Reject invalid DAP request (microsoft#466)

Author: testforstephen

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/DebugAdapterContext.java

@@ -56,6 +56,7 @@ public class DebugAdapterContext implements IDebugAdapterContext {
     private StepFilters stepFilters;
     private Path classpathJar = null;
     private Path argsfile = null;
+    private boolean isInitialized = false;
 
     private long shellProcessId = -1;
     private long processId = -1;
@@ -407,4 +408,14 @@ public long getJDWPLatency() {
     public void setJDWPLatency(long baseLatency) {
         this.jdwpLatency = baseLatency;
     }
+
+    @Override
+    public boolean isInitialized() {
+        return isInitialized;
+    }
+
+    @Override
+    public void setInitialized(boolean isInitialized) {
+        this.isInitialized = isInitialized;
+    }
 }

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/ErrorCode.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
-* Copyright (c) 2017 Microsoft Corporation and others.
+* Copyright (c) 2017-2022 Microsoft Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
@@ -35,7 +35,8 @@ public enum ErrorCode {
     EXCEPTION_INFO_FAILURE(1018),
     EVALUATION_COMPILE_ERROR(2001),
     EVALUATE_NOT_SUSPENDED_THREAD(2002),
-    HCR_FAILURE(3001);
+    HCR_FAILURE(3001),
+    INVALID_DAP_HEADER(3002);
 
     private int id;
 

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/IDebugAdapterContext.java

@@ -154,4 +154,8 @@ public interface IDebugAdapterContext {
     long getJDWPLatency();
 
     void setJDWPLatency(long baseLatency);
+
+    boolean isInitialized();
+
+    void setInitialized(boolean isInitialized);
 }

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/handler/InitializeRequestHandler.java

@@ -67,6 +67,7 @@ public CompletableFuture<Messages.Response> handle(Requests.Command command, Req
         caps.supportsBreakpointLocationsRequest = true;
         caps.supportsStepInTargetsRequest = true;
         response.body = caps;
+        context.setInitialized(true);
         return CompletableFuture.completedFuture(response);
     }
 }

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/handler/LaunchRequestHandler.java

@@ -77,6 +77,12 @@ public List<Command> getTargetCommands() {
 
     @Override
     public CompletableFuture<Response> handle(Command command, Arguments arguments, Response response, IDebugAdapterContext context) {
+        if (!context.isInitialized()) {
+            final String errorMessage = "'launch' request is rejected since the debug session has not been initialized yet.";
+            logger.log(Level.SEVERE, errorMessage);
+            return CompletableFuture.completedFuture(
+                AdapterUtils.setErrorResponse(response, ErrorCode.LAUNCH_FAILURE, errorMessage));
+        }
         LaunchArguments launchArguments = (LaunchArguments) arguments;
         Map<String, Object> traceInfo = new HashMap<>();
         traceInfo.put("asyncJDWP", context.asyncJDWP());

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/protocol/AbstractProtocolServer.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
-* Copyright (c) 2017 Microsoft Corporation and others.
+* Copyright (c) 2017-2022 Microsoft Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
@@ -33,6 +33,8 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import com.microsoft.java.debug.core.adapter.AdapterUtils;
+import com.microsoft.java.debug.core.adapter.ErrorCode;
 import com.microsoft.java.debug.core.protocol.Events.DebugEvent;
 
 import io.reactivex.disposables.Disposable;
@@ -54,6 +56,7 @@ public abstract class AbstractProtocolServer implements IProtocolServer {
     private ByteBuffer rawData;
     private int contentLength = -1;
     private AtomicInteger sequenceNumber = new AtomicInteger(1);
+    private boolean isValidDAPRequest = true;
 
     private PublishSubject<Messages.Response> responseSubject = PublishSubject.<Messages.Response>create();
     private PublishSubject<Messages.Request> requestSubject = PublishSubject.<Messages.Request>create();
@@ -217,7 +220,14 @@ private void processData() {
 
                         if (message.type.equals("request")) {
                             Messages.Request request = JsonUtils.fromJson(messageData, Messages.Request.class);
-                            requestSubject.onNext(request);
+                            if (this.isValidDAPRequest) {
+                                requestSubject.onNext(request);
+                            } else {
+                                Messages.Response response = new Messages.Response(request.seq, request.command);
+                                sendResponse(AdapterUtils.setErrorResponse(response,
+                                    ErrorCode.INVALID_DAP_HEADER,
+                                    String.format("'%s' request is rejected due to not being a valid DAP message.", request.command)));
+                            }
                         } else if (message.type.equals("response")) {
                             Messages.Response response = JsonUtils.fromJson(messageData, Messages.Response.class);
                             responseSubject.onNext(response);
@@ -235,10 +245,20 @@ private void processData() {
             if (idx != -1) {
                 Matcher matcher = CONTENT_LENGTH_MATCHER.matcher(rawMessage);
                 if (matcher.find()) {
-                    this.contentLength = Integer.parseInt(matcher.group(1));
-                    int headerByteLength = rawMessage.substring(0, idx + TWO_CRLF.length())
-                            .getBytes(PROTOCOL_ENCODING).length;
+                    final String contentLengthText = matcher.group(1);
+                    this.contentLength = Integer.parseInt(contentLengthText);
+                    final String headerMessage = rawMessage.substring(0, idx + TWO_CRLF.length());
+                    final int headerByteLength = headerMessage.getBytes(PROTOCOL_ENCODING).length;
                     this.rawData.removeFirst(headerByteLength); // Remove the header from the raw message.
+
+                    int expectedHeaderLength = 16 /*"Content-Length: ".length()*/ + contentLengthText.length();
+                    int actualHeaderLength = idx;
+                    if (expectedHeaderLength != actualHeaderLength) {
+                        this.isValidDAPRequest = false;
+                        logger.log(Level.SEVERE, String.format("Illegal DAP request is detected: %s", headerMessage));
+                    } else {
+                        this.isValidDAPRequest = true;
+                    }
                     continue;
                 }
             }