Saeedalipoor01988 - Calculating Protocol Fee is susceptible to precision loss due to division before multiplication

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Saeedalipoor01988

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Calculating Protocol Fee is susceptible to precision loss due to division before multiplication

Summary

Protocol Fee may be lost (0) due to division before multiplication precision issues.

Vulnerability Detail

The StreamingFeeModule.sol.accrueFee function calculates the Protocol Fee by first dividing ( fee * totalSupply ) by ScaleFactor : (10e18) - fee to earn _feeQuantity and then multiplying _feeQuantity by protocolFee. If fee * totalSupply is small enough and ScaleFactor (10e18) - fee is large enough, the division may result in a value of 0, resulting in the Protocol Fee becoming 0.

Impact

protocol Fee Recipient may not receive fee due to precision loss.

Code Snippet

https://github.com/sherlock-audit/2023-05-Index/blob/3190057afd3085143a31746d65045a0d1bacc78c/index-protocol/contracts/protocol/modules/v1/StreamingFeeModule.sol#L94
https://github.com/sherlock-audit/2023-05-Index/blob/3190057afd3085143a31746d65045a0d1bacc78c/index-protocol/contracts/protocol/modules/v1/StreamingFeeModule.sol#L224
https://github.com/sherlock-audit/2023-05-Index/blob/3190057afd3085143a31746d65045a0d1bacc78c/index-protocol/contracts/protocol/modules/v1/StreamingFeeModule.sol#L256

Tool used

Manual Review

Recommendation

recommend avoid division before multiplication and always perform division operation at last.

Duplicate of #299