8277087: ZipException: zip END header not found at ZipFile#Source.findEND

Reviewed-by: lancea

Author: mrserb

src/java.base/share/classes/java/util/zip/ZipOutputStream.java

@@ -144,11 +144,14 @@ public ZipOutputStream(OutputStream out, Charset charset) {
      *            ZIP file comment is greater than 0xFFFF bytes
      */
     public void setComment(String comment) {
+        byte[] bytes = null;
         if (comment != null) {
-            this.comment = zc.getBytes(comment);
-            if (this.comment.length > 0xffff)
-                throw new IllegalArgumentException("ZIP file comment too long.");
+            bytes = zc.getBytes(comment);
+            if (bytes.length > 0xffff) {
+                throw new IllegalArgumentException("ZIP file comment too long");
+            }
         }
+        this.comment = bytes;
     }
 
     /**

test/jdk/java/util/zip/ZipOutputStream/EmptyComment.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.io.ByteArrayOutputStream;
+import java.util.function.Consumer;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+import java.util.zip.ZipOutputStream;
+
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+
+import static org.testng.Assert.assertThrows;
+
+/**
+ * @test
+ * @bug 8277087
+ * @summary Verifies various use cases when the zip comment should be empty
+ * @run testng EmptyComment
+ */
+public final class EmptyComment {
+
+    @DataProvider()
+    Object[][] longLengths() {
+        return new Object[][]{{0xFFFF + 1}, {0xFFFF + 2}, {0xFFFF * 2}};
+    }
+
+    /**
+     * Overflow, the text is too long to be stored as a comment.
+     */
+    @Test(dataProvider = "longLengths")
+    void testOverflow(int length) throws Exception {
+        test(zos -> assertThrows(IllegalArgumentException.class, () -> {
+            zos.setComment("X".repeat(length));
+        }));
+    }
+
+    /**
+     * Simple cases where the comment is set to the empty text.
+     */
+    @Test
+    void testSimpleCases() throws Exception {
+        test(zos -> {/* do nothing */});
+        test(zos -> zos.setComment(null));
+        test(zos -> zos.setComment(""));
+        test(zos -> {
+            zos.setComment("");
+            zos.setComment(null);
+        });
+        test(zos -> {
+            zos.setComment(null);
+            zos.setComment("");
+        });
+        test(zos -> {
+            zos.setComment("Comment");
+            zos.setComment(null);
+        });
+        test(zos -> {
+            zos.setComment("Comment");
+            zos.setComment("");
+        });
+    }
+
+    private static void test(Consumer<ZipOutputStream> test) throws Exception {
+        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
+             ZipOutputStream zos = new ZipOutputStream(baos)) {
+
+            test.accept(zos);
+
+            zos.putNextEntry(new ZipEntry("x"));
+            zos.finish();
+
+            byte[] data = baos.toByteArray();
+
+            if (data.length > 0xFFFF) { // just in case
+                throw new RuntimeException("data is too big: " + data.length);
+            }
+            int pk = data.length - ZipFile.ENDHDR;
+            if (data[pk] != 'P' || data[pk + 1] != 'K') {
+                throw new RuntimeException("PK is not found");
+            }
+            // Since the comment is empty this will be two last bytes
+            int pos = data.length - ZipFile.ENDHDR + ZipFile.ENDCOM;
+
+            int len = (data[pos] & 0xFF) + ((data[pos + 1] & 0xFF) << 8);
+            if (len != 0) {
+                throw new RuntimeException("zip comment is not empty: " + len);
+            }
+        }
+    }
+}