Submission Details
Severity:
approve()/safeApprove() may revert if the current approval is not zero
Summary
[L-6] approve()/safeApprove() may revert if the current approval is not zero
Calling approve() without first calling approve(0) if the current approval is non-zero will revert with some tokens, such as Tether (USDT). While Tether is known to do this, it applies to other tokens as well, which are trying to protect against this attack vector. safeApprove() itself also implements this protection.
Always reset the approval to zero before changing it to a new value (SafeERC20.forceApprove() does this for you), or use safeIncreaseAllowance()/safeDecreaseAllowance()
file: /contracts/strategy/gmx/GMXWorker.sol
118 IERC20(sp.tokenIn).approve(address(self.swapRouter), sp.amountIn);
133 IERC20(sp.tokenIn).approve(address(self.swapRouter), sp.amountIn);
file: /contracts/strategy/gmx/GMXTrove.sol
38 _store.tokenA.approve(address(vault), type(uint256).max);
39 _store.tokenB.approve(address(vault), type(uint256).max);
Prize pool breakdown
Total prize
35,000 USDC
nSLOC
2,28915 USDC / LOC
33,000 USDC
2,000 USDC
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