Discussion - ChainlinkPriceFeed Contingency Plans

[steve0xp]

Challenge:
Price manipulation is a common attack vector within DeFi. The protocol would benefit from having a contingency plan for every scenario that we can think of for the ChainlinkPriceFeed failing.

Context:

• Originally a thought that was brought up through researching Liquity contingencies (see links).
• Recently spurred on by Niv bringing up uints vs ints from chainlink pricefeeds and if that could mess us up. Especially if it could be negative, what does that mean for us? For now we are implementing a

require(price >= 0 && updatedAt!= 0 && answeredInRound >= roundID, "Invalid chainlink price"); similar to Frax

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Useful links to other contingency plans include:

• Liquity - good detailed outline on scenarios and how they manage things: https://docs.google.com/spreadsheets/d/18fdtTUoqgmsK3Mb6LBO-6na0oK-Y9LWBqnPCJRp5Hsg/edit#gid=0
• MakerDAO contingency: https://developer.makerdao.com/feeds/

[steve0xp]

Notes from past discussion on restrictions to ChainlinkPriceFeed.sol:

Deemed not necessary since a DDOS attack would be very costly to an attacker, and really it's just going to delay our calls to the PriceFeed.sol - that said, open to Dave's thoughts on this for sure.