uniswap-v4-hook-access-control

Uniswap v4 Hook Callback Access-Control Audit

Audit Uniswap v4 (and v4-style singleton/hook) integrations for the missing-caller-check class: a custom hook callback (beforeSwap/afterSwap/beforeAddLiquidity/donate/etc.) that does not verify msg.sender == address(poolManager) and does not validate the supplied PoolKey, letting an attacker call the hook directly with forged accounting parameters to mint unbacked tokens or drain the pool.

Source: corpus A §I.6 — Dedaub / Cyfrin / Cork Protocol, May 2025 ($11M pool drain). Impact class: funds theft / pool drain (intrinsic). Governing method: Phase-3a hypothesis lane of systematic-attacking; leads only into the full verification spine.

Method

1. Enumerate every hook callback the target exposes (slither, and read the Hooks permission bitmap on the deployed hook via cast).
2. For each callback, confirm BOTH guards: (a) a strict require(msg.sender == address(poolManager)) (or the framework's equivalent authority check), and (b) validation that the PoolKey / currency / fee parameters correspond to a pool the hook is actually authorized for — not attacker-chosen.
3. Trace the hook's internal accounting: identify any state (redemption balances, reserve counters, minted supply) mutated inside a callback from parameters the caller controls.
4. PoC on anvil --fork: call the unguarded callback directly (bypassing the PoolManager) with inflated deposit/redemption values; assert unbacked mint or drain. Link-level negative control = the same call through the real PoolManager reverts or nets to zero.
5. Add a forge/halmos invariant: "hook accounting only advances via PoolManager-originated calls with a registered PoolKey."

Acceptance

• Every hook callback is classified for the caller check AND PoolKey validation.
• The direct-call PoC drains/mints against a real fork; the PoolManager-routed negative control does not.
• Finding names the exact unguarded callback and the accounting field it corrupts; deduped against the Cork / v4-hook advisory corpus before submission.