src/share/classes/com/sun/crypto/provider/PKCS5Padding.java

rev 12526 : 8171252: Improve exception checking
8158517: Minor optimizations to ISO10126PADDING
Reviewed-by: ascarpino, mschoene

*** 1,7 ****
  /*
!  * Copyright (c) 1997, 2007, 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.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 1997, 2017, 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.  Oracle designates this
*** 24,33 ****
--- 24,34 ----
   */
  
  package com.sun.crypto.provider;
  
  import javax.crypto.ShortBufferException;
+ import java.util.Arrays;
  
  /**
   * This class implements padding as specified in the PKCS#5 standard.
   *
   * @author Gigi Ankeny
*** 61,78 ****
          throws ShortBufferException
      {
          if (in == null)
              return;
  
!         if ((off + len) > in.length) {
              throw new ShortBufferException("Buffer too small to hold padding");
          }
  
          byte paddingOctet = (byte) (len & 0xff);
!         for (int i = 0; i < len; i++) {
!             in[i + off] = paddingOctet;
!         }
          return;
      }
  
      /**
       * Returns the index where the padding starts.
--- 62,78 ----
          throws ShortBufferException
      {
          if (in == null)
              return;
  
!         int idx = Math.addExact(off, len);
!         if (idx > in.length) {
              throw new ShortBufferException("Buffer too small to hold padding");
          }
  
          byte paddingOctet = (byte) (len & 0xff);
!         Arrays.fill(in, off, idx, paddingOctet);
          return;
      }
  
      /**
       * Returns the index where the padding starts.
*** 90,118 ****
      public int unpad(byte[] in, int off, int len) {
          if ((in == null) ||
              (len == 0)) { // this can happen if input is really a padded buffer
              return 0;
          }
! 
!         byte lastByte = in[off + len - 1];
          int padValue = (int)lastByte & 0x0ff;
          if ((padValue < 0x01)
              || (padValue > blockSize)) {
              return -1;
          }
  
!         int start = off + len - ((int)lastByte & 0x0ff);
          if (start < off) {
              return -1;
          }
  
!         for (int i = 0; i < ((int)lastByte & 0x0ff); i++) {
!             if (in[start+i] != lastByte) {
                  return -1;
              }
          }
- 
          return start;
      }
  
      /**
       * Determines how long the padding will be for a given input length.
--- 90,117 ----
      public int unpad(byte[] in, int off, int len) {
          if ((in == null) ||
              (len == 0)) { // this can happen if input is really a padded buffer
              return 0;
          }
!         int idx = Math.addExact(off, len);
!         byte lastByte = in[idx - 1];
          int padValue = (int)lastByte & 0x0ff;
          if ((padValue < 0x01)
              || (padValue > blockSize)) {
              return -1;
          }
  
!         int start = idx - padValue;
          if (start < off) {
              return -1;
          }
  
!         for (int i = start; i < idx; i++) {
!             if (in[i] != lastByte) {
                  return -1;
              }
          }
          return start;
      }
  
      /**
       * Determines how long the padding will be for a given input length.