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
215
216
217
218
219
220
221
222
223
224
|
/*
* 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"
RCSID("$OpenBSD: auth.c,v 1.21 2001/03/19 17:07:23 markus Exp $");
#ifdef HAVE_LOGIN_H
#include <login.h>
#endif
#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
#include <shadow.h>
#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */
#include "xmalloc.h"
#include "match.h"
#include "groupaccess.h"
#include "log.h"
#include "servconf.h"
#include "auth.h"
#include "auth-options.h"
#include "canohost.h"
/* import */
extern ServerOptions options;
/*
* Check if the user is allowed to log in via ssh. If user is listed
* in DenyUsers or one of user's groups is listed in DenyGroups, false
* will be returned. If AllowUsers isn't empty and user isn't listed
* there, or if AllowGroups isn't empty and one of user's groups isn't
* listed there, false will be returned.
* If the user's shell is not executable, false will be returned.
* Otherwise true is returned.
*/
int
allowed_user(struct passwd * pw)
{
struct stat st;
char *shell;
int i;
#ifdef WITH_AIXAUTHENTICATE
char *loginmsg;
#endif /* WITH_AIXAUTHENTICATE */
#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
struct spwd *spw;
/* Shouldn't be called if pw is NULL, but better safe than sorry... */
if (!pw || !pw->pw_name)
return 0;
spw = getspnam(pw->pw_name);
if (spw != NULL) {
int days = time(NULL) / 86400;
/* Check account expiry */
if ((spw->sp_expire >= 0) && (days > spw->sp_expire))
return 0;
/* Check password expiry */
if ((spw->sp_lstchg >= 0) && (spw->sp_max >= 0) &&
(days > (spw->sp_lstchg + spw->sp_max)))
return 0;
}
#else
/* Shouldn't be called if pw is NULL, but better safe than sorry... */
if (!pw || !pw->pw_name)
return 0;
#endif
/*
* Get the shell from the password data. An empty shell field is
* legal, and means /bin/sh.
*/
shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
/* deny if shell does not exists or is not executable */
if (stat(shell, &st) != 0)
return 0;
if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP))))
return 0;
/* Return false if user is listed in DenyUsers */
if (options.num_deny_users > 0) {
for (i = 0; i < options.num_deny_users; i++)
if (match_pattern(pw->pw_name, options.deny_users[i]))
return 0;
}
/* Return false if AllowUsers isn't empty and user isn't listed there */
if (options.num_allow_users > 0) {
for (i = 0; i < options.num_allow_users; i++)
if (match_pattern(pw->pw_name, options.allow_users[i]))
break;
/* i < options.num_allow_users iff we break for loop */
if (i >= options.num_allow_users)
return 0;
}
if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
/* Get the user's group access list (primary and supplementary) */
if (ga_init(pw->pw_name, pw->pw_gid) == 0)
return 0;
/* Return false if one of user's groups is listed in DenyGroups */
if (options.num_deny_groups > 0)
if (ga_match(options.deny_groups,
options.num_deny_groups)) {
ga_free();
return 0;
}
/*
* Return false if AllowGroups isn't empty and one of user's groups
* isn't listed there
*/
if (options.num_allow_groups > 0)
if (!ga_match(options.allow_groups,
options.num_allow_groups)) {
ga_free();
return 0;
}
ga_free();
}
#ifdef WITH_AIXAUTHENTICATE
if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
if (loginmsg && *loginmsg) {
/* Remove embedded newlines (if any) */
char *p;
for (p = loginmsg; *p; p++) {
if (*p == '\n')
*p = ' ';
}
/* Remove trailing newline */
*--p = '\0';
log("Login restricted for %s: %.100s", pw->pw_name, loginmsg);
}
return 0;
}
#endif /* WITH_AIXAUTHENTICATE */
/* We found no reason not to let this user try to log on... */
return 1;
}
Authctxt *
authctxt_new(void)
{
Authctxt *authctxt = xmalloc(sizeof(*authctxt));
memset(authctxt, 0, sizeof(*authctxt));
return authctxt;
}
void
auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
{
void (*authlog) (const char *fmt,...) = verbose;
char *authmsg;
/* Raise logging level */
if (authenticated == 1 ||
!authctxt->valid ||
authctxt->failures >= AUTH_FAIL_LOG ||
strcmp(method, "password") == 0)
authlog = log;
if (authctxt->postponed)
authmsg = "Postponed";
else
authmsg = authenticated ? "Accepted" : "Failed";
authlog("%s %s for %s%.100s from %.200s port %d%s",
authmsg,
method,
authctxt->valid ? "" : "illegal user ",
authctxt->valid && authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user,
get_remote_ipaddr(),
get_remote_port(),
info);
}
/*
* Check whether root logins are disallowed.
*/
int
auth_root_allowed(char *method)
{
switch (options.permit_root_login) {
case PERMIT_YES:
return 1;
break;
case PERMIT_NO_PASSWD:
if (strcmp(method, "password") != 0)
return 1;
break;
case PERMIT_FORCED_ONLY:
if (forced_command) {
log("Root login accepted for forced command.");
return 1;
}
break;
}
log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
return 0;
}
|
