Summary

This PR mitigates manipulation on the ETH-FEI pair before calling the deposit() function on the EthUniswapPCVDeposit. It adds slippage protection so new deposits can only occur when FEI is trading within a specified percent from the peg. The percent will be set to 1% in the DAO vote.

As part of the fix, we will update the bonding curve so it sends new ETH to the EthReserveStabilizer via the dripper rather than depositing to Uniswap. This removes the attack vector as a malicious actor can no longer deposit arbitrarily large amounts of ETH through the protocol.

This code was reviewed by OpenZeppelin as a part of the issue disclosed here: https://medium.com/fei-protocol/fei-bonding-curve-bug-post-mortem-98d2c6f271e9

Contract Changes

EthUniswapPCVDeposit - 0x5d6446880FCD004c851EA8920a628c70Ca101117

• updated so liquidity provision can only occur when the FEI-ETH spot price is within maxBasisPointsFromPegLP basis points from the oracle price.
• maxBasisPointsFromPegLP is settable by governance

EthPCVDepositAdapter - 0x4c52aD4Ad171a58B57592893c37Cc81655e11611 (pointing to new EthUniswapPCVDeposit) and 0xB72dDeD4Fa321e093E2083B596404A56ffC5b574 (pointing to EthPCVDripper)

• allows ETH transfers to and from contracts that do not conform to the IPCVDeposit interface

RatioPCVController - 0xfC1aD6eb84351597cD3b9B65179633697d65B920

• allows for a percentage of PCV held in a contract to be withdrawn rather than a raw amount
• used to fully transfer ETH out of the old EthUniswapPCVDeposit even though the ETH amount can change

DAO Proposal Steps

1. Update Bonding Curve Allocation

• target: 0xe1578B4a32Eaefcd563a9E6d0dc02a4213f673B7

• method: setAllocation

• pcvDeposits: [0xB72dDeD4Fa321e093E2083B596404A56ffC5b574]

• ratios: [10000]

2. Grant PCV controller new RatioPCVController

• target: 0x8d5ED43dCa8C2F7dFB20CF7b53CC7E593635d7b9

• method: grantPCVController

• pcvController: 0xfC1aD6eb84351597cD3b9B65179633697d65B920

3. Grant Minter new EthUniswapPCVDeposit

• target: 0x8d5ED43dCa8C2F7dFB20CF7b53CC7E593635d7b9

• method: grantMinter

• minter: 0x5d6446880FCD004c851EA8920a628c70Ca101117

4. Revoke Minter old EthUniswapPCVDeposit

• target: 0x8d5ED43dCa8C2F7dFB20CF7b53CC7E593635d7b9

• method: revokeMinter

• minter: 0x9b0C6299D08fe823f2C0598d97A1141507e4ad86

5. Unpause old EthUniswapPCVDeposit

• target: 0x9b0C6299D08fe823f2C0598d97A1141507e4ad86

• method: unpause

6. Transfer liquidity to new EthUniswapPCVDeposit

• target: 0xfC1aD6eb84351597cD3b9B65179633697d65B920

• method: withdrawRatio

• from: 0x9b0C6299D08fe823f2C0598d97A1141507e4ad86

• to: 0x4c52aD4Ad171a58B57592893c37Cc81655e11611

• amount: 10000

7. Set maxBasisPointsFromPegLP on new EthUniswapPCVDeposit

• target: 0x5d6446880FCD004c851EA8920a628c70Ca101117

• method: setMaxBasisPointsFromPegLP

• amount: 100