1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 // This file is a nearly line-for-line copy of bspatch.c from the 18 // bsdiff-4.3 distribution; the primary differences being how the 19 // input and output data are read and the error handling. Running 20 // applypatch with the -l option will display the bsdiff license 21 // notice. 22 23 #include <stdio.h> 24 #include <sys/stat.h> 25 #include <errno.h> 26 #include <unistd.h> 27 #include <string.h> 28 29 #include <bzlib.h> 30 31 #include "mincrypt/sha.h" 32 #include "applypatch.h" 33 34 void ShowBSDiffLicense() { 35 puts("The bsdiff library used herein is:\n" 36 "\n" 37 "Copyright 2003-2005 Colin Percival\n" 38 "All rights reserved\n" 39 "\n" 40 "Redistribution and use in source and binary forms, with or without\n" 41 "modification, are permitted providing that the following conditions\n" 42 "are met:\n" 43 "1. Redistributions of source code must retain the above copyright\n" 44 " notice, this list of conditions and the following disclaimer.\n" 45 "2. Redistributions in binary form must reproduce the above copyright\n" 46 " notice, this list of conditions and the following disclaimer in the\n" 47 " documentation and/or other materials provided with the distribution.\n" 48 "\n" 49 "THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR\n" 50 "IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED\n" 51 "WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE\n" 52 "ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY\n" 53 "DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL\n" 54 "DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS\n" 55 "OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)\n" 56 "HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,\n" 57 "STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING\n" 58 "IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\n" 59 "POSSIBILITY OF SUCH DAMAGE.\n" 60 "\n------------------\n\n" 61 "This program uses Julian R Seward's \"libbzip2\" library, available\n" 62 "from http://www.bzip.org/.\n" 63 ); 64 } 65 66 static off_t offtin(u_char *buf) 67 { 68 off_t y; 69 70 y=buf[7]&0x7F; 71 y=y*256;y+=buf[6]; 72 y=y*256;y+=buf[5]; 73 y=y*256;y+=buf[4]; 74 y=y*256;y+=buf[3]; 75 y=y*256;y+=buf[2]; 76 y=y*256;y+=buf[1]; 77 y=y*256;y+=buf[0]; 78 79 if(buf[7]&0x80) y=-y; 80 81 return y; 82 } 83 84 int FillBuffer(unsigned char* buffer, int size, bz_stream* stream) { 85 stream->next_out = (char*)buffer; 86 stream->avail_out = size; 87 while (stream->avail_out > 0) { 88 int bzerr = BZ2_bzDecompress(stream); 89 if (bzerr != BZ_OK && bzerr != BZ_STREAM_END) { 90 printf("bz error %d decompressing\n", bzerr); 91 return -1; 92 } 93 if (stream->avail_out > 0) { 94 printf("need %d more bytes\n", stream->avail_out); 95 } 96 } 97 return 0; 98 } 99 100 int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size, 101 const Value* patch, ssize_t patch_offset, 102 SinkFn sink, void* token, SHA_CTX* ctx) { 103 104 unsigned char* new_data; 105 ssize_t new_size; 106 if (ApplyBSDiffPatchMem(old_data, old_size, patch, patch_offset, 107 &new_data, &new_size) != 0) { 108 return -1; 109 } 110 111 if (sink(new_data, new_size, token) < new_size) { 112 printf("short write of output: %d (%s)\n", errno, strerror(errno)); 113 return 1; 114 } 115 if (ctx) SHA_update(ctx, new_data, new_size); 116 free(new_data); 117 118 return 0; 119 } 120 121 int ApplyBSDiffPatchMem(const unsigned char* old_data, ssize_t old_size, 122 const Value* patch, ssize_t patch_offset, 123 unsigned char** new_data, ssize_t* new_size) { 124 // Patch data format: 125 // 0 8 "BSDIFF40" 126 // 8 8 X 127 // 16 8 Y 128 // 24 8 sizeof(newfile) 129 // 32 X bzip2(control block) 130 // 32+X Y bzip2(diff block) 131 // 32+X+Y ??? bzip2(extra block) 132 // with control block a set of triples (x,y,z) meaning "add x bytes 133 // from oldfile to x bytes from the diff block; copy y bytes from the 134 // extra block; seek forwards in oldfile by z bytes". 135 136 unsigned char* header = (unsigned char*) patch->data + patch_offset; 137 if (memcmp(header, "BSDIFF40", 8) != 0) { 138 printf("corrupt bsdiff patch file header (magic number)\n"); 139 return 1; 140 } 141 142 ssize_t ctrl_len, data_len; 143 ctrl_len = offtin(header+8); 144 data_len = offtin(header+16); 145 *new_size = offtin(header+24); 146 147 if (ctrl_len < 0 || data_len < 0 || *new_size < 0) { 148 printf("corrupt patch file header (data lengths)\n"); 149 return 1; 150 } 151 152 int bzerr; 153 154 bz_stream cstream; 155 cstream.next_in = patch->data + patch_offset + 32; 156 cstream.avail_in = ctrl_len; 157 cstream.bzalloc = NULL; 158 cstream.bzfree = NULL; 159 cstream.opaque = NULL; 160 if ((bzerr = BZ2_bzDecompressInit(&cstream, 0, 0)) != BZ_OK) { 161 printf("failed to bzinit control stream (%d)\n", bzerr); 162 } 163 164 bz_stream dstream; 165 dstream.next_in = patch->data + patch_offset + 32 + ctrl_len; 166 dstream.avail_in = data_len; 167 dstream.bzalloc = NULL; 168 dstream.bzfree = NULL; 169 dstream.opaque = NULL; 170 if ((bzerr = BZ2_bzDecompressInit(&dstream, 0, 0)) != BZ_OK) { 171 printf("failed to bzinit diff stream (%d)\n", bzerr); 172 } 173 174 bz_stream estream; 175 estream.next_in = patch->data + patch_offset + 32 + ctrl_len + data_len; 176 estream.avail_in = patch->size - (patch_offset + 32 + ctrl_len + data_len); 177 estream.bzalloc = NULL; 178 estream.bzfree = NULL; 179 estream.opaque = NULL; 180 if ((bzerr = BZ2_bzDecompressInit(&estream, 0, 0)) != BZ_OK) { 181 printf("failed to bzinit extra stream (%d)\n", bzerr); 182 } 183 184 *new_data = malloc(*new_size); 185 if (*new_data == NULL) { 186 printf("failed to allocate %ld bytes of memory for output file\n", 187 (long)*new_size); 188 return 1; 189 } 190 191 off_t oldpos = 0, newpos = 0; 192 off_t ctrl[3]; 193 off_t len_read; 194 int i; 195 unsigned char buf[24]; 196 while (newpos < *new_size) { 197 // Read control data 198 if (FillBuffer(buf, 24, &cstream) != 0) { 199 printf("error while reading control stream\n"); 200 return 1; 201 } 202 ctrl[0] = offtin(buf); 203 ctrl[1] = offtin(buf+8); 204 ctrl[2] = offtin(buf+16); 205 206 if (ctrl[0] < 0 || ctrl[1] < 0) { 207 printf("corrupt patch (negative byte counts)\n"); 208 return 1; 209 } 210 211 // Sanity check 212 if (newpos + ctrl[0] > *new_size) { 213 printf("corrupt patch (new file overrun)\n"); 214 return 1; 215 } 216 217 // Read diff string 218 if (FillBuffer(*new_data + newpos, ctrl[0], &dstream) != 0) { 219 printf("error while reading diff stream\n"); 220 return 1; 221 } 222 223 // Add old data to diff string 224 for (i = 0; i < ctrl[0]; ++i) { 225 if ((oldpos+i >= 0) && (oldpos+i < old_size)) { 226 (*new_data)[newpos+i] += old_data[oldpos+i]; 227 } 228 } 229 230 // Adjust pointers 231 newpos += ctrl[0]; 232 oldpos += ctrl[0]; 233 234 // Sanity check 235 if (newpos + ctrl[1] > *new_size) { 236 printf("corrupt patch (new file overrun)\n"); 237 return 1; 238 } 239 240 // Read extra string 241 if (FillBuffer(*new_data + newpos, ctrl[1], &estream) != 0) { 242 printf("error while reading extra stream\n"); 243 return 1; 244 } 245 246 // Adjust pointers 247 newpos += ctrl[1]; 248 oldpos += ctrl[2]; 249 } 250 251 BZ2_bzDecompressEnd(&cstream); 252 BZ2_bzDecompressEnd(&dstream); 253 BZ2_bzDecompressEnd(&estream); 254 return 0; 255 } 256
