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