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 <fcntl.h>
39 #include <libgen.h>
40 #include <limits.h>
41 #include <stdint.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46
47 #ifndef O_BINARY
48 #define O_BINARY 0
49 #endif
50 #define HEADER_SIZE 32
51
52 static char *newfile;
53 static int dirfd = -1;
54
55 static void
exit_cleanup(void)56 exit_cleanup(void)
57 {
58
59 if (dirfd != -1 && newfile != NULL)
60 if (unlinkat(dirfd, newfile, 0))
61 warn("unlinkat");
62 }
63
64 static inline off_t
add_off_t(off_t a,off_t b)65 add_off_t(off_t a, off_t b)
66 {
67 off_t result;
68
69 #if __GNUC__ >= 5 || \
70 (defined(__has_builtin) && __has_builtin(__builtin_add_overflow))
71 if (__builtin_add_overflow(a, b, &result))
72 errx(1, "Corrupt patch");
73 #else
74 if ((b > 0 && a > OFF_MAX - b) || (b < 0 && a < OFF_MIN - b))
75 errx(1, "Corrupt patch");
76 result = a + b;
77 #endif
78 return result;
79 }
80
offtin(u_char * buf)81 static off_t offtin(u_char *buf)
82 {
83 off_t y;
84
85 y = buf[7] & 0x7F;
86 y = y * 256; y += buf[6];
87 y = y * 256; y += buf[5];
88 y = y * 256; y += buf[4];
89 y = y * 256; y += buf[3];
90 y = y * 256; y += buf[2];
91 y = y * 256; y += buf[1];
92 y = y * 256; y += buf[0];
93
94 if (buf[7] & 0x80)
95 y = -y;
96
97 return (y);
98 }
99
100 static void
usage(void)101 usage(void)
102 {
103
104 fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n");
105 exit(1);
106 }
107
main(int argc,char * argv[])108 int main(int argc, char *argv[])
109 {
110 FILE *f, *cpf, *dpf, *epf;
111 BZFILE *cpfbz2, *dpfbz2, *epfbz2;
112 char *directory, *namebuf;
113 int cbz2err, dbz2err, ebz2err;
114 int newfd, oldfd;
115 off_t oldsize, newsize;
116 off_t bzctrllen, bzdatalen;
117 u_char header[HEADER_SIZE], buf[8];
118 u_char *old, *new;
119 off_t oldpos, newpos;
120 off_t ctrl[3];
121 off_t i, lenread, offset;
122 #ifndef WITHOUT_CAPSICUM
123 cap_rights_t rights_dir, rights_ro, rights_wr;
124 #endif
125
126 if (argc != 4)
127 usage();
128
129 /* Open patch file */
130 if ((f = fopen(argv[3], "rb")) == NULL)
131 err(1, "fopen(%s)", argv[3]);
132 /* Open patch file for control block */
133 if ((cpf = fopen(argv[3], "rb")) == NULL)
134 err(1, "fopen(%s)", argv[3]);
135 /* open patch file for diff block */
136 if ((dpf = fopen(argv[3], "rb")) == NULL)
137 err(1, "fopen(%s)", argv[3]);
138 /* open patch file for extra block */
139 if ((epf = fopen(argv[3], "rb")) == NULL)
140 err(1, "fopen(%s)", argv[3]);
141 /* open oldfile */
142 if ((oldfd = open(argv[1], O_RDONLY | O_BINARY, 0)) < 0)
143 err(1, "open(%s)", argv[1]);
144 /* open directory where we'll write newfile */
145 if ((namebuf = strdup(argv[2])) == NULL ||
146 (directory = dirname(namebuf)) == NULL ||
147 (dirfd = open(directory, O_DIRECTORY)) < 0)
148 err(1, "open %s", argv[2]);
149 free(namebuf);
150 if ((newfile = basename(argv[2])) == NULL)
151 err(1, "basename");
152 /* open newfile */
153 if ((newfd = openat(dirfd, newfile,
154 O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0666)) < 0)
155 err(1, "open(%s)", argv[2]);
156 atexit(exit_cleanup);
157
158 #ifndef WITHOUT_CAPSICUM
159 if (cap_enter() < 0)
160 err(1, "failed to enter security sandbox");
161
162 cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
163 cap_rights_init(&rights_wr, CAP_WRITE);
164 cap_rights_init(&rights_dir, CAP_UNLINKAT);
165
166 if (cap_rights_limit(fileno(f), &rights_ro) < 0 ||
167 cap_rights_limit(fileno(cpf), &rights_ro) < 0 ||
168 cap_rights_limit(fileno(dpf), &rights_ro) < 0 ||
169 cap_rights_limit(fileno(epf), &rights_ro) < 0 ||
170 cap_rights_limit(oldfd, &rights_ro) < 0 ||
171 cap_rights_limit(newfd, &rights_wr) < 0 ||
172 cap_rights_limit(dirfd, &rights_dir) < 0)
173 err(1, "cap_rights_limit() failed, could not restrict"
174 " capabilities");
175 #endif
176
177 /*
178 File format:
179 0 8 "BSDIFF40"
180 8 8 X
181 16 8 Y
182 24 8 sizeof(newfile)
183 32 X bzip2(control block)
184 32+X Y bzip2(diff block)
185 32+X+Y ??? bzip2(extra block)
186 with control block a set of triples (x,y,z) meaning "add x bytes
187 from oldfile to x bytes from the diff block; copy y bytes from the
188 extra block; seek forwards in oldfile by z bytes".
189 */
190
191 /* Read header */
192 if (fread(header, 1, HEADER_SIZE, f) < HEADER_SIZE) {
193 if (feof(f))
194 errx(1, "Corrupt patch");
195 err(1, "fread(%s)", argv[3]);
196 }
197
198 /* Check for appropriate magic */
199 if (memcmp(header, "BSDIFF40", 8) != 0)
200 errx(1, "Corrupt patch");
201
202 /* Read lengths from header */
203 bzctrllen = offtin(header + 8);
204 bzdatalen = offtin(header + 16);
205 newsize = offtin(header + 24);
206 if (bzctrllen < 0 || bzctrllen > OFF_MAX - HEADER_SIZE ||
207 bzdatalen < 0 || bzctrllen + HEADER_SIZE > OFF_MAX - bzdatalen ||
208 newsize < 0 || newsize > SSIZE_MAX)
209 errx(1, "Corrupt patch");
210
211 /* Close patch file and re-open it via libbzip2 at the right places */
212 if (fclose(f))
213 err(1, "fclose(%s)", argv[3]);
214 offset = HEADER_SIZE;
215 if (fseeko(cpf, offset, SEEK_SET))
216 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
217 if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
218 errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
219 offset = add_off_t(offset, bzctrllen);
220 if (fseeko(dpf, offset, SEEK_SET))
221 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
222 if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
223 errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
224 offset = add_off_t(offset, bzdatalen);
225 if (fseeko(epf, offset, SEEK_SET))
226 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
227 if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
228 errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
229
230 if ((oldsize = lseek(oldfd, 0, SEEK_END)) == -1 ||
231 oldsize > SSIZE_MAX ||
232 (old = malloc(oldsize)) == NULL ||
233 lseek(oldfd, 0, SEEK_SET) != 0 ||
234 read(oldfd, old, oldsize) != oldsize ||
235 close(oldfd) == -1)
236 err(1, "%s", argv[1]);
237 if ((new = malloc(newsize)) == NULL)
238 err(1, NULL);
239
240 oldpos = 0;
241 newpos = 0;
242 while (newpos < newsize) {
243 /* Read control data */
244 for (i = 0; i <= 2; i++) {
245 lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
246 if ((lenread < 8) || ((cbz2err != BZ_OK) &&
247 (cbz2err != BZ_STREAM_END)))
248 errx(1, "Corrupt patch");
249 ctrl[i] = offtin(buf);
250 }
251
252 /* Sanity-check */
253 if (ctrl[0] < 0 || ctrl[0] > INT_MAX ||
254 ctrl[1] < 0 || ctrl[1] > INT_MAX)
255 errx(1, "Corrupt patch");
256
257 /* Sanity-check */
258 if (add_off_t(newpos, ctrl[0]) > newsize)
259 errx(1, "Corrupt patch");
260
261 /* Read diff string */
262 lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
263 if ((lenread < ctrl[0]) ||
264 ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
265 errx(1, "Corrupt patch");
266
267 /* Add old data to diff string */
268 for (i = 0; i < ctrl[0]; i++)
269 if (add_off_t(oldpos, i) < oldsize)
270 new[newpos + i] += old[oldpos + i];
271
272 /* Adjust pointers */
273 newpos = add_off_t(newpos, ctrl[0]);
274 oldpos = add_off_t(oldpos, ctrl[0]);
275
276 /* Sanity-check */
277 if (add_off_t(newpos, ctrl[1]) > newsize)
278 errx(1, "Corrupt patch");
279
280 /* Read extra string */
281 lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
282 if ((lenread < ctrl[1]) ||
283 ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
284 errx(1, "Corrupt patch");
285
286 /* Adjust pointers */
287 newpos = add_off_t(newpos, ctrl[1]);
288 oldpos = add_off_t(oldpos, ctrl[2]);
289 }
290
291 /* Clean up the bzip2 reads */
292 BZ2_bzReadClose(&cbz2err, cpfbz2);
293 BZ2_bzReadClose(&dbz2err, dpfbz2);
294 BZ2_bzReadClose(&ebz2err, epfbz2);
295 if (fclose(cpf) || fclose(dpf) || fclose(epf))
296 err(1, "fclose(%s)", argv[3]);
297
298 /* Write the new file */
299 if (write(newfd, new, newsize) != newsize || close(newfd) == -1)
300 err(1, "%s", argv[2]);
301 /* Disable atexit cleanup */
302 newfile = NULL;
303
304 free(new);
305 free(old);
306
307 return (0);
308 }
309