1 /* $NetBSD: passwd.c,v 1.45 2006/12/20 16:47:13 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 1.45 2006/12/20 16:47:13 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 int 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 static int 294 pw_equal(char *buf, struct passwd *pw) 295 { 296 struct passwd buf_pw; 297 size_t len; 298 299 _DIAGASSERT(buf != NULL); 300 _DIAGASSERT(pw != NULL); 301 302 len = strlen (buf); 303 if (buf[len-1] == '\n') 304 buf[len-1] = '\0'; 305 if (!pw_scan(buf, &buf_pw, NULL)) 306 return 0; 307 return !strcmp(pw->pw_name, buf_pw.pw_name) 308 && pw->pw_uid == buf_pw.pw_uid 309 && pw->pw_gid == buf_pw.pw_gid 310 && !strcmp(pw->pw_class, buf_pw.pw_class) 311 && (long)pw->pw_change == (long)buf_pw.pw_change 312 && (long)pw->pw_expire == (long)buf_pw.pw_expire 313 && !strcmp(pw->pw_gecos, buf_pw.pw_gecos) 314 && !strcmp(pw->pw_dir, buf_pw.pw_dir) 315 && !strcmp(pw->pw_shell, buf_pw.pw_shell); 316 } 317 318 void 319 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw) 320 { 321 char errbuf[200]; 322 int rv; 323 324 rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf)); 325 if (rv == 0) { 326 warnx("%s", errbuf); 327 pw_error(NULL, 0, 1); 328 } 329 } 330 331 int 332 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw, 333 char *errbuf, size_t errbufsz) 334 { 335 const char *filename; 336 char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192]; 337 FILE *from, *to; 338 int done; 339 340 _DIAGASSERT(pw != NULL); 341 _DIAGASSERT(errbuf != NULL); 342 /* old_pw may be NULL */ 343 344 if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) { 345 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 346 strerror(errno)); 347 return (0); 348 } 349 (void)strcpy(mpwd, filename); 350 if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) { 351 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix, 352 strerror(errno)); 353 return (0); 354 } 355 (void)strcpy(mpwdl, filename); 356 357 if (!(from = fdopen(ffd, "r"))) { 358 snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno)); 359 return (0); 360 } 361 if (!(to = fdopen(tfd, "w"))) { 362 snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno)); 363 (void)fclose(from); 364 return (0); 365 } 366 367 for (done = 0; fgets(buf, (int)sizeof(buf), from);) { 368 if (!strchr(buf, '\n')) { 369 snprintf(errbuf, errbufsz, "%s: line too long", mpwd); 370 (void)fclose(from); 371 (void)fclose(to); 372 return (0); 373 } 374 if (done) { 375 (void)fprintf(to, "%s", buf); 376 if (ferror(to)) { 377 snprintf(errbuf, errbufsz, "%s", 378 strerror(errno)); 379 (void)fclose(from); 380 (void)fclose(to); 381 return (0); 382 } 383 continue; 384 } 385 if (!(p = strchr(buf, ':'))) { 386 snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd); 387 (void)fclose(from); 388 (void)fclose(to); 389 return (0); 390 } 391 *p = '\0'; 392 if (strcmp(buf, pw->pw_name)) { 393 *p = ':'; 394 (void)fprintf(to, "%s", buf); 395 if (ferror(to)) { 396 snprintf(errbuf, errbufsz, "%s", 397 strerror(errno)); 398 (void)fclose(from); 399 (void)fclose(to); 400 return (0); 401 } 402 continue; 403 } 404 *p = ':'; 405 if (old_pw && !pw_equal(buf, old_pw)) { 406 snprintf(errbuf, errbufsz, "%s: entry inconsistent", 407 mpwd); 408 (void)fclose(from); 409 (void)fclose(to); 410 return (0); 411 } 412 (void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n", 413 pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid, 414 pw->pw_class, (long)pw->pw_change, (long)pw->pw_expire, 415 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 416 done = 1; 417 if (ferror(to)) { 418 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 419 (void)fclose(from); 420 (void)fclose(to); 421 return (0); 422 } 423 } 424 /* Only append a new entry if real uid is root! */ 425 if (!done) { 426 if (getuid() == 0) { 427 (void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n", 428 pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid, 429 pw->pw_class, (long)pw->pw_change, 430 (long)pw->pw_expire, pw->pw_gecos, pw->pw_dir, 431 pw->pw_shell); 432 done = 1; 433 } else { 434 snprintf(errbuf, errbufsz, 435 "%s: changes not made, no such entry", mpwd); 436 } 437 } 438 439 if (ferror(to)) { 440 snprintf(errbuf, errbufsz, "%s", strerror(errno)); 441 (void)fclose(from); 442 (void)fclose(to); 443 return (0); 444 } 445 (void)fclose(from); 446 (void)fclose(to); 447 448 return (done); 449 } 450 451 void 452 pw_error(const char *name, int error, int eval) 453 { 454 455 if (error) { 456 if (name) 457 warn("%s", name); 458 else 459 warn(NULL); 460 } 461 462 warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD); 463 pw_abort(); 464 exit(eval); 465 } 466 467 /* Removes head and/or tail spaces. */ 468 static void 469 trim_whitespace(char *line) 470 { 471 char *p; 472 473 _DIAGASSERT(line != NULL); 474 475 /* Remove leading spaces */ 476 p = line; 477 while (isspace((unsigned char) *p)) 478 p++; 479 memmove(line, p, strlen(p) + 1); 480 481 /* Remove trailing spaces */ 482 p = line + strlen(line) - 1; 483 while (isspace((unsigned char) *p)) 484 p--; 485 *(p + 1) = '\0'; 486 } 487 488 489 /* Get one line, remove spaces from front and tail */ 490 static int 491 read_line(FILE *fp, char *line, int max) 492 { 493 char *p; 494 495 _DIAGASSERT(fp != NULL); 496 _DIAGASSERT(line != NULL); 497 498 /* Read one line of config */ 499 if (fgets(line, max, fp) == NULL) 500 return (0); 501 502 if ((p = strchr(line, '\n')) == NULL) { 503 warnx("line too long"); 504 return (0); 505 } 506 *p = '\0'; 507 508 /* Remove comments */ 509 if ((p = strchr(line, '#')) != NULL) 510 *p = '\0'; 511 512 trim_whitespace(line); 513 return (1); 514 } 515 516 static const char * 517 pw_default(const char *option) 518 { 519 static const char *options[][2] = { 520 { "localcipher", "old" }, 521 { "ypcipher", "old" }, 522 }; 523 int i; 524 525 _DIAGASSERT(option != NULL); 526 for (i = 0; i < sizeof(options) / sizeof(options[0]); i++) 527 if (strcmp(options[i][0], option) == 0) 528 return (options[i][1]); 529 530 return (NULL); 531 } 532 533 /* 534 * Retrieve password information from the /etc/passwd.conf file, at the 535 * moment this is only for choosing the cipher to use. It could easily be 536 * used for other authentication methods as well. 537 */ 538 void 539 pw_getconf(char *data, size_t max, const char *key, const char *option) 540 { 541 FILE *fp; 542 char line[LINE_MAX], *p, *p2; 543 static char result[LINE_MAX]; 544 int got, found; 545 const char *cp; 546 547 _DIAGASSERT(data != NULL); 548 _DIAGASSERT(key != NULL); 549 _DIAGASSERT(option != NULL); 550 551 got = 0; 552 found = 0; 553 result[0] = '\0'; 554 555 if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) { 556 if ((cp = pw_default(option)) != NULL) 557 strlcpy(data, cp, max); 558 else 559 data[0] = '\0'; 560 return; 561 } 562 563 while (!found && (got || read_line(fp, line, LINE_MAX))) { 564 got = 0; 565 566 if (strncmp(key, line, strlen(key)) != 0 || 567 line[strlen(key)] != ':') 568 continue; 569 570 /* Now we found our specified key */ 571 while (read_line(fp, line, LINE_MAX)) { 572 /* Leaving key field */ 573 if (line[0] != '\0' && strchr(line + 1, ':') != NULL) { 574 got = 1; 575 break; 576 } 577 p2 = line; 578 if ((p = strsep(&p2, "=")) == NULL || p2 == NULL) 579 continue; 580 trim_whitespace(p); 581 582 if (!strncmp(p, option, strlen(option))) { 583 trim_whitespace(p2); 584 strcpy(result, p2); 585 found = 1; 586 break; 587 } 588 } 589 } 590 fclose(fp); 591 592 if (!found) 593 errno = ENOENT; 594 if (!got) 595 errno = ENOTDIR; 596 597 /* 598 * If we got no result and were looking for a default 599 * value, try hard coded defaults. 600 */ 601 602 if (strlen(result) == 0 && strcmp(key, "default") == 0 && 603 (cp = pw_default(option)) != NULL) 604 strlcpy(data, cp, max); 605 else 606 strlcpy(data, result, max); 607 } 608 609 void 610 pw_getpwconf(char *data, size_t max, const struct passwd *pwd, 611 const char *option) 612 { 613 char grpkey[LINE_MAX]; 614 struct group grs, *grp; 615 char grbuf[1024]; 616 617 pw_getconf(data, max, pwd->pw_name, option); 618 619 /* Try to find an entry for the group */ 620 if (*data == '\0') { 621 (void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp); 622 if (grp != NULL) { 623 (void)snprintf(grpkey, sizeof(grpkey), ":%s", 624 grp->gr_name); 625 pw_getconf(data, max, grpkey, option); 626 } 627 if (*data == '\0') 628 pw_getconf(data, max, "default", option); 629 } 630 } 631