AA-282 L-02: Imprecise refresh requirement (eth-infinitism#424)

* AA-282 L-02: Imprecies refresh requirement

Author: forshtat

contracts/samples/utils/OracleHelper.sol

@@ -23,6 +23,9 @@ abstract contract OracleHelper {
         /// @notice The price cache will be returned without even fetching the oracles for this number of seconds
         uint48 cacheTimeToLive;
 
+        /// @notice The maximum acceptable age of the price oracle round
+        uint48 maxOracleRoundAge;
+
         /// @notice The Oracle contract used to fetch the latest token prices
         IOracle tokenOracle;
 
@@ -157,8 +160,7 @@ abstract contract OracleHelper {
     function fetchPrice(IOracle _oracle) internal view returns (uint256 price) {
         (uint80 roundId, int256 answer,, uint256 updatedAt, uint80 answeredInRound) = _oracle.latestRoundData();
         require(answer > 0, "TPM: Chainlink price <= 0");
-        // 2 days old price is considered stale since the price is updated every 24 hours
-        require(updatedAt >= block.timestamp - 60 * 60 * 24 * 2, "TPM: Incomplete round");
+        require(updatedAt >= block.timestamp - oracleHelperConfig.maxOracleRoundAge, "TPM: Incomplete round");
         require(answeredInRound >= roundId, "TPM: Stale price");
         price = uint256(answer);
     }

gascalc/5-token-paymaster.gas.ts

@@ -58,6 +58,7 @@ context('Token Paymaster', function () {
 
     const oracleHelperConfig: OracleHelperNamespace.OracleHelperConfigStruct = {
       cacheTimeToLive: 100000000,
+      maxOracleRoundAge: 0,
       nativeOracle: nativeAssetOracleAddress,
       nativeOracleReverse: false,
       priceUpdateThreshold: priceDenominator.mul(2).div(10), // +20%

reports/gas-checker.txt

@@ -44,12 +44,12 @@
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
 ║ paymaster+postOp with diff     │    11 │               │          42927 │               13948 ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ token paymaster                │     1 │        128491 │                │                     ║
+║ token paymaster                │     1 │        128503 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ token paymaster with diff      │     2 │               │          66145 │               37166 ║
+║ token paymaster with diff      │     2 │               │          66121 │               37142 ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ token paymaster                │    10 │        723875 │                │                     ║
+║ token paymaster                │    10 │        723935 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ token paymaster with diff      │    11 │               │          66228 │               37249 ║
+║ token paymaster with diff      │    11 │               │          66204 │               37225 ║
 ╚════════════════════════════════╧═══════╧═══════════════╧════════════════╧═════════════════════╝
 

test/samples/OracleHelper.test.ts

@@ -85,6 +85,7 @@ describe('OracleHelper', function () {
       nativeOracle: testEnv.nativeAssetOracle.address,
       tokenOracle: testEnv.tokenOracle.address,
       cacheTimeToLive: 0,
+      maxOracleRoundAge: 0,
       priceUpdateThreshold: 0
     }
   }

test/samples/TokenPaymaster.test.ts

@@ -99,6 +99,7 @@ describe('TokenPaymaster', function () {
 
     const oracleHelperConfig: OracleHelperNamespace.OracleHelperConfigStruct = {
       cacheTimeToLive: 0,
+      maxOracleRoundAge: 0,
       nativeOracle: nativeAssetOracle.address,
       nativeOracleReverse: false,
       priceUpdateThreshold: priceDenominator.mul(12).div(100).toString(), // 20%