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
39static const char sccsid[] = "@(#)pw_util.c 8.3 (Berkeley) 4/2/94";
40#endif
41static const char rcsid[] =
42 "$FreeBSD: head/lib/libutil/pw_util.c 244735 2012-12-27 14:09:50Z bapt $";
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
72static pid_t editpid = -1;
73static int lockfd = -1;
74static char masterpasswd[PATH_MAX];
75static char passwd_dir[PATH_MAX];
76static char tempname[PATH_MAX];
77static int initialized;
78
79#if 0
80void
81pw_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 */
93int
94pw_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 */
166int
167pw_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, 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 */
210int
211pw_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 */
248int
249pw_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 */
285int
286pw_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 */
354void
355pw_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 */
381int
382pw_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 */
398char *
399pw_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 */
413char *
414pw_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 */
428int
429pw_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 */
583const char *
584pw_tempname(void)
585{
586
587 return (tempname);
588}
589
590/*
591 * Duplicate a struct passwd.
592 */
593struct passwd *
594pw_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 */
649struct passwd *
650pw_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}