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.
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.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
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.
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
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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
36 * @(#)pw_util.c 8.3 (Berkeley) 4/2/94
37 * $FreeBSD: src/lib/libutil/pw_util.c,v 1.38 2007/01/09 01:02:05 imp Exp $
38 * $DragonFly: src/lib/libutil/pw_util.c,v 1.2 2007/12/30 13:44:33 matthias Exp $
42 * This file is used by all the "password" programs; vipw(8), chpass(1),
46 #include <sys/param.h>
47 #include <sys/errno.h>
49 #include <sys/resource.h>
68 static pid_t editpid = -1;
69 static int lockfd = -1;
70 static char masterpasswd[PATH_MAX];
71 static char passwd_dir[PATH_MAX];
72 static char tempname[PATH_MAX];
73 static int initialized;
86 * Initialize statics and set limits, signals & umask to try to avoid
87 * interruptions, crashes etc. that might expose passord data.
90 pw_init(const char *dir, const char *master)
97 strcpy(passwd_dir, _PATH_ETC);
99 if (strlen(dir) >= sizeof(passwd_dir)) {
100 errno = ENAMETOOLONG;
103 strcpy(passwd_dir, dir);
106 if (master == NULL) {
108 strcpy(masterpasswd, _PATH_MASTERPASSWD);
109 } else if (snprintf(masterpasswd, sizeof(masterpasswd), "%s/%s",
110 passwd_dir, _MASTERPASSWD) > (int)sizeof(masterpasswd)) {
111 errno = ENAMETOOLONG;
115 if (strlen(master) >= sizeof(masterpasswd)) {
116 errno = ENAMETOOLONG;
119 strcpy(masterpasswd, master);
123 * The code that follows is extremely disruptive to the calling
124 * process, and is therefore disabled until someone can conceive
125 * of a realistic scenario where it would fend off a compromise.
126 * Race conditions concerning the temporary files can be guarded
127 * against in other ways than masking signals (by checking stat(2)
128 * results after creation).
131 /* Unlimited resource limits. */
132 rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
133 (void)setrlimit(RLIMIT_CPU, &rlim);
134 (void)setrlimit(RLIMIT_FSIZE, &rlim);
135 (void)setrlimit(RLIMIT_STACK, &rlim);
136 (void)setrlimit(RLIMIT_DATA, &rlim);
137 (void)setrlimit(RLIMIT_RSS, &rlim);
139 /* Don't drop core (not really necessary, but GP's). */
140 rlim.rlim_cur = rlim.rlim_max = 0;
141 (void)setrlimit(RLIMIT_CORE, &rlim);
143 /* Turn off signals. */
144 (void)signal(SIGALRM, SIG_IGN);
145 (void)signal(SIGHUP, SIG_IGN);
146 (void)signal(SIGINT, SIG_IGN);
147 (void)signal(SIGPIPE, SIG_IGN);
148 (void)signal(SIGQUIT, SIG_IGN);
149 (void)signal(SIGTERM, SIG_IGN);
150 (void)signal(SIGCONT, pw_cont);
152 /* Create with exact permissions. */
160 * Lock the master password file.
166 if (*masterpasswd == '\0')
170 * If the master password file doesn't exist, the system is hosed.
171 * Might as well try to build one. Set the close-on-exec bit so
172 * that users can't get at the encrypted passwords while editing.
173 * Open should allow flock'ing the file; see 4.4BSD. XXX
178 lockfd = open(masterpasswd, O_RDONLY, 0);
179 if (lockfd < 0 || fcntl(lockfd, F_SETFD, 1) == -1)
180 err(1, "%s", masterpasswd);
181 /* XXX vulnerable to race conditions */
182 if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
183 if (errno == EWOULDBLOCK) {
184 errx(1, "the password db file is busy");
186 err(1, "could not lock the passwd file: ");
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
195 if (fstat(lockfd, &st) == -1)
196 err(1, "fstat() failed: ");
197 if (st.st_nlink != 0)
206 * Create and open a presumably safe temp file for editing the password
207 * data, and copy the master password file into it.
217 if (*masterpasswd == '\0')
219 if ((p = strrchr(masterpasswd, '/')))
223 if (snprintf(tempname, sizeof(tempname), "%.*spw.XXXXXX",
224 (int)(p - masterpasswd), masterpasswd) >= (int)sizeof(tempname)) {
225 errno = ENAMETOOLONG;
228 if ((tfd = mkstemp(tempname)) == -1)
231 while ((nr = read(mfd, buf, sizeof(buf))) > 0)
232 if (write(tfd, buf, (size_t)nr) != nr)
245 * Regenerate the password database.
248 pw_mkdb(const char *user)
253 (void)fflush(stderr);
254 switch ((pid = fork())) {
260 execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p",
261 "-d", passwd_dir, tempname, (char *)NULL);
263 execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p",
264 "-d", passwd_dir, "-u", user, tempname,
272 if (waitpid(pid, &pstat, 0) == -1)
274 if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
281 * Edit the temp file. Return -1 on error, >0 if the file was modified, 0
285 pw_edit(int notsetuid)
287 struct sigaction sa, sa_int, sa_quit;
288 sigset_t oldsigset, sigset;
289 struct stat st1, st2;
293 if ((editor = getenv("EDITOR")) == NULL)
295 if (stat(tempname, &st1) == -1)
297 sa.sa_handler = SIG_IGN;
298 sigemptyset(&sa.sa_mask);
300 sigaction(SIGINT, &sa, &sa_int);
301 sigaction(SIGQUIT, &sa, &sa_quit);
302 sigemptyset(&sigset);
303 sigaddset(&sigset, SIGCHLD);
304 sigprocmask(SIG_BLOCK, &sigset, &oldsigset);
305 switch ((editpid = fork())) {
309 sigaction(SIGINT, &sa_int, NULL);
310 sigaction(SIGQUIT, &sa_quit, NULL);
311 sigprocmask(SIG_SETMASK, &oldsigset, NULL);
317 execlp(editor, basename(editor), tempname, (char *)NULL);
324 if (waitpid(editpid, &pstat, WUNTRACED) == -1) {
330 } else if (WIFSTOPPED(pstat)) {
331 raise(WSTOPSIG(pstat));
332 } else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) {
341 sigaction(SIGINT, &sa_int, NULL);
342 sigaction(SIGQUIT, &sa_quit, NULL);
343 sigprocmask(SIG_SETMASK, &oldsigset, NULL);
344 if (stat(tempname, &st2) == -1)
346 return (st1.st_mtime != st2.st_mtime);
350 * Clean up. Preserve errno for the caller's convenience.
362 kill(editpid, SIGTERM);
363 kill(editpid, SIGCONT);
364 waitpid(editpid, &status, 0);
367 if (*tempname != '\0') {
377 * Compares two struct pwds.
380 pw_equal(const struct passwd *pw1, const struct passwd *pw2)
382 return (strcmp(pw1->pw_name, pw2->pw_name) == 0 &&
383 pw1->pw_uid == pw2->pw_uid &&
384 pw1->pw_gid == pw2->pw_gid &&
385 strcmp(pw1->pw_class, pw2->pw_class) == 0 &&
386 pw1->pw_change == pw2->pw_change &&
387 pw1->pw_expire == pw2->pw_expire &&
388 strcmp(pw1->pw_gecos, pw2->pw_gecos) == 0 &&
389 strcmp(pw1->pw_dir, pw2->pw_dir) == 0 &&
390 strcmp(pw1->pw_shell, pw2->pw_shell) == 0);
394 * Make a passwd line out of a struct passwd.
397 pw_make(const struct passwd *pw)
401 asprintf(&line, "%s:%s:%ju:%ju:%s:%ju:%ju:%s:%s:%s", pw->pw_name,
402 pw->pw_passwd, (uintmax_t)pw->pw_uid, (uintmax_t)pw->pw_gid,
403 pw->pw_class, (uintmax_t)pw->pw_change, (uintmax_t)pw->pw_expire,
404 pw->pw_gecos, pw->pw_dir, pw->pw_shell);
409 * Copy password file from one descriptor to another, replacing or adding
410 * a single record on the way.
413 pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
415 char buf[8192], *end, *line, *p, *q, *r, t;
420 if ((line = pw_make(pw)) == NULL)
427 /* find the end of the current line */
428 for (p = q; q < end && *q != '\0'; ++q)
432 /* if we don't have a complete line, fill up the buffer */
436 if ((size_t)(q - p) >= sizeof(buf)) {
437 warnx("passwd line too long");
438 errno = EINVAL; /* hack */
442 q = memmove(buf, p, end - p);
447 readlen = read(ffd, end, sizeof(buf) - (end - buf));
451 len = (size_t)readlen;
452 if (len == 0 && p == buf)
456 if (len < (ssize_t)sizeof(buf)) {
458 if (len > 0 && buf[len - 1] != '\n')
459 ++len, *end++ = '\n';
464 /* is it a blank line or a comment? */
465 for (r = p; r < q && isspace(*r); ++r)
467 if (r == q || *r == '#') {
469 if (write(tfd, p, q - p + 1) != q - p + 1)
475 /* is it the one we're looking for? */
480 fpw = pw_scan(r, PWSCAN_MASTER);
483 * fpw is either the struct passwd for the current line,
484 * or NULL if the line is malformed.
488 if (fpw == NULL || strcmp(fpw->pw_name, pw->pw_name) != 0) {
492 if (write(tfd, p, q - p + 1) != q - p + 1)
497 if (old_pw && !pw_equal(fpw, old_pw)) {
498 warnx("entry inconsistent");
500 errno = EINVAL; /* hack */
505 /* it is, replace it */
507 if (write(tfd, line, len) != (int)len)
510 /* we're done, just copy the rest over */
512 if (write(tfd, q, end - q) != end - q)
515 readlen = read(ffd, buf, sizeof(buf));
519 len = (size_t)readlen;
527 /* if we got here, we have a new entry */
529 if ((size_t)write(tfd, line, len) != len ||
530 write(tfd, "\n", 1) != 1)
541 * Return the current value of tempname.
551 * Duplicate a struct passwd.
554 pw_dup(const struct passwd *pw)
560 (pw->pw_name ? strlen(pw->pw_name) + 1 : 0) +
561 (pw->pw_passwd ? strlen(pw->pw_passwd) + 1 : 0) +
562 (pw->pw_class ? strlen(pw->pw_class) + 1 : 0) +
563 (pw->pw_gecos ? strlen(pw->pw_gecos) + 1 : 0) +
564 (pw->pw_dir ? strlen(pw->pw_dir) + 1 : 0) +
565 (pw->pw_shell ? strlen(pw->pw_shell) + 1 : 0);
566 if ((npw = malloc((size_t)len)) == NULL)
568 memcpy(npw, pw, sizeof(*npw));
571 npw->pw_name = ((char *)npw) + len;
572 len += sprintf(npw->pw_name, "%s", pw->pw_name) + 1;
575 npw->pw_passwd = ((char *)npw) + len;
576 len += sprintf(npw->pw_passwd, "%s", pw->pw_passwd) + 1;
579 npw->pw_class = ((char *)npw) + len;
580 len += sprintf(npw->pw_class, "%s", pw->pw_class) + 1;
583 npw->pw_gecos = ((char *)npw) + len;
584 len += sprintf(npw->pw_gecos, "%s", pw->pw_gecos) + 1;
587 npw->pw_dir = ((char *)npw) + len;
588 len += sprintf(npw->pw_dir, "%s", pw->pw_dir) + 1;
591 npw->pw_shell = ((char *)npw) + len;
592 len += sprintf(npw->pw_shell, "%s", pw->pw_shell) + 1;
600 * Wrapper around an internal libc function
603 pw_scan(const char *line, int flags)
605 struct passwd pw, *ret;
608 if ((bp = strdup(line)) == NULL)
610 if (!__pw_scan(bp, &pw, flags)) {