1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/* $OpenBSD: auth-passwd.c,v 1.43 2007/09/21 08:15:29 djm 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 "buffer.h"
#include "log.h"
#include "servconf.h"
#include "key.h"
#include "hostfile.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
{
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
|
