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
|
/*
* pam_localuser module
*
* Copyright 2001, 2004 Red Hat, Inc.
* Copyright (c) 2020 Dmitry V. Levin <ldv@altlinux.org>
*
* 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, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 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.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* the GNU Public License, in which case the provisions of the GPL are
* required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the GPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``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 "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <security/pam_modules.h>
#include <security/pam_ext.h>
#include "pam_inline.h"
static int
check_user_in_passwd(pam_handle_t *pamh, const char *user_name,
const char *file_name)
{
int rc;
size_t user_len;
FILE *fp;
char line[BUFSIZ];
/* Validate the user name. */
if ((user_len = strlen(user_name)) == 0) {
pam_syslog(pamh, LOG_NOTICE, "user name is not valid");
return PAM_SERVICE_ERR;
}
if (user_len > sizeof(line) - sizeof(":")) {
pam_syslog(pamh, LOG_NOTICE, "user name is too long");
return PAM_SERVICE_ERR;
}
if (strchr(user_name, ':') != NULL) {
/*
* "root:x" is not a local user name even if the passwd file
* contains a line starting with "root:x:".
*/
return PAM_PERM_DENIED;
}
/* Open the passwd file. */
if (file_name == NULL) {
file_name = "/etc/passwd";
}
if ((fp = fopen(file_name, "r")) == NULL) {
pam_syslog(pamh, LOG_ERR, "error opening %s: %m", file_name);
return PAM_SERVICE_ERR;
}
/*
* Scan the file using fgets() instead of fgetpwent_r() because
* the latter is not flexible enough in handling long lines
* in passwd files.
*/
rc = PAM_PERM_DENIED;
while (fgets(line, sizeof(line), fp) != NULL) {
size_t line_len;
const char *str;
/*
* Does this line start with the user name
* followed by a colon?
*/
if (strncmp(user_name, line, user_len) == 0 &&
line[user_len] == ':') {
rc = PAM_SUCCESS;
break;
}
/* Has a newline been read? */
line_len = strlen(line);
if (line_len < sizeof(line) - 1 ||
line[line_len - 1] == '\n') {
/* Yes, continue with the next line. */
continue;
}
/* No, read till the end of this line first. */
while ((str = fgets(line, sizeof(line), fp)) != NULL) {
line_len = strlen(line);
if (line_len == 0 ||
line[line_len - 1] == '\n') {
break;
}
}
if (str == NULL) {
/* fgets returned NULL, we are done. */
break;
}
/* Continue with the next line. */
}
fclose(fp);
return rc;
}
int
pam_sm_authenticate(pam_handle_t *pamh, int flags UNUSED,
int argc, const char **argv)
{
int i;
int rc;
int debug = 0;
const char *file_name = NULL;
const char *user_name = NULL;
/* Process arguments. */
for (i = 0; i < argc; ++i) {
if (strcmp("debug", argv[i]) == 0) {
debug = 1;
}
}
for (i = 0; i < argc; ++i) {
const char *str;
if (strcmp("debug", argv[i]) == 0) {
/* Already processed. */
continue;
}
if ((str = pam_str_skip_prefix(argv[i], "file=")) != NULL) {
file_name = str;
if (debug) {
pam_syslog(pamh, LOG_DEBUG,
"set filename to %s", file_name);
}
} else {
pam_syslog(pamh, LOG_ERR, "unrecognized option: %s",
argv[i]);
}
}
/* Obtain the user name. */
if ((rc = pam_get_user(pamh, &user_name, NULL)) != PAM_SUCCESS) {
pam_syslog(pamh, LOG_NOTICE, "cannot determine user name: %s",
pam_strerror(pamh, rc));
return rc == PAM_CONV_AGAIN ? PAM_INCOMPLETE : rc;
}
return check_user_in_passwd(pamh, user_name, file_name);
}
int
pam_sm_setcred(pam_handle_t *pamh UNUSED, int flags UNUSED,
int argc UNUSED, const char **argv UNUSED)
{
return PAM_SUCCESS;
}
int
pam_sm_acct_mgmt(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
return pam_sm_authenticate(pamh, flags, argc, argv);
}
int
pam_sm_open_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
return pam_sm_authenticate(pamh, flags, argc, argv);
}
int
pam_sm_close_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
return pam_sm_authenticate(pamh, flags, argc, argv);
}
int
pam_sm_chauthtok(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
return pam_sm_authenticate(pamh, flags, argc, argv);
}
|
