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 * 4. 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 <libgen.h> 62 #include <paths.h> 63 #include <pwd.h> 64 #include <signal.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <unistd.h> 69 70 #include "libutil.h" 71 72 static pid_t editpid = -1; 73 static int lockfd = -1; 74 static char masterpasswd[PATH_MAX]; 75 static char passwd_dir[PATH_MAX]; 76 static char tempname[PATH_MAX]; 77 static int initialized; 78 79 #if 0 80 void 81 pw_cont(int sig) 82 { 83 84 if (editpid != -1) 85 kill(editpid, sig); 86 } 87 #endif 88 89 /* 90 * Initialize statics and set limits, signals & umask to try to avoid 91 * interruptions, crashes etc. that might expose passord data. 92 */ 93 int 94 pw_init(const char *dir, const char *master) 95 { 96 #if 0 97 struct rlimit rlim; 98 #endif 99 100 if (dir == NULL) { 101 strcpy(passwd_dir, _PATH_ETC); 102 } else { 103 if (strlen(dir) >= sizeof(passwd_dir)) { 104 errno = ENAMETOOLONG; 105 return (-1); 106 } 107 strcpy(passwd_dir, dir); 108 } 109 110 if (master == NULL) { 111 if (dir == NULL) { 112 strcpy(masterpasswd, _PATH_MASTERPASSWD); 113 } else if (snprintf(masterpasswd, sizeof(masterpasswd), "%s/%s", 114 passwd_dir, _MASTERPASSWD) > (int)sizeof(masterpasswd)) { 115 errno = ENAMETOOLONG; 116 return (-1); 117 } 118 } else { 119 if (strlen(master) >= sizeof(masterpasswd)) { 120 errno = ENAMETOOLONG; 121 return (-1); 122 } 123 strcpy(masterpasswd, master); 124 } 125 126 /* 127 * The code that follows is extremely disruptive to the calling 128 * process, and is therefore disabled until someone can conceive 129 * of a realistic scenario where it would fend off a compromise. 130 * Race conditions concerning the temporary files can be guarded 131 * against in other ways than masking signals (by checking stat(2) 132 * results after creation). 133 */ 134 #if 0 135 /* Unlimited resource limits. */ 136 rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY; 137 (void)setrlimit(RLIMIT_CPU, &rlim); 138 (void)setrlimit(RLIMIT_FSIZE, &rlim); 139 (void)setrlimit(RLIMIT_STACK, &rlim); 140 (void)setrlimit(RLIMIT_DATA, &rlim); 141 (void)setrlimit(RLIMIT_RSS, &rlim); 142 143 /* Don't drop core (not really necessary, but GP's). */ 144 rlim.rlim_cur = rlim.rlim_max = 0; 145 (void)setrlimit(RLIMIT_CORE, &rlim); 146 147 /* Turn off signals. */ 148 (void)signal(SIGALRM, SIG_IGN); 149 (void)signal(SIGHUP, SIG_IGN); 150 (void)signal(SIGINT, SIG_IGN); 151 (void)signal(SIGPIPE, SIG_IGN); 152 (void)signal(SIGQUIT, SIG_IGN); 153 (void)signal(SIGTERM, SIG_IGN); 154 (void)signal(SIGCONT, pw_cont); 155 156 /* Create with exact permissions. */ 157 (void)umask(0); 158 #endif 159 initialized = 1; 160 return (0); 161 } 162 163 /* 164 * Lock the master password file. 165 */ 166 int 167 pw_lock(void) 168 { 169 170 if (*masterpasswd == '\0') 171 return (-1); 172 173 /* 174 * If the master password file doesn't exist, the system is hosed. 175 * Might as well try to build one. Set the close-on-exec bit so 176 * that users can't get at the encrypted passwords while editing. 177 * Open should allow flock'ing the file; see 4.4BSD. XXX 178 */ 179 for (;;) { 180 struct stat st; 181 182 lockfd = flopen(masterpasswd, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0); 183 if (lockfd == -1) { 184 if (errno == EWOULDBLOCK) { 185 errx(1, "the password db file is busy"); 186 } else { 187 err(1, "could not lock the passwd file: "); 188 } 189 } 190 191 /* 192 * If the password file was replaced while we were trying to 193 * get the lock, our hardlink count will be 0 and we have to 194 * close and retry. 195 */ 196 if (fstat(lockfd, &st) == -1) 197 err(1, "fstat() failed: "); 198 if (st.st_nlink != 0) 199 break; 200 close(lockfd); 201 lockfd = -1; 202 } 203 return (lockfd); 204 } 205 206 /* 207 * Create and open a presumably safe temp file for editing the password 208 * data, and copy the master password file into it. 209 */ 210 int 211 pw_tmp(int mfd) 212 { 213 char buf[8192]; 214 ssize_t nr; 215 const char *p; 216 int tfd; 217 218 if (*masterpasswd == '\0') 219 return (-1); 220 if ((p = strrchr(masterpasswd, '/'))) 221 ++p; 222 else 223 p = masterpasswd; 224 if (snprintf(tempname, sizeof(tempname), "%.*spw.XXXXXX", 225 (int)(p - masterpasswd), masterpasswd) >= (int)sizeof(tempname)) { 226 errno = ENAMETOOLONG; 227 return (-1); 228 } 229 if ((tfd = mkstemp(tempname)) == -1) 230 return (-1); 231 if (mfd != -1) { 232 while ((nr = read(mfd, buf, sizeof(buf))) > 0) 233 if (write(tfd, buf, (size_t)nr) != nr) 234 break; 235 if (nr != 0) { 236 unlink(tempname); 237 *tempname = '\0'; 238 close(tfd); 239 return (-1); 240 } 241 } 242 return (tfd); 243 } 244 245 /* 246 * Regenerate the password database. 247 */ 248 int 249 pw_mkdb(const char *user) 250 { 251 int pstat; 252 pid_t pid; 253 254 (void)fflush(stderr); 255 switch ((pid = fork())) { 256 case -1: 257 return (-1); 258 case 0: 259 /* child */ 260 if (user == NULL) 261 execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p", 262 "-d", passwd_dir, tempname, (char *)NULL); 263 else 264 execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p", 265 "-d", passwd_dir, "-u", user, tempname, 266 (char *)NULL); 267 _exit(1); 268 /* NOTREACHED */ 269 default: 270 /* parent */ 271 break; 272 } 273 if (waitpid(pid, &pstat, 0) == -1) 274 return (-1); 275 if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) 276 return (0); 277 errno = 0; 278 return (-1); 279 } 280 281 /* 282 * Edit the temp file. Return -1 on error, >0 if the file was modified, 0 283 * if it was not. 284 */ 285 int 286 pw_edit(int notsetuid) 287 { 288 struct sigaction sa, sa_int, sa_quit; 289 sigset_t oldsigset, nsigset; 290 struct stat st1, st2; 291 const char *editor; 292 int pstat; 293 294 if ((editor = getenv("EDITOR")) == NULL) 295 editor = _PATH_VI; 296 if (stat(tempname, &st1) == -1) 297 return (-1); 298 sa.sa_handler = SIG_IGN; 299 sigemptyset(&sa.sa_mask); 300 sa.sa_flags = 0; 301 sigaction(SIGINT, &sa, &sa_int); 302 sigaction(SIGQUIT, &sa, &sa_quit); 303 sigemptyset(&nsigset); 304 sigaddset(&nsigset, SIGCHLD); 305 sigprocmask(SIG_BLOCK, &nsigset, &oldsigset); 306 switch ((editpid = fork())) { 307 case -1: 308 return (-1); 309 case 0: 310 sigaction(SIGINT, &sa_int, NULL); 311 sigaction(SIGQUIT, &sa_quit, NULL); 312 sigprocmask(SIG_SETMASK, &oldsigset, NULL); 313 if (notsetuid) { 314 (void)setgid(getgid()); 315 (void)setuid(getuid()); 316 } 317 errno = 0; 318 execlp(editor, basename(editor), tempname, (char *)NULL); 319 _exit(errno); 320 default: 321 /* parent */ 322 break; 323 } 324 for (;;) { 325 if (waitpid(editpid, &pstat, WUNTRACED) == -1) { 326 if (errno == EINTR) 327 continue; 328 unlink(tempname); 329 editpid = -1; 330 break; 331 } else if (WIFSTOPPED(pstat)) { 332 raise(WSTOPSIG(pstat)); 333 } else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) { 334 editpid = -1; 335 break; 336 } else { 337 unlink(tempname); 338 editpid = -1; 339 break; 340 } 341 } 342 sigaction(SIGINT, &sa_int, NULL); 343 sigaction(SIGQUIT, &sa_quit, NULL); 344 sigprocmask(SIG_SETMASK, &oldsigset, NULL); 345 if (stat(tempname, &st2) == -1) 346 return (-1); 347 return (st1.st_mtim.tv_sec != st2.st_mtim.tv_sec || 348 st1.st_mtim.tv_nsec != st2.st_mtim.tv_nsec); 349 } 350 351 /* 352 * Clean up. Preserve errno for the caller's convenience. 353 */ 354 void 355 pw_fini(void) 356 { 357 int serrno, status; 358 359 if (!initialized) 360 return; 361 initialized = 0; 362 serrno = errno; 363 if (editpid != -1) { 364 kill(editpid, SIGTERM); 365 kill(editpid, SIGCONT); 366 waitpid(editpid, &status, 0); 367 editpid = -1; 368 } 369 if (*tempname != '\0') { 370 unlink(tempname); 371 *tempname = '\0'; 372 } 373 if (lockfd != -1) 374 close(lockfd); 375 errno = serrno; 376 } 377 378 /* 379 * Compares two struct pwds. 380 */ 381 int 382 pw_equal(const struct passwd *pw1, const struct passwd *pw2) 383 { 384 return (strcmp(pw1->pw_name, pw2->pw_name) == 0 && 385 pw1->pw_uid == pw2->pw_uid && 386 pw1->pw_gid == pw2->pw_gid && 387 strcmp(pw1->pw_class, pw2->pw_class) == 0 && 388 pw1->pw_change == pw2->pw_change && 389 pw1->pw_expire == pw2->pw_expire && 390 strcmp(pw1->pw_gecos, pw2->pw_gecos) == 0 && 391 strcmp(pw1->pw_dir, pw2->pw_dir) == 0 && 392 strcmp(pw1->pw_shell, pw2->pw_shell) == 0); 393 } 394 395 /* 396 * Make a passwd line out of a struct passwd. 397 */ 398 char * 399 pw_make(const struct passwd *pw) 400 { 401 char *line; 402 403 asprintf(&line, "%s:%s:%ju:%ju:%s:%ju:%ju:%s:%s:%s", pw->pw_name, 404 pw->pw_passwd, (uintmax_t)pw->pw_uid, (uintmax_t)pw->pw_gid, 405 pw->pw_class, (uintmax_t)pw->pw_change, (uintmax_t)pw->pw_expire, 406 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 407 return (line); 408 } 409 410 /* 411 * Make a passwd line (in v7 format) out of a struct passwd 412 */ 413 char * 414 pw_make_v7(const struct passwd *pw) 415 { 416 char *line; 417 418 asprintf(&line, "%s:*:%ju:%ju:%s:%s:%s", pw->pw_name, 419 (uintmax_t)pw->pw_uid, (uintmax_t)pw->pw_gid, 420 pw->pw_gecos, pw->pw_dir, pw->pw_shell); 421 return (line); 422 } 423 424 /* 425 * Copy password file from one descriptor to another, replacing, deleting 426 * or adding a single record on the way. 427 */ 428 int 429 pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw) 430 { 431 char buf[8192], *end, *line, *p, *q, *r, t; 432 struct passwd *fpw; 433 const struct passwd *spw; 434 size_t len; 435 int eof, readlen; 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 eof = 0; 454 len = 0; 455 p = q = end = buf; 456 for (;;) { 457 /* find the end of the current line */ 458 for (p = q; q < end && *q != '\0'; ++q) 459 if (*q == '\n') 460 break; 461 462 /* if we don't have a complete line, fill up the buffer */ 463 if (q >= end) { 464 if (eof) 465 break; 466 if ((size_t)(q - p) >= sizeof(buf)) { 467 warnx("passwd line too long"); 468 errno = EINVAL; /* hack */ 469 goto err; 470 } 471 if (p < end) { 472 q = memmove(buf, p, end - p); 473 end -= p - buf; 474 } else { 475 p = q = end = buf; 476 } 477 readlen = read(ffd, end, sizeof(buf) - (end - buf)); 478 if (readlen == -1) 479 goto err; 480 else 481 len = (size_t)readlen; 482 if (len == 0 && p == buf) 483 break; 484 end += len; 485 len = end - buf; 486 if (len < (ssize_t)sizeof(buf)) { 487 eof = 1; 488 if (len > 0 && buf[len - 1] != '\n') 489 ++len, *end++ = '\n'; 490 } 491 continue; 492 } 493 494 /* is it a blank line or a comment? */ 495 for (r = p; r < q && isspace(*r); ++r) 496 /* nothing */ ; 497 if (r == q || *r == '#') { 498 /* yep */ 499 if (write(tfd, p, q - p + 1) != q - p + 1) 500 goto err; 501 ++q; 502 continue; 503 } 504 505 /* is it the one we're looking for? */ 506 507 t = *q; 508 *q = '\0'; 509 510 fpw = pw_scan(r, PWSCAN_MASTER); 511 512 /* 513 * fpw is either the struct passwd for the current line, 514 * or NULL if the line is malformed. 515 */ 516 517 *q = t; 518 if (fpw == NULL || strcmp(fpw->pw_name, spw->pw_name) != 0) { 519 /* nope */ 520 if (fpw != NULL) 521 free(fpw); 522 if (write(tfd, p, q - p + 1) != q - p + 1) 523 goto err; 524 ++q; 525 continue; 526 } 527 if (old_pw && !pw_equal(fpw, old_pw)) { 528 warnx("entry inconsistent"); 529 free(fpw); 530 errno = EINVAL; /* hack */ 531 goto err; 532 } 533 free(fpw); 534 535 /* it is, replace or remove it */ 536 if (line != NULL) { 537 len = strlen(line); 538 if (write(tfd, line, len) != (int)len) 539 goto err; 540 } else { 541 /* when removed, avoid the \n */ 542 q++; 543 } 544 /* we're done, just copy the rest over */ 545 for (;;) { 546 if (write(tfd, q, end - q) != end - q) 547 goto err; 548 q = buf; 549 readlen = read(ffd, buf, sizeof(buf)); 550 if (readlen == 0) 551 break; 552 else 553 len = (size_t)readlen; 554 if (readlen == -1) 555 goto err; 556 end = buf + len; 557 } 558 goto done; 559 } 560 561 /* if we got here, we didn't find the old entry */ 562 if (line == NULL) { 563 errno = ENOENT; 564 goto err; 565 } 566 len = strlen(line); 567 if ((size_t)write(tfd, line, len) != len || 568 write(tfd, "\n", 1) != 1) 569 goto err; 570 done: 571 if (line != NULL) 572 free(line); 573 return (0); 574 err: 575 if (line != NULL) 576 free(line); 577 return (-1); 578 } 579 580 /* 581 * Return the current value of tempname. 582 */ 583 const char * 584 pw_tempname(void) 585 { 586 587 return (tempname); 588 } 589 590 /* 591 * Duplicate a struct passwd. 592 */ 593 struct passwd * 594 pw_dup(const struct passwd *pw) 595 { 596 char *dst; 597 struct passwd *npw; 598 ssize_t len; 599 600 len = sizeof(*npw); 601 if (pw->pw_name != NULL) 602 len += strlen(pw->pw_name) + 1; 603 if (pw->pw_passwd != NULL) 604 len += strlen(pw->pw_passwd) + 1; 605 if (pw->pw_class != NULL) 606 len += strlen(pw->pw_class) + 1; 607 if (pw->pw_gecos != NULL) 608 len += strlen(pw->pw_gecos) + 1; 609 if (pw->pw_dir != NULL) 610 len += strlen(pw->pw_dir) + 1; 611 if (pw->pw_shell != NULL) 612 len += strlen(pw->pw_shell) + 1; 613 if ((npw = malloc((size_t)len)) == NULL) 614 return (NULL); 615 memcpy(npw, pw, sizeof(*npw)); 616 dst = (char *)npw + sizeof(*npw); 617 if (pw->pw_name != NULL) { 618 npw->pw_name = dst; 619 dst = stpcpy(npw->pw_name, pw->pw_name) + 1; 620 } 621 if (pw->pw_passwd != NULL) { 622 npw->pw_passwd = dst; 623 dst = stpcpy(npw->pw_passwd, pw->pw_passwd) + 1; 624 } 625 if (pw->pw_class != NULL) { 626 npw->pw_class = dst; 627 dst = stpcpy(npw->pw_class, pw->pw_class) + 1; 628 } 629 if (pw->pw_gecos != NULL) { 630 npw->pw_gecos = dst; 631 dst = stpcpy(npw->pw_gecos, pw->pw_gecos) + 1; 632 } 633 if (pw->pw_dir != NULL) { 634 npw->pw_dir = dst; 635 dst = stpcpy(npw->pw_dir, pw->pw_dir) + 1; 636 } 637 if (pw->pw_shell != NULL) { 638 npw->pw_shell = dst; 639 dst = stpcpy(npw->pw_shell, pw->pw_shell) + 1; 640 } 641 return (npw); 642 } 643 644 #include "pw_scan.h" 645 646 /* 647 * Wrapper around an internal libc function 648 */ 649 struct passwd * 650 pw_scan(const char *line, int flags) 651 { 652 struct passwd pw, *ret; 653 char *bp; 654 655 if ((bp = strdup(line)) == NULL) 656 return (NULL); 657 if (!__pw_scan(bp, &pw, flags)) { 658 free(bp); 659 return (NULL); 660 } 661 ret = pw_dup(&pw); 662 free(bp); 663 return (ret); 664 } 665