Inadequate checks to confirm the correct status of the sequecncerUptimeFeed in ChainlinkUtil.getPrice() contract will cause getPrice() to not revert even when the sequecncerUptimeFeed is not updated or is called in an invalid round.
When getting the price for a market through ChainlinkUtil.getPrice
, first it is asserted that the sequencer is running but these checks are not implemented correctly. The chainlink docs say that sequencerUptimeFeed can return a 0 value for startedAt if it is called during an "invalid round":
Please note that an "invalid round" is described to mean there was a problem updating the sequencer's status, possibly due to network issues or problems with data from oracles, and is shown by a startedAt time of 0 and answer is 0. Further explanation can be seen as given by an official chainlink engineer as seen here in the chainlink public discord
This makes the implemented check below in the ChainlinkUtil.getPrice() to be useless if it is called in an invalid round:
as startedAt
will be 0, block.timestamp - startedAt
will result in a value greater than GRACE_PERIOD_TIME (which is hardcoded to be 3600) and the code won't revert.
Imagine a case where a round starts, at the beginning startedAt is recorded to be 0, and answer, the initial status is set to be 0. Note that docs say that if answer = 0, sequencer is up, if equals to 1, sequencer is down. But in this case here, answer and startedAt can be 0 initially, till after all data is gotten from oracles and update is confirmed then the values are reset to the correct values that show the correct status of the sequencer.
Based on the explenations aboge, the startedAt
value should be used in the check for if a sequencer is down/up or correctly updated.
Add a check that reverts if startedAt is returned as 0:
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