auth-passwd.c - third_party/openssh-portable - Git at Google

 /* $OpenBSD: auth-passwd.c,v 1.47 2018/07/09 21:26:02 markus 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 <stdio.h>
 #include <string.h>
 #include <stdarg.h>

 #include "packet.h"
 #include "sshbuf.h"
 #include "ssherr.h"
 #include "log.h"
 #include "misc.h"
 #include "servconf.h"
 #include "sshkey.h"
 #include "hostfile.h"
 #include "auth.h"
 #include "auth-options.h"

 extern struct sshbuf *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 */

 #define MAX_PASSWORD_LEN	1024

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

 	if (strlen(password) > MAX_PASSWORD_LEN)
 		return 0;

 #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
 	{
 		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(ssh, password);
 	if (authctxt->force_pwchange)
 		auth_restrict_session(ssh);
 	return (result && ok);
 }

 #ifdef BSD_AUTH
 static void
 warn_expiry(Authctxt *authctxt, auth_session_t *as)
 {
 	int r;
 	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;
 		if ((r = sshbuf_putf(loginmsg,
 		    "Your password will expire in %lld day%s.\n",
 		    daysleft, daysleft == 1 ? "" : "s")) != 0)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	}
 	if (actimeleft != 0 && actimeleft < acwarntime) {
 		daysleft = actimeleft / DAY + 1;
 		if ((r = sshbuf_putf(loginmsg,
 		    "Your account will expire in %lld day%s.\n",
 		    daysleft, daysleft == 1 ? "" : "s")) != 0)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	}
 }

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

 	as = auth_usercheck(authctxt->pw->pw_name, authctxt->style, "auth-ssh",
 	    (char *)password);
 	if (as == NULL)
 		return (0);
 	if (auth_getstate(as) & AUTH_PWEXPIRED) {
 		auth_close(as);
 		auth_restrict_session(ssh);
 		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(struct ssh *ssh, const char *password)
 {
 	Authctxt *authctxt = ssh->authctxt;
 	struct passwd *pw = authctxt->pw;
 	char *encrypted_password, *salt = NULL;

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

 	if (pw_password == NULL)
 		return 0;

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

 	/*
 	 * Encrypt the candidate password using the proper salt, or pass a
 	 * NULL and let xcrypt pick one.
 	 */
 	if (authctxt->valid && pw_password[0] && pw_password[1])
 		salt = pw_password;
 	encrypted_password = xcrypt(password, salt);

 	/*
 	 * Authentication is accepted if the encrypted passwords
 	 * are identical.
 	 */
 	return encrypted_password != NULL &&
 	    strcmp(encrypted_password, pw_password) == 0;
 }
 #endif
	/* $OpenBSD: auth-passwd.c,v 1.47 2018/07/09 21:26:02 markus 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 <stdio.h>
	#include <string.h>
	#include <stdarg.h>

	#include "packet.h"
	#include "sshbuf.h"
	#include "ssherr.h"
	#include "log.h"
	#include "misc.h"
	#include "servconf.h"
	#include "sshkey.h"
	#include "hostfile.h"
	#include "auth.h"
	#include "auth-options.h"

	extern struct sshbuf *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 */

	#define MAX_PASSWORD_LEN 1024

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

	if (strlen(password) > MAX_PASSWORD_LEN)
	return 0;

	#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
	{
	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(ssh, password);
	if (authctxt->force_pwchange)
	auth_restrict_session(ssh);
	return (result && ok);
	}

	#ifdef BSD_AUTH
	static void
	warn_expiry(Authctxt authctxt, auth_session_t as)
	{
	int r;
	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;
	if ((r = sshbuf_putf(loginmsg,
	"Your password will expire in %lld day%s.\n",
	daysleft, daysleft == 1 ? "" : "s")) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	}
	if (actimeleft != 0 && actimeleft < acwarntime) {
	daysleft = actimeleft / DAY + 1;
	if ((r = sshbuf_putf(loginmsg,
	"Your account will expire in %lld day%s.\n",
	daysleft, daysleft == 1 ? "" : "s")) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	}
	}

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

	as = auth_usercheck(authctxt->pw->pw_name, authctxt->style, "auth-ssh",
	(char *)password);
	if (as == NULL)
	return (0);
	if (auth_getstate(as) & AUTH_PWEXPIRED) {
	auth_close(as);
	auth_restrict_session(ssh);
	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(struct ssh ssh, const char password)
	{
	Authctxt *authctxt = ssh->authctxt;
	struct passwd *pw = authctxt->pw;
	char encrypted_password, salt = NULL;

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

	if (pw_password == NULL)
	return 0;

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

	/*
	* Encrypt the candidate password using the proper salt, or pass a
	* NULL and let xcrypt pick one.
	*/
	if (authctxt->valid && pw_password[0] && pw_password[1])
	salt = pw_password;
	encrypted_password = xcrypt(password, salt);

	/*
	* Authentication is accepted if the encrypted passwords
	* are identical.
	*/
	return encrypted_password != NULL &&
	strcmp(encrypted_password, pw_password) == 0;
	}
	#endif