Submission Details
Severity:
Memory Store to reserved slot
Summary
Using a reserved memory slot to store data.
Vulnerability Details
According to the following solidity documentation, the memory slot 0x40 is reserved for the currently allocated memory size and should not be used for other purposes.
However in MathMasters this slot is used in the following fashion. Which overwrites the current value, and could potentially lead to memory issues.
Impact
As the function reverts immediatly after this action the impact will only be that we'll not get the correct error message.
Tools Used
Manual review.
Recommendations
Make the following changes
- mstore(0x40, 0xbac65e5b) // `MathMasters__MulWadFailed()`.
- revert(0x1c, 0x04)
+ let ptr := mload(0x40) //Get free memory pointer
+ mstore(ptr, 0xa56044f7) //store error selector `MathMasters__MulWadFailed.selector`
+ revert(ptr, 0x04)
Updates
Lead Judging Commences
inallhonesty over 1 year ago
Submission Judgement Published Assigned finding tags:
Wrong error selector
Wrong error storage
Rewards breakdown
nSLOC
46This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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