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