1 /* 2 * Copyright 2016, Google LLC 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * Neither the name of Google LLC nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 package com.android.tools.smali.dexlib2.util; 32 33 import com.android.tools.smali.dexlib2.dexbacked.DexBackedDexFile.NotADexFile; 34 import com.android.tools.smali.dexlib2.dexbacked.DexBackedOdexFile.NotAnOdexFile; 35 import com.android.tools.smali.dexlib2.dexbacked.raw.CdexHeaderItem; 36 import com.android.tools.smali.dexlib2.dexbacked.raw.HeaderItem; 37 import com.android.tools.smali.dexlib2.dexbacked.raw.OdexHeaderItem; 38 import com.android.tools.smali.util.InputStreamUtil; 39 40 import javax.annotation.Nonnull; 41 import java.io.EOFException; 42 import java.io.IOException; 43 import java.io.InputStream; 44 45 public class DexUtil { 46 47 /** 48 * Reads in the dex header from the given input stream and verifies that it is valid and a supported version 49 * 50 * The inputStream must support mark(), and will be reset to initial position upon exiting the method 51 * 52 * @param inputStream An input stream that is positioned at a dex header 53 * @return The dex version 54 * @throws NotADexFile If the file is not a dex file 55 * @throws InvalidFile If the header appears to be a dex file, but is not valid for some reason 56 * @throws UnsupportedFile If the dex header is valid, but uses unsupported functionality 57 */ verifyDexHeader(@onnull InputStream inputStream)58 public static int verifyDexHeader(@Nonnull InputStream inputStream) throws IOException { 59 if (!inputStream.markSupported()) { 60 throw new IllegalArgumentException("InputStream must support mark"); 61 } 62 inputStream.mark(44); 63 byte[] partialHeader = new byte[44]; 64 try { 65 InputStreamUtil.readFully(inputStream, partialHeader); 66 } catch (EOFException ex) { 67 throw new NotADexFile("File is too short"); 68 } finally { 69 inputStream.reset(); 70 } 71 72 return verifyDexHeader(partialHeader, 0); 73 } 74 75 /** 76 * Verifies that the dex header is valid and a supported version 77 * 78 * @param buf A byte array containing at least the first 44 bytes of a dex file 79 * @param offset The offset within the array to the dex header 80 * @return The dex version 81 * @throws NotADexFile If the file is not a dex file 82 * @throws InvalidFile If the header appears to be a dex file, but is not valid for some reason 83 * @throws UnsupportedFile If the dex header is valid, but uses unsupported functionality 84 */ verifyDexHeader(@onnull byte[] buf, int offset)85 public static int verifyDexHeader(@Nonnull byte[] buf, int offset) { 86 int dexVersion = HeaderItem.getVersion(buf, offset); 87 if (dexVersion == -1) { 88 StringBuilder sb = new StringBuilder("Not a valid dex magic value:"); 89 for (int i=0; i<8; i++) { 90 sb.append(String.format(" %02x", buf[i])); 91 } 92 throw new NotADexFile(sb.toString()); 93 } 94 95 if (!HeaderItem.isSupportedDexVersion(dexVersion)) { 96 throw new UnsupportedFile(String.format("Dex version %03d is not supported", dexVersion)); 97 } 98 99 int endian = HeaderItem.getEndian(buf, offset); 100 if (endian == HeaderItem.BIG_ENDIAN_TAG) { 101 throw new UnsupportedFile("Big endian dex files are not supported"); 102 } 103 104 if (endian != HeaderItem.LITTLE_ENDIAN_TAG) { 105 throw new InvalidFile(String.format("Invalid endian tag: 0x%x", endian)); 106 } 107 108 return dexVersion; 109 } 110 111 /** 112 * Verifies that the cdex header is valid and a supported version 113 * 114 * @param buf A byte array containing at least the first 44 bytes of a cdex file 115 * @param offset The offset within the array to the dex header 116 * @return The dex version 117 * @throws NotADexFile If the file is not a cdex file 118 * @throws InvalidFile If the header appears to be a cdex file, but is not valid for some reason 119 * @throws UnsupportedFile If the cdex header is valid, but uses unsupported functionality 120 */ verifyCdexHeader(@onnull byte[] buf, int offset)121 public static int verifyCdexHeader(@Nonnull byte[] buf, int offset) { 122 int cdexVersion = CdexHeaderItem.getVersion(buf, offset); 123 if (cdexVersion == -1) { 124 StringBuilder sb = new StringBuilder("Not a valid cdex magic value:"); 125 for (int i=0; i<8; i++) { 126 sb.append(String.format(" %02x", buf[offset + i])); 127 } 128 throw new NotADexFile(sb.toString()); 129 } 130 131 if (!CdexHeaderItem.isSupportedCdexVersion(cdexVersion)) { 132 throw new UnsupportedFile(String.format("Dex version %03d is not supported", cdexVersion)); 133 } 134 135 int endian = HeaderItem.getEndian(buf, offset); 136 if (endian == HeaderItem.BIG_ENDIAN_TAG) { 137 throw new UnsupportedFile("Big endian dex files are not supported"); 138 } 139 140 if (endian != HeaderItem.LITTLE_ENDIAN_TAG) { 141 throw new InvalidFile(String.format("Invalid endian tag: 0x%x", endian)); 142 } 143 144 return cdexVersion; 145 } 146 147 /** 148 * Reads in the odex header from the given input stream and verifies that it is valid and a supported version 149 * 150 * The inputStream must support mark(), and will be reset to initial position upon exiting the method 151 * 152 * @param inputStream An input stream that is positioned at an odex header 153 * @throws NotAnOdexFile If the file is not an odex file 154 * @throws UnsupportedFile If the odex header is valid, but is an unsupported version 155 */ verifyOdexHeader(@onnull InputStream inputStream)156 public static void verifyOdexHeader(@Nonnull InputStream inputStream) throws IOException { 157 if (!inputStream.markSupported()) { 158 throw new IllegalArgumentException("InputStream must support mark"); 159 } 160 inputStream.mark(8); 161 byte[] partialHeader = new byte[8]; 162 try { 163 InputStreamUtil.readFully(inputStream, partialHeader); 164 } catch (EOFException ex) { 165 throw new NotAnOdexFile("File is too short"); 166 } finally { 167 inputStream.reset(); 168 } 169 170 verifyOdexHeader(partialHeader, 0); 171 } 172 173 /** 174 * Verifies that the odex header is valid and a supported version 175 * 176 * @param buf A byte array containing at least the first 8 bytes of an odex file 177 * @param offset The offset within the array to the odex header 178 * @throws NotAnOdexFile If the file is not an odex file 179 * @throws UnsupportedFile If the odex header is valid, but uses unsupported functionality 180 */ verifyOdexHeader(@onnull byte[] buf, int offset)181 public static void verifyOdexHeader(@Nonnull byte[] buf, int offset) { 182 int odexVersion = OdexHeaderItem.getVersion(buf, offset); 183 if (odexVersion == -1) { 184 StringBuilder sb = new StringBuilder("Not a valid odex magic value:"); 185 for (int i=0; i<8; i++) { 186 sb.append(String.format(" %02x", buf[i])); 187 } 188 throw new NotAnOdexFile(sb.toString()); 189 } 190 191 if (!OdexHeaderItem.isSupportedOdexVersion(odexVersion)) { 192 throw new UnsupportedFile(String.format("Odex version %03d is not supported", odexVersion)); 193 } 194 } 195 196 public static class InvalidFile extends RuntimeException { InvalidFile()197 public InvalidFile() { 198 } 199 InvalidFile(String message)200 public InvalidFile(String message) { 201 super(message); 202 } 203 InvalidFile(String message, Throwable cause)204 public InvalidFile(String message, Throwable cause) { 205 super(message, cause); 206 } 207 InvalidFile(Throwable cause)208 public InvalidFile(Throwable cause) { 209 super(cause); 210 } 211 } 212 213 public static class UnsupportedFile extends RuntimeException { UnsupportedFile()214 public UnsupportedFile() { 215 } 216 UnsupportedFile(String message)217 public UnsupportedFile(String message) { 218 super(message); 219 } 220 UnsupportedFile(String message, Throwable cause)221 public UnsupportedFile(String message, Throwable cause) { 222 super(message, cause); 223 } 224 UnsupportedFile(Throwable cause)225 public UnsupportedFile(Throwable cause) { 226 super(cause); 227 } 228 } 229 } 230