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 #ifndef __minix 213 struct rlimit rlim; 214 215 /* Unlimited resource limits. */ 216 rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY; 217 (void)setrlimit(RLIMIT_CPU, &rlim); 218 (void)setrlimit(RLIMIT_FSIZE, &rlim); 219 (void)setrlimit(RLIMIT_STACK, &rlim); 220 (void)setrlimit(RLIMIT_DATA, &rlim); 221 (void)setrlimit(RLIMIT_RSS, &rlim); 222 223 /* Don't drop core (not really necessary, but GP's). */ 224 rlim.rlim_cur = rlim.rlim_max = 0; 225 (void)setrlimit(RLIMIT_CORE, &rlim); 226 #endif 227 228 /* Turn off signals. */ 229 (void)signal(SIGALRM, SIG_IGN); 230 (void)signal(SIGHUP, SIG_IGN); 231 (void)signal(SIGINT, SIG_IGN); 232 (void)signal(SIGPIPE, SIG_IGN); 233 (void)signal(SIGQUIT, SIG_IGN); 234 (void)signal(SIGTERM, SIG_IGN); 235 (void)signal(SIGCONT, pw_cont); 236 } 237 238 void 239 pw_edit(int notsetuid, const char *filename) 240 { 241 int pstat; 242 char *p; 243 const char * volatile editor; 244 const char *argp[] = { "sh", "-c", NULL, NULL }; 245 246 if (filename == NULL) 247 filename = _PATH_MASTERPASSWD_LOCK; 248 249 filename = pw_filename(filename); 250 if (filename == NULL) 251 return; 252 253 if ((editor = getenv("EDITOR")) == NULL) 254 editor = _PATH_VI; 255 256 p = malloc(strlen(editor) + 1 + strlen(filename) + 1); 257 if (p == NULL) 258 return; 259 260 sprintf(p, "%s %s", editor, filename); 261 argp[2] = p; 262 263 switch(editpid = vfork()) { 264 case -1: 265 free(p); 266 return; 267 case 0: 268 if (notsetuid) { 269 setgid(getgid()); 270 setuid(getuid()); 271 } 272 execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp)); 273 _exit(1); 274 } 275 276 free(p); 277 278 for (;;) { 279 editpid = waitpid(editpid, (int *)&pstat, WUNTRACED); 280 if (editpid == -1) 281 pw_error(editor, 1, 1); 282 else if (WIFSTOPPED(pstat)) 283 raise(WSTOPSIG(pstat)); 284 else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) 285 break; 286 else 287 pw_error(editor, 1, 1); 288 } 289 editpid = -1; 290 } 291 292 void 293 pw_prompt(void) 294 { 295 int c; 296 297 (void)printf("re-edit the password file? [y]: "); 298 (void)fflush(stdout); 299 c = getchar(); 300 if (c != EOF && c != '\n') 301 while (getchar() != '\n'); 302 if (c == 'n') 303 pw_error(NULL, 0, 0); 304 } 305 306 /* for use in pw_copy(). Compare a pw entry to a pw struct. */ 307 /* returns a character string labelling the miscompared field or 0 */ 308 static const char * 309 pw_equal(char *buf, struct passwd *pw) 310 { 311 struct passwd buf_pw; 312 size_t len; 313 314 _DIAGASSERT(buf != NULL); 315 _DIAGASSERT(pw != NULL); 316 317 len = strlen (buf); 318 if (buf[len-1] == '\n') 319 buf[len-1] = '\0'; 320 if (!pw_scan(buf, &buf_pw, NULL)) 321 return "corrupt line"; 322 if (strcmp(pw->pw_name, buf_pw.pw_name) != 0) 323 return "name"; 324 if (pw->pw_uid != buf_pw.pw_uid) 325 return "uid"; 326 if (pw->pw_gid != buf_pw.pw_gid) 327 return "gid"; 328 if (strcmp( pw->pw_class, buf_pw.pw_class) != 0) 329 return "class"; 330 if (pw->pw_change != buf_pw.pw_change) 331 return "change"; 332 if (pw->pw_expire != buf_pw.pw_expire) 333 return "expire"; 334 if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0) 335 return "gecos"; 336 if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0) 337 return "dir"; 338 if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0) 339 return "shell"; 340 return (char *)0; 341 } 342 343 void 344 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw) 345 { 346 char errbuf[200]; 347 int rv; 348 349 rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf)); 350 if (rv == 0) { 351 warnx("%s", errbuf); 352 pw_error(NULL, 0, 1); 353 } 354 } 355 356 static void 357 pw_print(FILE *to, const struct passwd *pw) 358 { 359 (void)fprintf(to, "%s:%s:%d:%d:%s:%lld:%lld:%s:%s:%s\n", 360 pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid, 361 pw->pw_class, (long long)pw->pw_change, 362 (long long)pw->pw_expire, 363 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 364 } 365 366 int 367 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw, 368 char *errbuf, size_t errbufsz) 369 { 370 const char *filename; 371 char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192]; 372 FILE *from, *to; 373 int done; 374 375 _DIAGASSERT(pw != NULL); 376 _DIAGASSERT(errbuf != NULL); 377 /* old_pw may be NULL */ 378 379 if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) { 380 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 381 strerror(errno)); 382 return (0); 383 } 384 (void)strcpy(mpwd, filename); 385 if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) { 386 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 387 strerror(errno)); 388 return (0); 389 } 390 (void)strcpy(mpwdl, filename); 391 392 if (!(from = fdopen(ffd, "r"))) { 393 snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno)); 394 return (0); 395 } 396 if (!(to = fdopen(tfd, "w"))) { 397 snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno)); 398 (void)fclose(from); 399 return (0); 400 } 401 402 for (done = 0; fgets(buf, (int)sizeof(buf), from);) { 403 const char *neq; 404 if (!strchr(buf, '\n')) { 405 snprintf(errbuf, errbufsz, "%s: line too long", mpwd); 406 (void)fclose(from); 407 (void)fclose(to); 408 return (0); 409 } 410 if (done) { 411 (void)fprintf(to, "%s", buf); 412 if (ferror(to)) { 413 snprintf(errbuf, errbufsz, "%s", 414 strerror(errno)); 415 (void)fclose(from); 416 (void)fclose(to); 417 return (0); 418 } 419 continue; 420 } 421 if (!(p = strchr(buf, ':'))) { 422 snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd); 423 (void)fclose(from); 424 (void)fclose(to); 425 return (0); 426 } 427 *p = '\0'; 428 if (strcmp(buf, pw->pw_name)) { 429 *p = ':'; 430 (void)fprintf(to, "%s", buf); 431 if (ferror(to)) { 432 snprintf(errbuf, errbufsz, "%s", 433 strerror(errno)); 434 (void)fclose(from); 435 (void)fclose(to); 436 return (0); 437 } 438 continue; 439 } 440 *p = ':'; 441 if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) { 442 if (strcmp(neq, "corrupt line") == 0) 443 (void)snprintf(errbuf, errbufsz, 444 "%s: entry %s corrupted", mpwd, 445 pw->pw_name); 446 else 447 (void)snprintf(errbuf, errbufsz, 448 "%s: entry %s inconsistent %s", 449 mpwd, pw->pw_name, neq); 450 (void)fclose(from); 451 (void)fclose(to); 452 return (0); 453 } 454 pw_print(to, pw); 455 done = 1; 456 if (ferror(to)) { 457 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 458 (void)fclose(from); 459 (void)fclose(to); 460 return (0); 461 } 462 } 463 /* Only append a new entry if real uid is root! */ 464 if (!done) { 465 if (getuid() == 0) { 466 pw_print(to, pw); 467 done = 1; 468 } else { 469 snprintf(errbuf, errbufsz, 470 "%s: changes not made, no such entry", mpwd); 471 } 472 } 473 474 if (ferror(to)) { 475 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 476 (void)fclose(from); 477 (void)fclose(to); 478 return (0); 479 } 480 (void)fclose(from); 481 (void)fclose(to); 482 483 return (done); 484 } 485 486 void 487 pw_error(const char *name, int error, int eval) 488 { 489 490 if (error) { 491 if (name) 492 warn("%s", name); 493 else 494 warn(NULL); 495 } 496 497 warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD); 498 pw_abort(); 499 exit(eval); 500 } 501 502 /* Removes head and/or tail spaces. */ 503 static void 504 trim_whitespace(char *line) 505 { 506 char *p; 507 508 _DIAGASSERT(line != NULL); 509 510 /* Remove leading spaces */ 511 p = line; 512 while (isspace((unsigned char) *p)) 513 p++; 514 memmove(line, p, strlen(p) + 1); 515 516 /* Remove trailing spaces */ 517 p = line + strlen(line) - 1; 518 while (isspace((unsigned char) *p)) 519 p--; 520 *(p + 1) = '\0'; 521 } 522 523 524 /* Get one line, remove spaces from front and tail */ 525 static int 526 read_line(FILE *fp, char *line, int max) 527 { 528 char *p; 529 530 _DIAGASSERT(fp != NULL); 531 _DIAGASSERT(line != NULL); 532 533 /* Read one line of config */ 534 if (fgets(line, max, fp) == NULL) 535 return (0); 536 537 if ((p = strchr(line, '\n')) == NULL) { 538 warnx("line too long"); 539 return (0); 540 } 541 *p = '\0'; 542 543 /* Remove comments */ 544 if ((p = strchr(line, '#')) != NULL) 545 *p = '\0'; 546 547 trim_whitespace(line); 548 return (1); 549 } 550 551 static const char * 552 pw_default(const char *option) 553 { 554 static const char *options[][2] = { 555 { "localcipher", "old" }, 556 { "ypcipher", "old" }, 557 }; 558 size_t i; 559 560 _DIAGASSERT(option != NULL); 561 for (i = 0; i < sizeof(options) / sizeof(options[0]); i++) 562 if (strcmp(options[i][0], option) == 0) 563 return (options[i][1]); 564 565 return (NULL); 566 } 567 568 /* 569 * Retrieve password information from the /etc/passwd.conf file, at the 570 * moment this is only for choosing the cipher to use. It could easily be 571 * used for other authentication methods as well. 572 */ 573 void 574 pw_getconf(char *data, size_t max, const char *key, const char *option) 575 { 576 FILE *fp; 577 char line[LINE_MAX], *p, *p2; 578 static char result[LINE_MAX]; 579 int got, found; 580 const char *cp; 581 582 _DIAGASSERT(data != NULL); 583 _DIAGASSERT(key != NULL); 584 _DIAGASSERT(option != NULL); 585 586 got = 0; 587 found = 0; 588 result[0] = '\0'; 589 590 if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) { 591 if ((cp = pw_default(option)) != NULL) 592 strlcpy(data, cp, max); 593 else 594 data[0] = '\0'; 595 return; 596 } 597 598 while (!found && (got || read_line(fp, line, LINE_MAX))) { 599 got = 0; 600 601 if (strncmp(key, line, strlen(key)) != 0 || 602 line[strlen(key)] != ':') 603 continue; 604 605 /* Now we found our specified key */ 606 while (read_line(fp, line, LINE_MAX)) { 607 /* Leaving key field */ 608 if (line[0] != '\0' && strchr(line + 1, ':') != NULL) { 609 got = 1; 610 break; 611 } 612 p2 = line; 613 if ((p = strsep(&p2, "=")) == NULL || p2 == NULL) 614 continue; 615 trim_whitespace(p); 616 617 if (!strncmp(p, option, strlen(option))) { 618 trim_whitespace(p2); 619 strcpy(result, p2); 620 found = 1; 621 break; 622 } 623 } 624 } 625 fclose(fp); 626 627 if (!found) 628 errno = ENOENT; 629 if (!got) 630 errno = ENOTDIR; 631 632 /* 633 * If we got no result and were looking for a default 634 * value, try hard coded defaults. 635 */ 636 637 if (strlen(result) == 0 && strcmp(key, "default") == 0 && 638 (cp = pw_default(option)) != NULL) 639 strlcpy(data, cp, max); 640 else 641 strlcpy(data, result, max); 642 } 643 644 void 645 pw_getpwconf(char *data, size_t max, const struct passwd *pwd, 646 const char *option) 647 { 648 char grpkey[LINE_MAX]; 649 struct group grs, *grp; 650 char grbuf[1024]; 651 652 pw_getconf(data, max, pwd->pw_name, option); 653 654 /* Try to find an entry for the group */ 655 if (*data == '\0') { 656 (void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp); 657 if (grp != NULL) { 658 (void)snprintf(grpkey, sizeof(grpkey), ":%s", 659 grp->gr_name); 660 pw_getconf(data, max, grpkey, option); 661 } 662 if (*data == '\0') 663 pw_getconf(data, max, "default", option); 664 } 665 } 666