1 Executive Summary
This report presents the results of our engagement with Consensys Linea to review Linea Custom Bridged Token.
The review was conducted over two days, from November 30, 2023 to December 1, 2023, by
Rai Yang. A total of 1 person-days were spent.
No issues are found, however the deployer of the custom bridged token should take caution to initialize the token with the correct initialization function version and parameters.
Together with the Linea team, we identified the following priorities for our review:
- Correctness of the implementation, consistent with the intended functionality and without unintended edge cases.
- Identify known vulnerabilities particular to smart contract systems, as outlined in our Smart Contract Best Practices, and the Smart Contract Weakness Classification Registry.
- The correct initialization of the bridged token
3 System Overview
The Linea custom bridged token is inherited from Linea
BridgedToken contract, it’s used as same purpose as
The only difference is the custom bridged token allows token issuer to deploy the token or original deployer to transfer the ownership (usually is the proxy admin of a proxy contract behind which the bridged token is deployed) to the issuer so that they can later governance tasks such as upgrades as needed. In Lido’s
wstETH case, the ownership will be transfered from the orginal deployer (a Multisig controlled by Linea team) to
LineaBridgeExecutor, a contract which is controlled by the
Ethereum Governance Executor contract on Ethereum to execute governance tasks. While the original deployer of the
BridgedToken is always the
4 Security Specification
This section describes, from a security perspective, the expected behavior of the system under audit. It is not a substitute for documentation. The purpose of this section is to identify specific security properties that were validated by the audit team.
The relevant actors are listed below with their respective abilities:
- Token issuer: deploys bridged token and performs governance tasks (e.g. upgrade)
- Original bridged token deployer: deploys bridged token and transfers the ownership to token issuer or LineaBridgeExecutor
4.2 Trust Model
In any system, it’s important to identify what trust is expected/required between various actors. For this audit, we established the following trust model:
- Token issuer deploys and initializes the token with the correct initalization function
initializeV2and parameters especially
_bridge(address of canonical token bridge ) and performs governance tasks correctly.
- Original bridged token deployer deploys the token and transfers the ownership correctly.
LineaBridgeExecutorrelays and executes governance tasks correctly.
Appendix 1 - Files in Scope
This audit covered the following files:
Appendix 2 - Disclosure
Consensys Diligence (“CD”) typically receives compensation from one or more clients (the “Clients”) for performing the analysis contained in these reports (the “Reports”). The Reports may be distributed through other means, including via Consensys publications and other distributions.
The Reports are not an endorsement or indictment of any particular project or team, and the Reports do not guarantee the security of any particular project. This Report does not consider, and should not be interpreted as considering or having any bearing on, the potential economics of a token, token sale or any other product, service or other asset. Cryptographic tokens are emergent technologies and carry with them high levels of technical risk and uncertainty. No Report provides any warranty or representation to any third party in any respect, including regarding the bug-free nature of code, the business model or proprietors of any such business model, and the legal compliance of any such business. No third party should rely on the Reports in any way, including for the purpose of making any decisions to buy or sell any token, product, service or other asset. Specifically, for the avoidance of doubt, this Report does not constitute investment advice, is not intended to be relied upon as investment advice, is not an endorsement of this project or team, and it is not a guarantee as to the absolute security of the project. CD owes no duty to any third party by virtue of publishing these Reports.
A.2.1 Purpose of Reports
The Reports and the analysis described therein are created solely for Clients and published with their consent. The scope of our review is limited to a review of code and only the code we note as being within the scope of our review within this report. Any Solidity code itself presents unique and unquantifiable risks as the Solidity language itself remains under development and is subject to unknown risks and flaws. The review does not extend to the compiler layer, or any other areas beyond specified code that could present security risks. Cryptographic tokens are emergent technologies and carry with them high levels of technical risk and uncertainty. In some instances, we may perform penetration testing or infrastructure assessments depending on the scope of the particular engagement.
CD makes the Reports available to parties other than the Clients (i.e., “third parties”) on its website. CD hopes that by making these analyses publicly available, it can help the blockchain ecosystem develop technical best practices in this rapidly evolving area of innovation.
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A.2.3 Timeliness of Content
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