Forced buyouts can be performed by malicious buyers

[code423n4]

Lines of code

https://github.com/code-423n4/2022-07-fractional/blob/8f2697ae727c60c93ea47276f8fa128369abfe51/src/modules/Buyout.sol#L224-L238

Vulnerability details

Impact

In the end function of the Buyout contract, when the buyout fails, ERC1155 tokens are sent to the proposer. A malicious proposer can start a buyout using a contract that cannot receive ERC1155 tokens, and if the buyout fails, the end function fails because it cannot send ERC1155 tokens to the proposer. This prevents a new buyout from being started.

Proof of Concept

https://github.com/code-423n4/2022-07-fractional/blob/8f2697ae727c60c93ea47276f8fa128369abfe51/src/modules/Buyout.sol#L224-L238

Tools Used

None

Recommended Mitigation Steps

Consider saving the status of the proposer after a failed buyout and implementing functions to allow the proposer to withdraw the ERC1155 tokens and eth

[HardlyDifficult]

The 1155 receiver can prevent a failed buyout from ending, which prevents a new one from starting. Agree with severity.