[openssh.git] / auth-passwd.c

/* $OpenBSD: auth-passwd.c,v 1.37 2006/07/06 16:03:53 stevesk Exp $ */
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * Password authentication.  This file contains the functions to check whether
 * the password is valid for the user.
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 *
 * Copyright (c) 1999 Dug Song.  All rights reserved.
 * Copyright (c) 2000 Markus Friedl.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 "includes.h"

#include <sys/types.h>

#include <pwd.h>

#include "packet.h"
#include "buffer.h"
#include "log.h"
#include "servconf.h"
#include "auth.h"
#include "auth-options.h"

extern Buffer loginmsg;
extern ServerOptions options;

#ifdef HAVE_LOGIN_CAP
extern login_cap_t *lc;
#endif


#define DAY		(24L * 60 * 60) /* 1 day in seconds */
#define TWO_WEEKS	(2L * 7 * DAY)	/* 2 weeks in seconds */

void
disable_forwarding(void)
{
	no_port_forwarding_flag = 1;
	no_agent_forwarding_flag = 1;
	no_x11_forwarding_flag = 1;
}

/*
 * Tries to authenticate the user using password.  Returns true if
 * authentication succeeds.
 */
int
auth_password(Authctxt *authctxt, const char *password)
{
	struct passwd * pw = authctxt->pw;
	int result, ok = authctxt->valid;
#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
	static int expire_checked = 0;
#endif

#ifndef HAVE_CYGWIN
	if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
		ok = 0;
#endif
	if (*password == '\0' && options.permit_empty_passwd == 0)
		return 0;

#ifdef KRB5
	if (options.kerberos_authentication == 1) {
		int ret = auth_krb5_password(authctxt, password);
		if (ret == 1 || ret == 0)
			return ret && ok;
		/* Fall back to ordinary passwd authentication. */
	}
#endif
#ifdef HAVE_CYGWIN
	if (is_winnt) {
		HANDLE hToken = cygwin_logon_user(pw, password);

		if (hToken == INVALID_HANDLE_VALUE)
			return 0;
		cygwin_set_impersonation_token(hToken);
		return ok;
	}
#endif
#ifdef USE_PAM
	if (options.use_pam)
		return (sshpam_auth_passwd(authctxt, password) && ok);
#endif
#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
	if (!expire_checked) {
		expire_checked = 1;
		if (auth_shadow_pwexpired(authctxt))
			authctxt->force_pwchange = 1;
	}
#endif
	result = sys_auth_passwd(authctxt, password);
	if (authctxt->force_pwchange)
		disable_forwarding();
	return (result && ok);
}

#ifdef BSD_AUTH
static void
warn_expiry(Authctxt *authctxt, auth_session_t *as)
{
	char buf[256];
	quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime;

	pwwarntime = acwarntime = TWO_WEEKS;

	pwtimeleft = auth_check_change(as);
	actimeleft = auth_check_expire(as);
#ifdef HAVE_LOGIN_CAP
	if (authctxt->valid) {
		pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS,
		    TWO_WEEKS);
		acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS,
		    TWO_WEEKS);
	}
#endif
	if (pwtimeleft != 0 && pwtimeleft < pwwarntime) {
		daysleft = pwtimeleft / DAY + 1;
		snprintf(buf, sizeof(buf),
		    "Your password will expire in %lld day%s.\n",
		    daysleft, daysleft == 1 ? "" : "s");
		buffer_append(&loginmsg, buf, strlen(buf));
	}
	if (actimeleft != 0 && actimeleft < acwarntime) {
		daysleft = actimeleft / DAY + 1;
		snprintf(buf, sizeof(buf),
		    "Your account will expire in %lld day%s.\n",
		    daysleft, daysleft == 1 ? "" : "s");
		buffer_append(&loginmsg, buf, strlen(buf));
	}
}

int
sys_auth_passwd(Authctxt *authctxt, const char *password)
{
	struct passwd *pw = authctxt->pw;
	auth_session_t *as;
	static int expire_checked = 0;

	as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh",
	    (char *)password);
	if (as == NULL)
		return (0);
	if (auth_getstate(as) & AUTH_PWEXPIRED) {
		auth_close(as);
		disable_forwarding();
		authctxt->force_pwchange = 1;
		return (1);
	} else {
		if (!expire_checked) {
			expire_checked = 1;
			warn_expiry(authctxt, as);
		}
		return (auth_close(as));
	}
}
#elif !defined(CUSTOM_SYS_AUTH_PASSWD)
int
sys_auth_passwd(Authctxt *authctxt, const char *password)
{
	struct passwd *pw = authctxt->pw;
	char *encrypted_password;

	/* Just use the supplied fake password if authctxt is invalid */
	char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd;

	/* Check for users with no password. */
	if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0)
		return (1);

	/* Encrypt the candidate password using the proper salt. */
	encrypted_password = xcrypt(password,
	    (pw_password[0] && pw_password[1]) ? pw_password : "xx");

	/*
	 * Authentication is accepted if the encrypted passwords
	 * are identical.
	 */
	return (strcmp(encrypted_password, pw_password) == 0);
}
#endif
Commit	Line	Data
b1842393	1	/* $OpenBSD: auth-passwd.c,v 1.37 2006/07/06 16:03:53 stevesk Exp $ */
8efc0c15	2	/*
5260325f	3	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	4	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	5	* All rights reserved
5260325f	6	* Password authentication. This file contains the functions to check whether
5260325f	7	* the password is valid for the user.
bcbf86ec	8	*
	9	* As far as I am concerned, the code I have written for this software
	10	* can be used freely for any purpose. Any derived versions of this
	11	* software must be clearly marked as such, and if the derived work is
	12	* incompatible with the protocol description in the RFC file, it must be
	13	* called by a name other than "ssh" or "Secure Shell".
	14	*
bcbf86ec	15	* Copyright (c) 1999 Dug Song. All rights reserved.
bcbf86ec	16	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	17	*
	18	* Redistribution and use in source and binary forms, with or without
	19	* modification, are permitted provided that the following conditions
	20	* are met:
	21	* 1. Redistributions of source code must retain the above copyright
	22	* notice, this list of conditions and the following disclaimer.
	23	* 2. Redistributions in binary form must reproduce the above copyright
	24	* notice, this list of conditions and the following disclaimer in the
	25	* documentation and/or other materials provided with the distribution.
	26	*
	27	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	28	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	29	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	30	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	31	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	32	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	33	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	34	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	35	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	36	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
5260325f	37	*/
8efc0c15	38
8efc0c15	39	#include "includes.h"
8efc0c15	40
b1842393	41	#include <sys/types.h>
	42
	43	#include <pwd.h>
	44
8efc0c15	45	#include "packet.h"
022487ce	46	#include "buffer.h"
42f11eb2	47	#include "log.h"
42f11eb2	48	#include "servconf.h"
59c97189	49	#include "auth.h"
37656beb	50	#include "auth-options.h"
af774732	51
022487ce	52	extern Buffer loginmsg;
af774732	53	extern ServerOptions options;
37656beb	54
022487ce	55	#ifdef HAVE_LOGIN_CAP
	56	extern login_cap_t *lc;
	57	#endif
	58
	59
	60	#define DAY (24L * 60 * 60) /* 1 day in seconds */
	61	#define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */
	62
cadfc759	63	void
37656beb	64	disable_forwarding(void)
	65	{
	66	no_port_forwarding_flag = 1;
	67	no_agent_forwarding_flag = 1;
	68	no_x11_forwarding_flag = 1;
	69	}
af774732	70
5260325f	71	/*
	72	* Tries to authenticate the user using password. Returns true if
	73	* authentication succeeds.
	74	*/
6ae2364d	75	int
af774732	76	auth_password(Authctxt authctxt, const char password)
8efc0c15	77	{
f656b61e	78	struct passwd * pw = authctxt->pw;
751e5199	79	int result, ok = authctxt->valid;
02a57950	80	#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
23ef91d3	81	static int expire_checked = 0;
02a57950	82	#endif
8efc0c15	83
3c62e7eb	84	#ifndef HAVE_CYGWIN
fdaef11e	85	if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
68ece370	86	ok = 0;
3c62e7eb	87	#endif
f656b61e	88	if (*password == '\0' && options.permit_empty_passwd == 0)
68ece370	89	return 0;
7c6eb32f	90
37656beb	91	#ifdef KRB5
ced49be2	92	if (options.kerberos_authentication == 1) {
	93	int ret = auth_krb5_password(authctxt, password);
	94	if (ret == 1 \|\| ret == 0)
96d0bf74	95	return ret && ok;
ced49be2	96	/* Fall back to ordinary passwd authentication. */
ced49be2	97	}
37656beb	98	#endif
37656beb	99	#ifdef HAVE_CYGWIN
3c62e7eb	100	if (is_winnt) {
	101	HANDLE hToken = cygwin_logon_user(pw, password);
	102
	103	if (hToken == INVALID_HANDLE_VALUE)
96d0bf74	104	return 0;
3c62e7eb	105	cygwin_set_impersonation_token(hToken);
96d0bf74	106	return ok;
3c62e7eb	107	}
37656beb	108	#endif
5de92f17	109	#ifdef USE_PAM
	110	if (options.use_pam)
	111	return (sshpam_auth_passwd(authctxt, password) && ok);
	112	#endif
d78480be	113	#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
23ef91d3	114	if (!expire_checked) {
23ef91d3	115	expire_checked = 1;
751e5199	116	if (auth_shadow_pwexpired(authctxt))
23ef91d3	117	authctxt->force_pwchange = 1;
5a8bd0c3	118	}
5a8bd0c3	119	#endif
751e5199	120	result = sys_auth_passwd(authctxt, password);
	121	if (authctxt->force_pwchange)
	122	disable_forwarding();
	123	return (result && ok);
37656beb	124	}
	125
	126	#ifdef BSD_AUTH
022487ce	127	static void
	128	warn_expiry(Authctxt authctxt, auth_session_t as)
	129	{
	130	char buf[256];
	131	quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime;
	132
	133	pwwarntime = acwarntime = TWO_WEEKS;
	134
	135	pwtimeleft = auth_check_change(as);
	136	actimeleft = auth_check_expire(as);
6c0dc0dd	137	#ifdef HAVE_LOGIN_CAP
022487ce	138	if (authctxt->valid) {
	139	pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS,
	140	TWO_WEEKS);
	141	acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS,
	142	TWO_WEEKS);
	143	}
	144	#endif
	145	if (pwtimeleft != 0 && pwtimeleft < pwwarntime) {
	146	daysleft = pwtimeleft / DAY + 1;
	147	snprintf(buf, sizeof(buf),
	148	"Your password will expire in %lld day%s.\n",
	149	daysleft, daysleft == 1 ? "" : "s");
	150	buffer_append(&loginmsg, buf, strlen(buf));
	151	}
	152	if (actimeleft != 0 && actimeleft < acwarntime) {
	153	daysleft = actimeleft / DAY + 1;
	154	snprintf(buf, sizeof(buf),
	155	"Your account will expire in %lld day%s.\n",
	156	daysleft, daysleft == 1 ? "" : "s");
	157	buffer_append(&loginmsg, buf, strlen(buf));
	158	}
	159	}
	160
37656beb	161	int
	162	sys_auth_passwd(Authctxt authctxt, const char password)
	163	{
	164	struct passwd *pw = authctxt->pw;
	165	auth_session_t *as;
022487ce	166	static int expire_checked = 0;
37656beb	167
	168	as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh",
	169	(char *)password);
05c25368	170	if (as == NULL)
05c25368	171	return (0);
37656beb	172	if (auth_getstate(as) & AUTH_PWEXPIRED) {
	173	auth_close(as);
	174	disable_forwarding();
	175	authctxt->force_pwchange = 1;
	176	return (1);
	177	} else {
022487ce	178	if (!expire_checked) {
	179	expire_checked = 1;
	180	warn_expiry(authctxt, as);
	181	}
37656beb	182	return (auth_close(as));
	183	}
	184	}
cadfc759	185	#elif !defined(CUSTOM_SYS_AUTH_PASSWD)
37656beb	186	int
	187	sys_auth_passwd(Authctxt authctxt, const char password)
	188	{
	189	struct passwd *pw = authctxt->pw;
	190	char *encrypted_password;
	191
96d0bf74	192	/* Just use the supplied fake password if authctxt is invalid */
96d0bf74	193	char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd;
0bbfbdeb	194
0bbfbdeb	195	/* Check for users with no password. */
33fb67f0	196	if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0)
37656beb	197	return (1);
7c6eb32f	198
37656beb	199	/* Encrypt the candidate password using the proper salt. */
	200	encrypted_password = xcrypt(password,
	201	(pw_password[0] && pw_password[1]) ? pw_password : "xx");
b2344d54	202
37656beb	203	/*
	204	* Authentication is accepted if the encrypted passwords
	205	* are identical.
	206	*/
	207	return (strcmp(encrypted_password, pw_password) == 0);
fde58bd4	208	}
37656beb	209	#endif