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 #if defined(__FreeBSD__) 33 #include <sys/param.h> 34 #if __FreeBSD_version >= 1001511 35 #include <sys/capsicum.h> 36 #define HAVE_CAPSICUM 37 #endif 38 #endif 39 40 #include <bzlib.h> 41 #include <err.h> 42 #include <errno.h> 43 #include <fcntl.h> 44 #include <libgen.h> 45 #include <limits.h> 46 #include <stdint.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 52 #ifndef O_BINARY 53 #define O_BINARY 0 54 #endif 55 #define HEADER_SIZE 32 56 57 static char *newfile; 58 static int dirfd = -1; 59 60 static void 61 exit_cleanup(void) 62 { 63 64 if (dirfd != -1 && newfile != NULL) 65 if (unlinkat(dirfd, newfile, 0)) 66 warn("unlinkat"); 67 } 68 69 static off_t offtin(u_char *buf) 70 { 71 off_t y; 72 73 y = buf[7] & 0x7F; 74 y = y * 256; y += buf[6]; 75 y = y * 256; y += buf[5]; 76 y = y * 256; y += buf[4]; 77 y = y * 256; y += buf[3]; 78 y = y * 256; y += buf[2]; 79 y = y * 256; y += buf[1]; 80 y = y * 256; y += buf[0]; 81 82 if (buf[7] & 0x80) 83 y = -y; 84 85 return (y); 86 } 87 88 static void 89 usage(void) 90 { 91 92 fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n"); 93 exit(1); 94 } 95 96 int main(int argc, char *argv[]) 97 { 98 FILE *f, *cpf, *dpf, *epf; 99 BZFILE *cpfbz2, *dpfbz2, *epfbz2; 100 char *directory, *namebuf; 101 int cbz2err, dbz2err, ebz2err; 102 int newfd, oldfd; 103 off_t oldsize, newsize; 104 off_t bzctrllen, bzdatalen; 105 u_char header[HEADER_SIZE], buf[8]; 106 u_char *old, *new; 107 off_t oldpos, newpos; 108 off_t ctrl[3]; 109 off_t i, lenread, offset; 110 #ifdef HAVE_CAPSICUM 111 cap_rights_t rights_dir, rights_ro, rights_wr; 112 #endif 113 114 if (argc != 4) 115 usage(); 116 117 /* Open patch file */ 118 if ((f = fopen(argv[3], "rb")) == NULL) 119 err(1, "fopen(%s)", argv[3]); 120 /* Open patch file for control block */ 121 if ((cpf = fopen(argv[3], "rb")) == NULL) 122 err(1, "fopen(%s)", argv[3]); 123 /* open patch file for diff block */ 124 if ((dpf = fopen(argv[3], "rb")) == NULL) 125 err(1, "fopen(%s)", argv[3]); 126 /* open patch file for extra block */ 127 if ((epf = fopen(argv[3], "rb")) == NULL) 128 err(1, "fopen(%s)", argv[3]); 129 /* open oldfile */ 130 if ((oldfd = open(argv[1], O_RDONLY | O_BINARY, 0)) < 0) 131 err(1, "open(%s)", argv[1]); 132 /* open directory where we'll write newfile */ 133 if ((namebuf = strdup(argv[2])) == NULL || 134 (directory = dirname(namebuf)) == NULL || 135 (dirfd = open(directory, O_DIRECTORY)) < 0) 136 err(1, "open %s", argv[2]); 137 free(namebuf); 138 if ((newfile = basename(argv[2])) == NULL) 139 err(1, "basename"); 140 /* open newfile */ 141 if ((newfd = openat(dirfd, newfile, 142 O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0666)) < 0) 143 err(1, "open(%s)", argv[2]); 144 atexit(exit_cleanup); 145 146 #ifdef HAVE_CAPSICUM 147 if (cap_enter() < 0) 148 err(1, "failed to enter security sandbox"); 149 150 cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK); 151 cap_rights_init(&rights_wr, CAP_WRITE); 152 cap_rights_init(&rights_dir, CAP_UNLINKAT); 153 154 if (cap_rights_limit(fileno(f), &rights_ro) < 0 || 155 cap_rights_limit(fileno(cpf), &rights_ro) < 0 || 156 cap_rights_limit(fileno(dpf), &rights_ro) < 0 || 157 cap_rights_limit(fileno(epf), &rights_ro) < 0 || 158 cap_rights_limit(oldfd, &rights_ro) < 0 || 159 cap_rights_limit(newfd, &rights_wr) < 0 || 160 cap_rights_limit(dirfd, &rights_dir) < 0) 161 err(1, "cap_rights_limit() failed, could not restrict" 162 " capabilities"); 163 #endif 164 165 /* 166 File format: 167 0 8 "BSDIFF40" 168 8 8 X 169 16 8 Y 170 24 8 sizeof(newfile) 171 32 X bzip2(control block) 172 32+X Y bzip2(diff block) 173 32+X+Y ??? bzip2(extra block) 174 with control block a set of triples (x,y,z) meaning "add x bytes 175 from oldfile to x bytes from the diff block; copy y bytes from the 176 extra block; seek forwards in oldfile by z bytes". 177 */ 178 179 /* Read header */ 180 if (fread(header, 1, HEADER_SIZE, f) < HEADER_SIZE) { 181 if (feof(f)) 182 errx(1, "Corrupt patch"); 183 err(1, "fread(%s)", argv[3]); 184 } 185 186 /* Check for appropriate magic */ 187 if (memcmp(header, "BSDIFF40", 8) != 0) 188 errx(1, "Corrupt patch"); 189 190 /* Read lengths from header */ 191 bzctrllen = offtin(header + 8); 192 bzdatalen = offtin(header + 16); 193 newsize = offtin(header + 24); 194 if (bzctrllen < 0 || bzctrllen > OFF_MAX - HEADER_SIZE || 195 bzdatalen < 0 || bzctrllen + HEADER_SIZE > OFF_MAX - bzdatalen || 196 newsize < 0 || newsize > SSIZE_MAX) 197 errx(1, "Corrupt patch"); 198 199 /* Close patch file and re-open it via libbzip2 at the right places */ 200 if (fclose(f)) 201 err(1, "fclose(%s)", argv[3]); 202 offset = HEADER_SIZE; 203 if (fseeko(cpf, offset, SEEK_SET)) 204 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset); 205 if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL) 206 errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err); 207 offset += bzctrllen; 208 if (fseeko(dpf, offset, SEEK_SET)) 209 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset); 210 if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL) 211 errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err); 212 offset += bzdatalen; 213 if (fseeko(epf, offset, SEEK_SET)) 214 err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset); 215 if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL) 216 errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err); 217 218 if ((oldsize = lseek(oldfd, 0, SEEK_END)) == -1 || 219 oldsize > SSIZE_MAX || 220 (old = malloc(oldsize)) == NULL || 221 lseek(oldfd, 0, SEEK_SET) != 0 || 222 read(oldfd, old, oldsize) != oldsize || 223 close(oldfd) == -1) 224 err(1, "%s", argv[1]); 225 if ((new = malloc(newsize)) == NULL) 226 err(1, NULL); 227 228 oldpos = 0; 229 newpos = 0; 230 while (newpos < newsize) { 231 /* Read control data */ 232 for (i = 0; i <= 2; i++) { 233 lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8); 234 if ((lenread < 8) || ((cbz2err != BZ_OK) && 235 (cbz2err != BZ_STREAM_END))) 236 errx(1, "Corrupt patch"); 237 ctrl[i] = offtin(buf); 238 } 239 240 /* Sanity-check */ 241 if (ctrl[0] < 0 || ctrl[0] > INT_MAX || 242 ctrl[1] < 0 || ctrl[1] > INT_MAX) 243 errx(1, "Corrupt patch"); 244 245 /* Sanity-check */ 246 if (newpos + ctrl[0] > newsize) 247 errx(1, "Corrupt patch"); 248 249 /* Read diff string */ 250 lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]); 251 if ((lenread < ctrl[0]) || 252 ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END))) 253 errx(1, "Corrupt patch"); 254 255 /* Add old data to diff string */ 256 for (i = 0; i < ctrl[0]; i++) 257 if ((oldpos + i >= 0) && (oldpos + i < oldsize)) 258 new[newpos + i] += old[oldpos + i]; 259 260 /* Adjust pointers */ 261 newpos += ctrl[0]; 262 oldpos += ctrl[0]; 263 264 /* Sanity-check */ 265 if (newpos + ctrl[1] > newsize) 266 errx(1, "Corrupt patch"); 267 268 /* Read extra string */ 269 lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]); 270 if ((lenread < ctrl[1]) || 271 ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END))) 272 errx(1, "Corrupt patch"); 273 274 /* Adjust pointers */ 275 newpos+=ctrl[1]; 276 oldpos+=ctrl[2]; 277 } 278 279 /* Clean up the bzip2 reads */ 280 BZ2_bzReadClose(&cbz2err, cpfbz2); 281 BZ2_bzReadClose(&dbz2err, dpfbz2); 282 BZ2_bzReadClose(&ebz2err, epfbz2); 283 if (fclose(cpf) || fclose(dpf) || fclose(epf)) 284 err(1, "fclose(%s)", argv[3]); 285 286 /* Write the new file */ 287 if (write(newfd, new, newsize) != newsize || close(newfd) == -1) 288 err(1, "%s", argv[2]); 289 /* Disable atexit cleanup */ 290 newfile = NULL; 291 292 free(new); 293 free(old); 294 295 return (0); 296 } 297