Stable2::decodeWellData() - Incorrect check leads to return of wrong decimal precision of decimal1 inside decimals array

[howlbot-integration]

Lines of code

https://github.com/code-423n4/2024-07-basin/blob/main/src/functions/Stable2.sol#L317-L319

Vulnerability details

Impact

On decoding the encoded well data in Stable2::decodeWellData() decimals array will be returned containing values of decimal0 and decimal1 but within this function when abi.decode() returns any of these value as 0 then 18 decimals should be assumed and set before returning array but in this case due to incorrect check decimals array is being returned with decimal1 = 0, due to this when this array used in other functions for scaling reserves by precision then it will scale reserves[1] with wrong decimal precision.

Proof of Concept

// if well data returns 0, assume 18 decimals.
if (decimal0 == 0) {
decimal0 = 18;
}
if (decimal0 == 0) { // @ audit - wrong check
decimal1 = 18;
}
Here in Stable2::decodeWellData() if decimal0 != 0 and decimal1 == 0 then here decimal array will contain decimal1 = 0 but in actual it should assume decimal1 as 18 decimals and set decimal1 = 18 before returning decimals array.

Tools Used

Manual review

Recommended Mitigation Steps

// if well data returns 0, assume 18 decimals.
if (decimal0 == 0) {
decimal0 = 18;
}
if (decimal1 == 0) { // @ correct
decimal1 = 18;
}

Assessed type

Decimal

[c4-judge]

alex-ppg changed the severity to 3 (High Risk)

[c4-judge]

alex-ppg marked the issue as satisfactory