The Standard
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Submission Details
Severity: low
Invalid

Lack of reentrancy protection

wardenpaul

Summary

Functions that perform several external interactions lack basic reentrancy protection.

Vulnerability Details

Functions do not have re-entrancy protection and do not follow the Check-Effects-Interaction pattern, thus they are vulnerable to exploits. For instance, increasePosition first transfers the tokens before updating the state:

function increasePosition(uint256 _tstVal, uint256 _eurosVal) external {
require(_tstVal > 0 || _eurosVal > 0);
consolidatePendingStakes();
ILiquidationPoolManager(manager).distributeFees();
if (_tstVal > 0) IERC20(TST).safeTransferFrom(msg.sender, address(this), _tstVal);
if (_eurosVal > 0) IERC20(EUROs).safeTransferFrom(msg.sender, address(this), _eurosVal);
pendingStakes.push(PendingStake(msg.sender, block.timestamp, _tstVal, _eurosVal));
addUniqueHolder(msg.sender);
}

Similarly, when decreasing position:

function decreasePosition(uint256 _tstVal, uint256 _eurosVal) external {
consolidatePendingStakes();
ILiquidationPoolManager(manager).distributeFees();
require(_tstVal <= positions[msg.sender].TST && _eurosVal <= positions[msg.sender].EUROs, "invalid-decr-amount");
if (_tstVal > 0) {
IERC20(TST).safeTransfer(msg.sender, _tstVal);
positions[msg.sender].TST -= _tstVal;
}
if (_eurosVal > 0) {
IERC20(EUROs).safeTransfer(msg.sender, _eurosVal);
positions[msg.sender].EUROs -= _eurosVal;
}
if (empty(positions[msg.sender])) deletePosition(positions[msg.sender]);
}

First, tokens are transferred to the user and only then the position is decreased. The order of operations leaves a gap to repeat the action and gain benefits more than once.

Impact

The contract will be deployed with tokens like LINK support and LINK is ERC677 compatible, it contains transferAndCall function to support action hooks. This makes it very easy for malicious users to exploit, e.g. repeatedly withdrawals.

Tools Used

Manual review.

Recommendations

Add reentrancy protection modifiers to critical functions that perform external interactions.

Updates

Lead Judging Commences

hrishibhat Lead Judge over 1 year ago
Submission Judgement Published
Invalidated
Reason: Too generic
Assigned finding tags:

informational/invalid

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