Omniscia Mean Finance Audit

Finding Types

Finding Types

A description of each finding type included in the report can be found below and is linked by each respective finding. A full list of finding types Omniscia has defined will be viewable at the central audit methodology we will publish soon.

External Call Validation

Many contracts that interact with DeFi contain a set of complex external call executions that need to happen in a particular sequence and whose execution is usually taken for granted whereby it is not always the case. External calls should always be validated, either in the form of require checks imposed at the contract-level or via more intricate mechanisms such as invoking an external getter-variable and ensuring that it has been properly updated.

Input Sanitization

As there are no inherent guarantees to the inputs a function accepts, a set of guards should always be in place to sanitize the values passed in to a particular function.

Indeterminate Code

These types of issues arise when a linked code segment may not behave as expected, either due to mistyped code, convoluted if blocks, overlapping functions / variable names and other ambiguous statements.

Language Specific

Language specific issues arise from certain peculiarities that the Solidity language boasts that discerns it from other conventional programming languages. For example, the EVM is a 256-bit machine meaning that operations on less-than-256-bit types are more costly for the EVM in terms of gas costs, meaning that loops utilizing a uint8 variable because their limit will never exceed the 8-bit range actually cost more than redundantly using a uint256 variable.

Code Style

An official Solidity style guide exists that is constantly under development and is adjusted on each new Solidity release, designating how the overall look and feel of a codebase should be. In these types of findings, we identify whether a project conforms to a particular naming convention and whether that convention is consistent within the codebase and legible. In case of inconsistencies, we point them out under this category. Additionally, variable shadowing falls under this category as well which is identified when a local-level variable contains the same name as a contract-level variable that is present in the inheritance chain of the local execution level's context.

Gas Optimization

Gas optimization findings relate to ways the codebase can be optimized to reduce the gas cost involved with interacting with it to various degrees. These types of findings are completely optional and are pointed out for the benefit of the project's developers.

Standard Conformity

These types of findings relate to incompatibility between a particular standard's implementation and the project's implementation, oftentimes causing significant issues in the usability of the contracts.

Mathematical Operations

In Solidity, math generally behaves differently than other programming languages due to the constraints of the EVM. A prime example of this difference is the truncation of values during a division which in turn leads to loss of precision and can cause systems to behave incorrectly when dealing with percentages and proportion calculations.

Logical Fault

This category is a bit broad and is meant to cover implementations that contain flaws in the way they are implemented, either due to unimplemented functionality, unaccounted-for edge cases or similar extraordinary scenarios.

Centralization Concern

This category covers all findings that relate to a significant degree of centralization present in the project and as such the potential of a Single-Point-of-Failure (SPoF) for the project that we urge them to re-consider and potentially omit.

Reentrant Call

This category relates to findings that arise from re-entrant external calls (such as EIP-721 minting operations) and revolve around the inapplicacy of the Checks-Effects-Interactions (CEI) pattern, a pattern that dictates checks (require statements etc.) should occur before effects (local storage updates) and interactions (external calls) should be performed last.