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 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 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 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 93 usage(void) 94 { 95 96 fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n"); 97 exit(1); 98 } 99 100 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