Inconsistencies when checking if the auction is active

[code423n4]

Handle

pauliax

Vulnerability details

Impact

When auction.endingTime == now, function purchaseArbitrageTokens thinks that auction is still active, while isAuctionFinished and earlyExitReturn think that it has ended:
purchaseArbitrageTokens:

  require(auction.endingTime >= now, "Auction is already over");

isAuctionFinished:

  return auction.endingTime > 0 && (now >= auction.endingTime || ...);

earlyExitReturn:

  if(active || block.timestamp < auctionEndTime) {
    return 0;
  }

Recommended Mitigation Steps

Consider unifying it across the functions.

[GalloDaSballo]

The warden has identified an inconsistency from what seems to be the same logical state in the finite state machine of the contracts.
I agree with the finding, and the sponsor confirms as well