Arbitrary CPI

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Objectives

By the end of this lesson, you'll be able to:

Explain the security risks associated with invoking a CPI to an unknown program
Showcase how Anchor’s CPI module prevents this from happening when making a CPI from one Anchor program to another
Safely and securely make a CPI from an Anchor program to an arbitrary non-anchor program

Progress

How to approach the Program Security unit

Signer authorization

Lab: Check signers are correct before processing transactions

Owner checks

Lab: Check owners are correct before processing transactions

Account data matching

Lab: Check account data is correct before processing transactions

Reinitialization attacks

Lab: Ensure accounts can only be initialised once to prevent overriding existing data

Duplicate mutable accounts

Lab: Ensure accounts are distinct

Type cosplay

Lab: Implement checks for correct account types

Arbitrary CPIs

Lab: Ensure CPIs are only called by the correct program

Bump seed canonicalization

Lab: Ensure bump seeds are always canonical

Closing accounts and revival attacks

Lab: Ensure accounts that are closed can't be reused

PDA sharing

Lab: Ensure PDA design avoids shared accounts