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
ShowBSDiffLicense()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
offtin(u_char * buf)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
FillBuffer(unsigned char * buffer,int size,bz_stream * stream)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
ApplyBSDiffPatch(const unsigned char * old_data,ssize_t old_size,const Value * patch,ssize_t patch_offset,SinkFn sink,void * token,SHA_CTX * ctx)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) {
116 SHA_update(ctx, new_data, new_size);
117 }
118 free(new_data);
119
120 return 0;
121 }
122
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)123 int ApplyBSDiffPatchMem(const unsigned char* old_data, ssize_t old_size,
124 const Value* patch, ssize_t patch_offset,
125 unsigned char** new_data, ssize_t* new_size) {
126 // Patch data format:
127 // 0 8 "BSDIFF40"
128 // 8 8 X
129 // 16 8 Y
130 // 24 8 sizeof(newfile)
131 // 32 X bzip2(control block)
132 // 32+X Y bzip2(diff block)
133 // 32+X+Y ??? bzip2(extra block)
134 // with control block a set of triples (x,y,z) meaning "add x bytes
135 // from oldfile to x bytes from the diff block; copy y bytes from the
136 // extra block; seek forwards in oldfile by z bytes".
137
138 unsigned char* header = (unsigned char*) patch->data + patch_offset;
139 if (memcmp(header, "BSDIFF40", 8) != 0) {
140 printf("corrupt bsdiff patch file header (magic number)\n");
141 return 1;
142 }
143
144 ssize_t ctrl_len, data_len;
145 ctrl_len = offtin(header+8);
146 data_len = offtin(header+16);
147 *new_size = offtin(header+24);
148
149 if (ctrl_len < 0 || data_len < 0 || *new_size < 0) {
150 printf("corrupt patch file header (data lengths)\n");
151 return 1;
152 }
153
154 int bzerr;
155
156 bz_stream cstream;
157 cstream.next_in = patch->data + patch_offset + 32;
158 cstream.avail_in = ctrl_len;
159 cstream.bzalloc = NULL;
160 cstream.bzfree = NULL;
161 cstream.opaque = NULL;
162 if ((bzerr = BZ2_bzDecompressInit(&cstream, 0, 0)) != BZ_OK) {
163 printf("failed to bzinit control stream (%d)\n", bzerr);
164 }
165
166 bz_stream dstream;
167 dstream.next_in = patch->data + patch_offset + 32 + ctrl_len;
168 dstream.avail_in = data_len;
169 dstream.bzalloc = NULL;
170 dstream.bzfree = NULL;
171 dstream.opaque = NULL;
172 if ((bzerr = BZ2_bzDecompressInit(&dstream, 0, 0)) != BZ_OK) {
173 printf("failed to bzinit diff stream (%d)\n", bzerr);
174 }
175
176 bz_stream estream;
177 estream.next_in = patch->data + patch_offset + 32 + ctrl_len + data_len;
178 estream.avail_in = patch->size - (patch_offset + 32 + ctrl_len + data_len);
179 estream.bzalloc = NULL;
180 estream.bzfree = NULL;
181 estream.opaque = NULL;
182 if ((bzerr = BZ2_bzDecompressInit(&estream, 0, 0)) != BZ_OK) {
183 printf("failed to bzinit extra stream (%d)\n", bzerr);
184 }
185
186 *new_data = malloc(*new_size);
187 if (*new_data == NULL) {
188 printf("failed to allocate %ld bytes of memory for output file\n",
189 (long)*new_size);
190 return 1;
191 }
192
193 off_t oldpos = 0, newpos = 0;
194 off_t ctrl[3];
195 off_t len_read;
196 int i;
197 unsigned char buf[24];
198 while (newpos < *new_size) {
199 // Read control data
200 if (FillBuffer(buf, 24, &cstream) != 0) {
201 printf("error while reading control stream\n");
202 return 1;
203 }
204 ctrl[0] = offtin(buf);
205 ctrl[1] = offtin(buf+8);
206 ctrl[2] = offtin(buf+16);
207
208 // Sanity check
209 if (newpos + ctrl[0] > *new_size) {
210 printf("corrupt patch (new file overrun)\n");
211 return 1;
212 }
213
214 // Read diff string
215 if (FillBuffer(*new_data + newpos, ctrl[0], &dstream) != 0) {
216 printf("error while reading diff stream\n");
217 return 1;
218 }
219
220 // Add old data to diff string
221 for (i = 0; i < ctrl[0]; ++i) {
222 if ((oldpos+i >= 0) && (oldpos+i < old_size)) {
223 (*new_data)[newpos+i] += old_data[oldpos+i];
224 }
225 }
226
227 // Adjust pointers
228 newpos += ctrl[0];
229 oldpos += ctrl[0];
230
231 // Sanity check
232 if (newpos + ctrl[1] > *new_size) {
233 printf("corrupt patch (new file overrun)\n");
234 return 1;
235 }
236
237 // Read extra string
238 if (FillBuffer(*new_data + newpos, ctrl[1], &estream) != 0) {
239 printf("error while reading extra stream\n");
240 return 1;
241 }
242
243 // Adjust pointers
244 newpos += ctrl[1];
245 oldpos += ctrl[2];
246 }
247
248 BZ2_bzDecompressEnd(&cstream);
249 BZ2_bzDecompressEnd(&dstream);
250 BZ2_bzDecompressEnd(&estream);
251 return 0;
252 }
253