and it is not eip7702
            if !bytecode.is_empty() && !bytecode.is_eip7702() {
                reject!();
            }
        }

        // 6. Verify the nonce of `authority` is equal to `nonce`. In case `authority` does not exist in the trie, verify that `nonce` is equal to `0`.
        if authorization.nonce() != authority_acc_info.nonce {
            reject!();
        }

        // Refund-relevant facts for this accepted authorization (mirrors
        // execution-specs `set_delegation` / evm2 `apply_one_auth`).
        //   existed             — the authority account already existed in state.
        //   delegated_now       — its current code is a delegation (non-empty code
        //                          is necessarily EIP-7702 here, having passed the
        //                          validity check above).
        //   delegated_before_tx — its code at the start of the transaction was a
        //                          delegation (may differ from `delegated_now` when
        //                          an earlier authorization in this tx cleared it).
        //   clearing            — this authorization clears the delegation.
        let existed = !(authority_acc_info.is_empty()
            && authority_acc
                .account()
                .is_loaded_as_not_existing_not_touched());
        let delegated_now = !authority_acc_info.is_code_hash_empty_or_zero();
        let delegated_before_tx = authority_acc
            .account()
            .original_info()
            .code
            .as_ref()
            .is_some_and(Bytecode::is_eip7702);
        let clearing = authorization.address().is_zero();

        // Existing authority: the worst-case `ACCOUNT_WRITE` regular gas and the
        // per-account `NEW_ACCOUNT` state gas were not needed.
        if existed {
            refunded_accounts += 1;
        }

        // Bytecode (`AUTH_BASE`) state-gas refunds.
        if clearing {
            refunded_bytecodes += 1;
            // Clearing a delegation freshly installed earlier in this transaction
            // refills the bytecode state gas a second time.
            if delegated_now && !delegated_before_tx {
                refunded_bytecodes += 1;
            }
        } else if delegated_now || delegated_before_tx {
            refunded_bytecodes += 1;
        }

        // 8. Set the code of `authority` to be `0xef0100 || address`. This is a delegation designation.
        //  * As a special case, if `address` is `0x0000000000000000000000000000000000000000` do not write the designation.
        //    Clear the accounts code and reset the account's code hash to the empty hash `0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470`.
        // 9. Increase the nonce of `authority` by one.
        authority_acc.delegate(authorization.address());
    }

    Ok((refunded_accounts, refunded_bytecodes))
}

#[cfg(test)]
mod tests {
    use super::validate_account_nonce_and_code;
    use context_interface::result::InvalidTransaction;
    use state::AccountInfo;

    #[test]
    fn rejects_transactions_when_sender_nonce_is_max() {
        let caller_info = AccountInfo {
            nonce: u64::MAX,
            ..AccountInfo::default()
        };

        let err = validate_account_nonce_and_code(&caller_info, u64::MAX, false, false)
            .expect_err("nonce-max sender should be rejected before execution");

        assert_eq!(err, InvalidTransaction::NonceOverflowInTransaction);
    }

    #[test]
    fn allows_matching_non_max_nonce() {
        let caller_info = AccountInfo {
            nonce: 7,
            ..AccountInfo::default()
        };

        assert!(validate_account_nonce_and_code(&caller_info, 7, false, false).is_ok());
    }
}