Method Block

Overview

This policy provides a way to blocklist consumers from interacting with specific methods of your smart contract. Some example use cases include:

1. Preventing specific contracts from accessing your protocol (as in malicious or phishing contracts)

2. In the event of an on-going security incident, you could limit access to your protocol instead of completely pausing it

Protected Attack Vector

Intended as an additional layer of security, this policy protects against cases where a known malicious address shouldn't be allowed to interact with your protocol.

How It Works

1. A known malicious contract sends a transaction to your protocol.

2. The policy checks the contract's address and method they want to execute.

3. If the address and method are blocklisted, the transaction will be blocked.

Setup Instructions

1. Deploy your own version of this policy (see Source Code).
2. Call the setConsumerForbiddenMethod() method to configure addresses and methods that you want to prevent access to.
3. Add the newly deployed policy to the Firewall (you can do this Globally or Per-Method, see Policy Administration).
4. That's it!

Properties

Name	Type	Description
consumerMethodStatus	mapping (address => mapping (bytes4 => bool) )	the list of consumers and the methods they're blocklisted from calling for example: [consumerAddress][methodSig] = true
hasEnteredForbiddenMethod	mapping (bytes32 => bool)	used internally to track which methods the consumer has called throughout the transaction execution

Methods

setConsumerForbiddenMethod()

function setConsumerForbiddenMethod(address consumer, bytes4 methodSig, bool status)

Callable only by the policy owner. Sets or unsets the consumer address as forbidden from calling the method with methodSig.

Parameter Name	Type	Description
consumer	address	the consumer address
methodSig	bytes4	the method signature
status	bool	the status of the approval

Security Lifecycle

This policy runs during both the Firewall's Pre Execution and the Post Execution hooks.

Source Code

On our GitHub repository: ForbiddenMethodsPolicy.sol