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| Original file line number | Diff line number | Diff line change |
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| /* | ||
| * SPDX-License-Identitifer: MIT | ||
| */ | ||
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| pragma solidity ^0.4.24; | ||
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| import "../common/UnstructuredStorage.sol"; | ||
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| contract ReentrancyGuard { | ||
| using UnstructuredStorage for bytes32; | ||
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| /* Hardcoded constants to save gas | ||
| bytes32 internal constant REENTRANCY_MUTEX_POSITION = keccak256("aragonOS.reentrancyGuard.mutex"); | ||
| */ | ||
| bytes32 private constant REENTRANCY_MUTEX_POSITION = 0xe855346402235fdd185c890e68d2c4ecad599b88587635ee285bce2fda58dacb; | ||
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| string private constant ERROR_REENTRANT = "REENTRANCY_REENTRANT_CALL"; | ||
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| modifier nonReentrant() { | ||
| // Ensure mutex is unlocked | ||
| require(!REENTRANCY_MUTEX_POSITION.getStorageBool(), ERROR_REENTRANT); | ||
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| // Lock mutex before function call | ||
| REENTRANCY_MUTEX_POSITION.setStorageBool(true); | ||
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| // Perform function call | ||
| _; | ||
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| // Unlock mutex after function call | ||
| REENTRANCY_MUTEX_POSITION.setStorageBool(false); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,53 @@ | ||
| pragma solidity 0.4.24; | ||
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| import "../../common/ReentrancyGuard.sol"; | ||
| import "../../common/UnstructuredStorage.sol"; | ||
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| contract ReentrantActor { | ||
| bool reenterNonReentrant; | ||
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| constructor(bool _reenterNonReentrant) public { | ||
| reenterNonReentrant = _reenterNonReentrant; | ||
| } | ||
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| function reenter(ReentrancyGuardMock _mock) public { | ||
| // Set the reentrancy target to 0 so we don't infinite loop | ||
| ReentrantActor reentrancyTarget = ReentrantActor(0); | ||
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| if (reenterNonReentrant) { | ||
| _mock.nonReentrantCall(reentrancyTarget); | ||
| } else { | ||
| _mock.reentrantCall(reentrancyTarget); | ||
| } | ||
| } | ||
| } | ||
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| contract ReentrancyGuardMock is ReentrancyGuard { | ||
| using UnstructuredStorage for bytes32; | ||
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| uint256 public callCounter; | ||
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| function nonReentrantCall(ReentrantActor _target) public nonReentrant { | ||
| callCounter++; | ||
| if (_target != address(0)) { | ||
| _target.reenter(this); | ||
| } | ||
| } | ||
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| function reentrantCall(ReentrantActor _target) public { | ||
| callCounter++; | ||
| if (_target != address(0)) { | ||
| _target.reenter(this); | ||
| } | ||
| } | ||
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| function setReentrancyMutex(bool _mutex) public { | ||
| getReentrancyMutexPosition().setStorageBool(_mutex); | ||
| } | ||
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| function getReentrancyMutexPosition() public pure returns (bytes32) { | ||
| return keccak256("aragonOS.reentrancyGuard.mutex"); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,100 @@ | ||
| const { assertRevert } = require('./helpers/assertThrow') | ||
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| const ZERO_ADDR = '0x0000000000000000000000000000000000000000' | ||
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| contract('ReentrancyGuard', accounts => { | ||
| let reentrancyMock | ||
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| async function assertReentrancyGuard(guard, msg) { | ||
| assert.equal( | ||
| await web3.eth.getStorageAt(reentrancyMock.address, (await reentrancyMock.getReentrancyMutexPosition())), | ||
| guard, | ||
| msg | ||
| ) | ||
| } | ||
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| beforeEach(async () => { | ||
| reentrancyMock = await artifacts.require('ReentrancyGuardMock').new() | ||
| }) | ||
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| it('starts with false mutex', async () => { | ||
| await assertReentrancyGuard(false, 're-entrancy mutex should start false') | ||
| }) | ||
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| it('starts with no calls', async () => { | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 0, 'should start with no calls') | ||
| }) | ||
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| it('can call re-entrant function normally', async () => { | ||
| await reentrancyMock.reentrantCall(ZERO_ADDR) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 1, 'should have registered one call') | ||
| await assertReentrancyGuard(false, 're-entrancy mutex should end false') | ||
| }) | ||
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| it('can call non-re-entrant function normally', async () => { | ||
| await reentrancyMock.nonReentrantCall(ZERO_ADDR) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 1, 'should have registered one call') | ||
| await assertReentrancyGuard(false, 're-entrancy mutex should end false') | ||
| }) | ||
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| context('> Enabled re-entrancy mutex', () => { | ||
| beforeEach(async () => { | ||
| // Manually set re-entrancy mutex | ||
| await reentrancyMock.setReentrancyMutex(true) | ||
| }) | ||
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| it('can call re-entrant function if re-entrancy mutex is enabled', async () => { | ||
| await reentrancyMock.reentrantCall(ZERO_ADDR) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 1, 'should have called') | ||
| }) | ||
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| it('can not call non-re-entrant function if re-entrancy mutex is enabled', async () => { | ||
| await assertRevert(async () => { | ||
| await reentrancyMock.nonReentrantCall(ZERO_ADDR) | ||
| }) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 0, 'should not have called') | ||
| }) | ||
| }) | ||
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| context('> Re-entering through contract', async () => { | ||
| let reentrantActor | ||
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| afterEach(async () => { | ||
| await assertReentrancyGuard(false, 're-entrancy mutex should end false') | ||
| }) | ||
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| context('> Re-enters re-entrant call', async () => { | ||
| before(async () => { | ||
| reentrantActor = await artifacts.require('ReentrantActor').new(false) | ||
| }) | ||
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| it('allows re-entering re-entrant call', async () => { | ||
| await reentrancyMock.reentrantCall(reentrantActor.address) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 2, 'should have called twice') | ||
| }) | ||
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| it('allows entering non-re-entrant call from re-entrant call', async () => { | ||
| await reentrancyMock.nonReentrantCall(reentrantActor.address) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 2, 'should have called twice') | ||
| }) | ||
| }) | ||
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| context('> Re-enters non-reentrant call', async () => { | ||
| before(async () => { | ||
| reentrantActor = await artifacts.require('ReentrantActor').new(true) | ||
| }) | ||
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| it('disallows re-entering non-re-entrant call', async () => { | ||
| await assertRevert(async () => { | ||
| await reentrancyMock.nonReentrantCall(reentrantActor.address) | ||
| }) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 0, 'should not have completed any calls') | ||
| }) | ||
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| it('allows entering non-entrant call from re-entrant call', async () => { | ||
| await reentrancyMock.reentrantCall(reentrantActor.address) | ||
| assert.equal((await reentrancyMock.callCounter()).toString(), 2, 'should have called twice') | ||
| }) | ||
| }) | ||
| }) | ||
| }) |
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