1 /*-
2  * Copyright (c) 2003 Networks Associates Technology, Inc.
3  * All rights reserved.
4  *
5  * Portions of this software were developed for the FreeBSD Project by
6  * ThinkSec AS and NAI Labs, the Security Research Division of Network
7  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
8  * ("CBOSS"), as part of the DARPA CHATS research program.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. The name of the author may not be used to endorse or promote
19  *    products derived from this software without specific prior written
20  *    permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * $FreeBSD: src/lib/libpam/modules/pam_guest/pam_guest.c,v 1.1 2003/05/31 16:52:58 des Exp $
35  */
36 
37 #include <string.h>
38 
39 #define PAM_SM_AUTH
40 
41 #include <security/pam_appl.h>
42 #include <security/pam_modules.h>
43 #include <security/openpam.h>
44 
45 #define DEFAULT_GUESTS	"guest"
46 
47 static int
48 lookup(const char *str, const char *list)
49 {
50 	const char *next;
51 	size_t len;
52 
53 	len = strlen(str);
54 	while (*list != '\0') {
55 		while (*list == ',')
56 			++list;
57 		if ((next = strchr(list, ',')) == NULL)
58 			next = strchr(list, '\0');
59 		if (next - list == (ptrdiff_t)len &&
60 		    strncmp(list, str, len) == 0)
61 			return (1);
62 		list = next;
63 	}
64 	return (0);
65 }
66 
67 PAM_EXTERN int
68 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
69 		    int argc __unused, const char *argv[] __unused)
70 {
71 	const char *authtok, *guests, *user;
72 	int err, is_guest;
73 
74 	/* get target account */
75 	if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || user == NULL)
76 		return (PAM_AUTH_ERR);
77 
78 	/* get list of guest logins */
79 	if ((guests = openpam_get_option(pamh, "guests")) == NULL)
80 		guests = DEFAULT_GUESTS;
81 
82 	/* check if the target account is on the list */
83 	is_guest = lookup(user, guests);
84 
85 	/* check password */
86 	if (!openpam_get_option(pamh, "nopass")) {
87 		err = pam_get_authtok(pamh, PAM_AUTHTOK, &authtok, NULL);
88 		if (err != PAM_SUCCESS)
89 			return (err);
90 		if (openpam_get_option(pamh, "pass_is_user") &&
91 		    strcmp(user, authtok) != 0)
92 			return (PAM_AUTH_ERR);
93 		if (openpam_get_option(pamh, "pass_as_ruser"))
94 			pam_set_item(pamh, PAM_RUSER, authtok);
95 	}
96 
97 	/* done */
98 	if (is_guest) {
99 		pam_setenv(pamh, "GUEST", user, 1);
100 		return (PAM_SUCCESS);
101 	}
102 	return (PAM_AUTH_ERR);
103 }
104 
105 PAM_EXTERN int
106 pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
107 	       int argc __unused, const char *argv[] __unused)
108 {
109 
110 	return (PAM_SUCCESS);
111 }
112 
113 PAM_MODULE_ENTRY("pam_guest");
114