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integrate password quality checking, disallow all digit passwords motivated
by Solar Designer.  External password checking program can be spawned now,
number of password trials configurable.  work by me and Bob Beck.

/*	$OpenBSD: yp_passwd.c,v 1.14 2000/08/01 22:27:51 provos Exp $	*/

/*
 * Copyright (c) 1988 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 sccsid[] = "from: @(#)yp_passwd.c	1.0 2/2/93";*/
static char rcsid[] = "$OpenBSD: yp_passwd.c,v 1.14 2000/08/01 22:27:51 provos Exp $";
#endif /* not lint */

#ifdef	YP

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <time.h>
#include <pwd.h>
#include <err.h>
#include <errno.h>
#include <ctype.h>
#include <rpc/rpc.h>
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#define passwd yp_passwd_rec
#include <rpcsvc/yppasswd.h>
#undef passwd

#ifndef _PASSWORD_LEN
#define _PASSWORD_LEN PASS_MAX
#endif

extern	int pwd_gensalt __P(( char *, int, struct passwd *, char));
extern	int pwd_check __P((struct passwd *, char *));
extern	int pwd_gettries __P((struct passwd *));

static char *getnewpasswd();
static struct passwd *ypgetpwnam();

static uid_t uid;
char *domain;

static int
pw_error(name, err, eval)
	char *name;
	int err, eval;
{
	if(err) 
		warn("%s", name);

	warnx("YP passwd database unchanged.");
	exit(eval);
}

int
yp_passwd(username)
	char *username;
{
	char *master;
	int r, rpcport, status;
	struct yppasswd yppasswd;
	struct passwd *pw;
	struct timeval tv;
	CLIENT *client;
	
	uid = getuid();

	/*
	 * Get local domain
	 */
	if ((r = yp_get_default_domain(&domain)) != 0) {
		warnx("can't get local YP domain. Reason: %s", yperr_string(r));
		exit(1);
	}

	/*
	 * Find the host for the passwd map; it should be running
	 * the daemon.
	 */
	if ((r = yp_master(domain, "passwd.byname", &master)) != 0) {
		warnx("can't find the master YP server. Reason: %s",
		    yperr_string(r));
		exit(1);
	}

	/*
	 * Ask the portmapper for the port of the daemon.
	 */
	if ((rpcport = getrpcport(master, YPPASSWDPROG,
	    YPPASSWDPROC_UPDATE, IPPROTO_UDP)) == 0) {
		warnx("master YP server not running yppasswd daemon.");
		warnx("Can't change password.");
		exit(1);
	}

	/*
	 * Be sure the port is priviledged
	 */
	if (rpcport >= IPPORT_RESERVED) {
		warnx("yppasswd daemon is on an invalid port.");
		exit(1);
	}

	/* Get user's login identity */
	if (!(pw = ypgetpwnam(username))) {
		warnx("unknown user %s.", username);
		exit(1);
	}
		
	if (uid && uid != pw->pw_uid) {
		warnx("you may only change your own password: %s", strerror(EACCES));
		exit(1);
	}

	/* prompt for new password */
	yppasswd.newpw.pw_passwd = getnewpasswd(pw, &yppasswd.oldpass);

	/* tell rpc.yppasswdd */
	yppasswd.newpw.pw_name	= pw->pw_name;
	yppasswd.newpw.pw_uid 	= pw->pw_uid;
	yppasswd.newpw.pw_gid	= pw->pw_gid;
	yppasswd.newpw.pw_gecos = pw->pw_gecos;
	yppasswd.newpw.pw_dir	= pw->pw_dir;
	yppasswd.newpw.pw_shell	= pw->pw_shell;
	
	client = clnt_create(master, YPPASSWDPROG, YPPASSWDVERS, "udp");
	if (client==NULL) {
		warnx("cannot contact yppasswdd on %s: Reason: %s",
		    master, yperr_string(YPERR_YPBIND));
		free(yppasswd.newpw.pw_passwd);
		return(YPERR_YPBIND);
	}
	client->cl_auth = authunix_create_default();
	tv.tv_sec = 2;
	tv.tv_usec = 0;
	r = clnt_call(client, YPPASSWDPROC_UPDATE,
	    xdr_yppasswd, &yppasswd, xdr_int, &status, tv);
	if (r)
		warnx("rpc to yppasswdd failed.");
	else if (status) {
		printf("Couldn't change YP password.\n");
		free(yppasswd.newpw.pw_passwd);
		exit(1);
	}
	printf("The YP password has been changed on %s, the master YP passwd server.\n",
	    master);
	free(yppasswd.newpw.pw_passwd);
	exit(0);
}

static char *
getnewpasswd(pw, old_pass)
	register struct passwd *pw;
	char **old_pass;
{
	static char buf[_PASSWORD_LEN+1];
	register char *p, *t;
	int tries, pwd_tries;
	char salt[_PASSWORD_LEN], *crypt(), *getpass();
	
	printf("Changing YP password for %s.\n", pw->pw_name);

	if (old_pass) {
		*old_pass = NULL;
	
		if (pw->pw_passwd[0]) {
			p = getpass("Old password:");
			if (strcmp(crypt(p, pw->pw_passwd), pw->pw_passwd)) {
				errno = EACCES;
				pw_error(NULL, 1, 1);
			}
		} else
			p = "";
		*old_pass = strdup(p);
	}

	pwd_tries = pwd_gettries(pw);

	for (buf[0] = '\0', tries = 0;;) {
		p = getpass("New password:");
		if (!*p) {
			printf("Password unchanged.\n");
			pw_error(NULL, 0, 0);
		}
		if (strcmp(p, "s/key") == 0) {
			printf("That password collides with a system feature. Choose another.\n");
			continue;
		}
		if ((tries++ < pwd_tries || pwd_tries == 0) 
		    && pwd_check(pw, p) == 0)
			continue;
		strncpy(buf, p, sizeof buf-1);
		buf[sizeof buf-1] = '\0';
		if (!strcmp(buf, getpass("Retype new password:")))
			break;
		(void)printf("Mismatch; try again, EOF to quit.\n");
	}
        if( !pwd_gensalt( salt, _PASSWORD_LEN, pw, 'y' )) {
                (void)printf("Couldn't generate salt.\n");
                pw_error(NULL, 0, 0);
        }
	return(strdup(crypt(buf, salt)));
}

static char *
pwskip(register char *p)
{
	while (*p && *p != ':' && *p != '\n')
		++p;
	if (*p)
		*p++ = 0;
	return (p);
}

struct passwd *
interpret(struct passwd *pwent, char *line)
{
	register char	*p = line;

	pwent->pw_passwd = "*";
	pwent->pw_uid = 0;
	pwent->pw_gid = 0;
	pwent->pw_gecos = "";
	pwent->pw_dir = "";
	pwent->pw_shell = "";
	pwent->pw_change = 0;
	pwent->pw_expire = 0;
	pwent->pw_class = "";
	
	/* line without colon separators is no good, so ignore it */
	if(!strchr(p, ':'))
		return(NULL);

	pwent->pw_name = p;
	p = pwskip(p);
	pwent->pw_passwd = p;
	p = pwskip(p);
	pwent->pw_uid = (uid_t)strtoul(p, NULL, 10);
	p = pwskip(p);
	pwent->pw_gid = (gid_t)strtoul(p, NULL, 10);
	p = pwskip(p);
	pwent->pw_gecos = p;
	p = pwskip(p);
	pwent->pw_dir = p;
	p = pwskip(p);
	pwent->pw_shell = p;
	while (*p && *p != '\n')
		p++;
	*p = '\0';
	return (pwent);
}

static char *__yplin;

static struct passwd *
ypgetpwnam(nam)
	char *nam;
{
	static struct passwd pwent;
	char *val;
	int reason, vallen;
	
	reason = yp_match(domain, "passwd.byname", nam, strlen(nam),
	    &val, &vallen);
	switch(reason) {
	case 0:
		break;
	default:
		return (NULL);
		break;
	}
	val[vallen] = '\0';
	if (__yplin)
		free(__yplin);
	__yplin = (char *)malloc(vallen + 1);
	strncpy(__yplin, val, vallen);
	__yplin[vallen] = '\0';
	free(val);

	return(interpret(&pwent, __yplin));
}

#endif	/* YP */