> For the complete documentation index, see [llms.txt](https://docs.ironblocks.com/firewall/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ironblocks.com/firewall/policies/method-block.md).

# 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.<br>
2. The policy checks the contract's address and method they want to execute.<br>
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*](#source-code)*)*.<br>
2. Call the [setConsumerForbiddenMethod()](#setconsumerforbiddenmethod) method to configure addresses and methods that you want to prevent access to.<br>
3. Add the newly deployed policy to the [Firewall](/firewall/glossary.md#firewall) *(you can do this* [*Globally*](/firewall/configuration/firewall-configuration.md#global-policies) *or* [*Per-Method*](/firewall/configuration/firewall-configuration.md#per-method-policies)*, see* [*Policy Administration*](/firewall/configuration/policy-administration.md)*)*.<br>
4. That's it!

## Properties

<table><thead><tr><th width="302">Name</th><th width="256.3333333333333">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>consumerMethodStatus</code></td><td><p><code>mapping</code></p><p><code>(address =></code></p><p>   <code>mapping</code></p><p>   <code>(bytes4 => bool)</code></p><p><code>)</code></p></td><td>the list of consumers and the methods they're blocklisted from calling<br><br>for example:<br><code>[consumerAddress][methodSig] = true</code></td></tr><tr><td><code>hasEnteredForbiddenMethod</code></td><td><p><code>mapping</code></p><p><code>(bytes32 => bool)</code></p></td><td>used internally to track which methods the consumer has called throughout the transaction execution</td></tr></tbody></table>

## 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`.<br>

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

<br>

## **Security Lifecycle**

This policy runs during both the Firewall's [Pre Execution](/firewall/glossary.md#pre-execution) and the [Post Execution](/firewall/glossary.md#post-execution) hooks.

## Source Code

On our GitHub repository: [ForbiddenMethodsPolicy.sol](https://github.com/ironblocks/onchain-firewall/blob/main/packages/onchain-firewall/contracts/policies/ForbiddenMethodsPolicy.sol)