fee_protocol cannot be set, protocol is not able to earn fees.

[c4-bot-8]

Lines of code

https://github.com/code-423n4/2024-08-superposition/blob/4528c9d2dbe1550d2660dac903a8246076044905/pkg/seawater/src/pool.rs#L31

Vulnerability details

Impact

fee_protocol cannot be set, protocol is not able to earn fees.

Proof of Concept

StoragePool::fee_protocol needs to be set non-zero for protocol to earn trading fees. However, there is no method to set fee_protocol, neither is fee_protocol initialized during pool creation. As a result, fee_protocol will always be zero. And the protocol can never earn or collect trading fees.

In swap(), wee see only when fee_protocol is greater than zero, will protocol fee be accumulated.

//pkg/seawater/src/pool.rs
    pub fn swap(
        &mut self,
        zero_for_one: bool,
        amount: I256,
        mut price_limit: U256,
    ) -> Result<(I256, I256, i32), Revert> {
...
            if fee_protocol > 0 {
                let delta = step_fee_amount.wrapping_div(U256::from(fee_protocol));
                step_fee_amount -= delta;
                state.protocol_fee += u128::try_from(delta).or(Err(Error::FeeTooHigh))?;
            }
...

(https://github.com/code-423n4/2024-08-superposition/blob/4528c9d2dbe1550d2660dac903a8246076044905/pkg/seawater/src/pool.rs#L449-L452)

But here is no method to initialize or modify fee_protocol of a pool. See init() where only the overall trading fees(pool::fee) are initialized, but fee_protocol cannot be set.

    pub fn init(
        &mut self,
        price: U256,
        fee: u32,
        tick_spacing: u8,
        max_liquidity_per_tick: u128,
    ) -> Result<(), Revert> {
        assert_eq_or!(
            self.sqrt_price.get(),
            U256::ZERO,
            Error::PoolAlreadyInitialised
        );

        self.sqrt_price.set(price);
        self.cur_tick
            .set(I32::lib(&tick_math::get_tick_at_sqrt_ratio(price)?));

        self.fee.set(U32::lib(&fee));
        self.tick_spacing.set(U8::lib(&tick_spacing));
        self.max_liquidity_per_tick
            .set(U128::lib(&max_liquidity_per_tick));

        Ok(())
    }

(https://github.com/code-423n4/2024-08-superposition/blob/4528c9d2dbe1550d2660dac903a8246076044905/pkg/seawater/src/pool.rs#L49)

Tools Used

Manual

Recommended Mitigation Steps

Add a method to allow the admin to set a pool’s fee_protocol when needed.

Assessed type

Other

[c4-judge]

alex-ppg marked the issue as satisfactory