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Return pay amount (#4)
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* return paid amount from claims

* update readme

* update flow img

* update flow img
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@merklejerk
merklejerk authored Mar 9, 2024
1 parent 8ebe82b commit d72a175
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4 changes: 2 additions & 2 deletions README.md
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Expand Up @@ -36,7 +36,7 @@ A whitehat that has discovered an exploit on a registered project will submit a

> ⚠️ On Ethereum mainnet, it is critical that the whitehat uses a private mempool mechanism (e.g., Flashbots Protect with max privacy) to submit the transaction in order to prevent discovery of the exploit mechanism before the transaction is mined and the protocol can be paused! On other chains where sequencing cannot be practically frontrun, it may be sufficient to submit directly to the tx sequencer.
You can check out an example trace of a claim tx [here](https://phalcon.blocksec.com/explorer/tx/sepolia/0x1b957becc3839f34d1e7f221eeb7353e6073b69da91ac717478a64c3fd2bf291).
You can check out an example trace of a claim tx [here](https://phalcon.blocksec.com/explorer/tx/sepolia/0x1b957becc3839f34d1e7f221eeb7353e6073b69da91ac717478a64c3fd2bf291) (older version).

## Writing Verifiers
**Verifier**s must confirm that some critical invariants or health checks have been violated in the post-exploit state. Projects need to do the legwork of identifying a robust set of checks that would be considered critical enough to warrant pausing the entire protocol. These would typically be invariants that do not get checked during normal user interactions due to gas constraints.
Expand Down Expand Up @@ -68,7 +68,7 @@ The simplest **Payer** implementation will transfer the bounty directly out of a
| Chain | Address |
|-------|---------|
| Ethereum Mainnet | `TBD` |
| Ethereum Sepolia | [`0x4730fe5DB07c5092893B87A3Cf6740cA25ffE52A`](https://sepolia.etherscan.io/address/0x4730fe5DB07c5092893B87A3Cf6740cA25ffE52A) |
| Ethereum Sepolia | [`0x81cb0ba5E7B724B03C8B64A5FAF4f2C655aD15E4`](https://sepolia.etherscan.io/address/0x81cb0ba5E7B724B03C8B64A5FAF4f2C655aD15E4) |

## Credits

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3 changes: 2 additions & 1 deletion script/demo/Testnet.s.sol
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Expand Up @@ -72,7 +72,8 @@ contract Testnet is Script {
hash,
operator
);
require(honey.verifyBountyCanPay(d.bountyId(), payable(tx.origin)), 'cannot pay');
(bool canPay,) = honey.verifyBountyCanPay(d.bountyId(), payable(tx.origin));
require(canPay, 'cannot pay');
}

function _broadcast() private {
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41 changes: 30 additions & 11 deletions src/HoneyPause.sol
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Expand Up @@ -204,17 +204,18 @@ contract HoneyPause {
bytes memory exploiterData,
bytes memory verifierData
)
external
external returns (uint256 payAmount)
{
Bounty memory bounty = _claim({
Bounty memory bounty;
(bounty, payAmount) = _claim({
bountyId: bountyId,
payReceiver: payReceiver,
exploiter: exploiter,
exploiterData: exploiterData,
verifierData: verifierData,
skipExploit: false
});
emit Claimed(bountyId, bounty.payoutToken, bounty.payoutAmount);
emit Claimed(bountyId, bounty.payoutToken, payAmount);
}

/// @notice Carries out an exploit, verifies it, then reverts the call frame.
Expand Down Expand Up @@ -243,23 +244,32 @@ contract HoneyPause {
verifier.assertExploit,
(verifierData, verifierStateData)
));
revert SandboxSucceededError();
revert SandboxSucceededError('');
}

/// @notice Check whether a bounty can actually pay out its reward.
/// @dev Not read-only because state needs to be temporarily modified to make this
/// determination. All state is reverted before returning so this can
/// be safely called on-chain but most likely it will be consumed off-chain
/// via eth_call.
/// @param bountyId ID of a valid, active bounty.
/// @param payReceiver Recepient of bounty.
/// @return bountyCanPay Whether the payer sent at least the bounty amount to the receiver.
/// @return payAmount Actual amount sent to receiver (may be more than bounty amount).
function verifyBountyCanPay(uint256 bountyId, address payable payReceiver)
external returns (bool bountyCanPay)
external returns (bool bountyCanPay, uint256 payAmount)
{
try this.sandboxTryPayBounty(bountyId, payReceiver) {
// Should always fail.
assert(false);
} catch (bytes memory errData) {
return LibSandbox.handleSandboxCallRevert(errData, true);
if (!LibSandbox.handleSandboxCallRevert(errData, true)) {
return (false, 0);
}
// The data inside the SandboxSucceededError is the pay amount.
payAmount = abi.decode(abi.decode(errData.skip(4), (bytes)), (uint256));
}
return (true, payAmount);
}

/// @notice Mimics the logic for a successful claim() to verify that a bounty can
Expand All @@ -269,7 +279,7 @@ contract HoneyPause {
function sandboxTryPayBounty(uint256 bountyId, address payable payReceiver)
external
{
_claim({
(, uint256 payAmount) = _claim({
bountyId: bountyId,
payReceiver: payReceiver,
exploiter: IExploiter(address(0)),
Expand All @@ -279,7 +289,7 @@ contract HoneyPause {
// it does minus the exploit verification.
skipExploit: true
});
revert SandboxSucceededError();
revert SandboxSucceededError(abi.encode(payAmount));
}

/// @dev The logic of claim(), refactored out for sandboxTryPayBounty().
Expand All @@ -292,7 +302,7 @@ contract HoneyPause {
bool skipExploit
)
internal
returns (Bounty memory bounty)
returns (Bounty memory bounty, uint256 payAmount)
{
bounty = getBounty[bountyId];
if (bounty.operator == address(0)) {
Expand All @@ -318,11 +328,18 @@ contract HoneyPause {
// Pause the protocol.
address(bounty.pauser).safeCall(abi.encodeCall(bounty.pauser.pause, (bountyId)));
// Pay the bounty.
_payout(bountyId, bounty.payer, bounty.payoutToken, payReceiver, bounty.payoutAmount);
payAmount = _payout(
bountyId,
bounty.payer,
bounty.payoutToken,
payReceiver,
bounty.payoutAmount
);
}


// Call a bounty's payer contract and verify that it transferred the payment.
// Call a bounty's payer contract, verify that it transferred the payment, and
// return the amount transferred.
function _payout(
uint256 bountyId,
IPayer payer,
Expand All @@ -331,6 +348,7 @@ contract HoneyPause {
uint256 amount
)
internal
returns (uint256 payAmount)
{
uint256 balBefore = _balanceOf(token, to);
address(payer).safeCall(abi.encodeCall(
Expand All @@ -341,6 +359,7 @@ contract HoneyPause {
if (balBefore > balAfter || balAfter - balBefore < amount) {
revert InsufficientPayoutError();
}
return balAfter - balBefore;
}

// Get the balance of a token (or ETH) of an account.
Expand Down
2 changes: 1 addition & 1 deletion src/LibSandbox.sol
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Expand Up @@ -4,7 +4,7 @@ pragma solidity ^0.8.24;
import { LibBytes } from './LibBytes.sol';

error SandboxFailedError(bytes innerError);
error SandboxSucceededError();
error SandboxSucceededError(bytes data);

library LibSandbox {
using LibBytes for bytes;
Expand Down
64 changes: 45 additions & 19 deletions test/HoneyPause.t.sol
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Expand Up @@ -38,9 +38,9 @@ contract HoneyPauseTest is Test {
TestHoneyPause honey = new TestHoneyPause();
TestERC20 testToken = new TestERC20();
bytes TEST_ERROR = abi.encodeWithSelector(TestError.selector, 'FAILED');
bytes SANDBOX_SUCCEEDED_ERROR = abi.encodeWithSelector(SandboxSucceededError.selector);
bytes EMPTY_SANDBOX_SUCCEEDED_ERROR = abi.encodeWithSelector(SandboxSucceededError.selector, "");
bytes WRAPPED_SANDBOX_SUCCEEDED_ERROR = abi.encodeWithSelector(SandboxFailedError.selector,
abi.encodeWithSelector(SandboxSucceededError.selector)
abi.encodeWithSelector(SandboxSucceededError.selector, "")
);

function test_errorSelectorsCanBeSandboxed() external {
Expand Down Expand Up @@ -99,7 +99,7 @@ contract HoneyPauseTest is Test {
function test_sandboxExploit_revertsOnSuccess() external {
IVerifier verifier = new TestVerifier();
IExploiter exploiter = new TestExploiter();
vm.expectRevert(SandboxSucceededError.selector);
vm.expectRevert(EMPTY_SANDBOX_SUCCEEDED_ERROR);
honey.sandboxExploit(exploiter, verifier, "", "");
}

Expand Down Expand Up @@ -136,7 +136,7 @@ contract HoneyPauseTest is Test {
function test_sandboxExploit_wrapsSandboxSuccessFromVerifierBeforeExploitCall() external {
IVerifier verifier = IVerifier(_createFailingFnContract(
IVerifier.beforeExploit.selector,
SANDBOX_SUCCEEDED_ERROR
EMPTY_SANDBOX_SUCCEEDED_ERROR
));
IExploiter exploiter = new TestExploiter();
vm.expectRevert(WRAPPED_SANDBOX_SUCCEEDED_ERROR);
Expand All @@ -146,7 +146,7 @@ contract HoneyPauseTest is Test {
function test_sandboxExploit_wrapsSandboxSuccessFromVerifierAssertExploitCall() external {
IVerifier verifier = IVerifier(_createFailingFnContract(
IVerifier.assertExploit.selector,
SANDBOX_SUCCEEDED_ERROR
EMPTY_SANDBOX_SUCCEEDED_ERROR
));
TestExploiter exploiter = new TestExploiter();
vm.expectRevert(WRAPPED_SANDBOX_SUCCEEDED_ERROR);
Expand All @@ -157,7 +157,7 @@ contract HoneyPauseTest is Test {
IVerifier verifier = new TestVerifier();
IExploiter exploiter = IExploiter(_createFailingFnContract(
IExploiter.exploit.selector,
SANDBOX_SUCCEEDED_ERROR
EMPTY_SANDBOX_SUCCEEDED_ERROR
));
vm.expectRevert(WRAPPED_SANDBOX_SUCCEEDED_ERROR);
honey.sandboxExploit(exploiter, verifier, "", "");
Expand All @@ -176,7 +176,7 @@ contract HoneyPauseTest is Test {
emit TestExploiter.ExploitCalled(exploiterData);
vm.expectEmit(true, true, true, true);
emit TestVerifier.AssertExploitCalled(verifierData, verifierStateData);
vm.expectRevert(SandboxSucceededError.selector);
vm.expectRevert(EMPTY_SANDBOX_SUCCEEDED_ERROR);
honey.sandboxExploit(exploiter, verifier, exploiterData, verifierData);
}

Expand Down Expand Up @@ -349,8 +349,9 @@ contract HoneyPauseTest is Test {
IExploiter exploiter = new TestExploiter();
vm.expectEmit(true, true, true, true);
emit Claimed(bountyId, ETH_TOKEN, 100);
honey.claim(bountyId, RECEIVER, exploiter, "", "");
uint256 payAmount = honey.claim(bountyId, RECEIVER, exploiter, "", "");
assertEq(honey.isBountyClaimed(bountyId), true);
assertEq(payAmount, TEST_BOUNTY_AMOUNT);
}

function test_claim_passesData() external {
Expand Down Expand Up @@ -431,15 +432,26 @@ contract HoneyPauseTest is Test {
uint256 bountyId = _addTestBounty();
IExploiter exploiter = IExploiter(_createFailingFnContract(
IExploiter.exploit.selector,
SANDBOX_SUCCEEDED_ERROR
EMPTY_SANDBOX_SUCCEEDED_ERROR
));
vm.expectRevert(SANDBOX_SUCCEEDED_ERROR);
vm.expectRevert(EMPTY_SANDBOX_SUCCEEDED_ERROR);
honey.claim(bountyId, RECEIVER, exploiter, "", "");
}

function test_verifyBountyCanPay_returnsTrueIfBountyPays() external {
uint256 bountyId = _addTestBounty();
assertEq(honey.verifyBountyCanPay(bountyId, RECEIVER), true);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, true);
assertEq(payAmount, TEST_BOUNTY_AMOUNT);
}

function test_verifyBountyCanPay_returnsTrueIfBountyPaysTooMuch() external {
uint256 bountyId = _addTestBounty();
(,,,,, IPayer payer) = honey.getBounty(bountyId);
payable(address(payer)).transfer(1);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, true);
assertEq(payAmount, TEST_BOUNTY_AMOUNT + 1);
}

function test_verifyBountyCanPay_doesNotModifyState() external {
Expand All @@ -457,7 +469,9 @@ contract HoneyPauseTest is Test {
IPayer.payExploiter.selector,
TEST_ERROR
)));
assertEq(honey.verifyBountyCanPay(bountyId, RECEIVER), false);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, false);
assertEq(payAmount, 0);
}

function test_verifyBountyCanPay_returnsFalseIfPauserReverts() external {
Expand All @@ -466,37 +480,47 @@ contract HoneyPauseTest is Test {
IPauser.pause.selector,
TEST_ERROR
)));
assertEq(honey.verifyBountyCanPay(bountyId, RECEIVER), false);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, false);
assertEq(payAmount, 0);
}

function test_verifyBountyCanPay_returnsFalseIfPayerDoesNotPayEnoughEth() external {
uint256 bountyId = _addTestBounty();
honey.__testSetBountyPayer(bountyId, new TestEthPayer{value: TEST_BOUNTY_AMOUNT - 1}());
assertEq(honey.verifyBountyCanPay(bountyId, RECEIVER), false);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, false);
assertEq(payAmount, 0);
}

function test_verifyBountyCanPay_returnsFalseIfPayerDoesNotPayEnoughErc20() external {
uint256 bountyId = _addTestBounty();
honey.__testSetBountyPayer(bountyId, new TestERC20Payer(testToken, TEST_BOUNTY_AMOUNT - 1));
assertEq(honey.verifyBountyCanPay(bountyId, RECEIVER), false);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, false);
assertEq(payAmount, 0);
}

function test_verifyBountyCanPay_returnsFalseIfPayerRevertsWithSandoxSucceeded() external {
uint256 bountyId = _addTestBounty();
honey.__testSetBountyPayer(bountyId, IPayer(_createFailingFnContract(
IPayer.payExploiter.selector,
SANDBOX_SUCCEEDED_ERROR
EMPTY_SANDBOX_SUCCEEDED_ERROR
)));
assertEq(honey.verifyBountyCanPay(bountyId, RECEIVER), false);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, false);
assertEq(payAmount, 0);
}

function test_verifyBountyCanPay_returnsFalseIfPauserRevertsWithSandoxSucceeded() external {
uint256 bountyId = _addTestBounty();
honey.__testSetBountyPauser(bountyId, IPauser(_createFailingFnContract(
IPauser.pause.selector,
SANDBOX_SUCCEEDED_ERROR
EMPTY_SANDBOX_SUCCEEDED_ERROR
)));
assertEq(honey.verifyBountyCanPay(bountyId, RECEIVER), false);
(bool canPay, uint256 payAmount) = honey.verifyBountyCanPay(bountyId, RECEIVER);
assertEq(canPay, false);
assertEq(payAmount, 0);
}

function test_bountyCannotUseAnotherBountyPauserPayer() external {
Expand Down Expand Up @@ -702,6 +726,8 @@ contract TestEthPayer is IPayer {
assert(token == ETH_TOKEN);
return to.transfer(address(this).balance);
}

receive() external payable {}
}

contract TestHoneyPause is HoneyPause {
Expand Down

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