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/* $OpenBSD: chpass.c,v 1.48 2021/10/24 21:24:16 deraadt 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. 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.
*/
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.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"
extern char *__progname;
enum { NEWSH, LOADENTRY, EDITENTRY } op;
uid_t uid;
void baduser(void);
void kbintr(int);
void usage(void);
int
main(int argc, char *argv[])
{
struct passwd *pw = NULL, *opw = NULL, lpw;
int i, ch, pfd, tfd, dfd;
char *tz, *arg = NULL;
sigset_t fullset;
/* We need to use the system timezone for date conversions. */
if ((tz = getenv("TZ")) != NULL) {
unsetenv("TZ");
tzset();
setenv("TZ", tz, 1);
}
op = EDITENTRY;
while ((ch = getopt(argc, argv, "a:s:")) != -1)
switch(ch) {
case 'a':
op = LOADENTRY;
arg = optarg;
break;
case 's':
op = NEWSH;
arg = optarg;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
uid = getuid();
if (op == EDITENTRY || op == NEWSH)
switch(argc) {
case 0:
pw = getpwuid_shadow(uid);
if (!pw)
errx(1, "unknown user: uid %u", uid);
break;
case 1:
pw = getpwnam_shadow(*argv);
if (!pw)
errx(1, "unknown user: %s", *argv);
if (uid && uid != pw->pw_uid)
baduser();
break;
default:
usage();
}
if (op == LOADENTRY) {
if (argc != 0)
errx(1, "option -a does not accept user argument");
if (uid)
baduser();
pw = &lpw;
if (!pw_scan(arg, pw, NULL))
exit(1);
opw = getpwnam_shadow(pw->pw_name);
}
if (opw == NULL && (opw = pw_dup(pw)) == NULL)
err(1, NULL);
/* Edit the user passwd information if requested. */
if (op == EDITENTRY) {
char tempname[] = _PATH_VARTMP "pw.XXXXXXXXXX";
int edit_status;
if ((pw = pw_dup(pw)) == NULL)
pw_error(NULL, 1, 1);
dfd = mkostemp(tempname, O_CLOEXEC);
if (dfd == -1)
pw_error(tempname, 1, 1);
display(tempname, dfd, pw);
if (unveil(_PATH_BSHELL, "x") == -1)
err(1, "unveil %s", _PATH_BSHELL);
if (unveil(_PATH_SHELLS, "r") == -1)
err(1, "unveil %s", _PATH_SHELLS);
if (unveil(tempname, "rc") == -1)
err(1, "unveil %s", tempname);
if (pledge("stdio rpath wpath cpath id proc exec unveil",
NULL) == -1)
err(1, "pledge");
edit_status = edit(tempname, pw);
close(dfd);
unlink(tempname);
switch (edit_status) {
case EDIT_OK:
break;
case EDIT_NOCHANGE:
pw_error(NULL, 0, 0);
break;
case EDIT_ERROR:
default:
pw_error(tempname, 1, 1);
break;
}
}
if (op == NEWSH) {
if (unveil(_PATH_SHELLS, "r") == -1)
err(1, "unveil %s", _PATH_SHELLS);
if (pledge("stdio rpath wpath cpath id proc exec unveil",
NULL) == -1)
err(1, "pledge");
/* protect p_shell -- it thinks NULL is /bin/sh */
if (!arg[0])
usage();
if (p_shell(arg, pw, NULL))
pw_error(NULL, 0, 1);
}
/* 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);
if (unveil(_PATH_MASTERPASSWD_LOCK, "rwc") == -1)
err(1, "unveil %s", _PATH_MASTERPASSWD_LOCK);
if (unveil(_PATH_MASTERPASSWD, "r") == -1)
err(1, "unveil %s", _PATH_MASTERPASSWD);
if (unveil(_PATH_PWD_MKDB, "x") == -1)
err(1, "unveil %s", _PATH_PWD_MKDB);
if (pledge("stdio rpath wpath cpath proc exec", NULL) == -1)
err(1, "pledge");
/* Get the passwd lock file and open the passwd file for reading. */
pw_init();
for (i = 1; (tfd = pw_lock(0)) == -1; i++) {
if (i == 4)
(void)fputs("Attempting to lock password file, "
"please wait or press ^C to abort", stderr);
(void)signal(SIGINT, kbintr);
if (i % 16 == 0)
fputc('.', stderr);
usleep(250000);
(void)signal(SIGINT, SIG_IGN);
}
if (i >= 4)
fputc('\n', stderr);
pfd = open(_PATH_MASTERPASSWD, O_RDONLY|O_CLOEXEC);
if (pfd == -1)
pw_error(_PATH_MASTERPASSWD, 1, 1);
/* Copy the passwd file to the lock file, updating pw. */
pw_copy(pfd, tfd, pw, opw);
/* If username changed we need to rebuild the entire db. */
arg = !strcmp(opw->pw_name, pw->pw_name) ? pw->pw_name : NULL;
/* Now finish the passwd file update. */
if (pw_mkdb(arg, 0) == -1)
pw_error(NULL, 0, 1);
exit(0);
}
void
baduser(void)
{
errx(1, "%s", strerror(EACCES));
}
/* ARGSUSED */
void
kbintr(int signo)
{
dprintf(STDERR_FILENO, "\n%s: %s unchanged\n",
__progname, _PATH_MASTERPASSWD);
_exit(1);
}
void
usage(void)
{
(void)fprintf(stderr, "usage: %s [-s newshell] [user]\n", __progname);
(void)fprintf(stderr, " %s -a list\n", __progname);
exit(1);
}
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