1 /*- 2 * Copyright (c) 1990, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * Copyright (c) 2002 Networks Associates Technology, Inc. 5 * All rights reserved. 6 * 7 * Portions of this software were developed for the FreeBSD Project by 8 * ThinkSec AS and NAI Labs, the Security Research Division of Network 9 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 10 * ("CBOSS"), as part of the DARPA CHATS research program. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static const char sccsid[] = "@(#)pw_util.c 8.3 (Berkeley) 4/2/94"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif /* not lint */ 44 45 /* 46 * This file is used by all the "password" programs; vipw(8), chpass(1), 47 * and passwd(1). 48 */ 49 50 #include <sys/param.h> 51 #include <sys/errno.h> 52 #include <sys/time.h> 53 #include <sys/resource.h> 54 #include <sys/stat.h> 55 #include <sys/wait.h> 56 57 #include <ctype.h> 58 #include <err.h> 59 #include <fcntl.h> 60 #include <inttypes.h> 61 #include <paths.h> 62 #include <pwd.h> 63 #include <signal.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <unistd.h> 68 69 #include "libutil.h" 70 71 static pid_t editpid = -1; 72 static int lockfd = -1; 73 static char masterpasswd[PATH_MAX]; 74 static char passwd_dir[PATH_MAX]; 75 static char tempname[PATH_MAX]; 76 static int initialized; 77 78 #if 0 79 void 80 pw_cont(int sig) 81 { 82 83 if (editpid != -1) 84 kill(editpid, sig); 85 } 86 #endif 87 88 /* 89 * Initialize statics and set limits, signals & umask to try to avoid 90 * interruptions, crashes etc. that might expose passord data. 91 */ 92 int 93 pw_init(const char *dir, const char *master) 94 { 95 #if 0 96 struct rlimit rlim; 97 #endif 98 99 if (dir == NULL) { 100 strcpy(passwd_dir, _PATH_ETC); 101 } else { 102 if (strlen(dir) >= sizeof(passwd_dir)) { 103 errno = ENAMETOOLONG; 104 return (-1); 105 } 106 strcpy(passwd_dir, dir); 107 } 108 109 if (master == NULL) { 110 if (dir == NULL) { 111 strcpy(masterpasswd, _PATH_MASTERPASSWD); 112 } else if (snprintf(masterpasswd, sizeof(masterpasswd), "%s/%s", 113 passwd_dir, _MASTERPASSWD) > (int)sizeof(masterpasswd)) { 114 errno = ENAMETOOLONG; 115 return (-1); 116 } 117 } else { 118 if (strlen(master) >= sizeof(masterpasswd)) { 119 errno = ENAMETOOLONG; 120 return (-1); 121 } 122 strcpy(masterpasswd, master); 123 } 124 125 /* 126 * The code that follows is extremely disruptive to the calling 127 * process, and is therefore disabled until someone can conceive 128 * of a realistic scenario where it would fend off a compromise. 129 * Race conditions concerning the temporary files can be guarded 130 * against in other ways than masking signals (by checking stat(2) 131 * results after creation). 132 */ 133 #if 0 134 /* Unlimited resource limits. */ 135 rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY; 136 (void)setrlimit(RLIMIT_CPU, &rlim); 137 (void)setrlimit(RLIMIT_FSIZE, &rlim); 138 (void)setrlimit(RLIMIT_STACK, &rlim); 139 (void)setrlimit(RLIMIT_DATA, &rlim); 140 (void)setrlimit(RLIMIT_RSS, &rlim); 141 142 /* Don't drop core (not really necessary, but GP's). */ 143 rlim.rlim_cur = rlim.rlim_max = 0; 144 (void)setrlimit(RLIMIT_CORE, &rlim); 145 146 /* Turn off signals. */ 147 (void)signal(SIGALRM, SIG_IGN); 148 (void)signal(SIGHUP, SIG_IGN); 149 (void)signal(SIGINT, SIG_IGN); 150 (void)signal(SIGPIPE, SIG_IGN); 151 (void)signal(SIGQUIT, SIG_IGN); 152 (void)signal(SIGTERM, SIG_IGN); 153 (void)signal(SIGCONT, pw_cont); 154 155 /* Create with exact permissions. */ 156 (void)umask(0); 157 #endif 158 initialized = 1; 159 return (0); 160 } 161 162 /* 163 * Lock the master password file. 164 */ 165 int 166 pw_lock(void) 167 { 168 169 if (*masterpasswd == '\0') 170 return (-1); 171 172 /* 173 * If the master password file doesn't exist, the system is hosed. 174 * Might as well try to build one. Set the close-on-exec bit so 175 * that users can't get at the encrypted passwords while editing. 176 * Open should allow flock'ing the file; see 4.4BSD. XXX 177 */ 178 for (;;) { 179 struct stat st; 180 181 lockfd = flopen(masterpasswd, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0); 182 if (lockfd == -1) { 183 if (errno == EWOULDBLOCK) { 184 errx(1, "the password db file is busy"); 185 } else { 186 err(1, "could not lock the passwd file: "); 187 } 188 } 189 190 /* 191 * If the password file was replaced while we were trying to 192 * get the lock, our hardlink count will be 0 and we have to 193 * close and retry. 194 */ 195 if (fstat(lockfd, &st) == -1) 196 err(1, "fstat() failed: "); 197 if (st.st_nlink != 0) 198 break; 199 close(lockfd); 200 lockfd = -1; 201 } 202 return (lockfd); 203 } 204 205 /* 206 * Create and open a presumably safe temp file for editing the password 207 * data, and copy the master password file into it. 208 */ 209 int 210 pw_tmp(int mfd) 211 { 212 char buf[8192]; 213 ssize_t nr; 214 const char *p; 215 int tfd; 216 217 if (*masterpasswd == '\0') 218 return (-1); 219 if ((p = strrchr(masterpasswd, '/'))) 220 ++p; 221 else 222 p = masterpasswd; 223 if (snprintf(tempname, sizeof(tempname), "%.*spw.XXXXXX", 224 (int)(p - masterpasswd), masterpasswd) >= (int)sizeof(tempname)) { 225 errno = ENAMETOOLONG; 226 return (-1); 227 } 228 if ((tfd = mkostemp(tempname, 0)) == -1) 229 return (-1); 230 if (mfd != -1) { 231 while ((nr = read(mfd, buf, sizeof(buf))) > 0) 232 if (write(tfd, buf, (size_t)nr) != nr) 233 break; 234 if (nr != 0) { 235 unlink(tempname); 236 *tempname = '\0'; 237 close(tfd); 238 return (-1); 239 } 240 } 241 return (tfd); 242 } 243 244 /* 245 * Regenerate the password database. 246 */ 247 int 248 pw_mkdb(const char *user) 249 { 250 int pstat; 251 pid_t pid; 252 253 (void)fflush(stderr); 254 switch ((pid = fork())) { 255 case -1: 256 return (-1); 257 case 0: 258 /* child */ 259 if (user == NULL) 260 execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p", 261 "-d", passwd_dir, tempname, (char *)NULL); 262 else 263 execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p", 264 "-d", passwd_dir, "-u", user, tempname, 265 (char *)NULL); 266 _exit(1); 267 /* NOTREACHED */ 268 default: 269 /* parent */ 270 break; 271 } 272 if (waitpid(pid, &pstat, 0) == -1) 273 return (-1); 274 if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) 275 return (0); 276 errno = 0; 277 return (-1); 278 } 279 280 /* 281 * Edit the temp file. Return -1 on error, >0 if the file was modified, 0 282 * if it was not. 283 */ 284 int 285 pw_edit(int notsetuid) 286 { 287 struct sigaction sa, sa_int, sa_quit; 288 sigset_t oldsigset, nsigset; 289 struct stat st1, st2; 290 const char *editor; 291 int pstat; 292 293 if ((editor = getenv("EDITOR")) == NULL) 294 editor = _PATH_VI; 295 if (stat(tempname, &st1) == -1) 296 return (-1); 297 sa.sa_handler = SIG_IGN; 298 sigemptyset(&sa.sa_mask); 299 sa.sa_flags = 0; 300 sigaction(SIGINT, &sa, &sa_int); 301 sigaction(SIGQUIT, &sa, &sa_quit); 302 sigemptyset(&nsigset); 303 sigaddset(&nsigset, SIGCHLD); 304 sigprocmask(SIG_BLOCK, &nsigset, &oldsigset); 305 switch ((editpid = fork())) { 306 case -1: 307 return (-1); 308 case 0: 309 sigaction(SIGINT, &sa_int, NULL); 310 sigaction(SIGQUIT, &sa_quit, NULL); 311 sigprocmask(SIG_SETMASK, &oldsigset, NULL); 312 if (notsetuid) { 313 (void)setgid(getgid()); 314 (void)setuid(getuid()); 315 } 316 errno = 0; 317 execlp(editor, editor, tempname, (char *)NULL); 318 _exit(errno); 319 default: 320 /* parent */ 321 break; 322 } 323 for (;;) { 324 if (waitpid(editpid, &pstat, WUNTRACED) == -1) { 325 if (errno == EINTR) 326 continue; 327 unlink(tempname); 328 editpid = -1; 329 break; 330 } else if (WIFSTOPPED(pstat)) { 331 raise(WSTOPSIG(pstat)); 332 } else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) { 333 editpid = -1; 334 break; 335 } else { 336 unlink(tempname); 337 editpid = -1; 338 break; 339 } 340 } 341 sigaction(SIGINT, &sa_int, NULL); 342 sigaction(SIGQUIT, &sa_quit, NULL); 343 sigprocmask(SIG_SETMASK, &oldsigset, NULL); 344 if (stat(tempname, &st2) == -1) 345 return (-1); 346 return (st1.st_mtim.tv_sec != st2.st_mtim.tv_sec || 347 st1.st_mtim.tv_nsec != st2.st_mtim.tv_nsec); 348 } 349 350 /* 351 * Clean up. Preserve errno for the caller's convenience. 352 */ 353 void 354 pw_fini(void) 355 { 356 int serrno, status; 357 358 if (!initialized) 359 return; 360 initialized = 0; 361 serrno = errno; 362 if (editpid != -1) { 363 kill(editpid, SIGTERM); 364 kill(editpid, SIGCONT); 365 waitpid(editpid, &status, 0); 366 editpid = -1; 367 } 368 if (*tempname != '\0') { 369 unlink(tempname); 370 *tempname = '\0'; 371 } 372 if (lockfd != -1) 373 close(lockfd); 374 errno = serrno; 375 } 376 377 /* 378 * Compares two struct pwds. 379 */ 380 int 381 pw_equal(const struct passwd *pw1, const struct passwd *pw2) 382 { 383 return (strcmp(pw1->pw_name, pw2->pw_name) == 0 && 384 pw1->pw_uid == pw2->pw_uid && 385 pw1->pw_gid == pw2->pw_gid && 386 strcmp(pw1->pw_class, pw2->pw_class) == 0 && 387 pw1->pw_change == pw2->pw_change && 388 pw1->pw_expire == pw2->pw_expire && 389 strcmp(pw1->pw_gecos, pw2->pw_gecos) == 0 && 390 strcmp(pw1->pw_dir, pw2->pw_dir) == 0 && 391 strcmp(pw1->pw_shell, pw2->pw_shell) == 0); 392 } 393 394 /* 395 * Make a passwd line out of a struct passwd. 396 */ 397 char * 398 pw_make(const struct passwd *pw) 399 { 400 char *line; 401 402 asprintf(&line, "%s:%s:%ju:%ju:%s:%ju:%ju:%s:%s:%s", pw->pw_name, 403 pw->pw_passwd, (uintmax_t)pw->pw_uid, (uintmax_t)pw->pw_gid, 404 pw->pw_class, (uintmax_t)pw->pw_change, (uintmax_t)pw->pw_expire, 405 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 406 return (line); 407 } 408 409 /* 410 * Make a passwd line (in v7 format) out of a struct passwd 411 */ 412 char * 413 pw_make_v7(const struct passwd *pw) 414 { 415 char *line; 416 417 asprintf(&line, "%s:*:%ju:%ju:%s:%s:%s", pw->pw_name, 418 (uintmax_t)pw->pw_uid, (uintmax_t)pw->pw_gid, 419 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 420 return (line); 421 } 422 423 /* 424 * Copy password file from one descriptor to another, replacing, deleting 425 * or adding a single record on the way. 426 */ 427 int 428 pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw) 429 { 430 char *buf, *end, *line, *p, *q, *r, *tmp; 431 struct passwd *fpw; 432 const struct passwd *spw; 433 size_t len, size; 434 int eof, readlen; 435 char t; 436 437 if (old_pw == NULL && pw == NULL) 438 return (-1); 439 440 spw = old_pw; 441 /* deleting a user */ 442 if (pw == NULL) { 443 line = NULL; 444 } else { 445 if ((line = pw_make(pw)) == NULL) 446 return (-1); 447 } 448 449 /* adding a user */ 450 if (spw == NULL) 451 spw = pw; 452 453 /* initialize the buffer */ 454 if ((buf = malloc(size = 1024)) == NULL) 455 goto err; 456 457 eof = 0; 458 len = 0; 459 p = q = end = buf; 460 for (;;) { 461 /* find the end of the current line */ 462 for (p = q; q < end && *q != '\0'; ++q) 463 if (*q == '\n') 464 break; 465 466 /* if we don't have a complete line, fill up the buffer */ 467 if (q >= end) { 468 if (eof) 469 break; 470 while ((size_t)(q - p) >= size) { 471 if ((tmp = realloc(buf, size * 2)) == NULL) { 472 warnx("passwd line too long"); 473 goto err; 474 } 475 p = tmp + (p - buf); 476 q = tmp + (q - buf); 477 end = tmp + (end - buf); 478 buf = tmp; 479 size = size * 2; 480 } 481 if (p < end) { 482 q = memmove(buf, p, end - p); 483 end -= p - buf; 484 } else { 485 p = q = end = buf; 486 } 487 readlen = read(ffd, end, size - (end - buf)); 488 if (readlen == -1) 489 goto err; 490 else 491 len = (size_t)readlen; 492 if (len == 0 && p == buf) 493 break; 494 end += len; 495 len = end - buf; 496 if (len < size) { 497 eof = 1; 498 if (len > 0 && buf[len - 1] != '\n') 499 ++len, *end++ = '\n'; 500 } 501 continue; 502 } 503 504 /* is it a blank line or a comment? */ 505 for (r = p; r < q && isspace(*r); ++r) 506 /* nothing */ ; 507 if (r == q || *r == '#') { 508 /* yep */ 509 if (write(tfd, p, q - p + 1) != q - p + 1) 510 goto err; 511 ++q; 512 continue; 513 } 514 515 /* is it the one we're looking for? */ 516 517 t = *q; 518 *q = '\0'; 519 520 fpw = pw_scan(r, PWSCAN_MASTER); 521 522 /* 523 * fpw is either the struct passwd for the current line, 524 * or NULL if the line is malformed. 525 */ 526 527 *q = t; 528 if (fpw == NULL || strcmp(fpw->pw_name, spw->pw_name) != 0) { 529 /* nope */ 530 if (fpw != NULL) 531 free(fpw); 532 if (write(tfd, p, q - p + 1) != q - p + 1) 533 goto err; 534 ++q; 535 continue; 536 } 537 if (old_pw && !pw_equal(fpw, old_pw)) { 538 warnx("entry inconsistent"); 539 free(fpw); 540 errno = EINVAL; /* hack */ 541 goto err; 542 } 543 free(fpw); 544 545 /* it is, replace or remove it */ 546 if (line != NULL) { 547 len = strlen(line); 548 if (write(tfd, line, len) != (int)len) 549 goto err; 550 } else { 551 /* when removed, avoid the \n */ 552 q++; 553 } 554 /* we're done, just copy the rest over */ 555 for (;;) { 556 if (write(tfd, q, end - q) != end - q) 557 goto err; 558 q = buf; 559 readlen = read(ffd, buf, size); 560 if (readlen == 0) 561 break; 562 else 563 len = (size_t)readlen; 564 if (readlen == -1) 565 goto err; 566 end = buf + len; 567 } 568 goto done; 569 } 570 571 /* if we got here, we didn't find the old entry */ 572 if (line == NULL) { 573 errno = ENOENT; 574 goto err; 575 } 576 len = strlen(line); 577 if ((size_t)write(tfd, line, len) != len || 578 write(tfd, "\n", 1) != 1) 579 goto err; 580 done: 581 free(line); 582 free(buf); 583 return (0); 584 err: 585 free(line); 586 free(buf); 587 return (-1); 588 } 589 590 /* 591 * Return the current value of tempname. 592 */ 593 const char * 594 pw_tempname(void) 595 { 596 597 return (tempname); 598 } 599 600 /* 601 * Duplicate a struct passwd. 602 */ 603 struct passwd * 604 pw_dup(const struct passwd *pw) 605 { 606 char *dst; 607 struct passwd *npw; 608 ssize_t len; 609 610 len = sizeof(*npw); 611 if (pw->pw_name != NULL) 612 len += strlen(pw->pw_name) + 1; 613 if (pw->pw_passwd != NULL) 614 len += strlen(pw->pw_passwd) + 1; 615 if (pw->pw_class != NULL) 616 len += strlen(pw->pw_class) + 1; 617 if (pw->pw_gecos != NULL) 618 len += strlen(pw->pw_gecos) + 1; 619 if (pw->pw_dir != NULL) 620 len += strlen(pw->pw_dir) + 1; 621 if (pw->pw_shell != NULL) 622 len += strlen(pw->pw_shell) + 1; 623 if ((npw = malloc((size_t)len)) == NULL) 624 return (NULL); 625 memcpy(npw, pw, sizeof(*npw)); 626 dst = (char *)npw + sizeof(*npw); 627 if (pw->pw_name != NULL) { 628 npw->pw_name = dst; 629 dst = stpcpy(npw->pw_name, pw->pw_name) + 1; 630 } 631 if (pw->pw_passwd != NULL) { 632 npw->pw_passwd = dst; 633 dst = stpcpy(npw->pw_passwd, pw->pw_passwd) + 1; 634 } 635 if (pw->pw_class != NULL) { 636 npw->pw_class = dst; 637 dst = stpcpy(npw->pw_class, pw->pw_class) + 1; 638 } 639 if (pw->pw_gecos != NULL) { 640 npw->pw_gecos = dst; 641 dst = stpcpy(npw->pw_gecos, pw->pw_gecos) + 1; 642 } 643 if (pw->pw_dir != NULL) { 644 npw->pw_dir = dst; 645 dst = stpcpy(npw->pw_dir, pw->pw_dir) + 1; 646 } 647 if (pw->pw_shell != NULL) { 648 npw->pw_shell = dst; 649 dst = stpcpy(npw->pw_shell, pw->pw_shell) + 1; 650 } 651 return (npw); 652 } 653 654 #include "pw_scan.h" 655 656 /* 657 * Wrapper around an internal libc function 658 */ 659 struct passwd * 660 pw_scan(const char *line, int flags) 661 { 662 struct passwd pw, *ret; 663 char *bp; 664 665 if ((bp = strdup(line)) == NULL) 666 return (NULL); 667 if (!__pw_scan(bp, &pw, flags)) { 668 free(bp); 669 return (NULL); 670 } 671 ret = pw_dup(&pw); 672 free(bp); 673 return (ret); 674 } 675