1/*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 * Password authentication. This file contains the functions to check whether
6 * the password is valid for the user.
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 *
14 * Copyright (c) 1999 Dug Song. All rights reserved.
15 * Copyright (c) 2000 Markus Friedl. All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 */
37
38#include "includes.h"
39RCSID("$OpenBSD: auth-passwd.c,v 1.31 2004/01/30 09:48:57 markus Exp $");
40RCSID("$FreeBSD: head/crypto/openssh/auth-passwd.c 137019 2004-10-28 16:11:31Z des $");
41
42#include "packet.h"
43#include "log.h"
44#include "servconf.h"
45#include "auth.h"
46#include "auth-options.h"
47
48extern ServerOptions options;
49int sys_auth_passwd(Authctxt *, const char *);
50
51void
52disable_forwarding(void)
53{
54 no_port_forwarding_flag = 1;
55 no_agent_forwarding_flag = 1;
56 no_x11_forwarding_flag = 1;
57}
58
59/*
60 * Tries to authenticate the user using password. Returns true if
61 * authentication succeeds.
62 */
63int
64auth_password(Authctxt *authctxt, const char *password)
65{
66 struct passwd * pw = authctxt->pw;
67 int ok = authctxt->valid;
68#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
69 static int expire_checked = 0;
70#endif
71
72#ifndef HAVE_CYGWIN
73 if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
74 ok = 0;
75#endif
76 if (*password == '\0' && options.permit_empty_passwd == 0)
77 return 0;
78
79#ifdef KRB5
80 if (options.kerberos_authentication == 1) {
81 int ret = auth_krb5_password(authctxt, password);
82 if (ret == 1 || ret == 0)
83 return ret && ok;
84 /* Fall back to ordinary passwd authentication. */
85 }
86#endif
87#ifdef HAVE_CYGWIN
88 if (is_winnt) {
89 HANDLE hToken = cygwin_logon_user(pw, password);
90
91 if (hToken == INVALID_HANDLE_VALUE)
92 return 0;
93 cygwin_set_impersonation_token(hToken);
94 return ok;
95 }
96#endif
97#ifdef USE_PAM
98 if (options.use_pam)
99 return (sshpam_auth_passwd(authctxt, password) && ok);
100#endif
101#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
102 if (!expire_checked) {
103 expire_checked = 1;
104 if (auth_shadow_pwexpired(authctxt)) {
105 disable_forwarding();
106 authctxt->force_pwchange = 1;
107 }
108 }
109#endif
110
111 return (sys_auth_passwd(authctxt, password) && ok);
112}
113
114#ifdef BSD_AUTH
115int
116sys_auth_passwd(Authctxt *authctxt, const char *password)
117{
118 struct passwd *pw = authctxt->pw;
119 auth_session_t *as;
120
121 as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh",
122 (char *)password);
123 if (auth_getstate(as) & AUTH_PWEXPIRED) {
124 auth_close(as);
125 disable_forwarding();
126 authctxt->force_pwchange = 1;
127 return (1);
128 } else {
129 return (auth_close(as));
130 }
131}
132#elif !defined(CUSTOM_SYS_AUTH_PASSWD)
133int
134sys_auth_passwd(Authctxt *authctxt, const char *password)
135{
136 struct passwd *pw = authctxt->pw;
137 char *encrypted_password;
138
139 /* Just use the supplied fake password if authctxt is invalid */
140 char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd;
141
142 /* Check for users with no password. */
143 if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0)
144 return (1);
145
146 /* Encrypt the candidate password using the proper salt. */
147 encrypted_password = xcrypt(password,
148 (pw_password[0] && pw_password[1]) ? pw_password : "xx");
149
150 /*
151 * Authentication is accepted if the encrypted passwords
152 * are identical.
153 */
154 return (strcmp(encrypted_password, pw_password) == 0);
155}
156#endif