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 * 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
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 *
 * 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.
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 */

/*
 * @test
 * @bug 8303866
 * @summary ZipInputStream should read 8-byte data descriptors if the LOC has
 *   a ZIP64 extended information extra field
 * @run junit Zip64DataDescriptor
 */


import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.BeforeEach;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.StandardCharsets;
import java.util.HexFormat;
import java.util.zip.*;

import static org.junit.jupiter.api.Assertions.*;

public class Zip64DataDescriptor {

    // A byte array holding a small-sized Zip64 ZIP file, described below
    private byte[] zip64File;

    // A byte array holding a ZIP used for testing invalid Zip64 extra fields
    private byte[] invalidZip64;

    @BeforeEach
    public void setup() throws IOException {
        /*
         * Structure of the ZIP64 file used below . Note the presence
         * of a Zip64 extended information extra field and the
         * Data Descriptor having 8-byte values for csize and size.
         *
         * The file was produced using the zip command on MacOS
         * (zip 3.0, by Info-ZIP), in streamming mode (to enable Zip64),
         * using the -fd option (to force the use of data descriptors)
         *
         * The following command was used:
         * <pre>echo hello | zip -fd > hello.zip</pre>
         *
         * ------  Local File Header  ------
         * 000000  signature          0x04034b50
         * 000004  version            45
         * 000006  flags              0x0008
         * 000008  method             8              Deflated
         * 000010  time               0xb180         22:12
         * 000012  date               0x565c         2023-02-28
         * 000014  crc                0x00000000
         * 000018  csize              -1
         * 000022  size               -1
         * 000026  nlen               1
         * 000028  elen               20
         * 000030  name               1 bytes        '-'
         * 000031  ext id             0x0001         Zip64 extended information extra field
         * 000033  ext size           16
         * 000035  z64 size           0
         * 000043  z64 csize          0
         *
         * ------  File Data  ------
         * 000051  data               8 bytes
         *
         * ------  Data Desciptor  ------
         * 000059  signature          0x08074b50
         * 000063  crc                0x363a3020
         * 000067  csize              8
         * 000075  size               6
         * 000083  ...
         */

        String hex = """
                504b03042d000800080080b15c5600000000ffffffffffffffff01001400
                2d0100100000000000000000000000000000000000cb48cdc9c9e7020050
                4b070820303a3608000000000000000600000000000000504b01021e032d
                000800080080b15c5620303a360800000006000000010000000000000001
                000000b011000000002d504b050600000000010001002f00000053000000
                0000""";

        zip64File = HexFormat.of().parseHex(hex.replaceAll("\n", ""));

        // Create the ZIP file used for testing that invalid Zip64 extra fields are ignored
        // This ZIP has the regular 4-bit data descriptor

        byte[] extra = new byte[Long.BYTES + Long.BYTES + Short.BYTES * 2]; // Size of a regular Zip64 extra field
        ByteBuffer buffer = ByteBuffer.wrap(extra).order(ByteOrder.LITTLE_ENDIAN);
        buffer.putShort(0, (short) 123); // Not processed by ZipEntry.setExtra
        buffer.putShort(Short.BYTES, (short) (extra.length - 4));

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try (ZipOutputStream zo = new ZipOutputStream(baos)) {
            ZipEntry ze = new ZipEntry("-");
            ze.setExtra(extra);
            zo.putNextEntry(ze);
            zo.write("hello\n".getBytes(StandardCharsets.UTF_8));
        }

        invalidZip64 = baos.toByteArray();

        // Set Zip64 magic values on compressed and uncompressed size fields
        ByteBuffer.wrap(invalidZip64).order(ByteOrder.LITTLE_ENDIAN)
                .putInt(ZipFile.LOCSIZ, 0xFFFFFFFF)
                .putInt(ZipFile.LOCLEN, 0xFFFFFFFF);

        // Set the Zip64 header ID 0x1 on the extra field in the invalid file
        setExtraHeaderId((short) 0x1);
    }

    /*
     * Verify that small-sized Zip64 entries can be parsed by ZipInputStream
     */
    @Test
    public void shouldReadZip64Descriptor() throws IOException {
        readZipInputStream(zip64File);
    }

    /*
     * For maximal backward compatibility when reading Zip64 descriptors, invalid
     * Zip64 extra data sizes should be ignored
     */
    @Test
    public void shouldIgnoreInvalidExtraSize() throws IOException {
        setExtraSize((short) 42);
        readZipInputStream(invalidZip64);
    }

    /*
     * Files with Zip64 magic values but no Zip64 field should be ignored
     * when considering 8 byte data descriptors
     */
    @Test
    public void shouldIgnoreNoZip64Header() throws IOException {
        setExtraSize((short) 123);
        readZipInputStream(invalidZip64);
    }

    /*
     * Theoretically, ZIP files may exist with ZIP64 format, but with 4-byte
     * data descriptors. Such files will fail to parse, as demonstrated by this test.
     */
    @Test
    public void shouldFailParsingZip64With4ByteDataDescriptor() throws IOException {
        ZipException ex = assertThrows(ZipException.class, () -> {
            readZipInputStream(invalidZip64);
        });

        String msg = String.format("Expected exeption message to contain 'invalid entry size', was %s",
                ex.getMessage());
        assertTrue(ex.getMessage().contains("invalid entry size"), msg);
    }

    /*
     * Validate that an extra data size exceeding the length of the extra field is ignored
     */
    @Test
    public void shouldIgnoreExcessiveExtraSize() throws IOException {

        setExtraSize(Short.MAX_VALUE);


        readZipInputStream(invalidZip64);
    }

    /*
     * Validate that the Data Descriptor is read with 32-bit fields if neither the
     * LOC's 'uncompressed size' or 'compressed size' fields have the Zip64 magic value,
     * even when there is a Zip64 field in the extra field.
     */
    @Test
    public void shouldIgnoreNoMagicMarkers() throws IOException {
        // Set compressed and uncompressed size fields to zero
        ByteBuffer.wrap(invalidZip64).order(ByteOrder.LITTLE_ENDIAN)
                .putInt(ZipFile.LOCSIZ, 0)
                .putInt(ZipFile.LOCLEN, 0);


        readZipInputStream(invalidZip64);
    }

    /*
     * Validate that an extra data size exceeding the length of the extra field is ignored
     */
    @Test
    public void shouldIgnoreTrucatedZip64Extra() throws IOException {

        truncateZip64();

        readZipInputStream(invalidZip64);
    }

    /**
     * Update the Extra field header ID of the invalid file
     */
    private void setExtraHeaderId(short id) {
        // Set the header ID on the extra field
        ByteBuffer buffer = ByteBuffer.wrap(invalidZip64).order(ByteOrder.LITTLE_ENDIAN);
        int nlen = buffer.getShort(ZipFile.LOCNAM);
        buffer.putShort(ZipFile.LOCHDR + nlen, id);
    }

    /**
     * Updates the 16-bit 'data size' field of the Zip64 extended information field,
     * potentially to an invalid value.
     * @param size the value to set in the 'data size' field.
     */
    private void setExtraSize(short size) {
        ByteBuffer buffer = ByteBuffer.wrap(invalidZip64).order(ByteOrder.LITTLE_ENDIAN);
        // Compute the offset to the Zip64 data block size field
        short nlen = buffer.getShort(ZipFile.LOCNAM);
        int dataSizeOffset = ZipFile.LOCHDR + nlen + Short.BYTES;
        buffer.putShort(dataSizeOffset, size);
    }

    /**
     * Puts a truncated Zip64 field (just the tag) at the end of the LOC extra field.
     * The beginning of the extra field is filled with a generic extra field containing
     * just zeros.
     */
    private void truncateZip64() {
        ByteBuffer buffer = ByteBuffer.wrap(invalidZip64).order(ByteOrder.LITTLE_ENDIAN);
        // Get the LOC name and extra sizes
        short nlen = buffer.getShort(ZipFile.LOCNAM);
        short elen = buffer.getShort(ZipFile.LOCEXT);
        int cenOffset = ZipFile.LOCHDR + nlen + elen;

        // Zero out the extra field
        int estart = ZipFile.LOCHDR + nlen;
        buffer.put(estart, new byte[elen]);
        // Put a generic extra field in the start
        buffer.putShort(estart, (short) 42);
        buffer.putShort(estart + Short.BYTES, (short) (elen - 4 - 2));
        // Put a truncated (just the tag) Zip64 field at the end
        buffer.putShort(cenOffset - Short.BYTES, (short) 0x0001);
    }

    /*
     * Consume and verify the ZIP file using ZipInputStream
     */
    private void readZipInputStream(byte[] zip) throws IOException {
        try (ZipInputStream in = new ZipInputStream(new ByteArrayInputStream(zip))) {
            // Read the ZIP entry, this calls readLOC
            ZipEntry e = in.getNextEntry();

            // Sanity check the zip entry
            assertNotNull(e, "Missing zip entry");
            assertEquals("-", e.getName());

            // Read the entry data, this causes readEND to parse the data descriptor
            assertEquals("hello\n", new String(in.readAllBytes(), StandardCharsets.UTF_8));

            // There should only be a single zip entry
            assertNull(in.getNextEntry(), "Unexpected additional zip entry");
        }
    }
}