1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright 2003-2005 Colin Percival
5 * All rights reserved
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted providing that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
25 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #ifndef WITHOUT_CAPSICUM
33 #include <sys/capsicum.h>
34 #endif
35
36 #include <bzlib.h>
37 #include <err.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <libgen.h>
41 #include <limits.h>
42 #include <stdint.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <unistd.h>
47
48 #ifndef O_BINARY
49 #define O_BINARY 0
50 #endif
51 #define HEADER_SIZE 32
52
53 static char *newfile;
54 static int dirfd = -1;
55
56 static void
exit_cleanup(void)57 exit_cleanup(void)
58 {
59
60 if (dirfd != -1 && newfile != NULL)
61 if (unlinkat(dirfd, newfile, 0))
62 warn("unlinkat");
63 }
64
offtin(u_char * buf)65 static off_t offtin(u_char *buf)
66 {
67 off_t y;
68
69 y = buf[7] & 0x7F;
70 y = y * 256; y += buf[6];
71 y = y * 256; y += buf[5];
72 y = y * 256; y += buf[4];
73 y = y * 256; y += buf[3];
74 y = y * 256; y += buf[2];
75 y = y * 256; y += buf[1];
76 y = y * 256; y += buf[0];
77
78 if (buf[7] & 0x80)
79 y = -y;
80
81 return (y);
82 }
83
84 static void
usage(void)85 usage(void)
86 {
87
88 fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n");
89 exit(1);
90 }
91
main(int argc,char * argv[])92 int main(int argc, char *argv[])
93 {
94 FILE *f, *cpf, *dpf, *epf;
95 BZFILE *cpfbz2, *dpfbz2, *epfbz2;
96 char *directory, *namebuf;
97 int cbz2err, dbz2err, ebz2err;
98 int newfd, oldfd;
99 off_t oldsize, newsize;
100 off_t bzctrllen, bzdatalen;
101 u_char header[HEADER_SIZE], buf[8];
102 u_char *old, *new;
103 off_t oldpos, newpos;
104 off_t ctrl[3];
105 off_t i, lenread, offset;
106 #ifndef WITHOUT_CAPSICUM
107 cap_rights_t rights_dir, rights_ro, rights_wr;
108 #endif
109
110 if (argc != 4)
111 usage();
112
113 /* Open patch file */
114 if ((f = fopen(argv[3], "rb")) == NULL)
115 err(1, "fopen(%s)", argv[3]);
116 /* Open patch file for control block */
117 if ((cpf = fopen(argv[3], "rb")) == NULL)
118 err(1, "fopen(%s)", argv[3]);
119 /* open patch file for diff block */
120 if ((dpf = fopen(argv[3], "rb")) == NULL)
121 err(1, "fopen(%s)", argv[3]);
122 /* open patch file for extra block */
123 if ((epf = fopen(argv[3], "rb")) == NULL)
124 err(1, "fopen(%s)", argv[3]);
125 /* open oldfile */
126 if ((oldfd = open(argv[1], O_RDONLY | O_BINARY, 0)) < 0)
127 err(1, "open(%s)", argv[1]);
128 /* open directory where we'll write newfile */
129 if ((namebuf = strdup(argv[2])) == NULL ||
130 (directory = dirname(namebuf)) == NULL ||
131 (dirfd = open(directory, O_DIRECTORY)) < 0)
132 err(1, "open %s", argv[2]);
133 free(namebuf);
134 if ((newfile = basename(argv[2])) == NULL)
135 err(1, "basename");
136 /* open newfile */
137 if ((newfd = openat(dirfd, newfile,
138 O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0666)) < 0)
139 err(1, "open(%s)", argv[2]);
140 atexit(exit_cleanup);
141
142 #ifndef WITHOUT_CAPSICUM
143 if (cap_enter() < 0) {
144 /* Failed to sandbox, fatal if CAPABILITY_MODE enabled */
145 if (errno != ENOSYS)
146 err(1, "failed to enter security sandbox");
147 } else {
148 /* Capsicum Available */
149 cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
150 cap_rights_init(&rights_wr, CAP_WRITE);
151 cap_rights_init(&rights_dir, CAP_UNLINKAT);
152
153 if (cap_rights_limit(fileno(f), &rights_ro) < 0 ||
154 cap_rights_limit(fileno(cpf), &rights_ro) < 0 ||
155 cap_rights_limit(fileno(dpf), &rights_ro) < 0 ||
156 cap_rights_limit(fileno(epf), &rights_ro) < 0 ||
157 cap_rights_limit(oldfd, &rights_ro) < 0 ||
158 cap_rights_limit(newfd, &rights_wr) < 0 ||
159 cap_rights_limit(dirfd, &rights_dir) < 0)
160 err(1, "cap_rights_limit() failed, could not restrict"
161 " capabilities");
162 }
163 #endif
164
165 /*
166 File format:
167 0 8 "BSDIFF40"
168 8 8 X
169 16 8 Y
170 24 8 sizeof(newfile)
171 32 X bzip2(control block)
172 32+X Y bzip2(diff block)
173 32+X+Y ??? bzip2(extra block)
174 with control block a set of triples (x,y,z) meaning "add x bytes
175 from oldfile to x bytes from the diff block; copy y bytes from the
176 extra block; seek forwards in oldfile by z bytes".
177 */
178
179 /* Read header */
180 if (fread(header, 1, HEADER_SIZE, f) < HEADER_SIZE) {
181 if (feof(f))
182 errx(1, "Corrupt patch");
183 err(1, "fread(%s)", argv[3]);
184 }
185
186 /* Check for appropriate magic */
187 if (memcmp(header, "BSDIFF40", 8) != 0)
188 errx(1, "Corrupt patch");
189
190 /* Read lengths from header */
191 bzctrllen = offtin(header + 8);
192 bzdatalen = offtin(header + 16);
193 newsize = offtin(header + 24);
194 if (bzctrllen < 0 || bzctrllen > OFF_MAX - HEADER_SIZE ||
195 bzdatalen < 0 || bzctrllen + HEADER_SIZE > OFF_MAX - bzdatalen ||
196 newsize < 0 || newsize > SSIZE_MAX)
197 errx(1, "Corrupt patch");
198
199 /* Close patch file and re-open it via libbzip2 at the right places */
200 if (fclose(f))
201 err(1, "fclose(%s)", argv[3]);
202 offset = HEADER_SIZE;
203 if (fseeko(cpf, offset, SEEK_SET))
204 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
205 if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
206 errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
207 offset += bzctrllen;
208 if (fseeko(dpf, offset, SEEK_SET))
209 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
210 if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
211 errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
212 offset += bzdatalen;
213 if (fseeko(epf, offset, SEEK_SET))
214 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
215 if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
216 errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
217
218 if ((oldsize = lseek(oldfd, 0, SEEK_END)) == -1 ||
219 oldsize > SSIZE_MAX ||
220 (old = malloc(oldsize)) == NULL ||
221 lseek(oldfd, 0, SEEK_SET) != 0 ||
222 read(oldfd, old, oldsize) != oldsize ||
223 close(oldfd) == -1)
224 err(1, "%s", argv[1]);
225 if ((new = malloc(newsize)) == NULL)
226 err(1, NULL);
227
228 oldpos = 0;
229 newpos = 0;
230 while (newpos < newsize) {
231 /* Read control data */
232 for (i = 0; i <= 2; i++) {
233 lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
234 if ((lenread < 8) || ((cbz2err != BZ_OK) &&
235 (cbz2err != BZ_STREAM_END)))
236 errx(1, "Corrupt patch");
237 ctrl[i] = offtin(buf);
238 }
239
240 /* Sanity-check */
241 if (ctrl[0] < 0 || ctrl[0] > INT_MAX ||
242 ctrl[1] < 0 || ctrl[1] > INT_MAX)
243 errx(1, "Corrupt patch");
244
245 /* Sanity-check */
246 if (newpos + ctrl[0] > newsize)
247 errx(1, "Corrupt patch");
248
249 /* Read diff string */
250 lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
251 if ((lenread < ctrl[0]) ||
252 ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
253 errx(1, "Corrupt patch");
254
255 /* Add old data to diff string */
256 for (i = 0; i < ctrl[0]; i++)
257 if ((oldpos + i >= 0) && (oldpos + i < oldsize))
258 new[newpos + i] += old[oldpos + i];
259
260 /* Adjust pointers */
261 newpos += ctrl[0];
262 oldpos += ctrl[0];
263
264 /* Sanity-check */
265 if (newpos + ctrl[1] > newsize)
266 errx(1, "Corrupt patch");
267
268 /* Read extra string */
269 lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
270 if ((lenread < ctrl[1]) ||
271 ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
272 errx(1, "Corrupt patch");
273
274 /* Adjust pointers */
275 newpos+=ctrl[1];
276 oldpos+=ctrl[2];
277 }
278
279 /* Clean up the bzip2 reads */
280 BZ2_bzReadClose(&cbz2err, cpfbz2);
281 BZ2_bzReadClose(&dbz2err, dpfbz2);
282 BZ2_bzReadClose(&ebz2err, epfbz2);
283 if (fclose(cpf) || fclose(dpf) || fclose(epf))
284 err(1, "fclose(%s)", argv[3]);
285
286 /* Write the new file */
287 if (write(newfd, new, newsize) != newsize || close(newfd) == -1)
288 err(1, "%s", argv[2]);
289 /* Disable atexit cleanup */
290 newfile = NULL;
291
292 free(new);
293 free(old);
294
295 return (0);
296 }
297