Merge: 2.6.1 into develop from master (#546)

* Feat(standalone): Add debug tracing of remaining gas values (#391) * Balance type refactoring (#386) * Remove standalone binary (#403) * Eth Address cleanup (#387) * Fix(dep) Pass std feature on to rjson library (#402) * Feat(benchmarks): update gas bounds after wasm cost reduction (#406) * Feat(tests): Mock touching trie nodes (#408) * Fix: Only allow owner to call deploy_upgrade (#410) * Feat(tests): Uniswap multi-hop swap benchmark (#415) * Fix(engine): Return revert error message during contract deploy (#424) * Move engine transactions module to engine-transactions crate (#418) * Avoid using wasmer directly (#420) * Fix compilation after #418 merge * Use default git attributes for Cargo.lock (#421) * Switch to rebranded blake2 (#422) * Remove unused unused (#423) * Chore: make aurora compatible with latest nightlies (#425) * Chore: upgrade to the recent nightly (#426) * chore: upgrade to the latest nearcore version (#427) * chore: move to 2021 edition (#428) * Benchmark contract performing only pure arithmetic and memory operations (#429) * Fix(engine): Require chain_id (#432) * chore: make sure aurora is using the latest cost config (#435) * Fix(test): make uniswap benchmarks reproducible (#437) * Fix(test): lower gas limit on OOG test; this is needed because the solidity compiler got more efficient, not because of a regression in EVM gas metering correctness * Fix(engine): Cache generation values to avoid repeated state reads (#438) * Fix(engine): Optimize is_account_empty (#439) * Fix(test): update uniswap wasm fraction; this is needed because optimizations from #438 and #439 together lowered the fraction of gas spent on IO * Fix(engine): Upgrade to latest SputnikVM (#445) * Fix(engine): Simple cache to stop consecutive duplicate reads (#446) * Version update and change log Co-authored-by: Aleksey Kladov <aleksey@near.org> Co-authored-by: Evgeny Ukhanov <evgeny.ukhanov@aurora.dev> Co-authored-by: Michael Birch <michael.birch@aurora.dev> Release 2.5.0. (#460) * Engine: Upgrade to latest SputnikVM changes (#455) * Engine: further caching optimizations (#456) * Use EthTransactionKind reference to serialize into bytes (#457) * Test: Reproduce GdASJ3KESs8VegpFECTveCwLQp8fxw8yvsauNEmGb6pZ gas failure (#454) * Fix typo: promise_create (#452) * Fix(Engine): Transactions to the zero address are not the same as transactions with empty to field (#458) Co-authored-by: Marcelo Fornet <marcelo.fornet@aurora.dev> Co-authored-by: Michael Birch <michael.birch@aurora.dev> Release 2.5.1. (#470) * Feat(Engine): Precompiles for predecessor_account_id and current_account_id (#462) * Implement a NEAR native version of the Solidity pure arithmetic benchmark to compare EVM execution cost with direct wasm cost (#463) * Fix features related to panic_info_message (#466) * Fix(standalone): set predecessor_account_id appropriately when executing promise callbacks (#467) * Fix(engine): fix bug in checking if an address exists (#469) * Version update * Update unreleased link Co-authored-by: Joshua J. Bouw <joshua.j.bouw@aurora.dev> Release 2.5.2. (#475) * Revert "Feat(Engine): Precompiles for predecessor_account_id and current_account_id (#462)" Release 2.5.3. (#527) * Fix(precompile): ExitToNear ExitToEthereum vulnerability patch Fix vulnerability Include exploit contract * Release 2.5.3 notes * Update solidity version Co-authored-by: Michael Birch <michael.birch@aurora.dev> Release 2.6.0. (#494) * Feat(Engine): Precompiles for predecessor_account_id and current_account_id (#462) * Fix(precompiles): Allow native precompiles to work in the standalone engine (#473) * Standalone engine improvements (#478) * Fix(Engine): Predecessor id precompile works in view calls (#477) * Feat(standalone): Persist transaction data (#481) * Feat(Engine): Add custom precompile for NEAR prepaid_gas (#479) * Test: Reproduce 8ru7VEAEbyfZdbC1W2PYQv2cY3W92rbTToDEN4yTp8aZ gas failure (#485) * Feat(standalone): Function to get latest/earliest block (#482) * Engine optimization: cache all reads from NEAR state (#488) * Feat(standalone): Handle call to new method of Engine contract (#490) * Feat(engine-types): optional serde integration (#468) * Changed near-blake2 dependency (#484) * Feat(standalone): thread-safety and serde (#496) * Refactor repro tests to have less boilerplate (#497) * Add serde for TraceTransaction (#495) * Fix(standalone): include possible execution errors in the TransactionIncludedOutcome result field (#500) * Reproduce transaction FRcorNvFojoxBrdiVMTy9gRD3H8EYXXKau4feevMZmFV (#498) * Reproduce transaction 5bEgfRQ5TSJfN9XCqYkMr9cgBLToM7JmS1bNzKpDXJhT (#499) * Fix(connector): Return an error when storage cannot be read instead of panicking (#501) * Standalone: forward underlying rocksdb crate features (#502) * Feat(tests): Multisender benchmark (#503) * Feat(test): Reproduce D98vwmi44hAYs8KtX5aLne1zEkj3MUss42e5SkG2a4SC (#504) * Standalone engine storage saves the AccountId of the associated engine deployed on chain (#510) * Fix(precompiles): Fix secp256k1 run not returning empty slice on an incorrect V byte (#513) * Self-contained wasm contract for testing 5bEgfRQ (#514) * Update gas estimation code to use new data from NEAR protocol v53 (#517) * Fix: Legacy transactions must be allowed (#520) * Chore(precompiles): Include blake2 compression only (#528) * Build(deps): Upgrade `libsecp256k1` version 0.3.5 => 0.7.0 (#515) * Bump regex from 1.5.4 to 1.5.6 (#526) * Bump regex from 1.5.4 to 1.5.6 in /etc/ft-receiver (#525) * Bump zeroize_derive from 1.1.0 to 1.3.2 (#523) * Bump crossbeam-deque from 0.8.0 to 0.8.1 (#521) * Bump crossbeam-utils from 0.8.4 to 0.8.8 (#524) * Bump cross-fetch from 2.2.3 to 2.2.6 in /etc/eth-contracts (#508) * Bump simple-get from 2.8.1 to 2.8.2 in /etc/eth-contracts (#507) * Bump follow-redirects from 1.14.0 to 1.15.1 in /etc/eth-contracts (#529) * Bump shelljs from 0.8.4 to 0.8.5 in /etc/eth-contracts * Fix(ecrecover): Set malleability flag to `0` for ecrecover. (#474) Co-authored-by: Evgeny Ukhanov <evgeny.ukhanov@aurora.dev> Co-authored-by: Marcelo Fornet <marcelo.fornet@aurora.dev> Co-authored-by: Michael Birch <michael.birch@aurora.dev> Co-authored-by: Roman Hodulák <roman.hodulak@aurora.dev> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Release 2.6.1. (#537) * Fix: Don't allow fee stealing. * Fix: Don't allow bridge receipt forging. * Fix(engine): Correctly account for changes in total supply of ETH on Aurora (#536) Co-authored-by: Michael Birch <michael.birch@aurora.dev> Co-authored-by: Michael Birch <michael.birch@aurora.dev>
aurora-is-near · Jul 1, 2022 · 6307874 · 6307874
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diff --git a/AUTHORS b/AUTHORS
@@ -1,3 +1,12 @@
-* Arto Bendiken <arto@bendiken.net>
-
-* Illia Polosukhin <ilblackdragon@gmail.com>
+Aleksey Kladov	 <aleksey.kladov@gmail.com>
+Andrew Bednoff	 <andrew.bednoff@aurora.dev>
+Arto Bendiken	 <arto@aurora.dev>
+Evgeny Kuzyakov	 <h3r0k1ll3r@gmail.com>
+Evgeny Ukhanov	 <evgeny@aurora.dev>
+Frank Braun	     <frank@aurora.dev>
+Illia Polosukhin <ilblackdragon@gmail.com>
+Joshua J. Bouw	 <joshua@aurora.dev>
+Kirill Abramov	 <kirill@aurora.dev>
+Marcelo Fornet	 <marcelo@aurora.dev>
+Michael Birch	 <michael.birch@aurora.dev>
+Roman Hodulak    <roman@aurora.dev>
diff --git a/CHANGES.md b/CHANGES.md
@@ -7,26 +7,127 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.6.1] 2022-06-23
+
+### Fixes
+
+- Fixed an issue with accounting being problematic with the total supply of ETH on Aurora as it could artificially deplete by @[birchmd]. ([#536])
+- Fixed the possibility of forging receipts to allow for withdrawals on the Rainbow Bridge by [@birchmd], [@mfornet], [@sept-en] and [@joshuajbouw]. Written by [@birchmd].
+- Fixed the ability the steal funds from those by setting a fee when receiving NEP-141 as ERC-20 by [@birchmd], [@mfornet], and [@joshuajbouw]. Written by [@joshuajbouw].
+
+[#536]: https://github.com/aurora-is-near/aurora-engine/pull/536
+
+## [2.6.0] 2022-06-08
+
+### Added
+
+- A precompile at the address `0x536822d27de53629ef1f84c60555689e9488609f` was created to expose the prepaid gas from the NEAR host function by [@birchmd]. ([#479])
+
+### Changes
+
+- A better implementation of caching was added to reduce the overall gas costs of storage reads resulting in roughly a 15% - 18% reduction of gas costs by [@birchmd]. ([#488])
+
+### Fixes
+
+- If the `v` byte of secp256k1 is incorrect, it now returns correctly an empty vector by [@RomanHodulak]. ([#513])
+- Original ETH transactions which do not contain a Chain ID are allowed again to allow for use of [EIP-1820] by [@joshuajbouw]. ([#520])
+- Ecrecover didn't reject `r`, `s` values larger than curve order by [@RomanHodulak]. ([#515])
+- The predecessor account ID was failing in the `view` method by [@birchmd]. ([#477])
+- Ecrecover was incorrectly setting the NEAR ecrecover malleability flag by [@birchmd] and [@joshuajbouw]. ([#474])
+
+[EIP-1820]: https://eips.ethereum.org/EIPS/eip-1820
+[#520]: https://github.com/aurora-is-near/aurora-engine/pull/520
+[#515]: https://github.com/aurora-is-near/aurora-engine/pull/515
+[#513]: https://github.com/aurora-is-near/aurora-engine/pull/513
+[#488]: https://github.com/aurora-is-near/aurora-engine/pull/488
+[#479]: https://github.com/aurora-is-near/aurora-engine/pull/479
+[#477]: https://github.com/aurora-is-near/aurora-engine/pull/477
+[#474]: https://github.com/aurora-is-near/aurora-engine/pull/474
+
+## [2.5.3] 2022-04-27
+
+### Fixes
+
+- Fixed inflation vulnerability relating to ExitToNear and ExitToEthereum by [@birchmd], [@mfornet], and [@joshuajbouw]. Written by [@birchmd].
+
+## [2.5.2] 2022-03-22
+
+### Removed
+
+- New Aurora-only precompiles removed since they do not work in NEAR view calls. This will need to be fixed and they will be re-added to a future release.
+
+## [2.5.1] - 2022-03-16
+
+### Fixes
+
+- Fix for bug in checking address exists introduced in the v2.5.0 release by [@birchmd]. ([#469])
+
+### Added
+
+- New Aurora-only precompiles for checking the current and predecessor NEAR account IDs by [@birchmd]. ([#462])
+
+[#462]: https://github.com/aurora-is-near/aurora-engine/pull/462
+[#469]: https://github.com/aurora-is-near/aurora-engine/pull/469
+
+## [2.5.0] - 2022-03-09
+
+### Changes
+
+- Performance improvement by [@birchmd] and [@olonho]: ([#455]) ([#456])
+
+### Fixes
+
+- Bug fix for the behaviour of transactions to the zero address by [@birchmd]. ([#458])
+
+[#455]: https://github.com/aurora-is-near/aurora-engine/pull/455
+[#456]: https://github.com/aurora-is-near/aurora-engine/pull/456
+[#458]: https://github.com/aurora-is-near/aurora-engine/pull/458
+
+## [2.4.0] - 2022-02-16
+
+### Changes
+
+- Performance improvements by [@birchmd] and [@matklad]; the engine should now consume much less NEAR gas: ([#427]) ([#438]) ([#439]) ([#445]) ([#446])
+- Security improvment: only Engine contract owner can use the `deploy_upgrade` method by [@birchmd]. ([#410])
+- Bug fix: Engine now returns the error message in the case of a revert during an EVM contract deploy, previously it would always return an address (even when the deploy failed) by [@birchmd]. ([#424])
+- Security improvment: Engine will no longer accept EVM transactions without a chain ID as part of their signature by [@birchmd]. This should have no impact on users as all modern Ethereum tooling includes the chain ID. ([#432])
+- Improvements to code quality by [@mrLSD]: ([#386]) ([#387])
+- Improvements and additions to internal tests and benchmarks by [@birchmd]: ([#408]) ([#415]) ([#429])
+
+[#386]: https://github.com/aurora-is-near/aurora-engine/pull/386
+[#387]: https://github.com/aurora-is-near/aurora-engine/pull/387
+[#408]: https://github.com/aurora-is-near/aurora-engine/pull/408
+[#410]: https://github.com/aurora-is-near/aurora-engine/pull/410
+[#415]: https://github.com/aurora-is-near/aurora-engine/pull/415
+[#424]: https://github.com/aurora-is-near/aurora-engine/pull/424
+[#427]: https://github.com/aurora-is-near/aurora-engine/pull/427
+[#429]: https://github.com/aurora-is-near/aurora-engine/pull/429
+[#432]: https://github.com/aurora-is-near/aurora-engine/pull/432
+[#438]: https://github.com/aurora-is-near/aurora-engine/pull/438
+[#439]: https://github.com/aurora-is-near/aurora-engine/pull/439
+[#445]: https://github.com/aurora-is-near/aurora-engine/pull/445
+[#446]: https://github.com/aurora-is-near/aurora-engine/pull/446
+
 ## [2.3.0] - 2021-12-10
 
 ### Added
 
-- A precompile which exposes NEAR's random number generator was added by [@mfornet] as requested by 
-[@birchmd]. ([#368] [#297])
+- A precompile which exposes NEAR's random number generator was added by [@mfornet] as requested by
+  [@birchmd]. ([#368] [#297])
 - London hard fork support was added by [@birchmd]. ([#244])
 
 ### Changes
 
 - The gas limit for `deposit` and `ft_on_transfer` were changed as they were not attaching enough
-gas, as changed by [@mrLSD]. ([#389])
+  gas, as changed by [@mrLSD]. ([#389])
 
 ### Fixes
 
-- There was an issue with the original storage not actually being stored. Unfortunately, previous 
-transactions can't be updated with this change. This has been fixed by [@birchmd]. ([#390])
+- There was an issue with the original storage not actually being stored. Unfortunately, previous
+  transactions can't be updated with this change. This has been fixed by [@birchmd]. ([#390])
 - Call arguments were intended to have a value attached to them to make it equivalent to an ETH
-call. This was fixed in a backwards compatible manner by [@andrcmdr], as reported by [@birchmd].
-([#351] [#309])
+  call. This was fixed in a backwards compatible manner by [@andrcmdr], as reported by [@birchmd].
+  ([#351] [#309])
 
 ### Removed
 
@@ -37,10 +138,10 @@ call. This was fixed in a backwards compatible manner by [@andrcmdr], as reporte
 [#388]: https://github.com/aurora-is-near/aurora-engine/pull/388
 [#368]: https://github.com/aurora-is-near/aurora-engine/pull/368
 [#351]: https://github.com/aurora-is-near/aurora-engine/pull/351
-[#311]: https://github.com/aurora-is-near/aurora-engine/pull/311 
+[#311]: https://github.com/aurora-is-near/aurora-engine/pull/311
 [#309]: https://github.com/aurora-is-near/aurora-engine/issues/309
 [#297]: https://github.com/aurora-is-near/aurora-engine/issues/297
-[#244]: https://github.com/aurora-is-near/aurora-engine/pull/244 
+[#244]: https://github.com/aurora-is-near/aurora-engine/pull/244
 
 ## [2.2.0] - 2021-11-09
 
@@ -180,7 +281,14 @@ struct SubmitResult {
 
 ## [1.0.0] - 2021-05-12
 
-[Unreleased]: https://github.com/aurora-is-near/aurora-engine/compare/2.3.0...master
+[Unreleased]: https://github.com/aurora-is-near/aurora-engine/compare/2.6.1...develop
+[2.6.1]: https://github.com/aurora-is-near/aurora-engine/compare/2.6.0...2.6.1 
+[2.6.0]: https://github.com/aurora-is-near/aurora-engine/compare/2.5.3...2.6.0
+[2.5.3]: https://github.com/aurora-is-near/aurora-engine/compare/2.5.2...2.5.3
+[2.5.2]: https://github.com/aurora-is-near/aurora-engine/compare/2.5.1...2.5.2
+[2.5.1]: https://github.com/aurora-is-near/aurora-engine/compare/2.5.0...2.5.1
+[2.5.0]: https://github.com/aurora-is-near/aurora-engine/compare/2.4.0...2.5.0
+[2.4.0]: https://github.com/aurora-is-near/aurora-engine/compare/2.3.0...2.4.0
 [2.3.0]: https://github.com/aurora-is-near/aurora-engine/compare/2.2.0...2.3.0 
 [2.2.0]: https://github.com/aurora-is-near/aurora-engine/compare/2.1.0...2.2.0
 [2.1.0]: https://github.com/aurora-is-near/aurora-engine/compare/2.0.2...2.1.0
@@ -208,4 +316,7 @@ struct SubmitResult {
 [@joshuajbouw]: https://github.com/joshuajbouw
 [@mfornet]: https://github.com/mfornet
 [@mrLSD]: https://github.com/mrLSD
+[@RomanHodulak]: https://github.com/RomanHodulak
 [@sept-en]: https://github.com/sept-en
+[@matklad]: https://github.com/matklad
+[@olonho]: https://github.com/olonho
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/README.md b/README.md
@@ -14,9 +14,9 @@ documentation.
 
 Network | Contract ID         | Chain ID   | Version
 ------- | ------------------- | ---------- | ------
-Mainnet | [`aurora`][Mainnet] | 1313161554 | 2.2.0
-Testnet | [`aurora`][Testnet] | 1313161555 | 2.3.0
-Local   | `aurora.test.near`  | 1313161556 | 2.3.0
+Mainnet | [`aurora`][Mainnet] | 1313161554 | 2.6.1
+Testnet | [`aurora`][Testnet] | 1313161555 | 2.6.1
+Local   | `aurora.test.near`  | 1313161556 | 2.6.1
 
 [Mainnet]: https://explorer.near.org/accounts/aurora
 [Testnet]: https://explorer.testnet.near.org/accounts/aurora

diff --git a/TODO.md b/TODO.md
diff --git a/VERSION b/VERSION
@@ -1 +1 @@
-2.3.0
+2.6.1
diff --git a/engine-precompiles/src/native.rs b/engine-precompiles/src/native.rs
@@ -257,6 +257,8 @@ impl<I: IO> Precompile for ExitToNear<I> {
         // It's not allowed to call exit precompiles in static mode
         if is_static {
             return Err(ExitError::Other(Cow::from("ERR_INVALID_IN_STATIC")));
+        } else if context.address != exit_to_near::ADDRESS.raw() {
+            return Err(ExitError::Other(Cow::from("ERR_INVALID_IN_DELEGATE")));
         }
 
         // First byte of the input is a flag, selecting the behavior to be triggered:
@@ -451,6 +453,8 @@ impl<I: IO> Precompile for ExitToEthereum<I> {
         // It's not allowed to call exit precompiles in static mode
         if is_static {
             return Err(ExitError::Other(Cow::from("ERR_INVALID_IN_STATIC")));
+        } else if context.address != exit_to_ethereum::ADDRESS.raw() {
+            return Err(ExitError::Other(Cow::from("ERR_INVALID_IN_DELEGATE")));
         }
 
         // First byte of the input is a flag, selecting the behavior to be triggered:

diff --git a/engine-sdk/Cargo.toml b/engine-sdk/Cargo.toml
@@ -22,3 +22,5 @@ sha2 = { version = "0.9.3", default-features = false }
 std = ["aurora-engine-types/std"]
 contract = []
 log = []
+mainnet = []
+testnet = []
diff --git a/engine-sdk/src/near_runtime.rs b/engine-sdk/src/near_runtime.rs
@@ -6,6 +6,18 @@ use aurora_engine_types::parameters::{PromiseAction, PromiseBatchAction, Promise
 use aurora_engine_types::types::PromiseResult;
 use aurora_engine_types::H256;
 
+#[cfg(feature = "mainnet")]
+/// The mainnet eth_custodian address 0x6BFaD42cFC4EfC96f529D786D643Ff4A8B89FA52
+const CUSTODIAN_ADDRESS: &[u8] = &[
+    107, 250, 212, 44, 252, 78, 252, 150, 245, 41, 215, 134, 214, 67, 255, 74, 139, 137, 250, 82,
+];
+
+#[cfg(feature = "testnet")]
+/// The testnet eth_custodian address 0x84a82Bb39c83989D5Dc07e1310281923D2544dC2
+const CUSTODIAN_ADDRESS: &[u8] = &[
+    132, 168, 43, 179, 156, 131, 152, 157, 93, 192, 126, 19, 16, 40, 25, 35, 210, 84, 77, 194,
+];
+
 /// Wrapper type for indices in NEAR's register API.
 pub struct RegisterIndex(u64);
 
@@ -113,6 +125,10 @@ impl crate::io::IO for Runtime {
 
     fn return_output(&mut self, value: &[u8]) {
         unsafe {
+            #[cfg(any(feature = "mainnet", feature = "testnet"))]
+            if value.len() >= 56 && &value[36..56] == CUSTODIAN_ADDRESS {
+                panic!("ERR_ILLEGAL_RETURN");
+            }
             exports::value_return(value.len() as u64, value.as_ptr() as u64);
         }
     }

diff --git a/engine-standalone-tracing/Cargo.toml b/engine-standalone-tracing/Cargo.toml
@@ -21,7 +21,6 @@ evm-core = { git = "https://github.com/aurora-is-near/sputnikvm.git", rev = "374
 evm = { git = "https://github.com/aurora-is-near/sputnikvm.git", rev = "37448b6cacd98b06282cff5a559684505c29bd2b", default-features = false, features = ["std", "tracing"] }
 evm-runtime = { git = "https://github.com/aurora-is-near/sputnikvm.git", rev = "37448b6cacd98b06282cff5a559684505c29bd2b", default-features = false, features = ["std", "tracing"] }
 evm-gasometer = { git = "https://github.com/aurora-is-near/sputnikvm.git", rev = "37448b6cacd98b06282cff5a559684505c29bd2b", default-features = false, features = ["std", "tracing"] }
-hex = { version = "0.4" }
 serde = { version = "1", features = ["derive"], optional = true }
 
 [features]

diff --git a/engine-standalone-tracing/src/sputnik.rs b/engine-standalone-tracing/src/sputnik.rs
@@ -48,14 +48,18 @@ impl evm_gasometer::tracing::EventListener for TransactionTraceBuilder {
     fn event(&mut self, event: evm_gasometer::tracing::Event) {
         use evm_gasometer::tracing::Event;
         match event {
-            Event::RecordCost { cost, snapshot: _ } => {
+            Event::RecordCost { cost, snapshot } => {
                 self.current.gas_cost = EthGas::new(cost);
+                if let Some(snapshot) = snapshot {
+                    self.current.gas =
+                        EthGas::new(snapshot.gas_limit - snapshot.used_gas - snapshot.memory_gas);
+                }
             }
             Event::RecordDynamicCost {
                 gas_cost,
                 memory_gas,
                 gas_refund: _,
-                snapshot: _,
+                snapshot,
             } => {
                 // In SputnikVM memory gas is cumulative (ie this event always shows the total) gas
                 // spent on memory up to this point. But geth traces simply show how much gas each step
@@ -68,6 +72,10 @@ impl evm_gasometer::tracing::EventListener for TransactionTraceBuilder {
                 };
                 self.current_memory_gas = memory_gas;
                 self.current.gas_cost = EthGas::new(gas_cost + memory_cost_diff);
+                if let Some(snapshot) = snapshot {
+                    self.current.gas =
+                        EthGas::new(snapshot.gas_limit - snapshot.used_gas - snapshot.memory_gas);
+                }
             }
             Event::RecordRefund {
                 refund: _,

diff --git a/engine-standalone-tracing/src/types/mod.rs b/engine-standalone-tracing/src/types/mod.rs
@@ -163,9 +163,9 @@ pub struct TraceLog {
     pub depth: Depth,
     /// Any errors that may have occurred during execution.
     pub error: Option<String>,
-    /// Gas used to execute the transaction.
+    /// Remaining (unused) gas.
     pub gas: EthGas,
-    /// Gas cost for the transaction.
+    /// Gas cost for the opcode at this step.
     pub gas_cost: EthGas,
     /// The bounded memory.
     pub memory: LogMemory,