Tadle
Tadle
DeFiFoundry
27,750 USDC
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Submission Details
Severity: high
Valid

There is an error in the _transfer function of the TokenManager

azanux

Summary

There is a typo that makes it impossible to transfer tokens from the CapitalPool to the TokenManager.

Vulnerability Details

If a user tries to withdraw their tokens, he won't get hos refund

ICapitalPool(_capitalPoolAddr).approve(address(this));

address(this) refers to the TokenManager instead of the token, but TokenManager does not have an approve(address,uint256) method.

Impact

user won't be able tp wothdraw their toekn from the CapitalPool

Tools Used

manual review

Recommendations

function _transfer(address _token, address _from, address _to, uint256 _amount, address _capitalPoolAddr)
internal
{
uint256 fromBalanceBef = IERC20(_token).balanceOf(_from);
uint256 toBalanceBef = IERC20(_token).balanceOf(_to);
​
if (_from == _capitalPoolAddr && IERC20(_token).allowance(_from, address(this)) == 0x0) {
- ICapitalPool(_capitalPoolAddr).approve(address(this));
+ ICapitalPool(_capitalPoolAddr).approve(token);
approve function in TokenManager
}
​
_safe_transfer_from(_token, _from, _to, _amount);
​
uint256 fromBalanceAft = IERC20(_token).balanceOf(_from);
uint256 toBalanceAft = IERC20(_token).balanceOf(_to);
​
if (fromBalanceAft != fromBalanceBef - _amount) {
revert TransferFailed();
}
​
if (toBalanceAft != toBalanceBef + _amount) {
//won't work with fee tier token or token with transfer tax
revert TransferFailed();
}
}
Updates

Lead Judging Commences

0xnevi Lead Judge 12 months ago
Submission Judgement Published
Validated
Assigned finding tags:

finding-TokenManager-approve-wrong-address-input

If we consider the correct permissioned implementation for the `approve()` function within `CapitalPool.sol`, this would be a critical severity issue, because the withdrawal of funds will be permanently blocked and must be rescued by the admin via the `Rescuable.sol` contract, given it will always revert [here](https://github.com/Cyfrin/2024-08-tadle/blob/04fd8634701697184a3f3a5558b41c109866e5f8/src/core/CapitalPool.sol#L36-L38) when attempting to call a non-existent function selector `approve` within the TokenManager contract. The argument up in the air is since the approval function `approve` was made permisionless, the `if` block within the internal `_transfer()` function will never be invoked if somebody beforehand calls approval for the TokenManager for the required token, so the transfer will infact not revert when a withdrawal is invoked. I will leave open for escalation discussions, but based on my first point, I believe high severity is appropriate.

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