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

Missing approve for ERC20 tokens

gkrastenov
## Summary
Missing approve for ERC20 tokens.
​
## Vulnerability Details
When the user decides to withdraw their tokens, the `_safe_transfer_from` function is called, where the required token amount is transferred from the Capital Pool to `msg.sender`.
​
The problem here is that the approval from the Capital Pool to the TokenManager contract is missing because the `approval` function is only called when `from == _capitalPoolAddr`, which is only true when `_tokenAddress == wrappedNativeToken`.
​
```solidity
​
if (_tokenAddress == wrappedNativeToken) {
/**
* @dev token is native token
* @dev transfer from capital pool to msg sender
* @dev withdraw native token to token manager contract
* @dev transfer native token to msg sender
*/
_transfer(
wrappedNativeToken,
capitalPoolAddr,
address(this),
claimAbleAmount,
capitalPoolAddr
);
```
## Impact
Blocking ERC20 withdrawing.
​
## Tools Used
Manual Review
## Recommendations
Approve the tokens before calling `_safe_transfer_from`.
Updates

Lead Judging Commences

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

finding-TokenManager-safeTransferFrom-withdraw-missing-approve

This issue's severity has similar reasonings to #252, whereby 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. Similarly, the argument here is the approval function `approve` was made permisionless, so if somebody beforehand calls approval for the TokenManager for the required token, 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. It also has a slightly different root cause and fix whereby an explicit approval needs to be provided before a call to `_safe_transfer_from()`, if not, the alternative `_transfer()` function should be used to provide an approval, assuming a fix was implemented for issue #252

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