8243674: Remove language tag length limit for iTXt chunk in PNGImageReader

Reviewed-by: prr, serb

src/java.desktop/share/classes/com/sun/imageio/plugins/png/PNGImageReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2020, Oracle and/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
@@ -459,13 +459,18 @@ public class PNGImageReader extends ImageReader {
         int compressionMethod = stream.readUnsignedByte();
         metadata.iTXt_compressionMethod.add(Integer.valueOf(compressionMethod));
 
-        String languageTag = readNullTerminatedString("UTF8", 80);
+        long pos = stream.getStreamPosition();
+        int remainingLen = (int)(chunkStart + chunkLength - pos);
+        String languageTag = readNullTerminatedString("UTF8", remainingLen);
         metadata.iTXt_languageTag.add(languageTag);
 
-        long pos = stream.getStreamPosition();
+        pos = stream.getStreamPosition();
-        int maxLen = (int)(chunkStart + chunkLength - pos);
+        remainingLen = (int)(chunkStart + chunkLength - pos);
+        if (remainingLen < 0) {
+            throw new IIOException("iTXt chunk length is not proper");
+        }
         String translatedKeyword =
-            readNullTerminatedString("UTF8", maxLen);
+            readNullTerminatedString("UTF8", remainingLen);
         metadata.iTXt_translatedKeyword.add(translatedKeyword);
 
         String text;

test/jdk/javax/imageio/plugins/png/ReadLongLanguageTagTest.java

@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2020, Oracle and/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.
+ */
+
+/*
+ * @test
+ * @bug     8243674
+ * @summary Test verifies that PNGImageReader is able to read iTXt chunk
+ *          with language tag having length more than 80
+ * @run     main ReadLongLanguageTagTest
+ */
+
+import java.awt.Graphics2D;
+import java.awt.image.BufferedImage;
+import java.awt.Color;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Iterator;
+import javax.imageio.*;
+import javax.imageio.metadata.IIOInvalidTreeException;
+import javax.imageio.metadata.IIOMetadata;
+import javax.imageio.metadata.IIOMetadataNode;
+import javax.imageio.stream.ImageInputStream;
+import javax.imageio.stream.ImageOutputStream;
+
+public class ReadLongLanguageTagTest {
+
+    private static BufferedImage img;
+    private static ImageWriter writer;
+    private static ImageWriteParam param;
+    private static IIOMetadata metadata;
+    private static byte[] imageByteArray;
+
+    private static void initialize(int type) {
+        int width = 1;
+        int height = 1;
+        img = new BufferedImage(width, height, type);
+        Graphics2D g2D = img.createGraphics();
+        g2D.setColor(new Color(255, 255, 255));
+        g2D.fillRect(0, 0, width, width);
+        g2D.dispose();
+
+        Iterator<ImageWriter> iterWriter =
+                ImageIO.getImageWritersBySuffix("png");
+        writer = iterWriter.next();
+
+        param = writer.getDefaultWriteParam();
+        ImageTypeSpecifier specifier =
+                ImageTypeSpecifier.
+                        createFromBufferedImageType(type);
+        metadata = writer.getDefaultImageMetadata(specifier, param);
+    }
+
+    private static void createITXTNode()
+            throws IIOInvalidTreeException {
+        IIOMetadataNode iTXt_Entry = new IIOMetadataNode("iTXtEntry");
+        iTXt_Entry.setAttribute("keyword", "ImageIO");
+        iTXt_Entry.setAttribute("compressionFlag", "FALSE");
+        iTXt_Entry.setAttribute("compressionMethod", "0");
+        iTXt_Entry.setAttribute("languageTag", "en-Java" +
+                "JavaJavaJavaJavaJavaJavaJavaJavaJavaJavaJavaJava" +
+                "JavaJavaJavaJavaJavaJavaJavaJavaJavaJavaJavaJava");
+        iTXt_Entry.setAttribute("translatedKeyword", "");
+        iTXt_Entry.setAttribute("text", "");
+
+        IIOMetadataNode iTXt = new IIOMetadataNode("iTXt");
+        iTXt.appendChild(iTXt_Entry);
+        IIOMetadataNode root = new IIOMetadataNode("javax_imageio_png_1.0");
+        root.appendChild(iTXt);
+        metadata.mergeTree("javax_imageio_png_1.0", root);
+    }
+
+    private static void writeImage() throws IOException {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ImageOutputStream ios = ImageIO.createImageOutputStream(baos);
+        writer.setOutput(ios);
+        writer.write(metadata, new IIOImage(img, null, metadata), param);
+        writer.dispose();
+
+        baos.flush();
+        imageByteArray = baos.toByteArray();
+        baos.close();
+    }
+
+    private static void readITXTChunk() throws IOException {
+        initialize(BufferedImage.TYPE_BYTE_GRAY);
+        // Create iTXt node and merge it with default metadata
+        createITXTNode();
+
+        writeImage();
+
+        InputStream input= new ByteArrayInputStream(imageByteArray);
+        try {
+            Iterator<ImageReader> iterReader =
+                    ImageIO.getImageReadersBySuffix("PNG");
+            if (iterReader.hasNext()) {
+                ImageReader pngImageReader = iterReader.next();
+                ImageReadParam param = pngImageReader.getDefaultReadParam();
+                ImageInputStream imageStream =
+                        ImageIO.createImageInputStream(input);
+                pngImageReader.setInput(imageStream, false, false);
+                pngImageReader.read(0, param);
+            } else {
+                throw new RuntimeException("Requested PNGImageReader" +
+                        " not available");
+            }
+        } finally {
+            input.close();
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        // read PNG image having long language tag in iTXt chunk
+        readITXTChunk();
+    }
+}