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 <malloc.h>
27 #include <unistd.h>
28 #include <string.h>
29
30 #include <bzlib.h>
31
32 #include "mincrypt/sha.h"
33 #include "applypatch.h"
34
ShowBSDiffLicense()35 void ShowBSDiffLicense() {
36 puts("The bsdiff library used herein is:\n"
37 "\n"
38 "Copyright 2003-2005 Colin Percival\n"
39 "All rights reserved\n"
40 "\n"
41 "Redistribution and use in source and binary forms, with or without\n"
42 "modification, are permitted providing that the following conditions\n"
43 "are met:\n"
44 "1. Redistributions of source code must retain the above copyright\n"
45 " notice, this list of conditions and the following disclaimer.\n"
46 "2. Redistributions in binary form must reproduce the above copyright\n"
47 " notice, this list of conditions and the following disclaimer in the\n"
48 " documentation and/or other materials provided with the distribution.\n"
49 "\n"
50 "THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR\n"
51 "IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED\n"
52 "WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE\n"
53 "ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY\n"
54 "DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL\n"
55 "DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS\n"
56 "OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)\n"
57 "HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,\n"
58 "STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING\n"
59 "IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\n"
60 "POSSIBILITY OF SUCH DAMAGE.\n"
61 "\n------------------\n\n"
62 "This program uses Julian R Seward's \"libbzip2\" library, available\n"
63 "from http://www.bzip.org/.\n"
64 );
65 }
66
offtin(u_char * buf)67 static off_t offtin(u_char *buf)
68 {
69 off_t y;
70
71 y=buf[7]&0x7F;
72 y=y*256;y+=buf[6];
73 y=y*256;y+=buf[5];
74 y=y*256;y+=buf[4];
75 y=y*256;y+=buf[3];
76 y=y*256;y+=buf[2];
77 y=y*256;y+=buf[1];
78 y=y*256;y+=buf[0];
79
80 if(buf[7]&0x80) y=-y;
81
82 return y;
83 }
84
FillBuffer(unsigned char * buffer,int size,bz_stream * stream)85 int FillBuffer(unsigned char* buffer, int size, bz_stream* stream) {
86 stream->next_out = (char*)buffer;
87 stream->avail_out = size;
88 while (stream->avail_out > 0) {
89 int bzerr = BZ2_bzDecompress(stream);
90 if (bzerr != BZ_OK && bzerr != BZ_STREAM_END) {
91 printf("bz error %d decompressing\n", bzerr);
92 return -1;
93 }
94 if (stream->avail_out > 0) {
95 printf("need %d more bytes\n", stream->avail_out);
96 }
97 }
98 return 0;
99 }
100
ApplyBSDiffPatch(const unsigned char * old_data,ssize_t old_size,const Value * patch,ssize_t patch_offset,SinkFn sink,void * token,SHA_CTX * ctx)101 int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
102 const Value* patch, ssize_t patch_offset,
103 SinkFn sink, void* token, SHA_CTX* ctx) {
104
105 unsigned char* new_data;
106 ssize_t new_size;
107 if (ApplyBSDiffPatchMem(old_data, old_size, patch, patch_offset,
108 &new_data, &new_size) != 0) {
109 return -1;
110 }
111
112 if (sink(new_data, new_size, token) < new_size) {
113 printf("short write of output: %d (%s)\n", errno, strerror(errno));
114 return 1;
115 }
116 if (ctx) SHA_update(ctx, new_data, new_size);
117 free(new_data);
118
119 return 0;
120 }
121
ApplyBSDiffPatchMem(const unsigned char * old_data,ssize_t old_size,const Value * patch,ssize_t patch_offset,unsigned char ** new_data,ssize_t * new_size)122 int ApplyBSDiffPatchMem(const unsigned char* old_data, ssize_t old_size,
123 const Value* patch, ssize_t patch_offset,
124 unsigned char** new_data, ssize_t* new_size) {
125 // Patch data format:
126 // 0 8 "BSDIFF40"
127 // 8 8 X
128 // 16 8 Y
129 // 24 8 sizeof(newfile)
130 // 32 X bzip2(control block)
131 // 32+X Y bzip2(diff block)
132 // 32+X+Y ??? bzip2(extra block)
133 // with control block a set of triples (x,y,z) meaning "add x bytes
134 // from oldfile to x bytes from the diff block; copy y bytes from the
135 // extra block; seek forwards in oldfile by z bytes".
136
137 unsigned char* header = (unsigned char*) patch->data + patch_offset;
138 if (memcmp(header, "BSDIFF40", 8) != 0) {
139 printf("corrupt bsdiff patch file header (magic number)\n");
140 return 1;
141 }
142
143 ssize_t ctrl_len, data_len;
144 ctrl_len = offtin(header+8);
145 data_len = offtin(header+16);
146 *new_size = offtin(header+24);
147
148 if (ctrl_len < 0 || data_len < 0 || *new_size < 0) {
149 printf("corrupt patch file header (data lengths)\n");
150 return 1;
151 }
152
153 int bzerr;
154
155 bz_stream cstream;
156 cstream.next_in = patch->data + patch_offset + 32;
157 cstream.avail_in = ctrl_len;
158 cstream.bzalloc = NULL;
159 cstream.bzfree = NULL;
160 cstream.opaque = NULL;
161 if ((bzerr = BZ2_bzDecompressInit(&cstream, 0, 0)) != BZ_OK) {
162 printf("failed to bzinit control stream (%d)\n", bzerr);
163 }
164
165 bz_stream dstream;
166 dstream.next_in = patch->data + patch_offset + 32 + ctrl_len;
167 dstream.avail_in = data_len;
168 dstream.bzalloc = NULL;
169 dstream.bzfree = NULL;
170 dstream.opaque = NULL;
171 if ((bzerr = BZ2_bzDecompressInit(&dstream, 0, 0)) != BZ_OK) {
172 printf("failed to bzinit diff stream (%d)\n", bzerr);
173 }
174
175 bz_stream estream;
176 estream.next_in = patch->data + patch_offset + 32 + ctrl_len + data_len;
177 estream.avail_in = patch->size - (patch_offset + 32 + ctrl_len + data_len);
178 estream.bzalloc = NULL;
179 estream.bzfree = NULL;
180 estream.opaque = NULL;
181 if ((bzerr = BZ2_bzDecompressInit(&estream, 0, 0)) != BZ_OK) {
182 printf("failed to bzinit extra stream (%d)\n", bzerr);
183 }
184
185 *new_data = malloc(*new_size);
186 if (*new_data == NULL) {
187 printf("failed to allocate %ld bytes of memory for output file\n",
188 (long)*new_size);
189 return 1;
190 }
191
192 off_t oldpos = 0, newpos = 0;
193 off_t ctrl[3];
194 off_t len_read;
195 int i;
196 unsigned char buf[24];
197 while (newpos < *new_size) {
198 // Read control data
199 if (FillBuffer(buf, 24, &cstream) != 0) {
200 printf("error while reading control stream\n");
201 return 1;
202 }
203 ctrl[0] = offtin(buf);
204 ctrl[1] = offtin(buf+8);
205 ctrl[2] = offtin(buf+16);
206
207 if (ctrl[0] < 0 || ctrl[1] < 0) {
208 printf("corrupt patch (negative byte counts)\n");
209 return 1;
210 }
211
212 // Sanity check
213 if (newpos + ctrl[0] > *new_size) {
214 printf("corrupt patch (new file overrun)\n");
215 return 1;
216 }
217
218 // Read diff string
219 if (FillBuffer(*new_data + newpos, ctrl[0], &dstream) != 0) {
220 printf("error while reading diff stream\n");
221 return 1;
222 }
223
224 // Add old data to diff string
225 for (i = 0; i < ctrl[0]; ++i) {
226 if ((oldpos+i >= 0) && (oldpos+i < old_size)) {
227 (*new_data)[newpos+i] += old_data[oldpos+i];
228 }
229 }
230
231 // Adjust pointers
232 newpos += ctrl[0];
233 oldpos += ctrl[0];
234
235 // Sanity check
236 if (newpos + ctrl[1] > *new_size) {
237 printf("corrupt patch (new file overrun)\n");
238 return 1;
239 }
240
241 // Read extra string
242 if (FillBuffer(*new_data + newpos, ctrl[1], &estream) != 0) {
243 printf("error while reading extra stream\n");
244 return 1;
245 }
246
247 // Adjust pointers
248 newpos += ctrl[1];
249 oldpos += ctrl[2];
250 }
251
252 BZ2_bzDecompressEnd(&cstream);
253 BZ2_bzDecompressEnd(&dstream);
254 BZ2_bzDecompressEnd(&estream);
255 return 0;
256 }
257