ether_sky - Incorrect totalAssets function.

[sherlock-admin3]

ether_sky

medium

Incorrect totalAssets function.

Summary

Vulnerability Detail

In the totalAssets function, the backupEarnings (unassignedEarnings in maturity pool) from the past maturity pools is not considered.

function totalAssets() public view override returns (uint256) {
  unchecked {
    uint256 backupEarnings = 0;

    uint256 latestMaturity = block.timestamp - (block.timestamp % FixedLib.INTERVAL);
    uint256 maxMaturity = latestMaturity + maxFuturePools * FixedLib.INTERVAL;

    for (uint256 maturity = latestMaturity; maturity <= maxMaturity; maturity += FixedLib.INTERVAL) {
      FixedLib.Pool storage pool = fixedPools[maturity];
      uint256 lastAccrual = pool.lastAccrual;

      if (maturity > lastAccrual) {
        backupEarnings += block.timestamp < maturity
          ? pool.unassignedEarnings.mulDivDown(block.timestamp - lastAccrual, maturity - lastAccrual)
          : pool.unassignedEarnings;
      }
    }

    return
      floatingAssets +
      backupEarnings +
      accumulatedEarnings() +
      (totalFloatingBorrowAssets() - floatingDebt).mulWadDown(1e18 - treasuryFeeRate);
  }
}

Obviously, there will be some past maturity pools which has unpaid debt.

Impact

Code Snippet

https://github.com/sherlock-audit/2024-04-interest-rate-model/blob/8f6ef1b0868d3ea3a98a5ab7e8b3a164857681d7/protocol/contracts/Market.sol#L925-L949

Tool used

Manual Review

Recommendation

[santipu03]

This issue wasn't marked a duplicate of #158 because it just identifies the root cause, without describing an attack path and a valid impact.