Submission Details
Severity:
The slot mismatch (tload(1), tstore(0, 1)) in modifier nonReentrant, InheritanceManager.sol
Summary
Slot mismatch due to incorrect use of (tload(1), tstore(0, 1)).
Vulnerability Details
The original code has a slot mismatch (tload(1), tstore(0, 1)) which is incorrect, and use different slot.
This means the check doesn't properly detect reentrancy, same slot must be used for checking and storing.
modifier nonReentrant() {
assembly {
if tload(1) { revert(0, 0) } // @ audit incorrect slot (1)
tstore(0, 1)
}
_;
assembly {
tstore(0, 0)
}
}
The check (tload(1)) is always false initially (since slot 1 is never set).
The lock (tstore(0,1)) is stored in the wrong place (slot 0), so it doesn’t actually prevent reentrancy.
Impact
Doesn't prevent reentrancy
Tools Used
Manual review
Recommendations
Fixed code:
modifier nonReentrant() {
assembly {
if tload(0) { revert(0, 0) }
tstore(0, 1)
}
_;
assembly {
tstore(0, 0)
}
}
Updates
Lead Judging Commences
0xtimefliez 10 months ago
Submission Judgement Published Assigned finding tags:
Wrong value in nonReentrant modifier
Rewards breakdown
nSLOC
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