1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2003 Networks Associates Technology, Inc.
5 * All rights reserved.
6 *
7 * Portions of this software were developed for the FreeBSD Project by
8 * ThinkSec AS and NAI Labs, the Security Research Division of Network
9 * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
10 * ("CBOSS"), as part of the DARPA CHATS research program.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. The name of the author may not be used to endorse or promote
21 *    products derived from this software without specific prior written
22 *    permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD$");
39
40#include <string.h>
41
42#define PAM_SM_AUTH
43
44#include <security/pam_appl.h>
45#include <security/pam_modules.h>
46#include <security/openpam.h>
47
48#define DEFAULT_GUESTS	"guest"
49
50static int
51lookup(const char *str, const char *list)
52{
53	const char *next;
54	size_t len;
55
56	len = strlen(str);
57	while (*list != '\0') {
58		while (*list == ',')
59			++list;
60		if ((next = strchr(list, ',')) == NULL)
61			next = strchr(list, '\0');
62		if (next - list == (ptrdiff_t)len &&
63		    strncmp(list, str, len) == 0)
64			return (1);
65		list = next;
66	}
67	return (0);
68}
69
70PAM_EXTERN int
71pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
72    int argc __unused, const char *argv[] __unused)
73{
74	const char *authtok, *guests, *user;
75	int err, is_guest;
76
77	/* get target account */
78	if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || user == NULL)
79		return (PAM_AUTH_ERR);
80
81	/* get list of guest logins */
82	if ((guests = openpam_get_option(pamh, "guests")) == NULL)
83		guests = DEFAULT_GUESTS;
84
85	/* check if the target account is on the list */
86	is_guest = lookup(user, guests);
87
88	/* check password */
89	if (!openpam_get_option(pamh, "nopass")) {
90		err = pam_get_authtok(pamh, PAM_AUTHTOK, &authtok, NULL);
91		if (err != PAM_SUCCESS)
92			return (err);
93		if (openpam_get_option(pamh, "pass_is_user") &&
94		    strcmp(user, authtok) != 0)
95			return (PAM_AUTH_ERR);
96		if (openpam_get_option(pamh, "pass_as_ruser"))
97			pam_set_item(pamh, PAM_RUSER, authtok);
98	}
99
100	/* done */
101	if (is_guest) {
102		pam_setenv(pamh, "GUEST", user, 1);
103		return (PAM_SUCCESS);
104	}
105	return (PAM_AUTH_ERR);
106}
107
108PAM_EXTERN int
109pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
110    int argc __unused, const char *argv[] __unused)
111{
112
113	return (PAM_SUCCESS);
114}
115
116PAM_MODULE_ENTRY("pam_guest");
117