1 /* $OpenBSD: auth-passwd.c,v 1.46 2018/03/03 03:15:51 djm Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * Password authentication. This file contains the functions to check whether
7 * the password is valid for the user.
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".
15 * Copyright (c) 1999 Dug Song. All rights reserved.
16 * Copyright (c) 2000 Markus Friedl. All rights reserved.
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
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.
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.
41 #include <sys/types.h>
56 #include "auth-options.h"
58 extern Buffer loginmsg;
59 extern ServerOptions options;
62 extern login_cap_t *lc;
66 #define DAY (24L * 60 * 60) /* 1 day in seconds */
67 #define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */
69 #define MAX_PASSWORD_LEN 1024
72 * Tries to authenticate the user using password. Returns true if
73 * authentication succeeds.
76 auth_password(struct ssh *ssh, const char *password)
78 Authctxt *authctxt = ssh->authctxt;
79 struct passwd *pw = authctxt->pw;
80 int result, ok = authctxt->valid;
81 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
82 static int expire_checked = 0;
85 if (strlen(password) > MAX_PASSWORD_LEN)
89 if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
92 if (*password == '\0' && options.permit_empty_passwd == 0)
96 if (options.kerberos_authentication == 1) {
97 int ret = auth_krb5_password(authctxt, password);
98 if (ret == 1 || ret == 0)
100 /* Fall back to ordinary passwd authentication. */
105 HANDLE hToken = cygwin_logon_user(pw, password);
107 if (hToken == INVALID_HANDLE_VALUE)
109 cygwin_set_impersonation_token(hToken);
115 return (sshpam_auth_passwd(authctxt, password) && ok);
117 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
118 if (!expire_checked) {
120 if (auth_shadow_pwexpired(authctxt))
121 authctxt->force_pwchange = 1;
124 result = sys_auth_passwd(ssh, password);
125 if (authctxt->force_pwchange)
126 auth_restrict_session(ssh);
127 return (result && ok);
132 warn_expiry(Authctxt *authctxt, auth_session_t *as)
135 quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime;
137 pwwarntime = acwarntime = TWO_WEEKS;
139 pwtimeleft = auth_check_change(as);
140 actimeleft = auth_check_expire(as);
141 #ifdef HAVE_LOGIN_CAP
142 if (authctxt->valid) {
143 pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS,
145 acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS,
149 if (pwtimeleft != 0 && pwtimeleft < pwwarntime) {
150 daysleft = pwtimeleft / DAY + 1;
151 snprintf(buf, sizeof(buf),
152 "Your password will expire in %lld day%s.\n",
153 daysleft, daysleft == 1 ? "" : "s");
154 buffer_append(&loginmsg, buf, strlen(buf));
156 if (actimeleft != 0 && actimeleft < acwarntime) {
157 daysleft = actimeleft / DAY + 1;
158 snprintf(buf, sizeof(buf),
159 "Your account will expire in %lld day%s.\n",
160 daysleft, daysleft == 1 ? "" : "s");
161 buffer_append(&loginmsg, buf, strlen(buf));
166 sys_auth_passwd(struct ssh *ssh, const char *password)
168 Authctxt *authctxt = ssh->authctxt;
170 static int expire_checked = 0;
172 as = auth_usercheck(authctxt->pw->pw_name, authctxt->style, "auth-ssh",
176 if (auth_getstate(as) & AUTH_PWEXPIRED) {
178 auth_restrict_session(ssh);
179 authctxt->force_pwchange = 1;
182 if (!expire_checked) {
184 warn_expiry(authctxt, as);
186 return (auth_close(as));
189 #elif !defined(CUSTOM_SYS_AUTH_PASSWD)
191 sys_auth_passwd(struct ssh *ssh, const char *password)
193 Authctxt *authctxt = ssh->authctxt;
194 struct passwd *pw = authctxt->pw;
195 char *encrypted_password, *salt = NULL;
197 /* Just use the supplied fake password if authctxt is invalid */
198 char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd;
200 /* Check for users with no password. */
201 if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0)
205 * Encrypt the candidate password using the proper salt, or pass a
206 * NULL and let xcrypt pick one.
208 if (authctxt->valid && pw_password[0] && pw_password[1])
210 encrypted_password = xcrypt(password, salt);
213 * Authentication is accepted if the encrypted passwords
216 return encrypted_password != NULL &&
217 strcmp(encrypted_password, pw_password) == 0;