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RewardDistributor:decrementRewards no underflow check needed #143

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code423n4 opened this issue Nov 29, 2021 · 1 comment
Open

RewardDistributor:decrementRewards no underflow check needed #143

code423n4 opened this issue Nov 29, 2021 · 1 comment
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bug Something isn't working G (Gas Optimization) sponsor confirmed Sponsor agrees this is a problem and intends to fix it (OK to use w/ "disagree with severity")

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@code423n4
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GiveMeTestEther

Vulnerability details

Impact

Require statement conditions checks that no underflow can happen, therefore we don't need to use safe subtraction (underflow check).

  • L275: require(amount <= _globals.declaredBalance, "Can't decrement more than total reward balance");
  • L278: _globals.declaredBalance = _globals.declaredBalance.sub(amount);
    => Rewrite L278 as: _globals.declaredBalance = _globals.declaredBalance - amount;

Proof of Concept

https://github.com/code-423n4/2021-11-malt/blob/c3a204a2c0f7c653c6c2dda9f4563fd1dc1cecf3/src/contracts/RewardSystem/RewardDistributor.sol#L271

Tools Used

Recommended Mitigation Steps

  • rewrite L278 as: _globals.declaredBalance = _globals.declaredBalance - amount;
@code423n4 code423n4 added bug Something isn't working G (Gas Optimization) labels Nov 29, 2021
code423n4 added a commit that referenced this issue Nov 29, 2021
@code423n4
GiveMeTestEther issue #143
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@0xScotch 0xScotch added the sponsor confirmed Sponsor agrees this is a problem and intends to fix it (OK to use w/ "disagree with severity") label Dec 9, 2021
@GalloDaSballo
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Agree that no longer need underflow checks

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bug Something isn't working G (Gas Optimization) sponsor confirmed Sponsor agrees this is a problem and intends to fix it (OK to use w/ "disagree with severity")
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@GalloDaSballo @0xScotch @code423n4