Tezoro Aggregator Contracts

Solidity smart contracts for the Tezoro Aggregator yield vault.

Overview

Tezoro Aggregator is an ERC-4626 compliant vault that allocates user deposits across multiple DeFi lending protocols (Aave V3, Compound V3, Spark, Morpho Blue, Fluid, and any ERC-4626 vault). A keeper rebalances allocations; a performance fee is charged on yield above a high water mark. Withdrawals are always open regardless of pause state.

Audit Scope

This repository contains two versions of the contracts:

• V1_1 -- currently deployed on Ethereum mainnet with live TVL (see Deployments).
• V1_2 -- contains fixes from an internal pre-audit review. These will replace V1_1 after audit, but redeployment requires TVL migration, so V1_1 remains in production for now.

Both versions should be audited. V1_1 is what users interact with today; V1_2 is what will be deployed next. The fixes in V1_2 address issues we identified internally -- we want the auditor to verify both that V1_1's known issues are correctly catalogued and that V1_2's fixes are sound.

Known Issues in V1_1 (fixed in V1_2)

#	Description
1	Single-pass rebalance does not converge in one call. _rebalance() processes strategies in array order. If an earlier strategy needs funds from a later one, the deposit fails because the withdrawal hasn't happened yet. Requires a second rebalance() call.
2	Pausing a strategy drops share price. totalAssets() excludes paused strategies' trackedBalance, even when funds are safe and the pause is precautionary. Creates an arbitrage window: buy during pause (cheap), sell after unpause (expensive).
3	Stale comment. _availableLiquidity comment says "reduced by 1" but code subtracts 2. Behavior is correct.
4	Simple strategies lack ReentrancyGuard. AaveV3Strategy, CompoundV3Strategy, FluidStrategy rely on vault's nonReentrant + onlyVault. Safe today, but defense-in-depth recommends adding it.
5	executeClaim return data discarded. Some claim targets return useful info (amounts claimed). Not exploitable.
6	routerData in swap() is opaque. Keeper trust assumption not documented. Balance-before/after check mitigates, but worth noting.
7	setKeeper in multi-strategies rejects address(0). Unlike the vault (which allows address(0) for admin-only mode), strategies cannot disable the keeper role.

V1_2 contracts (fixes applied)

Contract	Changes from V1_1
TezoroV1_2.sol	#1: Two-pass rebalance (withdrawals first, then deposits) for single-call convergence. #2: Paused strategies stay in totalAssets() -- no share price drop on pause. #3: Comment fix.
RewardsModuleV1_2.sol	#5: executeClaim emits return data. #6: Trust assumption documented in NatSpec.
AaveV3StrategyV1_2.sol	#4: Added ReentrancyGuard (defense-in-depth).
CompoundV3StrategyV1_2.sol	#4: Added ReentrancyGuard (defense-in-depth).
FluidStrategyV1_2.sol	#4: Added ReentrancyGuard (defense-in-depth).
ERC4626MultiStrategyV1_2.sol	#7: setKeeper(address(0)) allowed (admin-only mode).
MorphoBlueMultiStrategyV1_2.sol	#7: setKeeper(address(0)) allowed (admin-only mode).

V1_1 contracts (currently deployed)

V1_1 contracts are deployed on Ethereum mainnet with live TVL. They remain in the repo as the production reference. The known issues listed above are accepted risks until V1_2 is deployed.

Repository Structure

src/
    TezoroV1_2.sol                     Core ERC-4626 vault (V1_2 -- audit target)
    RewardsModuleV1_2.sol              Claims executor, swap engine (V1_2 -- audit target)
    TezoroV1_1.sol                     Core ERC-4626 vault (V1_1 -- currently deployed)
    RewardsModule.sol                  Claims executor, swap engine (V1_1 -- currently deployed)
    interfaces/
        IStrategy.sol                  Universal strategy adapter interface
        ITezoroV1_1.sol                Vault interface for RewardsModule
        IAaveV3Pool.sol                Aave V3 lending pool interface
        ICompoundV3Comet.sol           Compound V3 Comet interface
        ICometRewards.sol              Compound V3 rewards interface
        IMorpho.sol                    Morpho Blue singleton interface
        IRewardsController.sol         Aave/Spark rewards controller interface
    strategies/
        AaveV3StrategyV1_2.sol         Aave V3 adapter (V1_2 -- audit target)
        CompoundV3StrategyV1_2.sol     Compound V3 adapter (V1_2 -- audit target)
        FluidStrategyV1_2.sol          Fluid fToken adapter (V1_2 -- audit target)
        ERC4626MultiStrategyV1_2.sol   Multi-vault adapter (V1_2 -- audit target)
        MorphoBlueMultiStrategyV1_2.sol Multi-market Morpho adapter (V1_2 -- audit target)
        AaveV3Strategy.sol             Aave V3 adapter (V1_1 -- currently deployed)
        CompoundV3Strategy.sol         Compound V3 adapter (V1_1 -- currently deployed)
        FluidStrategy.sol              Fluid fToken adapter (V1_1 -- currently deployed)
        ERC4626MultiStrategy.sol       Multi-vault adapter (V1_1 -- currently deployed)
        MorphoBlueMultiStrategy.sol    Multi-market Morpho adapter (V1_1 -- currently deployed)
test/
    unit/                              Unit tests (mock-based, no RPC required)
        TezoroV1_2.t.sol               V1_2-specific regression tests (M-1, M-2)
    fuzz/                              Fuzz and invariant tests (mainnet fork)
    fork/                              Integration tests against live protocols (mainnet fork)
        shared/                        Shared test infrastructure

Architecture

                    +-------------------+
User deposits -->   |   TezoroV1_2.sol    |   <-- ERC-4626 vault
                    | (idle buffer)     |
                    +--------+----------+
                             |
              keeper calls allocate() with bps weights
                             |
         +-------------------+-------------------+
         |         |         |         |         |
      AaveV3  Compound   Fluid    Morpho    ERC4626Multi
      Strategy  Strategy Strategy MultiStrat MultiStrat
         |         |         |         |         |
      Aave V3  Comet V3   fTokens  Morpho    Morpho Vaults,
      (+ Spark)                    Blue      MetaMorpho, etc.
                             |
              +-----------------------------+
              |      RewardsModule.sol       |
              | claim -> swap -> compound    |
              +-----------------------------+

Deposit / Withdraw Flow

1. Deposit: User calls deposit(assets, receiver). Vault mints shares, holds assets in idle buffer. Keeper later calls allocate() to deploy idle funds to strategies.
2. Withdraw: User calls withdraw(assets, receiver, owner) or redeem(shares, receiver, owner). Vault first uses idle buffer; if insufficient, executes a waterfall withdrawal from strategies until the amount is covered. Try-catch on each strategy prevents a broken strategy from blocking withdrawals.

Strategy Interface

All strategies implement IStrategy:

function deposit(uint256 amount) external;
function withdraw(uint256 amount) external returns (uint256 withdrawn);
function emergencyWithdraw() external returns (uint256 withdrawn);
function balanceOf() external view returns (uint256);
function availableLiquidity() external view returns (uint256);

Multi-strategies (ERC4626MultiStrategy, MorphoBlueMultiStrategy) add sub-position management: the keeper allocates/deallocates across sub-vaults or sub-markets within the strategy.

Key Mechanisms

Virtual Shares Offset (Inflation Attack Defense)

_decimalsOffset() returns the underlying asset's decimals (read once at construction, stored as immutable). This creates a large virtual share supply that makes first-depositor inflation attacks economically infeasible. The offset scales automatically with the asset (6 for USDC, 18 for DAI, 8 for WBTC).

Performance Fee (HWM)

• Fee applies only to yield above the all-time high water mark share price.
• Fee is accrued before every withdrawal (dodge-proof): _accruePerformanceFee() mints fee shares before ERC-4626 conversion in withdraw() and redeem().
• Fee shares are minted to feeRecipient.
• Fee percentage changes are timelocked when increasing.
• Default: 15%. Range: 0--30%.

Preview Functions (ERC-4626 Compliance)

All four preview functions (previewDeposit, previewMint, previewWithdraw, previewRedeem) account for pending performance fee shares. This ensures preview values match actual execution outcomes, which is required by the ERC-4626 specification:

• previewDeposit(x) returns shares user will receive after fee accrual.
• previewWithdraw(x) returns shares that will be burned (>= actual, per spec).
• previewRedeem(x) returns assets that will be received (<= actual, per spec).

maxWithdraw / maxRedeem

Account for pending fee dilution and available liquidity across strategies. This ensures withdraw(maxWithdraw(x)) and redeem(maxRedeem(x)) never revert. Each strategy's available liquidity is reduced by 2 wei to absorb rounding in underlying protocol withdrawals.

Deposit Cap

Configurable depositCap (0 = unlimited). maxDeposit() and maxMint() use previewDeposit() (fee-aware) to accurately report remaining capacity.

Idle Buffer

Configurable percentage (max 20%) of total assets held as idle in the vault for instant small withdrawals without strategy interaction. Maintained by keeper during allocate().

Timelock

Force-redeem operations and fee increases support an optional timelock. When timelockDelay > 0:

1. Admin calls proposeTimelock(operationHash).
2. Wait for delay to pass.
3. Execute the operation.

Reducing the timelock delay itself is timelocked (at the current, longer delay). Increasing the delay is immediate (more restrictive = safe). Duplicate proposals for the same hash revert -- cancel first, then re-propose.

Two-Step Admin Transfer

Admin ownership is transferred via a two-step process (transferAdmin + acceptAdmin) to prevent accidental transfers to wrong addresses. All contracts (vault, strategies, rewards module) use this pattern.

Strategy Removal

removeStrategy() is non-reentrant. When removing a strategy with tracked funds, the vault attempts an emergency withdrawal. If recovery is partial, the lost amount is emitted via StrategyRemovalFundsLost for off-chain tracking. The total allocation is validated after removal to prevent exceeding 100%.

Force Redeem

Admin can force-redeem users (single or batch up to 50). Uses a dust tolerance per-strategy (2 wei each or 1 bps of the asset amount, whichever is larger) to cover protocol-specific rounding errors in Morpho and Aave.

Roles

Role	Key Permissions
Admin	Add/remove/pause strategies, set allocations/caps/fees, freeze deposits, recall to idle, force redeem, transfer admin, set guardian
Guardian	Pause strategies and vault, freeze strategy deposits. Cannot unpause or unfreeze (one-way emergency brake).
Keeper	Rebalance (allocate), reconcile strategy balances, harvest rewards, sweep strategy rewards, collect fees, allocate/deallocate within multi-strategies
User	Deposit (when not frozen/paused, within cap), withdraw and redeem (always open, even when paused)

Reward Flow

1. harvestAll()              Aave/Compound claim directly to RewardsModule
2. executeClaim()            Merkle claims (Morpho URD, Merkl) land on strategy
3. sweepStrategyReward()     Forward from strategy to RewardsModule
4. swap()                    Swap reward token to base asset via whitelisted DEX router
5. sweepToVault()            Deposit base asset back into vault (auto-compounding)

The RewardsModule holds reward tokens; swaps happen in isolation from the vault. DEX routers are admin-whitelisted.

Supported Protocols

Protocol	Strategy	Rewards Mechanism	Chains
Aave V3	AaveV3Strategy	ARB via RewardsController	Ethereum, Arbitrum
Compound V3	CompoundV3Strategy	COMP via CometRewards	Ethereum, Arbitrum
Spark	AaveV3Strategy (shared)	via RewardsController	Ethereum
Morpho Blue	MorphoBlueMultiStrategy	MORPHO via URD + sweepReward	Ethereum
Fluid	FluidStrategy	via Merkl + sweepReward	Ethereum, Arbitrum
ERC-4626 vaults	ERC4626MultiStrategy	Protocol-dependent	Ethereum, Arbitrum

Multi-Strategy Details

ERC4626MultiStrategy

Distributes funds across whitelisted ERC-4626 sub-vaults (e.g., MetaMorpho, Morpho Vaults). Keeper calls allocate(subVault, amount) / deallocate(subVault, amount). Sub-vaults can be added/removed by admin (removal requires zero position). All external calls are non-reentrant.

MorphoBlueMultiStrategy

Distributes funds across whitelisted Morpho Blue markets (supply-side only). Keeper calls allocate(marketId, amount) / deallocate(marketId, amount). Provides accrueAllInterest() for accurate balance reporting before vault reconciliation. Market removal requires zero position. All external calls are non-reentrant.

Security Properties

Invariants

• Withdrawals never blocked: withdraw() and redeem() work even when paused == true. Only deposits are frozen.
• Fee-dodge impossible: _accruePerformanceFee() runs inside withdraw(), redeem(), forceRedeem(), and batchForceRedeem() before share conversion.
• Broken strategy cannot DoS: All strategy calls in withdraw waterfall, rebalance, reconcile, and harvest use try-catch. A reverting strategy is skipped, not blocking.
• No reentrancy: ReentrancyGuard on all state-changing vault functions and all strategy entry points.
• No unsafe transfers: SafeERC20 used for all token transfers.

Attack Mitigations

Attack Vector	Defense
First-depositor inflation / donation	Virtual shares offset (_decimalsOffset = assetDecimals), internal accounting
Reentrancy	ReentrancyGuard on vault + all strategies
Unsafe ERC-20	SafeERC20 everywhere
Rounding exploits	ERC-4626 rounding in vault's favor, preview functions account for pending fees
Excessive deposits	Configurable deposit cap
Reward token contamination	Swaps isolated in RewardsModule, never in vault
Fee dodging	Performance fee accrued before withdrawal conversion
Admin transfer to wrong address	Two-step transfer (transferAdmin + acceptAdmin)
Sudden fee hike	Fee increases are timelocked
Timelock delay reduction	Reducing delay is itself timelocked at the current (longer) delay

Trust Model

Users trust:

1. The immutable vault contract code.
2. The admin (Safe multisig 0x9D7e68c2c0D43f97B873336471927d7C0171e78A). Admin can add/remove strategies, change allocations, change fees (timelocked), force-redeem users (optional timelock), and pause.
3. The keeper (bounded actions). Keeper can rebalance and harvest but cannot extract funds or change parameters.

Admin cannot block withdrawals. The only irreversible admin action is strategy removal with fund loss (emitted as event).

Testing

Prerequisites

• Foundry (forge, anvil)
• RPC endpoints for fork tests (Alchemy, Infura, or any archive node)

Setup

# Install dependencies
forge install

# Copy and configure RPC endpoints
cp .env.example .env
# Edit .env with your RPC URLs

Running Tests

# Unit tests (no RPC required, fast)
forge test --match-path "test/unit/*"

# Fuzz + invariant tests (requires Ethereum mainnet RPC)
forge test --match-path "test/fuzz/*"

# Fork tests -- all chains (requires all RPC endpoints)
forge test --match-path "test/fork/*"

# Full suite
forge test

Test Suite Overview

Category	Files	Tests	Description
Unit	7	390	Core vault, strategies, rewards module, performance fee, deposit freeze
Fuzz / Invariant	6	75	Property-based testing: share price monotonicity, solvency, ERC-4626 round-trips
Fork (per-chain)	6	~3,000	Live protocol integration across Ethereum, Arbitrum, Optimism, Base, BSC, Polygon
Fork (standalone)	11	~300	Security regressions, ERC-4626 compliance, multi-vault isolation, reward pipelines

Fork tests use shared infrastructure (test/fork/shared/) to run the same test suite against every supported chain and token combination.

Compiler Settings

• Solidity ^0.8.26
• OpenZeppelin Contracts v5.x (ERC4626, ERC20, ReentrancyGuard, SafeERC20, Math)

Deployments

Ethereum Mainnet

Contract	Address
TezoroV1_1 (tUSDC-A, conservative)	0x7cc42747862ecACe79FA89BeFcB29C94d2558dEC
TezoroV1_1 (tUSDC-B, moderate)	0xD0F2812F57D284c0d30Ddd8f73b146Ef0cD5a25c
TezoroV1_1 (tUSDC-C, aggressive)	0xa139C6a7dd1Bd76Ae3FBCCF4F8bEbA5C4f26513d
Admin (Safe multisig)	0x9D7e68c2c0D43f97B873336471927d7C0171e78A