xref: /illumos-gate/usr/src/lib/pam_modules/sample/sample_authenticate.c (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright 2023 OmniOS Community Edition (OmniOSce) Association.
27  */
28 
29 #include <security/pam_appl.h>
30 #include <security/pam_modules.h>
31 #include <string.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <sys/types.h>
35 #include <pwd.h>
36 #include <syslog.h>
37 #include <libintl.h>
38 
39 #include "sample_utils.h"
40 
41 /*
42  *
43  * Sample module for pam_sm_authenticate.
44  *
45  * options -
46  *
47  *	debug
48  *	use_first_pass
49  *	try_first_pass
50  *	first_pass_good  (first password is always good when used with use/try)
51  *	first_pass_bad   (first password is always bad when used with use/try)
52  *	pass=foobar	 (set good password to "foobar". default good password
53  *			 is test)
54  *	always_fail	 always return PAM_AUTH_ERR
55  *	always_succeed   always return PAM_SUCCESS
56  *	always_ignore
57  *
58  *
59  */
60 
61 /*
62  * pam_sm_authenticate		- Authenticate user
63  */
64 int
65 pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
66 {
67 	const char *user;
68 	const struct pam_conv *pam_convp;
69 	int err, result = PAM_AUTH_ERR;
70 	struct pam_response *ret_resp = (struct pam_response *)0;
71 	char messages[PAM_MAX_NUM_MSG][PAM_MAX_MSG_SIZE];
72 	int debug = 0;
73 	int try_first_pass = 0;
74 	int use_first_pass = 0;
75 	int first_pass_good = 0;
76 	int first_pass_bad = 0;
77 	int i, num_msg;
78 	const char *firstpass;
79 	char *password;
80 	char the_password[64];
81 
82 	if (debug)
83 		syslog(LOG_DEBUG, "Sample Authentication\n");
84 
85 	(void) strcpy(the_password, "test");
86 
87 	for (i = 0; i < argc; i++) {
88 		if (strcmp(argv[i], "debug") == 0)
89 			debug = 1;
90 		else if (strcmp(argv[i], "try_first_pass") == 0)
91 			try_first_pass = 1;
92 		else if (strcmp(argv[i], "first_pass_good") == 0)
93 			first_pass_good = 1;
94 		else if (strcmp(argv[i], "first_pass_bad") == 0)
95 			first_pass_bad = 1;
96 		else if (strcmp(argv[i], "use_first_pass") == 0)
97 			use_first_pass = 1;
98 		else if (strcmp(argv[i], "always_fail") == 0)
99 			return (PAM_AUTH_ERR);
100 		else if (strcmp(argv[i], "always_succeed") == 0)
101 			return (PAM_SUCCESS);
102 		else if (strcmp(argv[i], "always_ignore") == 0)
103 			return (PAM_IGNORE);
104 		else if (sscanf(argv[i], "pass=%64s", the_password) == 1) {
105 			/*EMPTY*/;
106 		}
107 		else
108 			syslog(LOG_DEBUG, "illegal scheme option %s", argv[i]);
109 	}
110 
111 	err = pam_get_user(pamh, &user, NULL);
112 	if (err != PAM_SUCCESS)
113 		return (err);
114 
115 	err = pam_get_item(pamh, PAM_CONV, (const void**)&pam_convp);
116 	if (err != PAM_SUCCESS)
117 		return (err);
118 
119 	(void) pam_get_item(pamh, PAM_AUTHTOK, (const void **)&firstpass);
120 
121 	if (firstpass && (use_first_pass || try_first_pass)) {
122 
123 		if ((first_pass_good ||
124 			strncmp(firstpass, the_password,
125 				strlen(the_password)) == 0) &&
126 				!first_pass_bad) {
127 					result = PAM_SUCCESS;
128 					goto out;
129 		}
130 		if (use_first_pass) goto out;
131 	}
132 
133 	/*
134 	 * Get the password from the user
135 	 */
136 	if (firstpass) {
137 		(void) snprintf(messages[0], sizeof (messages[0]),
138 			dgettext(TEXT_DOMAIN, "TEST Password: "));
139 	} else {
140 		(void) snprintf(messages[0], sizeof (messages[0]),
141 			dgettext(TEXT_DOMAIN, "Password: "));
142 	}
143 	num_msg = 1;
144 	err = __get_authtok(pam_convp->conv,
145 				num_msg, messages, NULL, &ret_resp);
146 
147 	if (err != PAM_SUCCESS) {
148 		result = err;
149 		goto out;
150 	}
151 
152 	password = ret_resp->resp;
153 
154 	if (password == NULL) {
155 		result = PAM_AUTH_ERR;
156 		goto out;
157 	}
158 
159 	/* one last ditch attempt to "login" to TEST */
160 
161 	if (strncmp(password, the_password, strlen(the_password)) == 0) {
162 		result = PAM_SUCCESS;
163 		if (firstpass == NULL) {
164 			/* this is the first password, stash it away */
165 			(void) pam_set_item(pamh, PAM_AUTHTOK, password);
166 		}
167 	}
168 
169 out:
170 	if (num_msg > 0) {
171 		if (ret_resp != 0) {
172 			if (ret_resp->resp != 0) {
173 				/* avoid leaving password cleartext around */
174 				(void) memset(ret_resp->resp, 0,
175 					strlen(ret_resp->resp));
176 			}
177 			__free_resp(num_msg, ret_resp);
178 			ret_resp = 0;
179 		}
180 	}
181 
182 	return (result);
183 }
184