1 /* 2 * Copyright 2013, Google Inc. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: 8 * 9 * * Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * * Redistributions in binary form must reproduce the above 12 * copyright notice, this list of conditions and the following disclaimer 13 * in the documentation and/or other materials provided with the 14 * distribution. 15 * * Neither the name of Google Inc. nor the names of its 16 * contributors may be used to endorse or promote products derived from 17 * this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 package org.jf.dexlib2.dexbacked.raw; 33 34 import org.jf.dexlib2.dexbacked.BaseDexBuffer; 35 36 public class OdexHeaderItem { 37 public static final int ITEM_SIZE = 40; 38 39 private static final byte[] MAGIC_VALUE = new byte[] { 0x64, 0x65, 0x79, 0x0A, 0x00, 0x00, 0x00, 0x00 }; 40 private static final int[] SUPPORTED_ODEX_VERSIONS = new int[] { 35, 36 }; 41 42 public static final int MAGIC_OFFSET = 0; 43 public static final int MAGIC_LENGTH = 8; 44 public static final int DEX_OFFSET = 8; 45 public static final int DEX_LENGTH_OFFSET = 12; 46 public static final int DEPENDENCIES_OFFSET = 16; 47 public static final int DEPENDENCIES_LENGTH_OFFSET = 20; 48 public static final int AUX_OFFSET = 24; 49 public static final int AUX_LENGTH_OFFSET = 28; 50 public static final int FLAGS_OFFSET = 32; 51 52 /** 53 * Verifies the magic value at the beginning of an odex file 54 * 55 * @param buf A byte array containing at least the first 8 bytes of an odex file 56 * @param offset The offset within the buffer to the beginning of the odex header 57 * @return True if the magic value is valid 58 */ verifyMagic(byte[] buf, int offset)59 public static boolean verifyMagic(byte[] buf, int offset) { 60 if (buf.length - offset < 8) { 61 return false; 62 } 63 64 for (int i=0; i<4; i++) { 65 if (buf[offset + i] != MAGIC_VALUE[i]) { 66 return false; 67 } 68 } 69 for (int i=4; i<7; i++) { 70 if (buf[offset + i] < '0' || 71 buf[offset + i] > '9') { 72 return false; 73 } 74 } 75 if (buf[offset + 7] != MAGIC_VALUE[7]) { 76 return false; 77 } 78 79 return true; 80 } 81 82 /** 83 * Gets the dex version from an odex header 84 * 85 * @param buf A byte array containing at least the first 7 bytes of an odex file 86 * @param offset The offset within the buffer to the beginning of the odex header 87 * @return The odex version if the header is valid or -1 if the header is invalid 88 */ getVersion(byte[] buf, int offset)89 public static int getVersion(byte[] buf, int offset) { 90 if (!verifyMagic(buf, offset)) { 91 return -1; 92 } 93 94 return getVersionUnchecked(buf, offset); 95 } 96 getVersionUnchecked(byte[] buf, int offset)97 private static int getVersionUnchecked(byte[] buf, int offset) { 98 int version = (buf[offset + 4] - '0') * 100; 99 version += (buf[offset + 5] - '0') * 10; 100 version += buf[offset + 6] - '0'; 101 102 return version; 103 } 104 isSupportedOdexVersion(int version)105 public static boolean isSupportedOdexVersion(int version) { 106 for (int i=0; i<SUPPORTED_ODEX_VERSIONS.length; i++) { 107 if (SUPPORTED_ODEX_VERSIONS[i] == version) { 108 return true; 109 } 110 } 111 return false; 112 } 113 getDexOffset(byte[] buf)114 public static int getDexOffset(byte[] buf) { 115 BaseDexBuffer bdb = new BaseDexBuffer(buf); 116 return bdb.readSmallUint(DEX_OFFSET); 117 } 118 getDependenciesOffset(byte[] buf)119 public static int getDependenciesOffset(byte[] buf) { 120 BaseDexBuffer bdb = new BaseDexBuffer(buf); 121 return bdb.readSmallUint(DEPENDENCIES_OFFSET); 122 } 123 } 124