Alexintosh · March 17, 2023 18:48 · Mar 17, 2023 · Mar 17, 2023
diff --git a/AtomicGuard.sol b/AtomicGuard.sol
@@ -1,5 +1,7 @@
 pragma solidity 0.8.13;
 
+import "hardhat/console.sol";
+
 contract AtomicityGuard {
 
     // address => block => status
@@ -20,6 +22,48 @@ contract AtomicityGuard {
     }
 }
 
+contract BufferGuard is AtomicityGuard {
+
+    // address => block => status
+    uint256 private blockBuffer;
+    uint256 private constant _ENTERED = 1;
+
+    mapping(address => uint256) lastSeen;
+
+    constructor(uint256 _buff) {
+        blockBuffer = _buff;
+    }
+
+    modifier buffered() {
+        console.log(lastSeen[msg.sender]);
+        console.log(block.number);
+        _buffered();
+        _;
+    }
+
+    function _buffered() private nonAtomic {
+        // On the first call to nonReentrant, _status will be _NOT_ENTERED
+        if(lastSeen[msg.sender] > 0) {
+            require(block.number > lastSeen[msg.sender] + blockBuffer, "BufferGuard: not buffered");
+        }
+
+        lastSeen[msg.sender] = block.number;
+    }
+}
+
+contract ImplementorBuffered is BufferGuard {
+
+    constructor() BufferGuard(10) {}
+
+    function deposit() external buffered {
+
+    }
+
+    function withdraw() external buffered {
+
+    }
+}
+
 contract Implementor is AtomicityGuard {
 
     function deposit() external nonAtomic {

diff --git a/AtomicGuard.sol b/AtomicGuard.sol
@@ -0,0 +1,66 @@
+pragma solidity 0.8.13;
+
+contract AtomicityGuard {
+
+    // address => block => status
+    uint256 private constant _ENTERED = 1;
+
+    mapping(address => mapping( uint256 => uint256)) ledger;
+
+    modifier nonAtomic() {
+         _nonAtomicBefore();
+        _;
+    }
+
+    function _nonAtomicBefore() private {
+        // On the first call to nonReentrant, _status will be _NOT_ENTERED
+        require(ledger[msg.sender][block.number] != _ENTERED, "AtomicityGuard: same block");
+
+        ledger[msg.sender][block.number] = _ENTERED;
+    }
+}
+
+contract Implementor is AtomicityGuard {
+
+    function deposit() external nonAtomic {
+
+    }
+
+    function withdraw() external nonAtomic {
+
+    }
+}
+
+interface IImplementor {
+    function deposit() external;
+    function withdraw() external;
+}
+
+contract Exploiter {
+    IImplementor c;
+
+    constructor (address _i) {
+        c = IImplementor(_i);
+    }
+
+    function atomic() external {
+        c.deposit();
+        c.withdraw();
+    }
+
+    function nonatomicDeposit() external {
+        c.deposit();
+    }
+
+    function nonatomicWithdraw() external {
+        c.withdraw();
+    }
+}
+
+contract Exploiter2 {
+    constructor (address _i) {
+        IImplementor(_i).deposit();
+        IImplementor(_i).withdraw();
+        selfdestruct(payable(msg.sender));
+    }
+}