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/* $OpenBSD: local_passwd.c,v 1.62 2021/10/24 21:24:17 deraadt Exp $ */
/*-
* Copyright (c) 1990 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/types.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
#include <login_cap.h>
#include <readpassphrase.h>
#define UNCHANGED_MSG "Password unchanged."
static uid_t uid;
extern int pwd_check(login_cap_t *, char *);
extern int pwd_gettries(login_cap_t *);
int local_passwd(char *, int);
char *getnewpasswd(struct passwd *, login_cap_t *, int);
void kbintr(int);
int
local_passwd(char *uname, int authenticated)
{
struct passwd *pw, *opw;
login_cap_t *lc;
sigset_t fullset;
time_t period;
int i, pfd, tfd = -1;
int pwflags = _PASSWORD_OMITV7;
if (!(pw = getpwnam_shadow(uname))) {
warnx("unknown user %s.", uname);
return(1);
}
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_LOGIN_CONF, "r") == -1)
err(1, "unveil %s", _PATH_LOGIN_CONF);
if (unveil(_PATH_LOGIN_CONF ".db", "r") == -1)
err(1, "unveil %s.db", _PATH_LOGIN_CONF);
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(_PATH_PWD_MKDB, "x") == -1)
err(1, "unveil %s", _PATH_PWD_MKDB);
if (pledge("stdio rpath wpath cpath getpw tty id proc exec", NULL) == -1)
err(1, "pledge");
if ((opw = pw_dup(pw)) == NULL) {
warn(NULL);
return(1);
}
if ((lc = login_getclass(pw->pw_class)) == NULL) {
warnx("unable to get login class for user %s.", uname);
free(opw);
return(1);
}
uid = authenticated ? pw->pw_uid : getuid();
if (uid && uid != pw->pw_uid) {
warnx("login/uid mismatch, username argument required.");
free(opw);
return(1);
}
/* Get the new password. */
pw->pw_passwd = getnewpasswd(pw, lc, authenticated);
if (pledge("stdio rpath wpath cpath getpw id proc exec", NULL) == -1)
err(1, "pledge");
/* Reset password change time based on login.conf. */
period = (time_t)login_getcaptime(lc, "passwordtime", 0, 0);
if (period > 0) {
pw->pw_change = time(NULL) + period;
} else {
/*
* If the pw change time is the same we only need
* to update the spwd.db file.
*/
if (pw->pw_change != 0)
pw->pw_change = 0;
else
pwflags = _PASSWORD_SECUREONLY;
}
/* 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 (pledge("stdio rpath wpath cpath proc exec", NULL) == -1)
err(1, "pledge");
/* Get a lock on the passwd file and open it. */
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);
/* Update master.passwd file and rebuild spwd.db. */
pw_copy(pfd, tfd, pw, opw);
free(opw);
if (pw_mkdb(uname, pwflags) == -1)
pw_error(NULL, 0, 1);
fprintf(stderr, "passwd: password updated successfully\n");
return(0);
}
char *
getnewpasswd(struct passwd *pw, login_cap_t *lc, int authenticated)
{
static char hash[_PASSWORD_LEN];
char newpass[1024];
char *p, *pref;
int tries, pwd_tries;
sig_t saveint, savequit;
saveint = signal(SIGINT, kbintr);
savequit = signal(SIGQUIT, kbintr);
if (!authenticated) {
fprintf(stderr, "Changing password for %s.\n", pw->pw_name);
if (uid != 0 && pw->pw_passwd[0] != '\0') {
char oldpass[1024];
p = readpassphrase("Old password:", oldpass,
sizeof(oldpass), RPP_ECHO_OFF);
if (p == NULL || *p == '\0') {
fprintf(stderr, "%s\n", UNCHANGED_MSG);
pw_abort();
exit(p == NULL ? 1 : 0);
}
if (crypt_checkpass(p, pw->pw_passwd) != 0) {
errno = EACCES;
explicit_bzero(oldpass, sizeof(oldpass));
pw_error(NULL, 1, 1);
}
explicit_bzero(oldpass, sizeof(oldpass));
}
}
pwd_tries = pwd_gettries(lc);
for (newpass[0] = '\0', tries = 0;;) {
char repeat[1024];
p = readpassphrase("New password:", newpass, sizeof(newpass),
RPP_ECHO_OFF);
if (p == NULL || *p == '\0') {
fprintf(stderr, "%s\n", UNCHANGED_MSG);
pw_abort();
exit(p == NULL ? 1 : 0);
}
if (strcmp(p, "s/key") == 0) {
fprintf(stderr, "That password collides with a system feature. Choose another.\n");
continue;
}
if ((tries++ < pwd_tries || pwd_tries == 0) &&
pwd_check(lc, p) == 0)
continue;
p = readpassphrase("Retype new password:", repeat, sizeof(repeat),
RPP_ECHO_OFF);
if (p != NULL && strcmp(newpass, p) == 0) {
explicit_bzero(repeat, sizeof(repeat));
break;
}
fprintf(stderr, "Mismatch; try again, EOF to quit.\n");
explicit_bzero(repeat, sizeof(repeat));
explicit_bzero(newpass, sizeof(newpass));
}
(void)signal(SIGINT, saveint);
(void)signal(SIGQUIT, savequit);
pref = login_getcapstr(lc, "localcipher", NULL, NULL);
if (crypt_newhash(newpass, pref, hash, sizeof(hash)) != 0) {
fprintf(stderr, "Couldn't generate hash.\n");
explicit_bzero(newpass, sizeof(newpass));
pw_error(NULL, 0, 0);
}
explicit_bzero(newpass, sizeof(newpass));
free(pref);
return hash;
}
void
kbintr(int signo)
{
dprintf(STDOUT_FILENO, "\n%s\n", UNCHANGED_MSG);
_exit(0);
}
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