1 /* $NetBSD: passwd.c,v 1.50 2010/08/18 08:32:02 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1987, 1993, 1994, 1995 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided 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 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: passwd.c,v 1.50 2010/08/18 08:32:02 christos Exp $"); 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include <sys/types.h> 38 #include <sys/param.h> 39 #include <sys/stat.h> 40 #include <sys/time.h> 41 #include <sys/resource.h> 42 #include <sys/wait.h> 43 44 #include <assert.h> 45 #include <ctype.h> 46 #include <err.h> 47 #include <errno.h> 48 #include <fcntl.h> 49 #include <limits.h> 50 #include <paths.h> 51 #include <pwd.h> 52 #include <grp.h> 53 #include <signal.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 #include <util.h> 59 60 static const char *pw_filename(const char *filename); 61 static void pw_cont(int sig); 62 static const char * pw_equal(char *buf, struct passwd *old_pw); 63 static const char *pw_default(const char *option); 64 static int read_line(FILE *fp, char *line, int max); 65 static void trim_whitespace(char *line); 66 67 static char pw_prefix[MAXPATHLEN]; 68 69 const char * 70 pw_getprefix(void) 71 { 72 73 return(pw_prefix); 74 } 75 76 int 77 pw_setprefix(const char *new_prefix) 78 { 79 size_t length; 80 81 _DIAGASSERT(new_prefix != NULL); 82 83 length = strlen(new_prefix); 84 if (length < sizeof(pw_prefix)) { 85 (void)strcpy(pw_prefix, new_prefix); 86 while (length > 0 && pw_prefix[length - 1] == '/') 87 pw_prefix[--length] = '\0'; 88 return(0); 89 } 90 errno = ENAMETOOLONG; 91 return(-1); 92 } 93 94 static const char * 95 pw_filename(const char *filename) 96 { 97 static char newfilename[MAXPATHLEN]; 98 99 _DIAGASSERT(filename != NULL); 100 101 if (pw_prefix[0] == '\0') 102 return filename; 103 104 if (strlen(pw_prefix) + strlen(filename) < sizeof(newfilename)) 105 return strcat(strcpy(newfilename, pw_prefix), filename); 106 107 errno = ENAMETOOLONG; 108 return(NULL); 109 } 110 111 int 112 pw_lock(int retries) 113 { 114 const char *filename; 115 int i, fd; 116 mode_t old_mode; 117 int oerrno; 118 119 /* Acquire the lock file. */ 120 filename = pw_filename(_PATH_MASTERPASSWD_LOCK); 121 if (filename == NULL) 122 return(-1); 123 old_mode = umask(0); 124 fd = open(filename, O_WRONLY|O_CREAT|O_EXCL, 0600); 125 for (i = 0; i < retries && fd < 0 && errno == EEXIST; i++) { 126 sleep(1); 127 fd = open(filename, O_WRONLY|O_CREAT|O_EXCL, 128 0600); 129 } 130 oerrno = errno; 131 (void)umask(old_mode); 132 errno = oerrno; 133 return(fd); 134 } 135 136 int 137 pw_mkdb(username, secureonly) 138 const char *username; 139 int secureonly; 140 { 141 const char *args[9]; 142 int pstat, i; 143 pid_t pid; 144 145 pid = vfork(); 146 if (pid == -1) 147 return -1; 148 149 if (pid == 0) { 150 args[0] = "pwd_mkdb"; 151 args[1] = "-d"; 152 args[2] = pw_prefix; 153 args[3] = "-pl"; 154 i = 4; 155 156 if (secureonly) 157 args[i++] = "-s"; 158 if (username != NULL) { 159 args[i++] = "-u"; 160 args[i++] = username; 161 } 162 163 args[i++] = pw_filename(_PATH_MASTERPASSWD_LOCK); 164 args[i] = NULL; 165 execv(_PATH_PWD_MKDB, (char * const *)__UNCONST(args)); 166 _exit(1); 167 } 168 pid = waitpid(pid, &pstat, 0); 169 if (pid == -1) { 170 warn("error waiting for pid %lu", (unsigned long)pid); 171 return -1; 172 } 173 if (WIFEXITED(pstat)) { 174 if (WEXITSTATUS(pstat) != 0) { 175 warnx("pwd_mkdb exited with static %d", 176 WEXITSTATUS(pstat)); 177 return -1; 178 } 179 } else if (WIFSIGNALED(pstat)) { 180 warnx("pwd_mkdb exited with signal %d", WTERMSIG(pstat)); 181 return -1; 182 } 183 return 0; 184 } 185 186 int 187 pw_abort(void) 188 { 189 const char *filename; 190 191 filename = pw_filename(_PATH_MASTERPASSWD_LOCK); 192 return((filename == NULL) ? -1 : unlink(filename)); 193 } 194 195 /* Everything below this point is intended for the convenience of programs 196 * which allow a user to interactively edit the passwd file. Errors in the 197 * routines below will cause the process to abort. */ 198 199 static pid_t editpid = -1; 200 201 static void 202 pw_cont(int sig) 203 { 204 205 if (editpid != -1) 206 kill(editpid, sig); 207 } 208 209 void 210 pw_init(void) 211 { 212 struct rlimit rlim; 213 214 /* Unlimited resource limits. */ 215 rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY; 216 (void)setrlimit(RLIMIT_CPU, &rlim); 217 (void)setrlimit(RLIMIT_FSIZE, &rlim); 218 (void)setrlimit(RLIMIT_STACK, &rlim); 219 (void)setrlimit(RLIMIT_DATA, &rlim); 220 (void)setrlimit(RLIMIT_RSS, &rlim); 221 222 /* Don't drop core (not really necessary, but GP's). */ 223 rlim.rlim_cur = rlim.rlim_max = 0; 224 (void)setrlimit(RLIMIT_CORE, &rlim); 225 226 /* Turn off signals. */ 227 (void)signal(SIGALRM, SIG_IGN); 228 (void)signal(SIGHUP, SIG_IGN); 229 (void)signal(SIGINT, SIG_IGN); 230 (void)signal(SIGPIPE, SIG_IGN); 231 (void)signal(SIGQUIT, SIG_IGN); 232 (void)signal(SIGTERM, SIG_IGN); 233 (void)signal(SIGCONT, pw_cont); 234 } 235 236 void 237 pw_edit(int notsetuid, const char *filename) 238 { 239 int pstat; 240 char *p; 241 const char * volatile editor; 242 const char *argp[] = { "sh", "-c", NULL, NULL }; 243 244 if (filename == NULL) 245 filename = _PATH_MASTERPASSWD_LOCK; 246 247 filename = pw_filename(filename); 248 if (filename == NULL) 249 return; 250 251 if ((editor = getenv("EDITOR")) == NULL) 252 editor = _PATH_VI; 253 254 p = malloc(strlen(editor) + 1 + strlen(filename) + 1); 255 if (p == NULL) 256 return; 257 258 sprintf(p, "%s %s", editor, filename); 259 argp[2] = p; 260 261 switch(editpid = vfork()) { 262 case -1: 263 free(p); 264 return; 265 case 0: 266 if (notsetuid) { 267 setgid(getgid()); 268 setuid(getuid()); 269 } 270 execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp)); 271 _exit(1); 272 } 273 274 free(p); 275 276 for (;;) { 277 editpid = waitpid(editpid, (int *)&pstat, WUNTRACED); 278 if (editpid == -1) 279 pw_error(editor, 1, 1); 280 else if (WIFSTOPPED(pstat)) 281 raise(WSTOPSIG(pstat)); 282 else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) 283 break; 284 else 285 pw_error(editor, 1, 1); 286 } 287 editpid = -1; 288 } 289 290 void 291 pw_prompt(void) 292 { 293 int c; 294 295 (void)printf("re-edit the password file? [y]: "); 296 (void)fflush(stdout); 297 c = getchar(); 298 if (c != EOF && c != '\n') 299 while (getchar() != '\n'); 300 if (c == 'n') 301 pw_error(NULL, 0, 0); 302 } 303 304 /* for use in pw_copy(). Compare a pw entry to a pw struct. */ 305 /* returns a character string labelling the miscompared field or 0 */ 306 static const char * 307 pw_equal(char *buf, struct passwd *pw) 308 { 309 struct passwd buf_pw; 310 size_t len; 311 312 _DIAGASSERT(buf != NULL); 313 _DIAGASSERT(pw != NULL); 314 315 len = strlen (buf); 316 if (buf[len-1] == '\n') 317 buf[len-1] = '\0'; 318 if (!pw_scan(buf, &buf_pw, NULL)) 319 return "corrupt line"; 320 if (strcmp(pw->pw_name, buf_pw.pw_name) != 0) 321 return "name"; 322 if (pw->pw_uid != buf_pw.pw_uid) 323 return "uid"; 324 if (pw->pw_gid != buf_pw.pw_gid) 325 return "gid"; 326 if (strcmp( pw->pw_class, buf_pw.pw_class) != 0) 327 return "class"; 328 if (pw->pw_change != buf_pw.pw_change) 329 return "change"; 330 if (pw->pw_expire != buf_pw.pw_expire) 331 return "expire"; 332 if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0) 333 return "gecos"; 334 if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0) 335 return "dir"; 336 if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0) 337 return "shell"; 338 return (char *)0; 339 } 340 341 void 342 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw) 343 { 344 char errbuf[200]; 345 int rv; 346 347 rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf)); 348 if (rv == 0) { 349 warnx("%s", errbuf); 350 pw_error(NULL, 0, 1); 351 } 352 } 353 354 static void 355 pw_print(FILE *to, const struct passwd *pw) 356 { 357 (void)fprintf(to, "%s:%s:%d:%d:%s:%lld:%lld:%s:%s:%s\n", 358 pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid, 359 pw->pw_class, (long long)pw->pw_change, 360 (long long)pw->pw_expire, 361 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 362 } 363 364 int 365 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw, 366 char *errbuf, size_t errbufsz) 367 { 368 const char *filename; 369 char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192]; 370 FILE *from, *to; 371 int done; 372 373 _DIAGASSERT(pw != NULL); 374 _DIAGASSERT(errbuf != NULL); 375 /* old_pw may be NULL */ 376 377 if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) { 378 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 379 strerror(errno)); 380 return (0); 381 } 382 (void)strcpy(mpwd, filename); 383 if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) { 384 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 385 strerror(errno)); 386 return (0); 387 } 388 (void)strcpy(mpwdl, filename); 389 390 if (!(from = fdopen(ffd, "r"))) { 391 snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno)); 392 return (0); 393 } 394 if (!(to = fdopen(tfd, "w"))) { 395 snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno)); 396 (void)fclose(from); 397 return (0); 398 } 399 400 for (done = 0; fgets(buf, (int)sizeof(buf), from);) { 401 const char *neq; 402 if (!strchr(buf, '\n')) { 403 snprintf(errbuf, errbufsz, "%s: line too long", mpwd); 404 (void)fclose(from); 405 (void)fclose(to); 406 return (0); 407 } 408 if (done) { 409 (void)fprintf(to, "%s", buf); 410 if (ferror(to)) { 411 snprintf(errbuf, errbufsz, "%s", 412 strerror(errno)); 413 (void)fclose(from); 414 (void)fclose(to); 415 return (0); 416 } 417 continue; 418 } 419 if (!(p = strchr(buf, ':'))) { 420 snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd); 421 (void)fclose(from); 422 (void)fclose(to); 423 return (0); 424 } 425 *p = '\0'; 426 if (strcmp(buf, pw->pw_name)) { 427 *p = ':'; 428 (void)fprintf(to, "%s", buf); 429 if (ferror(to)) { 430 snprintf(errbuf, errbufsz, "%s", 431 strerror(errno)); 432 (void)fclose(from); 433 (void)fclose(to); 434 return (0); 435 } 436 continue; 437 } 438 *p = ':'; 439 if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) { 440 if (strcmp(neq, "corrupt line") == 0) 441 (void)snprintf(errbuf, errbufsz, 442 "%s: entry %s corrupted", mpwd, 443 pw->pw_name); 444 else 445 (void)snprintf(errbuf, errbufsz, 446 "%s: entry %s inconsistent %s", 447 mpwd, pw->pw_name, neq); 448 (void)fclose(from); 449 (void)fclose(to); 450 return (0); 451 } 452 pw_print(to, pw); 453 done = 1; 454 if (ferror(to)) { 455 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 456 (void)fclose(from); 457 (void)fclose(to); 458 return (0); 459 } 460 } 461 /* Only append a new entry if real uid is root! */ 462 if (!done) { 463 if (getuid() == 0) { 464 pw_print(to, pw); 465 done = 1; 466 } else { 467 snprintf(errbuf, errbufsz, 468 "%s: changes not made, no such entry", mpwd); 469 } 470 } 471 472 if (ferror(to)) { 473 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 474 (void)fclose(from); 475 (void)fclose(to); 476 return (0); 477 } 478 (void)fclose(from); 479 (void)fclose(to); 480 481 return (done); 482 } 483 484 void 485 pw_error(const char *name, int error, int eval) 486 { 487 488 if (error) { 489 if (name) 490 warn("%s", name); 491 else 492 warn(NULL); 493 } 494 495 warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD); 496 pw_abort(); 497 exit(eval); 498 } 499 500 /* Removes head and/or tail spaces. */ 501 static void 502 trim_whitespace(char *line) 503 { 504 char *p; 505 506 _DIAGASSERT(line != NULL); 507 508 /* Remove leading spaces */ 509 p = line; 510 while (isspace((unsigned char) *p)) 511 p++; 512 memmove(line, p, strlen(p) + 1); 513 514 /* Remove trailing spaces */ 515 p = line + strlen(line) - 1; 516 while (isspace((unsigned char) *p)) 517 p--; 518 *(p + 1) = '\0'; 519 } 520 521 522 /* Get one line, remove spaces from front and tail */ 523 static int 524 read_line(FILE *fp, char *line, int max) 525 { 526 char *p; 527 528 _DIAGASSERT(fp != NULL); 529 _DIAGASSERT(line != NULL); 530 531 /* Read one line of config */ 532 if (fgets(line, max, fp) == NULL) 533 return (0); 534 535 if ((p = strchr(line, '\n')) == NULL) { 536 warnx("line too long"); 537 return (0); 538 } 539 *p = '\0'; 540 541 /* Remove comments */ 542 if ((p = strchr(line, '#')) != NULL) 543 *p = '\0'; 544 545 trim_whitespace(line); 546 return (1); 547 } 548 549 static const char * 550 pw_default(const char *option) 551 { 552 static const char *options[][2] = { 553 { "localcipher", "old" }, 554 { "ypcipher", "old" }, 555 }; 556 size_t i; 557 558 _DIAGASSERT(option != NULL); 559 for (i = 0; i < sizeof(options) / sizeof(options[0]); i++) 560 if (strcmp(options[i][0], option) == 0) 561 return (options[i][1]); 562 563 return (NULL); 564 } 565 566 /* 567 * Retrieve password information from the /etc/passwd.conf file, at the 568 * moment this is only for choosing the cipher to use. It could easily be 569 * used for other authentication methods as well. 570 */ 571 void 572 pw_getconf(char *data, size_t max, const char *key, const char *option) 573 { 574 FILE *fp; 575 char line[LINE_MAX], *p, *p2; 576 static char result[LINE_MAX]; 577 int got, found; 578 const char *cp; 579 580 _DIAGASSERT(data != NULL); 581 _DIAGASSERT(key != NULL); 582 _DIAGASSERT(option != NULL); 583 584 got = 0; 585 found = 0; 586 result[0] = '\0'; 587 588 if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) { 589 if ((cp = pw_default(option)) != NULL) 590 strlcpy(data, cp, max); 591 else 592 data[0] = '\0'; 593 return; 594 } 595 596 while (!found && (got || read_line(fp, line, LINE_MAX))) { 597 got = 0; 598 599 if (strncmp(key, line, strlen(key)) != 0 || 600 line[strlen(key)] != ':') 601 continue; 602 603 /* Now we found our specified key */ 604 while (read_line(fp, line, LINE_MAX)) { 605 /* Leaving key field */ 606 if (line[0] != '\0' && strchr(line + 1, ':') != NULL) { 607 got = 1; 608 break; 609 } 610 p2 = line; 611 if ((p = strsep(&p2, "=")) == NULL || p2 == NULL) 612 continue; 613 trim_whitespace(p); 614 615 if (!strncmp(p, option, strlen(option))) { 616 trim_whitespace(p2); 617 strcpy(result, p2); 618 found = 1; 619 break; 620 } 621 } 622 } 623 fclose(fp); 624 625 if (!found) 626 errno = ENOENT; 627 if (!got) 628 errno = ENOTDIR; 629 630 /* 631 * If we got no result and were looking for a default 632 * value, try hard coded defaults. 633 */ 634 635 if (strlen(result) == 0 && strcmp(key, "default") == 0 && 636 (cp = pw_default(option)) != NULL) 637 strlcpy(data, cp, max); 638 else 639 strlcpy(data, result, max); 640 } 641 642 void 643 pw_getpwconf(char *data, size_t max, const struct passwd *pwd, 644 const char *option) 645 { 646 char grpkey[LINE_MAX]; 647 struct group grs, *grp; 648 char grbuf[1024]; 649 650 pw_getconf(data, max, pwd->pw_name, option); 651 652 /* Try to find an entry for the group */ 653 if (*data == '\0') { 654 (void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp); 655 if (grp != NULL) { 656 (void)snprintf(grpkey, sizeof(grpkey), ":%s", 657 grp->gr_name); 658 pw_getconf(data, max, grpkey, option); 659 } 660 if (*data == '\0') 661 pw_getconf(data, max, "default", option); 662 } 663 } 664