1 /* 2 * Copyright (C) 2009 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 // See imgdiff.c in this directory for a description of the patch file 18 // format. 19 20 #include <stdio.h> 21 #include <sys/cdefs.h> 22 #include <sys/stat.h> 23 #include <errno.h> 24 #include <unistd.h> 25 #include <string.h> 26 27 #include "zlib.h" 28 #include "mincrypt/sha.h" 29 #include "applypatch.h" 30 #include "imgdiff.h" 31 #include "utils.h" 32 33 /* 34 * Apply the patch given in 'patch_filename' to the source data given 35 * by (old_data, old_size). Write the patched output to the 'output' 36 * file, and update the SHA context with the output data as well. 37 * Return 0 on success. 38 */ 39 int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size __unused, 40 const Value* patch, 41 SinkFn sink, void* token, SHA_CTX* ctx, 42 const Value* bonus_data) { 43 ssize_t pos = 12; 44 char* header = patch->data; 45 if (patch->size < 12) { 46 printf("patch too short to contain header\n"); 47 return -1; 48 } 49 50 // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW. 51 // (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and 52 // CHUNK_GZIP.) 53 if (memcmp(header, "IMGDIFF2", 8) != 0) { 54 printf("corrupt patch file header (magic number)\n"); 55 return -1; 56 } 57 58 int num_chunks = Read4(header+8); 59 60 int i; 61 for (i = 0; i < num_chunks; ++i) { 62 // each chunk's header record starts with 4 bytes. 63 if (pos + 4 > patch->size) { 64 printf("failed to read chunk %d record\n", i); 65 return -1; 66 } 67 int type = Read4(patch->data + pos); 68 pos += 4; 69 70 if (type == CHUNK_NORMAL) { 71 char* normal_header = patch->data + pos; 72 pos += 24; 73 if (pos > patch->size) { 74 printf("failed to read chunk %d normal header data\n", i); 75 return -1; 76 } 77 78 size_t src_start = Read8(normal_header); 79 size_t src_len = Read8(normal_header+8); 80 size_t patch_offset = Read8(normal_header+16); 81 82 ApplyBSDiffPatch(old_data + src_start, src_len, 83 patch, patch_offset, sink, token, ctx); 84 } else if (type == CHUNK_RAW) { 85 char* raw_header = patch->data + pos; 86 pos += 4; 87 if (pos > patch->size) { 88 printf("failed to read chunk %d raw header data\n", i); 89 return -1; 90 } 91 92 ssize_t data_len = Read4(raw_header); 93 94 if (pos + data_len > patch->size) { 95 printf("failed to read chunk %d raw data\n", i); 96 return -1; 97 } 98 if (ctx) SHA_update(ctx, patch->data + pos, data_len); 99 if (sink((unsigned char*)patch->data + pos, 100 data_len, token) != data_len) { 101 printf("failed to write chunk %d raw data\n", i); 102 return -1; 103 } 104 pos += data_len; 105 } else if (type == CHUNK_DEFLATE) { 106 // deflate chunks have an additional 60 bytes in their chunk header. 107 char* deflate_header = patch->data + pos; 108 pos += 60; 109 if (pos > patch->size) { 110 printf("failed to read chunk %d deflate header data\n", i); 111 return -1; 112 } 113 114 size_t src_start = Read8(deflate_header); 115 size_t src_len = Read8(deflate_header+8); 116 size_t patch_offset = Read8(deflate_header+16); 117 size_t expanded_len = Read8(deflate_header+24); 118 size_t target_len = Read8(deflate_header+32); 119 int level = Read4(deflate_header+40); 120 int method = Read4(deflate_header+44); 121 int windowBits = Read4(deflate_header+48); 122 int memLevel = Read4(deflate_header+52); 123 int strategy = Read4(deflate_header+56); 124 125 // Decompress the source data; the chunk header tells us exactly 126 // how big we expect it to be when decompressed. 127 128 // Note: expanded_len will include the bonus data size if 129 // the patch was constructed with bonus data. The 130 // deflation will come up 'bonus_size' bytes short; these 131 // must be appended from the bonus_data value. 132 size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0; 133 134 unsigned char* expanded_source = malloc(expanded_len); 135 if (expanded_source == NULL) { 136 printf("failed to allocate %zu bytes for expanded_source\n", 137 expanded_len); 138 return -1; 139 } 140 141 z_stream strm; 142 strm.zalloc = Z_NULL; 143 strm.zfree = Z_NULL; 144 strm.opaque = Z_NULL; 145 strm.avail_in = src_len; 146 strm.next_in = (unsigned char*)(old_data + src_start); 147 strm.avail_out = expanded_len; 148 strm.next_out = expanded_source; 149 150 int ret; 151 ret = inflateInit2(&strm, -15); 152 if (ret != Z_OK) { 153 printf("failed to init source inflation: %d\n", ret); 154 return -1; 155 } 156 157 // Because we've provided enough room to accommodate the output 158 // data, we expect one call to inflate() to suffice. 159 ret = inflate(&strm, Z_SYNC_FLUSH); 160 if (ret != Z_STREAM_END) { 161 printf("source inflation returned %d\n", ret); 162 return -1; 163 } 164 // We should have filled the output buffer exactly, except 165 // for the bonus_size. 166 if (strm.avail_out != bonus_size) { 167 printf("source inflation short by %zu bytes\n", strm.avail_out-bonus_size); 168 return -1; 169 } 170 inflateEnd(&strm); 171 172 if (bonus_size) { 173 memcpy(expanded_source + (expanded_len - bonus_size), 174 bonus_data->data, bonus_size); 175 } 176 177 // Next, apply the bsdiff patch (in memory) to the uncompressed 178 // data. 179 unsigned char* uncompressed_target_data; 180 ssize_t uncompressed_target_size; 181 if (ApplyBSDiffPatchMem(expanded_source, expanded_len, 182 patch, patch_offset, 183 &uncompressed_target_data, 184 &uncompressed_target_size) != 0) { 185 return -1; 186 } 187 188 // Now compress the target data and append it to the output. 189 190 // we're done with the expanded_source data buffer, so we'll 191 // reuse that memory to receive the output of deflate. 192 unsigned char* temp_data = expanded_source; 193 ssize_t temp_size = expanded_len; 194 if (temp_size < 32768) { 195 // ... unless the buffer is too small, in which case we'll 196 // allocate a fresh one. 197 free(temp_data); 198 temp_data = malloc(32768); 199 temp_size = 32768; 200 } 201 202 // now the deflate stream 203 strm.zalloc = Z_NULL; 204 strm.zfree = Z_NULL; 205 strm.opaque = Z_NULL; 206 strm.avail_in = uncompressed_target_size; 207 strm.next_in = uncompressed_target_data; 208 ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy); 209 do { 210 strm.avail_out = temp_size; 211 strm.next_out = temp_data; 212 ret = deflate(&strm, Z_FINISH); 213 ssize_t have = temp_size - strm.avail_out; 214 215 if (sink(temp_data, have, token) != have) { 216 printf("failed to write %ld compressed bytes to output\n", 217 (long)have); 218 return -1; 219 } 220 if (ctx) SHA_update(ctx, temp_data, have); 221 } while (ret != Z_STREAM_END); 222 deflateEnd(&strm); 223 224 free(temp_data); 225 free(uncompressed_target_data); 226 } else { 227 printf("patch chunk %d is unknown type %d\n", i, type); 228 return -1; 229 } 230 } 231 232 return 0; 233 } 234
