1 /* $NetBSD: passwd.c,v 1.46 2008/12/21 17:54:43 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 1.46 2008/12/21 17:54:43 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] = "-p"; 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 || !WIFEXITED(pstat) || WEXITSTATUS(pstat) != 0) 170 return(-1); 171 return(0); 172 } 173 174 int 175 pw_abort(void) 176 { 177 const char *filename; 178 179 filename = pw_filename(_PATH_MASTERPASSWD_LOCK); 180 return((filename == NULL) ? -1 : unlink(filename)); 181 } 182 183 /* Everything below this point is intended for the convenience of programs 184 * which allow a user to interactively edit the passwd file. Errors in the 185 * routines below will cause the process to abort. */ 186 187 static pid_t editpid = -1; 188 189 static void 190 pw_cont(int sig) 191 { 192 193 if (editpid != -1) 194 kill(editpid, sig); 195 } 196 197 void 198 pw_init(void) 199 { 200 struct rlimit rlim; 201 202 /* Unlimited resource limits. */ 203 rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY; 204 (void)setrlimit(RLIMIT_CPU, &rlim); 205 (void)setrlimit(RLIMIT_FSIZE, &rlim); 206 (void)setrlimit(RLIMIT_STACK, &rlim); 207 (void)setrlimit(RLIMIT_DATA, &rlim); 208 (void)setrlimit(RLIMIT_RSS, &rlim); 209 210 /* Don't drop core (not really necessary, but GP's). */ 211 rlim.rlim_cur = rlim.rlim_max = 0; 212 (void)setrlimit(RLIMIT_CORE, &rlim); 213 214 /* Turn off signals. */ 215 (void)signal(SIGALRM, SIG_IGN); 216 (void)signal(SIGHUP, SIG_IGN); 217 (void)signal(SIGINT, SIG_IGN); 218 (void)signal(SIGPIPE, SIG_IGN); 219 (void)signal(SIGQUIT, SIG_IGN); 220 (void)signal(SIGTERM, SIG_IGN); 221 (void)signal(SIGCONT, pw_cont); 222 } 223 224 void 225 pw_edit(int notsetuid, const char *filename) 226 { 227 int pstat; 228 char *p; 229 const char * volatile editor; 230 const char *argp[] = { "sh", "-c", NULL, NULL }; 231 232 if (filename == NULL) 233 filename = _PATH_MASTERPASSWD_LOCK; 234 235 filename = pw_filename(filename); 236 if (filename == NULL) 237 return; 238 239 if ((editor = getenv("EDITOR")) == NULL) 240 editor = _PATH_VI; 241 242 p = malloc(strlen(editor) + 1 + strlen(filename) + 1); 243 if (p == NULL) 244 return; 245 246 sprintf(p, "%s %s", editor, filename); 247 argp[2] = p; 248 249 switch(editpid = vfork()) { 250 case -1: 251 free(p); 252 return; 253 case 0: 254 if (notsetuid) { 255 setgid(getgid()); 256 setuid(getuid()); 257 } 258 execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp)); 259 _exit(1); 260 } 261 262 free(p); 263 264 for (;;) { 265 editpid = waitpid(editpid, (int *)&pstat, WUNTRACED); 266 if (editpid == -1) 267 pw_error(editor, 1, 1); 268 else if (WIFSTOPPED(pstat)) 269 raise(WSTOPSIG(pstat)); 270 else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) 271 break; 272 else 273 pw_error(editor, 1, 1); 274 } 275 editpid = -1; 276 } 277 278 void 279 pw_prompt(void) 280 { 281 int c; 282 283 (void)printf("re-edit the password file? [y]: "); 284 (void)fflush(stdout); 285 c = getchar(); 286 if (c != EOF && c != '\n') 287 while (getchar() != '\n'); 288 if (c == 'n') 289 pw_error(NULL, 0, 0); 290 } 291 292 /* for use in pw_copy(). Compare a pw entry to a pw struct. */ 293 /* returns a character string labelling the miscompared field or 0 */ 294 static const char * 295 pw_equal(char *buf, struct passwd *pw) 296 { 297 struct passwd buf_pw; 298 size_t len; 299 300 _DIAGASSERT(buf != NULL); 301 _DIAGASSERT(pw != NULL); 302 303 len = strlen (buf); 304 if (buf[len-1] == '\n') 305 buf[len-1] = '\0'; 306 if (!pw_scan(buf, &buf_pw, NULL)) 307 return "corrupt line"; 308 if (strcmp(pw->pw_name, buf_pw.pw_name) != 0) 309 return "name"; 310 if (pw->pw_uid != buf_pw.pw_uid) 311 return "uid"; 312 if (pw->pw_gid != buf_pw.pw_gid) 313 return "gid"; 314 if (strcmp( pw->pw_class, buf_pw.pw_class) != 0) 315 return "class"; 316 if (pw->pw_change != buf_pw.pw_change) 317 return "change"; 318 if (pw->pw_expire != buf_pw.pw_expire) 319 return "expire"; 320 if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0) 321 return "gecos"; 322 if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0) 323 return "dir"; 324 if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0) 325 return "shell"; 326 return (char *)0; 327 } 328 329 void 330 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw) 331 { 332 char errbuf[200]; 333 int rv; 334 335 rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf)); 336 if (rv == 0) { 337 warnx("%s", errbuf); 338 pw_error(NULL, 0, 1); 339 } 340 } 341 342 int 343 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw, 344 char *errbuf, size_t errbufsz) 345 { 346 const char *filename; 347 char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192]; 348 FILE *from, *to; 349 int done; 350 351 _DIAGASSERT(pw != NULL); 352 _DIAGASSERT(errbuf != NULL); 353 /* old_pw may be NULL */ 354 355 if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) { 356 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 357 strerror(errno)); 358 return (0); 359 } 360 (void)strcpy(mpwd, filename); 361 if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) { 362 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 363 strerror(errno)); 364 return (0); 365 } 366 (void)strcpy(mpwdl, filename); 367 368 if (!(from = fdopen(ffd, "r"))) { 369 snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno)); 370 return (0); 371 } 372 if (!(to = fdopen(tfd, "w"))) { 373 snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno)); 374 (void)fclose(from); 375 return (0); 376 } 377 378 for (done = 0; fgets(buf, (int)sizeof(buf), from);) { 379 const char *neq; 380 if (!strchr(buf, '\n')) { 381 snprintf(errbuf, errbufsz, "%s: line too long", mpwd); 382 (void)fclose(from); 383 (void)fclose(to); 384 return (0); 385 } 386 if (done) { 387 (void)fprintf(to, "%s", buf); 388 if (ferror(to)) { 389 snprintf(errbuf, errbufsz, "%s", 390 strerror(errno)); 391 (void)fclose(from); 392 (void)fclose(to); 393 return (0); 394 } 395 continue; 396 } 397 if (!(p = strchr(buf, ':'))) { 398 snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd); 399 (void)fclose(from); 400 (void)fclose(to); 401 return (0); 402 } 403 *p = '\0'; 404 if (strcmp(buf, pw->pw_name)) { 405 *p = ':'; 406 (void)fprintf(to, "%s", buf); 407 if (ferror(to)) { 408 snprintf(errbuf, errbufsz, "%s", 409 strerror(errno)); 410 (void)fclose(from); 411 (void)fclose(to); 412 return (0); 413 } 414 continue; 415 } 416 *p = ':'; 417 if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) { 418 if (strcmp(neq, "corrupt line") == 0) 419 (void)snprintf(errbuf, errbufsz, 420 "%s: entry %s corrupted", mpwd, 421 pw->pw_name); 422 else 423 (void)snprintf(errbuf, errbufsz, 424 "%s: entry %s inconsistent %s", 425 mpwd, pw->pw_name, neq); 426 (void)fclose(from); 427 (void)fclose(to); 428 return (0); 429 } 430 (void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n", 431 pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid, 432 pw->pw_class, (long)pw->pw_change, (long)pw->pw_expire, 433 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 434 done = 1; 435 if (ferror(to)) { 436 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 437 (void)fclose(from); 438 (void)fclose(to); 439 return (0); 440 } 441 } 442 /* Only append a new entry if real uid is root! */ 443 if (!done) { 444 if (getuid() == 0) { 445 (void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n", 446 pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid, 447 pw->pw_class, (long)pw->pw_change, 448 (long)pw->pw_expire, pw->pw_gecos, pw->pw_dir, 449 pw->pw_shell); 450 done = 1; 451 } else { 452 snprintf(errbuf, errbufsz, 453 "%s: changes not made, no such entry", mpwd); 454 } 455 } 456 457 if (ferror(to)) { 458 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 459 (void)fclose(from); 460 (void)fclose(to); 461 return (0); 462 } 463 (void)fclose(from); 464 (void)fclose(to); 465 466 return (done); 467 } 468 469 void 470 pw_error(const char *name, int error, int eval) 471 { 472 473 if (error) { 474 if (name) 475 warn("%s", name); 476 else 477 warn(NULL); 478 } 479 480 warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD); 481 pw_abort(); 482 exit(eval); 483 } 484 485 /* Removes head and/or tail spaces. */ 486 static void 487 trim_whitespace(char *line) 488 { 489 char *p; 490 491 _DIAGASSERT(line != NULL); 492 493 /* Remove leading spaces */ 494 p = line; 495 while (isspace((unsigned char) *p)) 496 p++; 497 memmove(line, p, strlen(p) + 1); 498 499 /* Remove trailing spaces */ 500 p = line + strlen(line) - 1; 501 while (isspace((unsigned char) *p)) 502 p--; 503 *(p + 1) = '\0'; 504 } 505 506 507 /* Get one line, remove spaces from front and tail */ 508 static int 509 read_line(FILE *fp, char *line, int max) 510 { 511 char *p; 512 513 _DIAGASSERT(fp != NULL); 514 _DIAGASSERT(line != NULL); 515 516 /* Read one line of config */ 517 if (fgets(line, max, fp) == NULL) 518 return (0); 519 520 if ((p = strchr(line, '\n')) == NULL) { 521 warnx("line too long"); 522 return (0); 523 } 524 *p = '\0'; 525 526 /* Remove comments */ 527 if ((p = strchr(line, '#')) != NULL) 528 *p = '\0'; 529 530 trim_whitespace(line); 531 return (1); 532 } 533 534 static const char * 535 pw_default(const char *option) 536 { 537 static const char *options[][2] = { 538 { "localcipher", "old" }, 539 { "ypcipher", "old" }, 540 }; 541 int i; 542 543 _DIAGASSERT(option != NULL); 544 for (i = 0; i < sizeof(options) / sizeof(options[0]); i++) 545 if (strcmp(options[i][0], option) == 0) 546 return (options[i][1]); 547 548 return (NULL); 549 } 550 551 /* 552 * Retrieve password information from the /etc/passwd.conf file, at the 553 * moment this is only for choosing the cipher to use. It could easily be 554 * used for other authentication methods as well. 555 */ 556 void 557 pw_getconf(char *data, size_t max, const char *key, const char *option) 558 { 559 FILE *fp; 560 char line[LINE_MAX], *p, *p2; 561 static char result[LINE_MAX]; 562 int got, found; 563 const char *cp; 564 565 _DIAGASSERT(data != NULL); 566 _DIAGASSERT(key != NULL); 567 _DIAGASSERT(option != NULL); 568 569 got = 0; 570 found = 0; 571 result[0] = '\0'; 572 573 if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) { 574 if ((cp = pw_default(option)) != NULL) 575 strlcpy(data, cp, max); 576 else 577 data[0] = '\0'; 578 return; 579 } 580 581 while (!found && (got || read_line(fp, line, LINE_MAX))) { 582 got = 0; 583 584 if (strncmp(key, line, strlen(key)) != 0 || 585 line[strlen(key)] != ':') 586 continue; 587 588 /* Now we found our specified key */ 589 while (read_line(fp, line, LINE_MAX)) { 590 /* Leaving key field */ 591 if (line[0] != '\0' && strchr(line + 1, ':') != NULL) { 592 got = 1; 593 break; 594 } 595 p2 = line; 596 if ((p = strsep(&p2, "=")) == NULL || p2 == NULL) 597 continue; 598 trim_whitespace(p); 599 600 if (!strncmp(p, option, strlen(option))) { 601 trim_whitespace(p2); 602 strcpy(result, p2); 603 found = 1; 604 break; 605 } 606 } 607 } 608 fclose(fp); 609 610 if (!found) 611 errno = ENOENT; 612 if (!got) 613 errno = ENOTDIR; 614 615 /* 616 * If we got no result and were looking for a default 617 * value, try hard coded defaults. 618 */ 619 620 if (strlen(result) == 0 && strcmp(key, "default") == 0 && 621 (cp = pw_default(option)) != NULL) 622 strlcpy(data, cp, max); 623 else 624 strlcpy(data, result, max); 625 } 626 627 void 628 pw_getpwconf(char *data, size_t max, const struct passwd *pwd, 629 const char *option) 630 { 631 char grpkey[LINE_MAX]; 632 struct group grs, *grp; 633 char grbuf[1024]; 634 635 pw_getconf(data, max, pwd->pw_name, option); 636 637 /* Try to find an entry for the group */ 638 if (*data == '\0') { 639 (void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp); 640 if (grp != NULL) { 641 (void)snprintf(grpkey, sizeof(grpkey), ":%s", 642 grp->gr_name); 643 pw_getconf(data, max, grpkey, option); 644 } 645 if (*data == '\0') 646 pw_getconf(data, max, "default", option); 647 } 648 } 649