xref: /freebsd/lib/libpam/modules/pam_group/pam_group.c (revision 3a92d97ff0f22d21608e1c19b83104c4937523b6)
1 /*-
2  * Copyright (c) 2003 Networks Associates Technology, Inc.
3  * Copyright (c) 2004-2011 Dag-Erling Smørgrav
4  * All rights reserved.
5  *
6  * Portions of this software were developed for the FreeBSD Project by
7  * ThinkSec AS and NAI Labs, the Security Research Division of Network
8  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
9  * ("CBOSS"), as part of the DARPA CHATS research program.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote
20  *    products derived from this software without specific prior written
21  *    permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include <sys/types.h>
40 
41 #include <grp.h>
42 #include <pwd.h>
43 #include <stdarg.h>
44 #include <stdio.h>
45 #include <string.h>
46 #include <syslog.h>
47 #include <unistd.h>
48 
49 #define PAM_SM_AUTH
50 
51 #include <security/pam_appl.h>
52 #include <security/pam_modules.h>
53 #include <security/openpam.h>
54 
55 
56 PAM_EXTERN int
57 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
58     int argc __unused, const char *argv[] __unused)
59 {
60 	int local, remote;
61 	const char *group, *user;
62 	const void *ruser;
63 	char *const *list;
64 	struct passwd *pwd;
65 	struct group *grp;
66 
67 	/* get target account */
68 	if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS ||
69 	    user == NULL || (pwd = getpwnam(user)) == NULL)
70 		return (PAM_AUTH_ERR);
71 	if (pwd->pw_uid != 0 && openpam_get_option(pamh, "root_only"))
72 		return (PAM_IGNORE);
73 
74 	/* check local / remote */
75 	local = openpam_get_option(pamh, "luser") ? 1 : 0;
76 	remote = openpam_get_option(pamh, "ruser") ? 1 : 0;
77 	if (local && remote) {
78 		openpam_log(PAM_LOG_ERROR, "(pam_group) "
79 		    "the luser and ruser options are mutually exclusive");
80 		return (PAM_SERVICE_ERR);
81 	} else if (local) {
82 		/* we already have the correct struct passwd */
83 	} else {
84 		if (!remote)
85 			openpam_log(PAM_LOG_NOTICE, "(pam_group) "
86 			    "neither luser nor ruser specified, assuming ruser");
87 		/* default / historical behavior */
88 		if (pam_get_item(pamh, PAM_RUSER, &ruser) != PAM_SUCCESS ||
89 		    ruser == NULL || (pwd = getpwnam(ruser)) == NULL)
90 			return (PAM_AUTH_ERR);
91 	}
92 
93 	/* get regulating group */
94 	if ((group = openpam_get_option(pamh, "group")) == NULL)
95 		group = "wheel";
96 	if ((grp = getgrnam(group)) == NULL || grp->gr_mem == NULL)
97 		goto failed;
98 
99 	/* check if the group is empty */
100 	if (*grp->gr_mem == NULL)
101 		goto failed;
102 
103 	/* check membership */
104 	if (pwd->pw_gid == grp->gr_gid)
105 		goto found;
106 	for (list = grp->gr_mem; *list != NULL; ++list)
107 		if (strcmp(*list, pwd->pw_name) == 0)
108 			goto found;
109 
110  not_found:
111 	if (openpam_get_option(pamh, "deny"))
112 		return (PAM_SUCCESS);
113 	return (PAM_AUTH_ERR);
114  found:
115 	if (openpam_get_option(pamh, "deny"))
116 		return (PAM_AUTH_ERR);
117 	return (PAM_SUCCESS);
118  failed:
119 	if (openpam_get_option(pamh, "fail_safe"))
120 		goto found;
121 	else
122 		goto not_found;
123 }
124 
125 PAM_EXTERN int
126 pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
127     int argc __unused, const char *argv[] __unused)
128 {
129 
130 	return (PAM_SUCCESS);
131 }
132 
133 PAM_MODULE_ENTRY("pam_group");
134