Alchemix Transmuter

Description

In the _initStrategy and setRouter functions, the contract grants an infinite approval to the router for the underlying token:

Granting infinite approval can lead to gas inefficiencies when approvals need to be updated or reset, as changing an approval from a non-zero value to another non-zero value requires an extra transaction due to some ERC20 tokens' implementation (e.g., USDT).

Impact

• Gas Waste: Users might incur higher gas costs if approvals need to be reset or updated, especially if the underlying token's approve function requires setting the allowance to zero before setting a new value.

• Operational Delay: Additional transactions may be needed to reset approvals, leading to delays in contract operations.

Recommendation

• Use safeIncreaseAllowance and safeDecreaseAllowance: Instead of setting infinite approvals, adjust the allowance as needed using safeIncreaseAllowance and safeDecreaseAllowance functions from OpenZeppelin's SafeERC20 library.

  function setRouter(address _router) external onlyManagement {

  // Reset approval for the old router

  underlying.safeApprove(router, 0);

  router = _router;

  // Increase allowance as needed

  underlying.safeIncreaseAllowance(router, requiredAllowance);

  }