feat(1559): constrain tx gas price == effective gas price (#1152)

* add tx gas price check * constrain effective_gas_price * increase width & bytes for lookup as more were required * clippy fix * increase STEP_WIDTH again for scroll feature * set tx gas price in test * enable more 1559 tests * correct effective gas * restore two tests * remove used comment * add missing constraint * remove gas price as it's set in mock block * add comment & rename * rename --------- Co-authored-by: Zhang Zhuo <[email protected]>
scroll-tech · Apr 22, 2024 · b1bb7c7 · b1bb7c7
1 parent cfcb073
commit b1bb7c7
Show file tree

Hide file tree

Showing 3 changed files with 63 additions and 2 deletions.
diff --git a/zkevm-circuits/src/evm_circuit/execution/begin_tx.rs b/zkevm-circuits/src/evm_circuit/execution/begin_tx.rs
@@ -371,6 +371,7 @@ impl<F: Field> ExecutionGadget<F> for BeginTxGadget<F> {
             tx_id.expr(),
             tx_type.expr(),
             tx_gas.expr(),
+            &tx_gas_price,
             tx_l1_fee.tx_l1_fee_word(),
             &tx_value,
             transfer_with_gas_fee.sender_balance_prev(),

diff --git a/zkevm-circuits/src/evm_circuit/param.rs b/zkevm-circuits/src/evm_circuit/param.rs
@@ -7,7 +7,7 @@ use halo2_proofs::{
 use std::{collections::HashMap, sync::LazyLock};
 
 // Step dimension
-pub(crate) const STEP_WIDTH: usize = 144;
+pub(crate) const STEP_WIDTH: usize = 153;
 /// Step height
 pub const MAX_STEP_HEIGHT: usize = 21;
 /// The height of the state of a step, used by gates that connect two
@@ -27,7 +27,7 @@ pub(crate) const N_COPY_COLUMNS: usize = 2;
 // Number of copy columns for phase2
 pub(crate) const N_PHASE2_COPY_COLUMNS: usize = 1;
 
-pub(crate) const N_BYTE_LOOKUPS: usize = 39;
+pub(crate) const N_BYTE_LOOKUPS: usize = 48;
 
 /// Amount of lookup columns in the EVM circuit dedicated to lookups.
 pub(crate) const EVM_LOOKUP_COLS: usize = FIXED_TABLE_LOOKUPS

diff --git a/zkevm-circuits/src/evm_circuit/util/common_gadget/tx_eip1559.rs b/zkevm-circuits/src/evm_circuit/util/common_gadget/tx_eip1559.rs
@@ -17,6 +17,7 @@ use crate::{
     table::{BlockContextFieldTag, TxFieldTag},
 };
 use eth_types::{geth_types::TxType, Field, ToLittleEndian, U256};
+use gadgets::util::select;
 use halo2_proofs::plonk::{Error, Expression};
 
 /// Transaction EIP-1559 gadget to check sender balance before transfer
@@ -27,6 +28,14 @@ pub(crate) struct TxEip1559Gadget<F> {
     gas_fee_cap: Word<F>,
     // MaxPriorityFeePerGas
     gas_tip_cap: Word<F>,
+    // condition for min(
+    // gas_tip_cap, gas_fee_cap - base_fee_per_gas)
+    lt_gas_tip_cap_vs_gas_fee_cap_sub_base_fee: LtWordGadget<F>,
+    // gas_fee_cap - base_fee_per_gas
+    gas_sub_base_fee: AddWordsGadget<F, 2, true>,
+    // check tx_gas_price = effective_gas_price = priority_fee_per_gas +
+    // block.base_fee_per_gas
+    effective_gas_price_check: AddWordsGadget<F, 2, true>,
     mul_gas_fee_cap_by_gas: MulWordByU64Gadget<F>,
     balance_check: AddWordsGadget<F, 3, true>,
     // Error condition
@@ -43,11 +52,14 @@ pub(crate) struct TxEip1559Gadget<F> {
 }
 
 impl<F: Field> TxEip1559Gadget<F> {
+    #[allow(clippy::too_many_arguments)]
     pub(crate) fn construct(
         cb: &mut EVMConstraintBuilder<F>,
         tx_id: Expression<F>,
         tx_type: Expression<F>,
         tx_gas: Expression<F>,
+        // tx_gas_price is looked up from TxTable in begin_tx gadget.
+        tx_gas_price: &Word<F>,
         tx_l1_fee: &Word<F>,
         value: &Word<F>,
         sender_balance: &Word<F>,
@@ -65,6 +77,9 @@ impl<F: Field> TxEip1559Gadget<F> {
             gas_fee_cap_lt_gas_tip_cap,
             base_fee,
             gas_fee_cap_lt_base_fee,
+            lt_gas_tip_gas_fee_sub_base_fee,
+            gas_sub_base_fee,
+            effective_gas_price_check,
         ) = cb.condition(is_eip1559_tx.expr(), |cb| {
             let mul_gas_fee_cap_by_gas =
                 MulWordByU64Gadget::construct(cb, gas_fee_cap.clone(), tx_gas);
@@ -90,6 +105,22 @@ impl<F: Field> TxEip1559Gadget<F> {
             let gas_fee_cap_lt_base_fee =
                 LtWordGadget::construct(cb, &gas_fee_cap, &base_fee);
 
+            // calculating min(
+            //     gas_tip_cap
+            //     gas_fee_cap - base_fee_per_gas,
+            // );
+            let diff_gas_base_fee = cb.query_word_rlc();
+            let gas_sub_base_fee = AddWordsGadget::construct(cb, [base_fee.clone(), diff_gas_base_fee.clone()], gas_fee_cap.clone());
+            let lt_gas_tip_gas_fee_sub_base_fee = LtWordGadget::construct(cb, &gas_tip_cap, &diff_gas_base_fee);
+            // let effective_gas_price = priority_fee_per_gas + base_fee_per_gas;
+            let priority_fee_per_gas = cb.query_word_rlc();
+            cb.require_equal("constrain priority_fee_per_gas = min(gas_tip_cap, gas_fee_cap - base_fee_per_gas)", priority_fee_per_gas.expr(), select::expr(
+                lt_gas_tip_gas_fee_sub_base_fee.expr(),
+                gas_tip_cap.expr(),
+                diff_gas_base_fee.expr()));
+            // constrain tx_gas_price = effective_gas_price within below `AddWordsGadget`.
+            let effective_gas_price_check = AddWordsGadget::construct(cb, [base_fee.clone(), priority_fee_per_gas], tx_gas_price.clone());
+
             cb.require_zero(
                 "Sender balance must be sufficient, and gas_fee_cap >= gas_tip_cap, and gas_fee_cap >= base_fee",
                 sum::expr([
@@ -106,13 +137,19 @@ impl<F: Field> TxEip1559Gadget<F> {
                 gas_fee_cap_lt_gas_tip_cap,
                 base_fee,
                 gas_fee_cap_lt_base_fee,
+                lt_gas_tip_gas_fee_sub_base_fee,
+                gas_sub_base_fee,
+                effective_gas_price_check,
             )
         });
 
         Self {
             is_eip1559_tx,
             gas_fee_cap,
             gas_tip_cap,
+            lt_gas_tip_cap_vs_gas_fee_cap_sub_base_fee: lt_gas_tip_gas_fee_sub_base_fee,
+            gas_sub_base_fee,
+            effective_gas_price_check,
             mul_gas_fee_cap_by_gas,
             balance_check,
             is_insufficient_balance,
@@ -144,6 +181,29 @@ impl<F: Field> TxEip1559Gadget<F> {
             offset,
             Some(tx.max_priority_fee_per_gas.to_le_bytes()),
         )?;
+
+        let diff_gas_base_fee = tx.max_fee_per_gas - base_fee;
+        let effective_gas_price = base_fee + tx.max_priority_fee_per_gas.min(diff_gas_base_fee);
+        self.gas_sub_base_fee.assign(
+            region,
+            offset,
+            [base_fee, diff_gas_base_fee],
+            tx.max_fee_per_gas,
+        )?;
+        self.lt_gas_tip_cap_vs_gas_fee_cap_sub_base_fee.assign(
+            region,
+            offset,
+            tx.max_priority_fee_per_gas,
+            diff_gas_base_fee,
+        )?;
+
+        self.effective_gas_price_check.assign(
+            region,
+            offset,
+            [base_fee, effective_gas_price],
+            tx.gas_price,
+        )?;
+
         let mul_gas_fee_cap_by_gas = tx.max_fee_per_gas * tx.gas;
         self.mul_gas_fee_cap_by_gas.assign(
             region,