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buyOption() allows the buyer to pay more than they need #123

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code423n4 opened this issue May 13, 2022 · 1 comment
Closed

buyOption() allows the buyer to pay more than they need #123

code423n4 opened this issue May 13, 2022 · 1 comment
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2 (Med Risk) Assets not at direct risk, but function/availability of the protocol could be impacted or leak value bug Something isn't working duplicate This issue or pull request already exists sponsor confirmed Sponsor agrees this is a problem and intends to fix it (OK to use w/ "disagree with severity")

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Lines of code

https://github.com/code-423n4/2022-05-cally/blob/main/contracts/src/Cally.sol#L223-L224
https://github.com/code-423n4/2022-05-cally/blob/main/contracts/src/Cally.sol#L90

Vulnerability details

Impact

The premium you have to pay to buy an option is fixed at the creation of the vault. There's an array with all the possible values. But, when buying an option the function allows the user to pay more than they actually need to. There's no benefit in paying more. It would just be a mistake by the buyer to the benefit of the vault owner.

Proof of Concept

Here the buyOption() function verifies the payment: https://github.com/code-423n4/2022-05-cally/blob/main/contracts/src/Cally.sol#L223-L224

It uses >= instead of ==.

Tools Used

none

Recommended Mitigation Steps

Use == to only allow the correct amount to be paid
@code423n4 code423n4 added 2 (Med Risk) Assets not at direct risk, but function/availability of the protocol could be impacted or leak value bug Something isn't working labels May 13, 2022
code423n4 added a commit that referenced this issue May 13, 2022
@code423n4
Ruhum issue #123
a6e50b6
@outdoteth outdoteth added the sponsor confirmed Sponsor agrees this is a problem and intends to fix it (OK to use w/ "disagree with severity") label May 15, 2022
@outdoteth
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reference issue: #84

@outdoteth outdoteth added the duplicate This issue or pull request already exists label May 15, 2022
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2 (Med Risk) Assets not at direct risk, but function/availability of the protocol could be impacted or leak value bug Something isn't working duplicate This issue or pull request already exists sponsor confirmed Sponsor agrees this is a problem and intends to fix it (OK to use w/ "disagree with severity")
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@outdoteth @code423n4