Eip 684: Prevent overwriting contracts

ethereumj-core/src/main/java/org/ethereum/core/AccountState.java

@@ -136,6 +136,10 @@ public byte[] getEncoded() {
         return rlpEncoded;
     }
 
+    public boolean isContractExist() {
+        return !FastByteComparisons.equal(codeHash, EMPTY_DATA_HASH) || !BigInteger.ZERO.equals(nonce);
+    }
+
     public boolean isEmpty() {
         return FastByteComparisons.equal(codeHash, EMPTY_DATA_HASH) &&
                 BigInteger.ZERO.equals(balance) &&

ethereumj-core/src/main/java/org/ethereum/core/TransactionExecutor.java

@@ -253,6 +253,13 @@ private void call() {
     private void create() {
         byte[] newContractAddress = tx.getContractAddress();
 
+        AccountState existingAddr = cacheTrack.getAccountState(newContractAddress);
+        if (existingAddr != null && existingAddr.isContractExist()) {
+            execError("Trying to create a contract with existing contract address: 0x" + Hex.toHexString(newContractAddress));
+            m_endGas = BigInteger.ZERO;
+            return;
+        }
+
         //In case of hashing collisions (for TCK tests only), check for any balance before createAccount()
         BigInteger oldBalance = track.getBalance(newContractAddress);
         cacheTrack.createAccount(tx.getContractAddress());

ethereumj-core/src/main/java/org/ethereum/vm/program/Program.java

@@ -21,6 +21,7 @@
 import org.ethereum.config.BlockchainConfig;
 import org.ethereum.config.CommonConfig;
 import org.ethereum.config.SystemProperties;
+import org.ethereum.core.AccountState;
 import org.ethereum.core.Repository;
 import org.ethereum.core.Transaction;
 import org.ethereum.crypto.HashUtil;
@@ -423,6 +424,9 @@ public void createContract(DataWord value, DataWord memStart, DataWord memSize)
         byte[] nonce = getStorage().getNonce(senderAddress).toByteArray();
         byte[] newAddress = HashUtil.calcNewAddr(getOwnerAddress().getLast20Bytes(), nonce);
 
+        AccountState existingAddr = getStorage().getAccountState(newAddress);
+        boolean contractAlreadyExists = existingAddr != null && existingAddr.isContractExist();
+
         if (byTestingSuite()) {
             // This keeps track of the contracts created for a test
             getResult().addCallCreate(programCode, EMPTY_BYTE_ARRAY,
@@ -460,9 +464,11 @@ public void createContract(DataWord value, DataWord memStart, DataWord memSize)
                 this, new DataWord(newAddress), getOwnerAddress(), value, gasLimit,
                 newBalance, null, track, this.invoke.getBlockStore(), false, byTestingSuite());
 
-        ProgramResult result = ProgramResult.empty();
+        ProgramResult result = ProgramResult.createEmpty();
 
-        if (isNotEmpty(programCode)) {
+        if (contractAlreadyExists) {
+            result.setException(new BytecodeExecutionException("Trying to create a contract with existing contract address: 0x" + Hex.toHexString(newAddress)));
+        } else if (isNotEmpty(programCode)) {
             VM vm = new VM(config);
             Program program = new Program(programCode, programInvoke, internalTx, config).withCommonConfig(commonConfig);
             vm.play(program);

ethereumj-core/src/main/java/org/ethereum/vm/program/ProgramResult.java

@@ -197,7 +197,7 @@ public void merge(ProgramResult another) {
         }
     }
 
-    public static ProgramResult empty() {
+    public static ProgramResult createEmpty() {
         ProgramResult result = new ProgramResult();
         result.setHReturn(EMPTY_BYTE_ARRAY);
         return result;

ethereumj-core/src/test/java/org/ethereum/jsontestsuite/GitHubStateTest.java

@@ -29,7 +29,7 @@
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
 public class GitHubStateTest {
 
-    static String commitSHA = "f17609b3c2fc7404addf3d228955b16ae8e0cfb4";
+    static String commitSHA = "d098a00a4e7108f7965d1ca81e2fd51fc5b1e11b";
     static String treeSHA = "fdcc301d8fdd65e6f1b56ffca9a786aa337c7bb8"; // https://github.com/ethereum/tests/tree/develop/GeneralStateTests/
     static GitHubJSONTestSuite.Network[] targetNets = {
             GitHubJSONTestSuite.Network.Frontier,
@@ -57,7 +57,7 @@ public void clean() {
     // it reduces impact on GitHub API
     public void stSingleTest() throws IOException {
         GeneralStateTestSuite.runSingle(
-                "stZeroKnowledge/pointAdd.json", commitSHA, GitHubJSONTestSuite.Network.Byzantium);
+                "stRevertTest/RevertDepthCreateAddressCollision.json", commitSHA, GitHubJSONTestSuite.Network.Byzantium);
     }
 
     @Test
@@ -96,11 +96,6 @@ public void stCallCreateCallCodeTest() throws IOException {
         Set<String> excluded = new HashSet<>();
         excluded.add("CallRecursiveBombPreCall"); // Max Gas value is pending to be < 2^63
 
-        // the test creates a contract with the same address as existing contract (which is not possible in
-        // live). In this case we need to clear the storage in TransactionExecutor.create
-        // return back to this case when the contract deleting will be implemented
-        excluded.add("createJS_ExampleContract");
-
         suite.runAll("stCallCreateCallCodeTest", excluded);
     }
 

ethereumj-core/src/test/java/org/ethereum/jsontestsuite/GitHubVMTest.java

@@ -160,8 +160,8 @@ public void testVMGitHub() throws ParseException {
     @Test // testing full suite
     public void testRandomVMGitHub() throws ParseException {
 
-        String shacommit = "c5eafb85390eee59b838a93ae31bc16a5fd4f7b1";
-        List<String> fileNames = getFileNamesForTreeSha(shacommit);
+        String treeSha = "c5eafb85390eee59b838a93ae31bc16a5fd4f7b1";
+        List<String> fileNames = getFileNamesForTreeSha(treeSha);
         List<String> excludedFiles =
                 Collections.singletonList(
                         ""
@@ -171,7 +171,7 @@ public void testRandomVMGitHub() throws ParseException {
 
             if (excludedFiles.contains(fileName)) continue;
             System.out.println("Running: " + fileName);
-            String json = JSONReader.loadJSON("VMTests//RandomTests/" + fileName);
+            String json = JSONReader.loadJSONFromCommit("VMTests//RandomTests/" + fileName, shacommit);
             GitHubJSONTestSuite.runGitHubJsonVMTest(json);
         }
 

ethereumj-core/src/test/java/org/ethereum/jsontestsuite/suite/BlockchainTestSuite.java

@@ -12,6 +12,7 @@
 
 import static org.ethereum.jsontestsuite.suite.JSONReader.listJsonBlobsForTreeSha;
 import static org.ethereum.jsontestsuite.suite.JSONReader.loadJSONFromCommit;
+import static org.ethereum.jsontestsuite.suite.JSONReader.loadJSONsFromCommit;
 
 /**
  * @author Mikhail Kalinin
@@ -49,8 +50,12 @@ private static void run(List<String> checkFiles,
         if (checkFiles.isEmpty()) return;
 
         List<BlockTestSuite> suites = new ArrayList<>();
+        List<String> filenames = new ArrayList<>();
         for (String file : checkFiles) {
-            String json = loadJSONFromCommit(TEST_ROOT + file, commitSHA);
+            filenames.add(TEST_ROOT + file);
+        }
+        List<String> jsons = loadJSONsFromCommit(filenames, commitSHA, 64);
+        for (String json : jsons) {
             suites.add(new BlockTestSuite(json));
         }
 

ethereumj-core/src/test/java/org/ethereum/jsontestsuite/suite/JSONReader.java

@@ -31,6 +31,7 @@
 import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.*;
 
 import org.apache.commons.codec.binary.Base64;
 import org.slf4j.Logger;
@@ -40,6 +41,31 @@ public class JSONReader {
 
     private static Logger logger = LoggerFactory.getLogger("TCK-Test");
 
+    public static List<String> loadJSONsFromCommit(List<String> filenames, final String shacommit, int threads) {
+        ExecutorService threadPool = Executors.newFixedThreadPool(threads);
+        List<Future<String>> retF = new ArrayList<>();
+        for (final String filename : filenames) {
+            Future<String> f = threadPool.submit(new Callable<String>() {
+                @Override
+                public String call() throws Exception {
+                    return loadJSONFromCommit(filename, shacommit);
+                }
+            });
+            retF.add(f);
+        }
+
+        List<String> ret = new ArrayList<>();
+        for (Future<String> f : retF) {
+            try {
+                ret.add(f.get());
+            } catch (InterruptedException | ExecutionException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+        return ret;
+    }
+
     public static String loadJSON(String filename) {
         String json = "";
         if (!SystemProperties.getDefault().vmTestLoadLocal())