1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright 2000 James Bloom
5 * All rights reserved.
6 * Based upon code Copyright 1998 Juniper Networks, Inc.
7 * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
8 * All rights reserved.
9 *
10 * Portions of this software were developed for the FreeBSD Project by
11 * ThinkSec AS and NAI Labs, the Security Research Division of Network
12 * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
13 * ("CBOSS"), as part of the DARPA CHATS research program.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 *    notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 *    notice, this list of conditions and the following disclaimer in the
22 *    documentation and/or other materials provided with the distribution.
23 * 3. The name of the author may not be used to endorse or promote
24 *    products derived from this software without specific prior written
25 *    permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 */
39
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD$");
42
43#include <sys/types.h>
44#include <opie.h>
45#include <pwd.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include <string.h>
49#include <unistd.h>
50
51#define PAM_SM_AUTH
52
53#include <security/pam_appl.h>
54#include <security/pam_modules.h>
55#include <security/pam_mod_misc.h>
56
57#define PAM_OPT_NO_FAKE_PROMPTS	"no_fake_prompts"
58
59PAM_EXTERN int
60pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
61    int argc __unused, const char *argv[] __unused)
62{
63	struct opie opie;
64	struct passwd *pwd;
65	int retval, i;
66	const char *(promptstr[]) = { "%s\nPassword: ", "%s\nPassword [echo on]: "};
67	char challenge[OPIE_CHALLENGE_MAX + 1];
68	char principal[OPIE_PRINCIPAL_MAX];
69	const char *user;
70	char *response;
71	int style;
72
73	user = NULL;
74	if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) {
75		if ((pwd = getpwnam(getlogin())) == NULL)
76			return (PAM_AUTH_ERR);
77		user = pwd->pw_name;
78	}
79	else {
80		retval = pam_get_user(pamh, &user, NULL);
81		if (retval != PAM_SUCCESS)
82			return (retval);
83	}
84
85	PAM_LOG("Got user: %s", user);
86
87	/*
88	 * Watch out: libopie feels entitled to truncate the user name
89	 * passed to it if it's longer than OPIE_PRINCIPAL_MAX, which is
90	 * not uncommon in Windows environments.
91	 */
92	if (strlen(user) >= sizeof(principal))
93		return (PAM_AUTH_ERR);
94	strlcpy(principal, user, sizeof(principal));
95
96	/*
97	 * Don't call the OPIE atexit() handler when our program exits,
98	 * since the module has been unloaded and we will SEGV.
99	 */
100	opiedisableaeh();
101
102	/*
103	 * If the no_fake_prompts option was given, and the user
104	 * doesn't have an OPIE key, just fail rather than present the
105	 * user with a bogus OPIE challenge.
106	 */
107	if (opiechallenge(&opie, principal, challenge) != 0 &&
108	    openpam_get_option(pamh, PAM_OPT_NO_FAKE_PROMPTS))
109		return (PAM_AUTH_ERR);
110
111	/*
112	 * It doesn't make sense to use a password that has already been
113	 * typed in, since we haven't presented the challenge to the user
114	 * yet, so clear the stored password.
115	 */
116	pam_set_item(pamh, PAM_AUTHTOK, NULL);
117
118	style = PAM_PROMPT_ECHO_OFF;
119	for (i = 0; i < 2; i++) {
120		retval = pam_prompt(pamh, style, &response,
121		    promptstr[i], challenge);
122		if (retval != PAM_SUCCESS) {
123			opieunlock();
124			return (retval);
125		}
126
127		PAM_LOG("Completed challenge %d: %s", i, response);
128
129		if (response[0] != '\0')
130			break;
131
132		/* Second time round, echo the password */
133		style = PAM_PROMPT_ECHO_ON;
134	}
135
136	pam_set_item(pamh, PAM_AUTHTOK, response);
137
138	/*
139	 * Opieverify is supposed to return -1 only if an error occurs.
140	 * But it returns -1 even if the response string isn't in the form
141	 * it expects.  Thus we can't log an error and can only check for
142	 * success or lack thereof.
143	 */
144	retval = opieverify(&opie, response);
145	free(response);
146	return (retval == 0 ? PAM_SUCCESS : PAM_AUTH_ERR);
147}
148
149PAM_EXTERN int
150pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
151    int argc __unused, const char *argv[] __unused)
152{
153
154	return (PAM_SUCCESS);
155}
156
157PAM_MODULE_ENTRY("pam_opie");
158