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Submission Details
Severity: low
Invalid

[M-4] `.transfer` is used in `GmxProxy.sol` in multiple places to transfer ETH

Description

In GmxProxy.sol the .transfer is used to transfer ETH in GmxProxy::refundExecutionFee and GmxPeoxy::withdrawEth functions , .transfer transfers a fixed amount of 2300 gas which may lead to reverts if :

  1. The receiver is not an EOA but a contract with a receive/fallback which requires more than 2300 gas

  2. The change in Gas Costs of EVM during Hard Forks , Example : EIP-1884:Repricing for trie-size dependent opcodes

Issue 1 only affects GmxProxy::refundExecutionFee but issue 2 affects even GmxPeoxy::withdrawEth leaving the protocol with upgrading the contract as only option and funds being permanently stuck in the previous implementation.

Reference to a similar Issue

Impact

Usage of .transfer may lead to reverts and in the worst case the funds will be permanently stuck in the contract

Proof of Concept

In the GmxProxy::refundExecutionFee function

function refundExecutionFee(address receipient, uint256 amount) external {
require(msg.sender == perpVault, "invalid caller");
@> payable(receipient).transfer(amount);
}

In the GmxProxy::withdrawEth function

function withdrawEth() external onlyOwner returns (uint256) {
uint256 balance = address(this).balance;
@> payable(msg.sender).transfer(balance);
return balance;
}

Tools Used

Manual Review

Recommendations

Use .call instead of .transfer and in GmxProxy::refundExecutionFee use .call with a configurable gas variable instead to prevent gas griefing attacks from Malicious users

payable(receipient).call{gas: _gas,value: _value}("")
Updates

Lead Judging Commences

n0kto Lead Judge 9 months ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity
Assigned finding tags:

Admin is trusted / Malicious keepers

Please read the CodeHawks documentation to know which submissions are valid. If you disagree, provide a coded PoC and explain the real likelihood and the detailed impact on the mainnet without any supposition (if, it could, etc) to prove your point. Keepers are added by the admin, there is no "malicious keeper" and if there is a problem in those keepers, that's out of scope. ReadMe and known issues states: " * System relies heavily on keeper for executing trades * Single keeper point of failure if not properly distributed * Malicious keeper could potentially front-run or delay transactions * Assume that Keeper will always have enough gas to execute transactions. There is a pay execution fee function, but the assumption should be that there's more than enough gas to cover transaction failures, retries, etc * There are two spot swap functionalies: (1) using GMX swap and (2) using Paraswap. We can assume that any swap failure will be retried until success. " " * Heavy dependency on GMX protocol functioning correctly * Owner can update GMX-related addresses * Changes in GMX protocol could impact system operations * We can assume that the GMX keeper won't misbehave, delay, or go offline. " "Issues related to GMX Keepers being DOS'd or losing functionality would be considered invalid."

Suppositions

There is no real proof, concrete root cause, specific impact, or enough details in those submissions. Examples include: "It could happen" without specifying when, "If this impossible case happens," "Unexpected behavior," etc. Make a Proof of Concept (PoC) using external functions and realistic parameters. Do not test only the internal function where you think you found something.

Users mistake, only impacting themselves.

Please read the CodeHawks documentation to know which submissions are valid. If you disagree, provide a coded PoC and explain the real likelihood and the detailed impact on the mainnet without any supposition (if, it could, etc) to prove your point.

Appeal created

codexbugmenot Submitter
9 months ago
n0kto Lead Judge
9 months ago
n0kto Lead Judge 8 months ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity
Assigned finding tags:

Admin is trusted / Malicious keepers

Please read the CodeHawks documentation to know which submissions are valid. If you disagree, provide a coded PoC and explain the real likelihood and the detailed impact on the mainnet without any supposition (if, it could, etc) to prove your point. Keepers are added by the admin, there is no "malicious keeper" and if there is a problem in those keepers, that's out of scope. ReadMe and known issues states: " * System relies heavily on keeper for executing trades * Single keeper point of failure if not properly distributed * Malicious keeper could potentially front-run or delay transactions * Assume that Keeper will always have enough gas to execute transactions. There is a pay execution fee function, but the assumption should be that there's more than enough gas to cover transaction failures, retries, etc * There are two spot swap functionalies: (1) using GMX swap and (2) using Paraswap. We can assume that any swap failure will be retried until success. " " * Heavy dependency on GMX protocol functioning correctly * Owner can update GMX-related addresses * Changes in GMX protocol could impact system operations * We can assume that the GMX keeper won't misbehave, delay, or go offline. " "Issues related to GMX Keepers being DOS'd or losing functionality would be considered invalid."

Suppositions

There is no real proof, concrete root cause, specific impact, or enough details in those submissions. Examples include: "It could happen" without specifying when, "If this impossible case happens," "Unexpected behavior," etc. Make a Proof of Concept (PoC) using external functions and realistic parameters. Do not test only the internal function where you think you found something.

Users mistake, only impacting themselves.

Please read the CodeHawks documentation to know which submissions are valid. If you disagree, provide a coded PoC and explain the real likelihood and the detailed impact on the mainnet without any supposition (if, it could, etc) to prove your point.

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