Tigris Trade contest - yixxas's results

Lines of code

https://github.com/code-423n4/2022-12-tigris/blob/588c84b7bb354d20cbca6034544c4faa46e6a80e/contracts/utils/TradingLibrary.sol#L113

Vulnerability details

Impact

latestAnswer is depreciated and no longer supported by chainlink. It can return stale data or return a value of 0 when an error occurs. This will give us an incorrect pricing or cause verifyPrice() to revert, preventing the protocol from functioning.

Proof of Concept

According to chainlink docs, latestAnswer is depreciated and no longer supported. We should use latestRoundData instead to receive our price feed.

Tools Used

Manual Review

Recommended Mitigation Steps

Use the latestRoundData api instead. It is also recommended to check the for stale data as well as incomplete rounds. For example,

(uint80 roundID, int256 price, , uint256 timeStamp, uint80 answeredInRound) = oracle.latestRoundData();
require(answeredInRound >= roundID, "Incomplete round");
require(timeStamp != 0, "Feed is stale");