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feat: functional implementation of EXTCODEHASH and EXTCODECOPY (#328)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,133 @@ | ||
| // SPDX-License-Identifier: AGPL-3.0 | ||
| pragma solidity >=0.8.0 <0.9.0; | ||
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| import "forge-std/Test.sol"; | ||
| import {SymTest} from "halmos-cheatcodes/SymTest.sol"; | ||
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| contract A {} | ||
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| contract B { | ||
| // make sure bytecode is different from A | ||
| function beep() public pure {} | ||
| } | ||
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| contract Empty { | ||
| // constructor returns 0-length runtime bytecode | ||
| constructor() { | ||
| assembly { | ||
| return(0, 0) | ||
| } | ||
| } | ||
| } | ||
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| contract ExtcodehashTest is Test, SymTest { | ||
| address a1; | ||
| bytes32 a1hash; | ||
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| function setUp() public { | ||
| address _a1 = address(new A()); | ||
| bytes32 _a1hash; | ||
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| assembly { | ||
| _a1hash := extcodehash(_a1) | ||
| } | ||
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| a1 = _a1; | ||
| a1hash = _a1hash; | ||
| } | ||
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| function check_extcodehash_a1_eq_a2() external { | ||
| address a2 = address(new A()); | ||
| bytes32 a2hash; | ||
| assembly { | ||
| a2hash := extcodehash(a2) | ||
| } | ||
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| // extcodehash(a1) == extcodehash(a2) | ||
| assertEq(a1hash, a2hash); | ||
| } | ||
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| function check_extcodehash_a1_ne_b1() external { | ||
| address b1 = address(new B()); | ||
| bytes32 b1hash; | ||
| assembly { | ||
| b1hash := extcodehash(b1) | ||
| } | ||
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| // extcodehash(a1) != extcodehash(b1) | ||
| assertNotEq(a1hash, b1hash); | ||
| } | ||
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| function check_extcodehash_a1_eq_directHash() external { | ||
| // extcodehash(a1) == keccak256(extcodecopy(a1)) | ||
| assertEq(a1hash, keccak256(a1.code)); | ||
| } | ||
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| function check_extcodehash_a1_eq_runtimeCodeHash() external { | ||
| assertEq(a1hash, keccak256(type(A).runtimeCode)); | ||
| } | ||
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| function check_extcodehash_eq_directHash() external { | ||
| uint256 thisCodeSize; | ||
| assembly { | ||
| thisCodeSize := codesize() | ||
| } | ||
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| bytes memory thisCode = new bytes(thisCodeSize); | ||
| bytes32 thisCodeHash; | ||
| assembly { | ||
| codecopy(add(thisCode, 0x20), 0, thisCodeSize) | ||
| thisCodeHash := extcodehash(address()) | ||
| } | ||
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| // extcodehash(address()) == keccak256(codecopy()) | ||
| assertEq(thisCodeHash, keccak256(thisCode)); | ||
| } | ||
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| function check_extcodehash_empty() external { | ||
| address emptyCodeAddr = address(new Empty()); | ||
| assertEq(emptyCodeAddr.code.length, 0, "Empty contract should have no code"); | ||
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| bytes32 codehash; | ||
| assembly { | ||
| codehash := extcodehash(emptyCodeAddr) | ||
| } | ||
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| assertEq(codehash, keccak256(""), "Expected codehash of the empty string"); | ||
| } | ||
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| /// yields a path where it is eq to 0, and a path where it is not | ||
| /// so we expect a counterexample for this and also its negation | ||
| function check_extcodehash_unknown_addr_eq_0() external { | ||
| bytes32 codehash; | ||
| assembly { | ||
| codehash := extcodehash(0x1337) | ||
| } | ||
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| assertEq(codehash, 0); | ||
| } | ||
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| /// yields a path where it is eq to 0, and a path where it is not | ||
| /// so we expect a counterexample for this and also its negation | ||
| function check_extcodehash_unknown_addr_noteq_0() external { | ||
| bytes32 codehash; | ||
| assembly { | ||
| codehash := extcodehash(0x1337) | ||
| } | ||
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| assertNotEq(codehash, 0); | ||
| } | ||
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| function check_extcodehash_after_etch() external { | ||
| address who = address(0x1337); | ||
| bytes memory code = svm.createBytes(42, "code"); | ||
| vm.etch(who, code); | ||
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| bytes32 codehash; | ||
| assembly { | ||
| codehash := extcodehash(who) | ||
| } | ||
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| assertEq(codehash, keccak256(code)); | ||
| } | ||
| } |