1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 #ifndef WITHOUT_CAPSICUM
31 #include <sys/capsicum.h>
32 #endif
33
34 #include <bzlib.h>
35 #include <err.h>
36 #include <fcntl.h>
37 #include <libgen.h>
38 #include <limits.h>
39 #include <stdckdint.h>
40 #include <stdint.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45
46 #ifndef O_BINARY
47 #define O_BINARY 0
48 #endif
49 #define HEADER_SIZE 32
50
51 static char *newfile;
52 static int dirfd = -1;
53
54 static void
exit_cleanup(void)55 exit_cleanup(void)
56 {
57
58 if (dirfd != -1 && newfile != NULL)
59 if (unlinkat(dirfd, newfile, 0))
60 warn("unlinkat");
61 }
62
63 static inline off_t
add_off_t(off_t a,off_t b)64 add_off_t(off_t a, off_t b)
65 {
66 off_t result;
67
68 if (ckd_add(&result, a, b))
69 errx(1, "Corrupt patch");
70 return result;
71 }
72
offtin(u_char * buf)73 static off_t offtin(u_char *buf)
74 {
75 off_t y;
76
77 y = buf[7] & 0x7F;
78 y = y * 256; y += buf[6];
79 y = y * 256; y += buf[5];
80 y = y * 256; y += buf[4];
81 y = y * 256; y += buf[3];
82 y = y * 256; y += buf[2];
83 y = y * 256; y += buf[1];
84 y = y * 256; y += buf[0];
85
86 if (buf[7] & 0x80)
87 y = -y;
88
89 return (y);
90 }
91
92 static void
usage(void)93 usage(void)
94 {
95
96 fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n");
97 exit(1);
98 }
99
main(int argc,char * argv[])100 int main(int argc, char *argv[])
101 {
102 FILE *f, *cpf, *dpf, *epf;
103 BZFILE *cpfbz2, *dpfbz2, *epfbz2;
104 char *directory, *namebuf;
105 int cbz2err, dbz2err, ebz2err;
106 int newfd, oldfd;
107 off_t oldsize, newsize;
108 off_t bzctrllen, bzdatalen;
109 u_char header[HEADER_SIZE], buf[8];
110 u_char *old, *new;
111 off_t oldpos, newpos;
112 off_t ctrl[3];
113 off_t i, lenread, offset;
114 #ifndef WITHOUT_CAPSICUM
115 cap_rights_t rights_dir, rights_ro, rights_wr;
116 #endif
117
118 if (argc != 4)
119 usage();
120
121 /* Open patch file */
122 if ((f = fopen(argv[3], "rb")) == NULL)
123 err(1, "fopen(%s)", argv[3]);
124 /* Open patch file for control block */
125 if ((cpf = fopen(argv[3], "rb")) == NULL)
126 err(1, "fopen(%s)", argv[3]);
127 /* open patch file for diff block */
128 if ((dpf = fopen(argv[3], "rb")) == NULL)
129 err(1, "fopen(%s)", argv[3]);
130 /* open patch file for extra block */
131 if ((epf = fopen(argv[3], "rb")) == NULL)
132 err(1, "fopen(%s)", argv[3]);
133 /* open oldfile */
134 if ((oldfd = open(argv[1], O_RDONLY | O_BINARY, 0)) < 0)
135 err(1, "open(%s)", argv[1]);
136 /* open directory where we'll write newfile */
137 if ((namebuf = strdup(argv[2])) == NULL ||
138 (directory = dirname(namebuf)) == NULL ||
139 (dirfd = open(directory, O_DIRECTORY)) < 0)
140 err(1, "open %s", argv[2]);
141 free(namebuf);
142 if ((newfile = basename(argv[2])) == NULL)
143 err(1, "basename");
144 /* open newfile */
145 if ((newfd = openat(dirfd, newfile,
146 O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0666)) < 0)
147 err(1, "open(%s)", argv[2]);
148 atexit(exit_cleanup);
149
150 #ifndef WITHOUT_CAPSICUM
151 if (cap_enter() < 0)
152 err(1, "failed to enter security sandbox");
153
154 cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
155 cap_rights_init(&rights_wr, CAP_WRITE);
156 cap_rights_init(&rights_dir, CAP_UNLINKAT);
157
158 if (cap_rights_limit(fileno(f), &rights_ro) < 0 ||
159 cap_rights_limit(fileno(cpf), &rights_ro) < 0 ||
160 cap_rights_limit(fileno(dpf), &rights_ro) < 0 ||
161 cap_rights_limit(fileno(epf), &rights_ro) < 0 ||
162 cap_rights_limit(oldfd, &rights_ro) < 0 ||
163 cap_rights_limit(newfd, &rights_wr) < 0 ||
164 cap_rights_limit(dirfd, &rights_dir) < 0)
165 err(1, "cap_rights_limit() failed, could not restrict"
166 " capabilities");
167 #endif
168
169 /*
170 File format:
171 0 8 "BSDIFF40"
172 8 8 X
173 16 8 Y
174 24 8 sizeof(newfile)
175 32 X bzip2(control block)
176 32+X Y bzip2(diff block)
177 32+X+Y ??? bzip2(extra block)
178 with control block a set of triples (x,y,z) meaning "add x bytes
179 from oldfile to x bytes from the diff block; copy y bytes from the
180 extra block; seek forwards in oldfile by z bytes".
181 */
182
183 /* Read header */
184 if (fread(header, 1, HEADER_SIZE, f) < HEADER_SIZE) {
185 if (feof(f))
186 errx(1, "Corrupt patch");
187 err(1, "fread(%s)", argv[3]);
188 }
189
190 /* Check for appropriate magic */
191 if (memcmp(header, "BSDIFF40", 8) != 0)
192 errx(1, "Corrupt patch");
193
194 /* Read lengths from header */
195 bzctrllen = offtin(header + 8);
196 bzdatalen = offtin(header + 16);
197 newsize = offtin(header + 24);
198 if (bzctrllen < 0 || bzctrllen > OFF_MAX - HEADER_SIZE ||
199 bzdatalen < 0 || bzctrllen + HEADER_SIZE > OFF_MAX - bzdatalen ||
200 newsize < 0 || newsize > SSIZE_MAX)
201 errx(1, "Corrupt patch");
202
203 /* Close patch file and re-open it via libbzip2 at the right places */
204 if (fclose(f))
205 err(1, "fclose(%s)", argv[3]);
206 offset = HEADER_SIZE;
207 if (fseeko(cpf, offset, SEEK_SET))
208 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
209 if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
210 errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
211 offset = add_off_t(offset, bzctrllen);
212 if (fseeko(dpf, offset, SEEK_SET))
213 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
214 if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
215 errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
216 offset = add_off_t(offset, bzdatalen);
217 if (fseeko(epf, offset, SEEK_SET))
218 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
219 if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
220 errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
221
222 if ((oldsize = lseek(oldfd, 0, SEEK_END)) == -1 ||
223 oldsize > SSIZE_MAX ||
224 (old = malloc(oldsize)) == NULL ||
225 lseek(oldfd, 0, SEEK_SET) != 0 ||
226 read(oldfd, old, oldsize) != oldsize ||
227 close(oldfd) == -1)
228 err(1, "%s", argv[1]);
229 if ((new = malloc(newsize)) == NULL)
230 err(1, NULL);
231
232 oldpos = 0;
233 newpos = 0;
234 while (newpos < newsize) {
235 /* Read control data */
236 for (i = 0; i <= 2; i++) {
237 lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
238 if ((lenread < 8) || ((cbz2err != BZ_OK) &&
239 (cbz2err != BZ_STREAM_END)))
240 errx(1, "Corrupt patch");
241 ctrl[i] = offtin(buf);
242 }
243
244 /* Sanity-check */
245 if (ctrl[0] < 0 || ctrl[0] > INT_MAX ||
246 ctrl[1] < 0 || ctrl[1] > INT_MAX)
247 errx(1, "Corrupt patch");
248
249 /* Sanity-check */
250 if (add_off_t(newpos, ctrl[0]) > newsize)
251 errx(1, "Corrupt patch");
252
253 /* Read diff string */
254 lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
255 if ((lenread < ctrl[0]) ||
256 ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
257 errx(1, "Corrupt patch");
258
259 /* Add old data to diff string */
260 for (i = 0; i < ctrl[0]; i++)
261 if (add_off_t(oldpos, i) < oldsize)
262 new[newpos + i] += old[oldpos + i];
263
264 /* Adjust pointers */
265 newpos = add_off_t(newpos, ctrl[0]);
266 oldpos = add_off_t(oldpos, ctrl[0]);
267
268 /* Sanity-check */
269 if (add_off_t(newpos, ctrl[1]) > newsize)
270 errx(1, "Corrupt patch");
271
272 /* Read extra string */
273 lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
274 if ((lenread < ctrl[1]) ||
275 ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
276 errx(1, "Corrupt patch");
277
278 /* Adjust pointers */
279 newpos = add_off_t(newpos, ctrl[1]);
280 oldpos = add_off_t(oldpos, ctrl[2]);
281 }
282
283 /* Clean up the bzip2 reads */
284 BZ2_bzReadClose(&cbz2err, cpfbz2);
285 BZ2_bzReadClose(&dbz2err, dpfbz2);
286 BZ2_bzReadClose(&ebz2err, epfbz2);
287 if (fclose(cpf) || fclose(dpf) || fclose(epf))
288 err(1, "fclose(%s)", argv[3]);
289
290 /* Write the new file */
291 if (write(newfd, new, newsize) != newsize || close(newfd) == -1)
292 err(1, "%s", argv[2]);
293 /* Disable atexit cleanup */
294 newfile = NULL;
295
296 free(new);
297 free(old);
298
299 return (0);
300 }
301