8339711: ZipFile.Source.initCEN needlessly reads END header

Reviewed-by: lancea, jpai, redestad

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

@@ -63,6 +63,7 @@
 import jdk.internal.access.JavaUtilZipFileAccess;
 import jdk.internal.access.JavaUtilJarAccess;
 import jdk.internal.access.SharedSecrets;
+import jdk.internal.util.ArraysSupport;
 import jdk.internal.util.OperatingSystem;
 import jdk.internal.perf.PerfCounter;
 import jdk.internal.ref.CleanerFactory;
@@ -1178,14 +1179,16 @@ private static class Source {
  // "META-INF/".length()
  private static final int META_INF_LEN = 9;
  private static final int[] EMPTY_META_VERSIONS = new int[0];
+ // CEN size is limited to the maximum array size in the JDK
+ private static final int MAX_CEN_SIZE = ArraysSupport.SOFT_MAX_ARRAY_LENGTH;
 
  private final Key key; // the key in files
  private final @Stable ZipCoder zc; // ZIP coder used to decode/encode
 
  private int refs = 1;
 
  private RandomAccessFile zfile; // zfile of the underlying ZIP file
- private byte[] cen; // CEN & ENDHDR
+ private byte[] cen; // CEN
  private long locpos; // position of first LOC header (usually 0)
  private byte[] comment; // ZIP file comment
  // list of meta entries in META-INF dir
@@ -1241,7 +1244,7 @@ private int checkAndAddEntry(int pos, int index)
  // should not exceed 65,535 bytes per the PKWare APP.NOTE
  // 4.4.10, 4.4.11, & 4.4.12. Also check that current CEN header will
  // not exceed the length of the CEN array
- if (headerSize > 0xFFFF || pos + headerSize > cen.length - ENDHDR) {
+ if (headerSize > 0xFFFF || pos + headerSize > cen.length) {
  zerror("invalid CEN header (bad header size)");
  }
 
@@ -1294,7 +1297,7 @@ private void checkExtraFields(int cenPos, int startingOffset,
  }
  // CEN Offset where this Extra field ends
  int extraEndOffset = startingOffset + extraFieldLen;
- if (extraEndOffset > cen.length - ENDHDR) {
+ if (extraEndOffset > cen.length) {
  zerror("Invalid CEN header (extra data field size too long)");
  }
  int currentOffset = startingOffset;
@@ -1732,12 +1735,12 @@ private void initCEN(int knownTotal) throws IOException {
  if (locpos < 0) {
  zerror("invalid END header (bad central directory offset)");
  }
- // read in the CEN and END
- if (end.cenlen + ENDHDR >= Integer.MAX_VALUE) {
+ // read in the CEN
+ if (end.cenlen > MAX_CEN_SIZE) {
  zerror("invalid END header (central directory size too large)");
  }
- cen = this.cen = new byte[(int)(end.cenlen + ENDHDR)];
- if (readFullyAt(cen, 0, cen.length, cenpos) != end.cenlen + ENDHDR) {
+ cen = this.cen = new byte[(int)end.cenlen];
+ if (readFullyAt(cen, 0, cen.length, cenpos) != end.cenlen) {
  zerror("read CEN tables failed");
  }
  this.total = end.centot;
@@ -1766,7 +1769,7 @@ private void initCEN(int knownTotal) throws IOException {
  int idx = 0; // Index into the entries array
  int pos = 0;
  int entryPos = CENHDR;
- int limit = cen.length - ENDHDR;
+ int limit = cen.length;
  manifestNum = 0;
  while (entryPos <= limit) {
  if (idx >= entriesLength) {
@@ -1829,7 +1832,7 @@ private void initCEN(int knownTotal) throws IOException {
  } else {
  metaVersions = EMPTY_META_VERSIONS;
  }
- if (pos + ENDHDR != cen.length) {
+ if (pos != cen.length) {
  zerror("invalid CEN header (bad header size)");
  }
  }

test/jdk/java/util/zip/ZipFile/CenSizeTooLarge.java

@@ -23,10 +23,12 @@
 
 /* @test
  * @bug 8272746
+ * @modules java.base/jdk.internal.util
  * @summary Verify that ZipFile rejects a ZIP with a CEN size which does not fit in a Java byte array
  * @run junit CenSizeTooLarge
  */
 
+import jdk.internal.util.ArraysSupport;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -49,7 +51,7 @@ public class CenSizeTooLarge {
  public static final int NAME_LENGTH = 10;
 
  // Maximum allowed CEN size allowed by the ZipFile implementation
- static final int MAX_CEN_SIZE = Integer.MAX_VALUE - ZipFile.ENDHDR - 1;
+ static final int MAX_CEN_SIZE = ArraysSupport.SOFT_MAX_ARRAY_LENGTH;
 
  /**
  * From the APPNOTE.txt specification:

test/jdk/java/util/zip/ZipFile/EndOfCenValidation.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, 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
@@ -23,10 +23,12 @@
 
 /* @test
  * @bug 8272746
+ * @modules java.base/jdk.internal.util
  * @summary Verify that ZipFile rejects files with CEN sizes exceeding the implementation limit
  * @run testng/othervm EndOfCenValidation
  */
 
+import jdk.internal.util.ArraysSupport;
 import org.testng.annotations.AfterTest;
 import org.testng.annotations.BeforeTest;
 import org.testng.annotations.Test;
@@ -68,7 +70,7 @@ public class EndOfCenValidation {
  private static final int ENDSIZ = ZipFile.ENDSIZ; // Offset of CEN size field within ENDHDR
  private static final int ENDOFF = ZipFile.ENDOFF; // Offset of CEN offset field within ENDHDR
  // Maximum allowed CEN size allowed by ZipFile
- private static int MAX_CEN_SIZE = Integer.MAX_VALUE - ENDHDR - 1;
+ private static int MAX_CEN_SIZE = ArraysSupport.SOFT_MAX_ARRAY_LENGTH;
 
  // Expected message when CEN size does not match file size
  private static final String INVALID_CEN_BAD_SIZE = "invalid END header (bad central directory size)";