1 /* Copyright 1988,1990,1993,1994 by Paul Vixie 2 * All rights reserved 3 * 4 * Distribute freely, except: don't remove my name from the source or 5 * documentation (don't take credit for my work), mark your changes (don't 6 * get me blamed for your possible bugs), don't alter or remove this 7 * notice. May be sold if buildable source is provided to buyer. No 8 * warrantee of any kind, express or implied, is included with this 9 * software; use at your own risk, responsibility for damages (if any) to 10 * anyone resulting from the use of this software rests entirely with the 11 * user. 12 * 13 * Send bug reports, bug fixes, enhancements, requests, flames, etc., and 14 * I'll try to keep a version up to date. I can be reached as follows: 15 * Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul 16 * From Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp 17 */ 18 19 #if !defined(lint) && !defined(LINT) 20 static const char rcsid[] = 21 "$FreeBSD$"; 22 #endif 23 24 /* crontab - install and manage per-user crontab files 25 * vix 02may87 [RCS has the rest of the log] 26 * vix 26jan87 [original] 27 */ 28 29 #define MAIN_PROGRAM 30 31 #include "cron.h" 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <md5.h> 35 #include <paths.h> 36 #include <sys/file.h> 37 #include <sys/stat.h> 38 #ifdef USE_UTIMES 39 # include <sys/time.h> 40 #else 41 # include <time.h> 42 # include <utime.h> 43 #endif 44 #if defined(POSIX) 45 # include <locale.h> 46 #endif 47 48 #define MD5_SIZE 33 49 #define NHEADER_LINES 3 50 51 52 enum opt_t { opt_unknown, opt_list, opt_delete, opt_edit, opt_replace }; 53 54 #if DEBUGGING 55 static char *Options[] = { "???", "list", "delete", "edit", "replace" }; 56 #endif 57 58 59 static PID_T Pid; 60 static char User[MAX_UNAME], RealUser[MAX_UNAME]; 61 static char Filename[MAX_FNAME]; 62 static FILE *NewCrontab; 63 static int CheckErrorCount; 64 static enum opt_t Option; 65 static struct passwd *pw; 66 static void list_cmd(void), 67 delete_cmd(void), 68 edit_cmd(void), 69 poke_daemon(void), 70 check_error(char *), 71 parse_args(int c, char *v[]); 72 static int replace_cmd(void); 73 74 75 static void 76 usage(msg) 77 char *msg; 78 { 79 fprintf(stderr, "crontab: usage error: %s\n", msg); 80 fprintf(stderr, "%s\n%s\n", 81 "usage: crontab [-u user] file", 82 " crontab [-u user] { -e | -l | -r }"); 83 exit(ERROR_EXIT); 84 } 85 86 87 int 88 main(argc, argv) 89 int argc; 90 char *argv[]; 91 { 92 int exitstatus; 93 94 Pid = getpid(); 95 ProgramName = argv[0]; 96 97 #if defined(POSIX) 98 setlocale(LC_ALL, ""); 99 #endif 100 101 #if defined(BSD) 102 setlinebuf(stderr); 103 #endif 104 parse_args(argc, argv); /* sets many globals, opens a file */ 105 set_cron_uid(); 106 set_cron_cwd(); 107 if (!allowed(User)) { 108 warnx("you (%s) are not allowed to use this program", User); 109 log_it(RealUser, Pid, "AUTH", "crontab command not allowed"); 110 exit(ERROR_EXIT); 111 } 112 exitstatus = OK_EXIT; 113 switch (Option) { 114 case opt_list: list_cmd(); 115 break; 116 case opt_delete: delete_cmd(); 117 break; 118 case opt_edit: edit_cmd(); 119 break; 120 case opt_replace: if (replace_cmd() < 0) 121 exitstatus = ERROR_EXIT; 122 break; 123 case opt_unknown: 124 break; 125 } 126 exit(exitstatus); 127 /*NOTREACHED*/ 128 } 129 130 131 static void 132 parse_args(argc, argv) 133 int argc; 134 char *argv[]; 135 { 136 int argch; 137 char resolved_path[PATH_MAX]; 138 139 if (!(pw = getpwuid(getuid()))) 140 errx(ERROR_EXIT, "your UID isn't in the passwd file, bailing out"); 141 (void) strncpy(User, pw->pw_name, (sizeof User)-1); 142 User[(sizeof User)-1] = '\0'; 143 strcpy(RealUser, User); 144 Filename[0] = '\0'; 145 Option = opt_unknown; 146 while ((argch = getopt(argc, argv, "u:lerx:")) != -1) { 147 switch (argch) { 148 case 'x': 149 if (!set_debug_flags(optarg)) 150 usage("bad debug option"); 151 break; 152 case 'u': 153 if (getuid() != ROOT_UID) 154 errx(ERROR_EXIT, "must be privileged to use -u"); 155 if (!(pw = getpwnam(optarg))) 156 errx(ERROR_EXIT, "user `%s' unknown", optarg); 157 (void) strncpy(User, pw->pw_name, (sizeof User)-1); 158 User[(sizeof User)-1] = '\0'; 159 break; 160 case 'l': 161 if (Option != opt_unknown) 162 usage("only one operation permitted"); 163 Option = opt_list; 164 break; 165 case 'r': 166 if (Option != opt_unknown) 167 usage("only one operation permitted"); 168 Option = opt_delete; 169 break; 170 case 'e': 171 if (Option != opt_unknown) 172 usage("only one operation permitted"); 173 Option = opt_edit; 174 break; 175 default: 176 usage("unrecognized option"); 177 } 178 } 179 180 endpwent(); 181 182 if (Option != opt_unknown) { 183 if (argv[optind] != NULL) { 184 usage("no arguments permitted after this option"); 185 } 186 } else { 187 if (argv[optind] != NULL) { 188 Option = opt_replace; 189 (void) strncpy (Filename, argv[optind], (sizeof Filename)-1); 190 Filename[(sizeof Filename)-1] = '\0'; 191 192 } else { 193 usage("file name must be specified for replace"); 194 } 195 } 196 197 if (Option == opt_replace) { 198 /* we have to open the file here because we're going to 199 * chdir(2) into /var/cron before we get around to 200 * reading the file. 201 */ 202 if (!strcmp(Filename, "-")) { 203 NewCrontab = stdin; 204 } else if (realpath(Filename, resolved_path) != NULL && 205 !strcmp(resolved_path, SYSCRONTAB)) { 206 err(ERROR_EXIT, SYSCRONTAB " must be edited manually"); 207 } else { 208 /* relinquish the setuid status of the binary during 209 * the open, lest nonroot users read files they should 210 * not be able to read. we can't use access() here 211 * since there's a race condition. thanks go out to 212 * Arnt Gulbrandsen <agulbra@pvv.unit.no> for spotting 213 * the race. 214 */ 215 216 if (swap_uids() < OK) 217 err(ERROR_EXIT, "swapping uids"); 218 if (!(NewCrontab = fopen(Filename, "r"))) 219 err(ERROR_EXIT, "%s", Filename); 220 if (swap_uids() < OK) 221 err(ERROR_EXIT, "swapping uids back"); 222 } 223 } 224 225 Debug(DMISC, ("user=%s, file=%s, option=%s\n", 226 User, Filename, Options[(int)Option])) 227 } 228 229 static void 230 copy_file(FILE *in, FILE *out) { 231 int x, ch; 232 233 Set_LineNum(1) 234 /* ignore the top few comments since we probably put them there. 235 */ 236 for (x = 0; x < NHEADER_LINES; x++) { 237 ch = get_char(in); 238 if (EOF == ch) 239 break; 240 if ('#' != ch) { 241 putc(ch, out); 242 break; 243 } 244 while (EOF != (ch = get_char(in))) 245 if (ch == '\n') 246 break; 247 if (EOF == ch) 248 break; 249 } 250 251 /* copy the rest of the crontab (if any) to the output file. 252 */ 253 if (EOF != ch) 254 while (EOF != (ch = get_char(in))) 255 putc(ch, out); 256 } 257 258 static void 259 list_cmd() { 260 char n[MAX_FNAME]; 261 FILE *f; 262 263 log_it(RealUser, Pid, "LIST", User); 264 (void) sprintf(n, CRON_TAB(User)); 265 if (!(f = fopen(n, "r"))) { 266 if (errno == ENOENT) 267 errx(ERROR_EXIT, "no crontab for %s", User); 268 else 269 err(ERROR_EXIT, "%s", n); 270 } 271 272 /* file is open. copy to stdout, close. 273 */ 274 copy_file(f, stdout); 275 fclose(f); 276 } 277 278 279 static void 280 delete_cmd() { 281 char n[MAX_FNAME]; 282 int ch, first; 283 284 if (isatty(STDIN_FILENO)) { 285 (void)fprintf(stderr, "remove crontab for %s? ", User); 286 first = ch = getchar(); 287 while (ch != '\n' && ch != EOF) 288 ch = getchar(); 289 if (first != 'y' && first != 'Y') 290 return; 291 } 292 293 log_it(RealUser, Pid, "DELETE", User); 294 (void) sprintf(n, CRON_TAB(User)); 295 if (unlink(n)) { 296 if (errno == ENOENT) 297 errx(ERROR_EXIT, "no crontab for %s", User); 298 else 299 err(ERROR_EXIT, "%s", n); 300 } 301 poke_daemon(); 302 } 303 304 305 static void 306 check_error(msg) 307 char *msg; 308 { 309 CheckErrorCount++; 310 fprintf(stderr, "\"%s\":%d: %s\n", Filename, LineNumber-1, msg); 311 } 312 313 314 static void 315 edit_cmd() { 316 char n[MAX_FNAME], q[MAX_TEMPSTR], *editor; 317 FILE *f; 318 int t; 319 struct stat statbuf, fsbuf; 320 WAIT_T waiter; 321 PID_T pid, xpid; 322 mode_t um; 323 int syntax_error = 0; 324 char orig_md5[MD5_SIZE]; 325 char new_md5[MD5_SIZE]; 326 327 log_it(RealUser, Pid, "BEGIN EDIT", User); 328 (void) sprintf(n, CRON_TAB(User)); 329 if (!(f = fopen(n, "r"))) { 330 if (errno != ENOENT) 331 err(ERROR_EXIT, "%s", n); 332 warnx("no crontab for %s - using an empty one", User); 333 if (!(f = fopen(_PATH_DEVNULL, "r"))) 334 err(ERROR_EXIT, _PATH_DEVNULL); 335 } 336 337 um = umask(077); 338 (void) sprintf(Filename, "/tmp/crontab.XXXXXXXXXX"); 339 if ((t = mkstemp(Filename)) == -1) { 340 warn("%s", Filename); 341 (void) umask(um); 342 goto fatal; 343 } 344 (void) umask(um); 345 #ifdef HAS_FCHOWN 346 if (fchown(t, getuid(), getgid()) < 0) { 347 #else 348 if (chown(Filename, getuid(), getgid()) < 0) { 349 #endif 350 warn("fchown"); 351 goto fatal; 352 } 353 if (!(NewCrontab = fdopen(t, "r+"))) { 354 warn("fdopen"); 355 goto fatal; 356 } 357 358 copy_file(f, NewCrontab); 359 fclose(f); 360 if (fflush(NewCrontab)) 361 err(ERROR_EXIT, "%s", Filename); 362 if (fstat(t, &fsbuf) < 0) { 363 warn("unable to fstat temp file"); 364 goto fatal; 365 } 366 again: 367 if (stat(Filename, &statbuf) < 0) { 368 warn("stat"); 369 fatal: unlink(Filename); 370 exit(ERROR_EXIT); 371 } 372 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 373 errx(ERROR_EXIT, "temp file must be edited in place"); 374 if (MD5File(Filename, orig_md5) == NULL) { 375 warn("MD5"); 376 goto fatal; 377 } 378 379 if ((!(editor = getenv("VISUAL"))) 380 && (!(editor = getenv("EDITOR"))) 381 ) { 382 editor = EDITOR; 383 } 384 385 /* we still have the file open. editors will generally rewrite the 386 * original file rather than renaming/unlinking it and starting a 387 * new one; even backup files are supposed to be made by copying 388 * rather than by renaming. if some editor does not support this, 389 * then don't use it. the security problems are more severe if we 390 * close and reopen the file around the edit. 391 */ 392 393 switch (pid = fork()) { 394 case -1: 395 warn("fork"); 396 goto fatal; 397 case 0: 398 /* child */ 399 if (setuid(getuid()) < 0) 400 err(ERROR_EXIT, "setuid(getuid())"); 401 if (chdir("/tmp") < 0) 402 err(ERROR_EXIT, "chdir(/tmp)"); 403 if (strlen(editor) + strlen(Filename) + 2 >= MAX_TEMPSTR) 404 errx(ERROR_EXIT, "editor or filename too long"); 405 execlp(editor, editor, Filename, (char *)NULL); 406 err(ERROR_EXIT, "%s", editor); 407 /*NOTREACHED*/ 408 default: 409 /* parent */ 410 break; 411 } 412 413 /* parent */ 414 { 415 void (*f[4])(); 416 f[0] = signal(SIGHUP, SIG_IGN); 417 f[1] = signal(SIGINT, SIG_IGN); 418 f[2] = signal(SIGTERM, SIG_IGN); 419 xpid = wait(&waiter); 420 signal(SIGHUP, f[0]); 421 signal(SIGINT, f[1]); 422 signal(SIGTERM, f[2]); 423 } 424 if (xpid != pid) { 425 warnx("wrong PID (%d != %d) from \"%s\"", xpid, pid, editor); 426 goto fatal; 427 } 428 if (WIFEXITED(waiter) && WEXITSTATUS(waiter)) { 429 warnx("\"%s\" exited with status %d", editor, WEXITSTATUS(waiter)); 430 goto fatal; 431 } 432 if (WIFSIGNALED(waiter)) { 433 warnx("\"%s\" killed; signal %d (%score dumped)", 434 editor, WTERMSIG(waiter), WCOREDUMP(waiter) ?"" :"no "); 435 goto fatal; 436 } 437 if (stat(Filename, &statbuf) < 0) { 438 warn("stat"); 439 goto fatal; 440 } 441 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 442 errx(ERROR_EXIT, "temp file must be edited in place"); 443 if (MD5File(Filename, new_md5) == NULL) { 444 warn("MD5"); 445 goto fatal; 446 } 447 if (strcmp(orig_md5, new_md5) == 0 && !syntax_error) { 448 warnx("no changes made to crontab"); 449 goto remove; 450 } 451 warnx("installing new crontab"); 452 switch (replace_cmd()) { 453 case 0: /* Success */ 454 break; 455 case -1: /* Syntax error */ 456 for (;;) { 457 printf("Do you want to retry the same edit? "); 458 fflush(stdout); 459 q[0] = '\0'; 460 (void) fgets(q, sizeof q, stdin); 461 switch (islower(q[0]) ? q[0] : tolower(q[0])) { 462 case 'y': 463 syntax_error = 1; 464 goto again; 465 case 'n': 466 goto abandon; 467 default: 468 fprintf(stderr, "Enter Y or N\n"); 469 } 470 } 471 /*NOTREACHED*/ 472 case -2: /* Install error */ 473 abandon: 474 warnx("edits left in %s", Filename); 475 goto done; 476 default: 477 warnx("panic: bad switch() in replace_cmd()"); 478 goto fatal; 479 } 480 remove: 481 unlink(Filename); 482 done: 483 log_it(RealUser, Pid, "END EDIT", User); 484 } 485 486 487 /* returns 0 on success 488 * -1 on syntax error 489 * -2 on install error 490 */ 491 static int 492 replace_cmd() { 493 char n[MAX_FNAME], envstr[MAX_ENVSTR], tn[MAX_FNAME]; 494 FILE *tmp; 495 int ch, eof; 496 entry *e; 497 time_t now = time(NULL); 498 char **envp = env_init(); 499 500 if (envp == NULL) { 501 warnx("cannot allocate memory"); 502 return (-2); 503 } 504 505 (void) sprintf(n, "tmp.%d", Pid); 506 (void) sprintf(tn, CRON_TAB(n)); 507 if (!(tmp = fopen(tn, "w+"))) { 508 warn("%s", tn); 509 return (-2); 510 } 511 512 /* write a signature at the top of the file. 513 * 514 * VERY IMPORTANT: make sure NHEADER_LINES agrees with this code. 515 */ 516 fprintf(tmp, "# DO NOT EDIT THIS FILE - edit the master and reinstall.\n"); 517 fprintf(tmp, "# (%s installed on %-24.24s)\n", Filename, ctime(&now)); 518 fprintf(tmp, "# (Cron version -- %s)\n", rcsid); 519 520 /* copy the crontab to the tmp 521 */ 522 rewind(NewCrontab); 523 Set_LineNum(1) 524 while (EOF != (ch = get_char(NewCrontab))) 525 putc(ch, tmp); 526 ftruncate(fileno(tmp), ftell(tmp)); 527 fflush(tmp); rewind(tmp); 528 529 if (ferror(tmp)) { 530 warnx("error while writing new crontab to %s", tn); 531 fclose(tmp); unlink(tn); 532 return (-2); 533 } 534 535 /* check the syntax of the file being installed. 536 */ 537 538 /* BUG: was reporting errors after the EOF if there were any errors 539 * in the file proper -- kludged it by stopping after first error. 540 * vix 31mar87 541 */ 542 Set_LineNum(1 - NHEADER_LINES) 543 CheckErrorCount = 0; eof = FALSE; 544 while (!CheckErrorCount && !eof) { 545 switch (load_env(envstr, tmp)) { 546 case ERR: 547 eof = TRUE; 548 break; 549 case FALSE: 550 e = load_entry(tmp, check_error, pw, envp); 551 if (e) 552 free(e); 553 break; 554 case TRUE: 555 break; 556 } 557 } 558 559 if (CheckErrorCount != 0) { 560 warnx("errors in crontab file, can't install"); 561 fclose(tmp); unlink(tn); 562 return (-1); 563 } 564 565 #ifdef HAS_FCHOWN 566 if (fchown(fileno(tmp), ROOT_UID, -1) < OK) 567 #else 568 if (chown(tn, ROOT_UID, -1) < OK) 569 #endif 570 { 571 warn("chown"); 572 fclose(tmp); unlink(tn); 573 return (-2); 574 } 575 576 #ifdef HAS_FCHMOD 577 if (fchmod(fileno(tmp), 0600) < OK) 578 #else 579 if (chmod(tn, 0600) < OK) 580 #endif 581 { 582 warn("chown"); 583 fclose(tmp); unlink(tn); 584 return (-2); 585 } 586 587 if (fclose(tmp) == EOF) { 588 warn("fclose"); 589 unlink(tn); 590 return (-2); 591 } 592 593 (void) sprintf(n, CRON_TAB(User)); 594 if (rename(tn, n)) { 595 warn("error renaming %s to %s", tn, n); 596 unlink(tn); 597 return (-2); 598 } 599 log_it(RealUser, Pid, "REPLACE", User); 600 601 poke_daemon(); 602 603 return (0); 604 } 605 606 607 static void 608 poke_daemon() { 609 #ifdef USE_UTIMES 610 struct timeval tvs[2]; 611 struct timezone tz; 612 613 (void) gettimeofday(&tvs[0], &tz); 614 tvs[1] = tvs[0]; 615 if (utimes(SPOOL_DIR, tvs) < OK) { 616 warn("can't update mtime on spooldir %s", SPOOL_DIR); 617 return; 618 } 619 #else 620 if (utime(SPOOL_DIR, NULL) < OK) { 621 warn("can't update mtime on spooldir %s", SPOOL_DIR); 622 return; 623 } 624 #endif /*USE_UTIMES*/ 625 } 626