Additional check when unpacking archives. Contributed by Wilfred Spiegelenburg.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/RunJar.java

@@ -109,6 +109,7 @@ public class RunJar {
       throws IOException {
     try (JarFile jar = new JarFile(jarFile)) {
       int numOfFailedLastModifiedSet = 0;
+      String targetDirPath = toDir.getCanonicalPath() + File.separator;
       Enumeration<JarEntry> entries = jar.entries();
       while (entries.hasMoreElements()) {
         final JarEntry entry = entries.nextElement();
@@ -117,6 +118,10 @@ public class RunJar {
           try (InputStream in = jar.getInputStream(entry)) {
             File file = new File(toDir, entry.getName());
             ensureDirectory(file.getParentFile());
+            if (!file.getCanonicalPath().startsWith(targetDirPath)) {
+              throw new IOException("expanding " + entry.getName()
+                  + " would create file outside of " + toDir);
+            }
             try (OutputStream out = new FileOutputStream(file)) {
               IOUtils.copyBytes(in, out, BUFFER_SIZE);
             }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestRunJar.java

@@ -20,12 +20,15 @@ package org.apache.hadoop.util;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
 
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.jar.JarEntry;
 import java.util.jar.JarOutputStream;
 import java.util.regex.Pattern;
 import java.util.zip.ZipEntry;
@@ -165,4 +168,37 @@ public class TestRunJar {
     runJar.run(args);
     // it should not throw an exception
   }
+
+  @Test
+  public void testUnJar2() throws IOException {
+    // make a simple zip
+    File jarFile = new File(TEST_ROOT_DIR, TEST_JAR_NAME);
+    JarOutputStream jstream =
+        new JarOutputStream(new FileOutputStream(jarFile));
+    JarEntry je = new JarEntry("META-INF/MANIFEST.MF");
+    byte[] data = "Manifest-Version: 1.0\nCreated-By: 1.8.0_1 (Manual)"
+        .getBytes(StandardCharsets.UTF_8);
+    je.setSize(data.length);
+    jstream.putNextEntry(je);
+    jstream.write(data);
+    jstream.closeEntry();
+    je = new JarEntry("../outside.path");
+    data = "any data here".getBytes(StandardCharsets.UTF_8);
+    je.setSize(data.length);
+    jstream.putNextEntry(je);
+    jstream.write(data);
+    jstream.closeEntry();
+    jstream.close();
+
+    File unjarDir = getUnjarDir("unjar-path");
+
+    // Unjar everything
+    try {
+      RunJar.unJar(jarFile, unjarDir);
+      fail("unJar should throw IOException.");
+    } catch (IOException e) {
+      GenericTestUtils.assertExceptionContains(
+          "would create file outside of", e);
+    }
+  }
 }