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 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 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 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 101 usage(void) 102 { 103 104 fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n"); 105 exit(1); 106 } 107 108 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