QA: Increase Allowance? -> If yes let's have them remove it
QA: Pause concern from Lourens -> Technically safe but also worth looking into
Sent, imo remove tx.origin crap, too much thinking, no good reason
2 Issues sent: https://github.com/cornbase/silo-thorchain-aggregator/issues
We need to verify that everyone can cash out their tokens I feel due to double fee some tokens may be unclaimable
Overall the swap facility needs a lot of tests
Some ideas:
// Process fee
uint256 fee = _processFee(amountIn18Decimals, _feeRate);
uint256 amountOut = amountIn18Decimals - fee;
emit SwapExactIn(msg.sender, amountIn, amountOut, fee, to, deadline);
mintedToken.mint(to, amountOut);
inputToken.transferFrom(msg.sender, address(vault), amountIn);
inputToken.transfer(feeRecipient, fee);You should take the fee in amountIn and not in amountOut
So you should do the following:
The current setup will reduce the wrong amount from minted, the fee will be too small and you'll overmint BTCN
uint256 amountOut18Decimals = amountOut * to18ConversionFactor;
uint256 fee = _processFee(amountOut, _feeRate);
uint256 amountInWithFee = amountOut18Decimals + fee;
require(amountInWithFee <= amountInMax, "Amount in with fee exceeds max");
emit SwapExactOut(msg.sender, amountOut, amountInWithFee, fee, to, deadline);
mintedToken.burnFrom(msg.sender, amountInWithFee);
inputToken.transferFrom(address(vault), to, amountOut);
mintedToken.transfer(feeRecipient, fee);Should be:
uint256 amountOut18Decimals = amountOut * to18ConversionFactor;
uint256 fee = _processFee(amountOut18Decimals, _feeRate); /// @audit Fee should be in 18 decimals since it' in minted Token!
uint256 amountInWithFee = amountOut18Decimals + fee;
require(amountInWithFee <= amountInMax, "Amount in with fee exceeds max");
emit SwapExactOut(msg.sender, amountOut, amountInWithFee, fee, to, deadline);
mintedToken.transferFrom(msg.sender, amountInWithFee); /// @audit Transfer 100%
mintedToken.burn(amountOut18Decimals); /// @audit Burn non-fee
mintedToken.transfer(feeRecipient, fee); /// @audit Fee is sent
inputToken.transferFrom(address(vault), to, amountOut); /// @audit User receives the amountOut
mintedToken.burnFrom(msg.sender, amountInWithFee);
Bitcorn doesn't have burnFrom https://github.com/cornbase/bitcorn-token/blob/main/src/Bitcorn.sol
feeRate = _feeRate.safeCastTo96();
/// @param _feeRate The inital fee rate for swaps, in basis points.
/// @notice Sets the fee rate for swaps.
/// @param _feeRate The new fee rate, as a percentage in basis points.
function setFeeRate(uint256 _feeRate) external requiresAuth {
feeRate = _feeRate.safeCastTo96();
} function _processFee(uint256 _amountIn, uint256 _feeRate) internal returns (uint256) {
return _amountIn * _feeRate / 1e18;
} function swapExactIn(uint256 amountIn, uint256 amountOutMin, address to, uint256 deadline)
amountOutMin is unused, best to use it since it's in the interface
And if fees change mid tx the user could lose a bit
A bit of a scammy finding so either fix or ack
uint256 MIN_AMOUNT_IN = 1e15; // Mitigate rounding issues through minimum size
IERC20 immutable inputToken;
IERC20Mintable immutable mintedToken;
IVault public immutable vault;
address public immutable feeRecipient;
uint256 public immutable to18ConversionFactor;
to18ConversionFactor = 10 ** uint256(18 - inputToken.decimals());
modifier onlySwapInEnabled() {
/// @param deadline The timestamp by which the swap must be completed.
_processFee uint256 _feeRate = uint256(feeRate);