File: [local] / src / usr.bin / chpass / chpass.c (download)
Revision 1.17, Wed Aug 15 20:47:53 2001 UTC (22 years, 10 months ago) by millert
Branch: MAIN
Changes since 1.16: +80 -20 lines
Move locking of the passwd file *after* we have gotten a new password
from the user. Set real/effective/saved uids to 0 and block all signals
so the lock cannot be kept longer than necessary. If we cannot lock,
try again every 1/4 second for 2 seconds and then ask the user what
they wish to do (keep trying, quit).
Same as in local_passwd.c but here we need to remove a temp file
in the SIGINT handler because _exit() doesn't call atexit() routines.
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/* $OpenBSD: chpass.c,v 1.17 2001/08/15 20:47:53 millert Exp $ */
/* $NetBSD: chpass.c,v 1.8 1996/05/15 21:50:43 jtc Exp $ */
/*-
* Copyright (c) 1988, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1988, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)chpass.c 8.4 (Berkeley) 4/2/94";
#else
static char rcsid[] = "$OpenBSD: chpass.c,v 1.17 2001/08/15 20:47:53 millert Exp $";
#endif
#endif /* not lint */
#include <sys/param.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
#include "chpass.h"
#include "pathnames.h"
char tempname[] = __CONCAT(_PATH_VARTMP,"pw.XXXXXXXX");
enum { NEWSH, LOADENTRY, EDITENTRY } op;
uid_t uid;
extern char *__progname;
#ifdef YP
int use_yp;
int force_yp = 0;
extern struct passwd *ypgetpwnam(), *ypgetpwuid();
int _yp_check __P((char **));
int pw_yp __P((struct passwd *, uid_t));
#endif
void baduser __P((void));
void tempcleanup __P((void));
void kbintr __P((int));
void usage __P((void));
int
main(argc, argv)
int argc;
char **argv;
{
struct passwd *pw, lpw;
int ch, pfd, tfd, dfd;
char *arg;
char *s = NULL;
sigset_t fullset;
#ifdef YP
use_yp = _yp_check(NULL);
#endif
op = EDITENTRY;
while ((ch = getopt(argc, argv, "a:s:ly")) != -1)
switch(ch) {
case 'a':
op = LOADENTRY;
arg = optarg;
break;
case 's':
op = NEWSH;
arg = optarg;
break;
#ifdef YP
case 'l':
use_yp = 0;
break;
case 'y':
if (!use_yp) {
warnx("YP not in use.");
usage();
}
force_yp = 1;
break;
#endif
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
#ifdef YP
if (op == LOADENTRY && use_yp)
errx(1, "cannot load entry using NIS.\n\tUse the -l flag to load local.");
#endif
uid = getuid();
if (op == EDITENTRY || op == NEWSH)
switch(argc) {
case 0:
pw = getpwuid(uid);
#ifdef YP
if (pw && !force_yp)
use_yp = 0;
else if (use_yp)
pw = ypgetpwuid(uid);
#endif /* YP */
if (!pw)
errx(1, "unknown user: uid %u\n", uid);
break;
case 1:
pw = getpwnam(*argv);
#ifdef YP
if (pw && !force_yp)
use_yp = 0;
else if (use_yp)
pw = ypgetpwnam(*argv);
#endif /* YP */
if (!pw)
errx(1, "unknown user: %s", *argv);
if (uid && uid != pw->pw_uid)
baduser();
break;
default:
usage();
}
if (op == NEWSH) {
/* protect p_shell -- it thinks NULL is /bin/sh */
if (!arg[0])
usage();
if (p_shell(arg, pw, NULL))
pw_error(NULL, 0, 1);
}
if (op == LOADENTRY) {
if (uid)
baduser();
pw = &lpw;
if (!pw_scan(arg, pw, NULL))
exit(1);
}
/* Edit the user passwd information if requested. */
if (op == EDITENTRY) {
dfd = mkstemp(tempname);
if (dfd == -1 || fcntl(dfd, F_SETFD, 1) == -1)
pw_error(tempname, 1, 1);
atexit(tempcleanup);
display(tempname, dfd, pw);
edit(tempname, pw);
}
/* Drop user's real uid and block all signals to avoid a DoS. */
setuid(0);
sigfillset(&fullset);
sigdelset(&fullset, SIGINT);
sigprocmask(SIG_BLOCK, &fullset, NULL);
/* Get the passwd lock file and open the passwd file for reading. */
pw_init();
for (;;) {
int i, c, d;
(void)fputs("Please wait", stderr);
for (i = 0; i < (s ? 64 : 8) && (tfd = pw_lock(0)) == -1; i++) {
(void)signal(SIGINT, kbintr);
fputc('.', stderr);
usleep(250000);
(void)signal(SIGINT, SIG_IGN);
}
fputc('\n', stderr);
if (tfd != -1)
break;
/* Unable to lock passwd file, let the user decide. */
if (errno == EEXIST) {
if (s == NULL)
s = "The passwd file is busy,";
else
s = "The passwd file is still busy,";
} else
s = "Unable to open passwd temp file,";
(void)fprintf(stderr,
"%s do you want to wait until it is available? [y/n] ", s);
(void)signal(SIGINT, kbintr);
c = getchar();
(void)signal(SIGINT, SIG_IGN);
if (c != '\n')
while ((d = getchar()) != '\n' && d != EOF)
;
if (tolower(c) != 'y')
pw_error(NULL, 0, 1);
}
pfd = open(_PATH_MASTERPASSWD, O_RDONLY, 0);
if (pfd == -1 || fcntl(pfd, F_SETFD, 1) == -1)
pw_error(_PATH_MASTERPASSWD, 1, 1);
#ifdef YP
if (use_yp) {
if (pw_yp(pw, uid))
pw_error(NULL, 0, 1);
else {
pw_abort();
exit(0);
}
} else
#endif /* YP */
{
/* Copy the passwd file to the lock file, updating pw. */
pw_copy(pfd, tfd, pw);
/* Now finish the passwd file update. */
if (pw_mkdb(pw->pw_name) == -1)
pw_error(NULL, 0, 1);
}
exit(0);
}
void
baduser()
{
errx(1, "%s", strerror(EACCES));
}
void
tempcleanup()
{
unlink(tempname);
}
void
kbintr(signo)
int signo;
{
struct iovec iv[5];
iv[0].iov_base = "\n";
iv[0].iov_len = 1;
iv[1].iov_base = __progname;
iv[1].iov_len = strlen(__progname);
iv[2].iov_base = ": ";
iv[2].iov_len = 2;
iv[3].iov_base = _PATH_MASTERPASSWD;
iv[3].iov_len = sizeof(_PATH_MASTERPASSWD) - 1;
iv[4].iov_base = " unchanged\n";
iv[4].iov_len = 11;
writev(STDERR_FILENO, iv, 5);
if (op == EDITENTRY)
unlink(tempname);
_exit(1);
}
void
usage()
{
#ifdef YP
(void)fprintf(stderr,
"usage: %s [-l%s] [-a list] [-s newshell] [user]\n",
__progname, use_yp ? "y" : "");
#else
(void)fprintf(stderr, "usage: %s [-a list] [-s newshell] [user]\n",
__progname);
#endif
exit(1);
}