Merge pull request #66 from Tenderize/nv/livepeer-remediation

Livepeer: correct handling of X96 Price
Tenderize · Sep 29, 2023 · b9f416a · b9f416a
2 parents ed8d90e + 3c2eefa
commit b9f416a
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/src/adapters/LivepeerAdapter.sol b/src/adapters/LivepeerAdapter.sol
@@ -136,7 +136,8 @@ contract LivepeerAdapter is Adapter {
         WETH.deposit{ value: ethBalance }();
         ERC20(address(WETH)).safeApprove(address(UNISWAP_ROUTER), ethBalance);
         // Calculate Slippage Threshold
-        uint256 twapPrice = TWAP.getPriceX96FromSqrtPriceX96(TWAP.getSqrtTwapX96(UNI_POOL, TWAP_INTERVAL));
+        uint256 twapPrice = TWAP.getInversePriceX96(TWAP.getPriceX96(TWAP.getSqrtTwapX96(UNI_POOL, TWAP_INTERVAL)));
+        uint256 amountOut = ethBalance * twapPrice >> 96;
         // Create initial params for swap
         ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({
             tokenIn: address(WETH),
@@ -145,7 +146,7 @@ contract LivepeerAdapter is Adapter {
             recipient: address(this),
             deadline: block.timestamp,
             amountIn: ethBalance,
-            amountOutMinimum: ethBalance * twapPrice * 90 / 100, // 10% slippage threshold
+            amountOutMinimum: amountOut * 897 / 1000, // 10% slippage threshold + 0.3% fee
             sqrtPriceLimitX96: 0
         });
 

diff --git a/src/utils/TWAP.sol b/src/utils/TWAP.sol
@@ -33,7 +33,11 @@ library TWAP {
         }
     }
 
-    function getPriceX96FromSqrtPriceX96(uint160 sqrtPriceX96) internal pure returns (uint256 priceX96) {
+    function getPriceX96(uint160 sqrtPriceX96) internal pure returns (uint256) {
         return FullMath.mulDiv(sqrtPriceX96, sqrtPriceX96, FixedPoint96.Q96);
     }
+
+    function getInversePriceX96(uint256 priceX96) internal pure returns (uint256) {
+        return FullMath.mulDiv(2 ** 96, 2 ** 96, priceX96);
+    }
 }