@vitalik.eth
The contract here is a sublinear staking contract: if you are in the whitelist (specified as an ERC1155 collection), then you can stake N coins, and get a return of N ** 0.75 coins per slot, for as long as the contract has coins to pay for it. There is a fundedUntil mechanism that ensures that if the contract runs out of money, every staker gets rewarded for every slot up to the fundedUntil timestamp, and the mechanism doesn't turn into a fractional reserve.
https://github.com/ethereum/research/blob/master/sublinear_staking/code.vy
Bounty of total 2 ETH for identifying any bugs / vulnerabilities in the contract and proposing specific fixes, if multiple issues are found the bounty will be split based on severity.
Amount: 2 ETH
@bountybot
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@farcasteradmin.eth
i wonder if line 88 should go before line 83 🤔
still exploring and trying to make sense of liabilities, just a hunch
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@androolloyd
something worth noting the isEligible check only happens on staking, so a user can acquire inline a token to flag true without having to actually hold the token for the duration of the staking.
You'd likely want to do something where the eligible tokenID is locked into the staking contract for the duration.
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@dcposch.eth
not a vulnerability, but you probably want a configurable multiplier on getReturnPerSlot, otherwise results depend on token decimals.
for example, stake 1 USDC = 1e6 ^ (3/4) = $0.03 reward per slot
stake 1 DAI = 1e18 ^ (3/4) = $0.00003 reward per slot
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@francescop
Not a critical vulnerability but considered a minor issue that can lead to inefficiencies and potential edge case behaviors:
- The `stake` function does not verify that the `amount` to stake is greater than zero. Allowing users to stake zero tokens can lead to unnecessary state changes and potential edge case behaviors.
- Recommendation: Add a require statement in the `stake` function to ensure that the `amount` is greater than zero before proceeding with the staking logic.
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@dennison
This is pretty incredible to see!
Have you seen our Governance Staking Contracts? To use staking to drive participation in governance?
https://github.com/withtally/govstaking
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@farcasteradmin.eth
here's one issue: technically if someone stakes enough, they can bring `_fundedUntil` down so much that no one will get any rewards, but the entity that stakes enough token will get all the rewards
moreover, the `isEligible` check just checks the balance of the token, which means if the token supports flash loans, one can flash loan large amount of token to stake, `stake`, bring down `_fundedUntil` to (maybe?) the same block, `unstake`, sell the rewarded token, cover cost of the flash loan and get profit
can probably be mitigated by having a time-lock mechanism for staking (this should eliminate the threat of flash loans); maybe also limiting amount of rewards per address (but then one can spawn many addresses); or maybe limit the rewards by the proportion of total supply of the token staked? not sure
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@noxxus
yo this staking contract seems lit! 🔥 love that there's a fundedUntil safety net. anyone up for the bounty hunt? 2 ETH is calling! 💰
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@zkfriendly.eth
a1 stakes 1 eth at time 0.
fast forward 1000 blocks.
a2 stakes 0.1 eth.
fundedUntil breaks
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@pabloz
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@leoyanzon
I don't get this.. I mean, what is the purpose of this sublinear staking contract? A social experiment or smthing?
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@serverconnectd
ive never relly looked into to vyper but in the _unstake function shouldnt there be a require like check if the total amount to be sent back to the user is available in the contract?
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@if
looks good overall, but I found a few potential issues:
1.
```vy
def _fundedUntil() -> uint256:
return (
self.liabilitiesLastUpdated
+ (staticcall STAKED_TOKEN_ADDRESS.balanceOf(self) - self.liabilities)
// max(self.totalPayoutPerSlot, 1)
```
If the contract’s balance of the staked token `balanceOf(self)` is less than the total liabilities `self.liabilities`, the subtraction will underflow, causing a revert on `_unstake` method. It might be okay, but it would be better to handle it properly.
2.
```vy
def stake(amount: uint256):
```
A user can stake an amount of 0, which could cause potential issues in other parts. I think adding an assertion `assert amount > 0` if staking a zero amount is not intended.
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