xref: /freebsd/lib/libpam/modules/pam_group/pam_group.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2003 Networks Associates Technology, Inc.
5  * Copyright (c) 2004-2011 Dag-Erling Smørgrav
6  * All rights reserved.
7  *
8  * Portions of this software were developed for the FreeBSD Project by
9  * ThinkSec AS and NAI Labs, the Security Research Division of Network
10  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
11  * ("CBOSS"), as part of the DARPA CHATS research program.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. The name of the author may not be used to endorse or promote
22  *    products derived from this software without specific prior written
23  *    permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <sys/types.h>
42 
43 #include <grp.h>
44 #include <pwd.h>
45 #include <stdarg.h>
46 #include <stdio.h>
47 #include <string.h>
48 #include <syslog.h>
49 #include <unistd.h>
50 
51 #define PAM_SM_AUTH
52 #define PAM_SM_ACCOUNT
53 
54 #include <security/pam_appl.h>
55 #include <security/pam_modules.h>
56 #include <security/openpam.h>
57 
58 static int
59 pam_group(pam_handle_t *pamh)
60 {
61 	int local, remote;
62 	const char *group, *user;
63 	const void *ruser;
64 	char *const *list;
65 	struct passwd *pwd;
66 	struct group *grp;
67 
68 	/* get target account */
69 	if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS ||
70 	    user == NULL || (pwd = getpwnam(user)) == NULL)
71 		return (PAM_AUTH_ERR);
72 	if (pwd->pw_uid != 0 && openpam_get_option(pamh, "root_only"))
73 		return (PAM_IGNORE);
74 
75 	/* check local / remote */
76 	local = openpam_get_option(pamh, "luser") ? 1 : 0;
77 	remote = openpam_get_option(pamh, "ruser") ? 1 : 0;
78 	if (local && remote) {
79 		openpam_log(PAM_LOG_ERROR, "(pam_group) "
80 		    "the luser and ruser options are mutually exclusive");
81 		return (PAM_SERVICE_ERR);
82 	} else if (local) {
83 		/* we already have the correct struct passwd */
84 	} else {
85 		if (!remote)
86 			openpam_log(PAM_LOG_NOTICE, "(pam_group) "
87 			    "neither luser nor ruser specified, assuming ruser");
88 		/* default / historical behavior */
89 		if (pam_get_item(pamh, PAM_RUSER, &ruser) != PAM_SUCCESS ||
90 		    ruser == NULL || (pwd = getpwnam(ruser)) == NULL)
91 			return (PAM_AUTH_ERR);
92 	}
93 
94 	/* get regulating group */
95 	if ((group = openpam_get_option(pamh, "group")) == NULL)
96 		group = "wheel";
97 	if ((grp = getgrnam(group)) == NULL || grp->gr_mem == NULL)
98 		goto failed;
99 
100 	/* check if user's own primary group */
101 	if (pwd->pw_gid == grp->gr_gid)
102 		goto found;
103 
104 	/* iterate over members */
105 	for (list = grp->gr_mem; list != NULL && *list != NULL; ++list)
106 		if (strcmp(*list, pwd->pw_name) == 0)
107 			goto found;
108 
109  not_found:
110 	if (openpam_get_option(pamh, "deny"))
111 		return (PAM_SUCCESS);
112 	return (PAM_AUTH_ERR);
113  found:
114 	if (openpam_get_option(pamh, "deny"))
115 		return (PAM_AUTH_ERR);
116 	return (PAM_SUCCESS);
117  failed:
118 	if (openpam_get_option(pamh, "fail_safe"))
119 		goto found;
120 	else
121 		goto not_found;
122 }
123 
124 PAM_EXTERN int
125 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
126     int argc __unused, const char *argv[] __unused)
127 {
128 
129 	return (pam_group(pamh));
130 }
131 
132 PAM_EXTERN int
133 pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
134     int argc __unused, const char *argv[] __unused)
135 {
136 
137 	return (PAM_SUCCESS);
138 }
139 
140 PAM_EXTERN int
141 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused,
142     int argc __unused, const char *argv[] __unused)
143 {
144 
145 	return (pam_group(pamh));
146 }
147 
148 PAM_MODULE_ENTRY("pam_group");
149