CAMEL-23319: Add deserialization filtering to camel-mina converter

components/camel-mina/src/main/java/org/apache/camel/component/mina/MinaConverter.java

@@ -19,18 +19,28 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.ObjectInput;
+import java.io.ObjectInputFilter;
 import java.io.ObjectInputStream;
 
 import org.apache.camel.Converter;
 import org.apache.camel.Exchange;
 import org.apache.camel.StreamCache;
 import org.apache.mina.core.buffer.IoBuffer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * A set of converter methods for working with MINA types
  */
 @Converter(generateLoader = true)
 public final class MinaConverter {
+    private static final Logger LOG = LoggerFactory.getLogger(MinaConverter.class);
+
+    /**
+     * Default deserialization filter that restricts which classes can be deserialized. Allows standard Java types and
+     * Apache Camel types. Can be overridden via the JVM system property {@code jdk.serialFilter}.
+     */
+    static final String DEFAULT_DESERIALIZATION_FILTER = "java.**;javax.**;org.apache.camel.**;!*";
 
     private MinaConverter() {
         //Utility Class
@@ -59,7 +69,16 @@ public static InputStream toInputStream(IoBuffer buffer) {
     @Converter
     public static ObjectInput toObjectInput(IoBuffer buffer) throws IOException {
         InputStream is = toInputStream(buffer);
-        return new ObjectInputStream(is);
+        ObjectInputStream ois = new ObjectInputStream(is);
+        ObjectInputFilter jvmFilter = ObjectInputFilter.Config.getSerialFilter();
+        if (jvmFilter != null) {
+            ois.setObjectInputFilter(jvmFilter);
+        } else {
+            LOG.debug("No JVM-wide deserialization filter set, applying default Camel filter: {}",
+                    DEFAULT_DESERIALIZATION_FILTER);
+            ois.setObjectInputFilter(ObjectInputFilter.Config.createFilter(DEFAULT_DESERIALIZATION_FILTER));
+        }
+        return ois;
     }
 
     @Converter

components/camel-mina/src/test/java/com/example/external/NotAllowedSerializable.java

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.example.external;
+
+import java.io.Serializable;
+
+/**
+ * Serializable type living outside the {@code java.**}, {@code javax.**} and {@code org.apache.camel.**} packages, used
+ * to verify that the default deserialization allowlist rejects unknown classes.
+ */
+public final class NotAllowedSerializable implements Serializable {
+    private static final long serialVersionUID = 1L;
+
+    private final String value;
+
+    public NotAllowedSerializable(String value) {
+        this.value = value;
+    }
+
+    public String getValue() {
+        return value;
+    }
+}

components/camel-mina/src/test/java/org/apache/camel/component/mina/MinaConverterTest.java

@@ -16,18 +16,25 @@
  */
 package org.apache.camel.component.mina;
 
+import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
+import java.io.InvalidClassException;
+import java.io.ObjectInput;
+import java.io.ObjectOutputStream;
 import java.io.UnsupportedEncodingException;
 import java.nio.charset.StandardCharsets;
 
+import com.example.external.NotAllowedSerializable;
 import org.apache.camel.Exchange;
 import org.apache.camel.impl.DefaultCamelContext;
 import org.apache.camel.support.DefaultExchange;
 import org.apache.mina.core.buffer.IoBuffer;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 public class MinaConverterTest {
 
@@ -97,4 +104,30 @@ public void testToByteBuffer() {
             assertEquals(in[i], out[i]);
         }
     }
+
+    @Test
+    public void testToObjectInputAcceptsAllowlistedTypes() throws Exception {
+        IoBuffer bb = serialize("hello");
+        try (ObjectInput in = MinaConverter.toObjectInput(bb)) {
+            Object value = in.readObject();
+            assertInstanceOf(String.class, value);
+            assertEquals("hello", value);
+        }
+    }
+
+    @Test
+    public void testToObjectInputRejectsUnlistedTypes() throws Exception {
+        IoBuffer bb = serialize(new NotAllowedSerializable("blocked"));
+        try (ObjectInput in = MinaConverter.toObjectInput(bb)) {
+            assertThrows(InvalidClassException.class, in::readObject);
+        }
+    }
+
+    private static IoBuffer serialize(Object value) throws Exception {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        try (ObjectOutputStream oos = new ObjectOutputStream(baos)) {
+            oos.writeObject(value);
+        }
+        return IoBuffer.wrap(baos.toByteArray());
+    }
 }