Stake pools

Description

The stake-pool bond system turns SOL staked into a stake pool into a bond. The deposited funds are segregated into principal and yield. The exact amount each PT and YT will redeem for is determined at the first redemption of a bond. The PTs and YTs can be used to redeem for LSTs, which in turn can be redeemed for SOL.

Invariants

• The amount of tokens minted should be correctly related to the amount deposited.

• The amount of PTs in circulation should not exceed the value in SOL deposited.

Test coverage

Cases covered

• Initializing a bond from a stake pool

• Depositing SOL into a bond generated from a stake pool

• Depositing LST into a bond generated from a stake pool

• Depositing mSOL into an mSOL bond

Cases not covered

• Redeeming PTs from a stake-pool bond

• Redeeming YTs from a stake-pool bond

• Redeeming PTs from an mSOL bond

• Redeeming YTs from an mSOL bond

• Changing in the value of LSTs before the first redemption and after bond maturity

• Trying to redeem before bond maturity

• Depositing multiple times from different accounts

• Depositing after bond maturity

Attack surface

• Depositing a custom LST coin type. A transfer will be attempted to an account that is enforced to be the correct coin type, which will fail in the case the incorrect type of coin account is given.

• Passing in a fake fee wallet to capture the fee. The fee-wallet authority is checked, which in turn is part of the global settings, which is a PDA with a specific seed.

• Using the PT/YT token mint for another, more valuable bond, causing the wrong PTs/YTs to be minted. The token mint is checked against the bond's data.

• Redeeming early. There is a check for the current time on Solana.