BugHunter101 - using latestRoundData() and turn int to uint but does not check if answer > 0

[sherlock-admin]

BugHunter101

medium

using latestRoundData() and turn int to uint but does not check if answer > 0

Summary

Using latestRoundData() and turn int to uint but does not check if answer > 0, it will cause the result is wrong

Vulnerability Detail

This could lead to stale prices according to the Chainlink documentation:
https://docs.chain.link/data-feeds/price-feeds/historical-data
Related report:
code-423n4/2021-05-fairside-findings#70

And all the contract have the same problem
such Vault.vy:
https://github.com/sherlock-audit/2023-06-unstoppable/blob/main/unstoppable-dex-audit/contracts/margin-dex/Vault.vy#L582

TrailingStopDex.vy:
https://github.com/sherlock-audit/2023-06-unstoppable/blob/main/unstoppable-dex-audit/contracts/spot-dex/TrailingStopDex.vy#L238

https://github.com/sherlock-audit/2023-06-unstoppable/blob/main/unstoppable-dex-audit/contracts/spot-dex/TrailingStopDex.vy#L245C1-L245C1

Impact

it will cause the result is wrong

This could lead to stale prices according to the Chainlink documentation:
https://docs.chain.link/data-feeds/price-feeds/historical-data
Related report:
code-423n4/2021-05-fairside-findings#70

Code Snippet

https://github.com/sherlock-audit/2023-06-unstoppable/blob/main/unstoppable-dex-audit/contracts/spot-dex/TrailingStopDex.vy#L238

https://github.com/sherlock-audit/2023-06-unstoppable/blob/main/unstoppable-dex-audit/contracts/spot-dex/TrailingStopDex.vy#L245C1-L245C1

https://github.com/sherlock-audit/2023-06-unstoppable/blob/main/unstoppable-dex-audit/contracts/margin-dex/Vault.vy#L582

Tool used

Manual Review

Recommendation

Please check latestRoundData() return value such like :
sherlock-audit/2023-02-blueberry-judging#94

Duplicate of #200