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) SHA_update(ctx, new_data, new_size);
116 free(new_data);
117
118 return 0;
119 }
120
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)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