1/* $OpenBSD: auth-chall.c,v 1.13 2013/05/17 00:13:13 djm Exp $ */
2/*
3 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "includes.h"
27
28#include <sys/types.h>
29
30#include <stdarg.h>
31
32#include "xmalloc.h"
33#include "key.h"
34#include "hostfile.h"
35#include "auth.h"
36#include "log.h"
37#include "servconf.h"
38
39/* limited protocol v1 interface to kbd-interactive authentication */
40
41extern KbdintDevice *devices[];
42static KbdintDevice *device;
43extern ServerOptions options;
44
45char *
46get_challenge(Authctxt *authctxt)
47{
48	char *challenge, *name, *info, **prompts;
49	u_int i, numprompts;
50	u_int *echo_on;
51
52#ifdef USE_PAM
53	if (!options.use_pam)
54		remove_kbdint_device("pam");
55#endif
56
57	device = devices[0]; /* we always use the 1st device for protocol 1 */
58	if (device == NULL)
59		return NULL;
60	if ((authctxt->kbdintctxt = device->init_ctx(authctxt)) == NULL)
61		return NULL;
62	if (device->query(authctxt->kbdintctxt, &name, &info,
63	    &numprompts, &prompts, &echo_on)) {
64		device->free_ctx(authctxt->kbdintctxt);
65		authctxt->kbdintctxt = NULL;
66		return NULL;
67	}
68	if (numprompts < 1)
69		fatal("get_challenge: numprompts < 1");
70	challenge = xstrdup(prompts[0]);
71	for (i = 0; i < numprompts; i++)
72		free(prompts[i]);
73	free(prompts);
74	free(name);
75	free(echo_on);
76	free(info);
77
78	return (challenge);
79}
80int
81verify_response(Authctxt *authctxt, const char *response)
82{
83	char *resp[1], *name, *info, **prompts;
84	u_int i, numprompts, *echo_on;
85	int authenticated = 0;
86
87	if (device == NULL)
88		return 0;
89	if (authctxt->kbdintctxt == NULL)
90		return 0;
91	resp[0] = (char *)response;
92	switch (device->respond(authctxt->kbdintctxt, 1, resp)) {
93	case 0: /* Success */
94		authenticated = 1;
95		break;
96	case 1: /* Postponed - retry with empty query for PAM */
97		if ((device->query(authctxt->kbdintctxt, &name, &info,
98		    &numprompts, &prompts, &echo_on)) != 0)
99			break;
100		if (numprompts == 0 &&
101		    device->respond(authctxt->kbdintctxt, 0, resp) == 0)
102			authenticated = 1;
103
104		for (i = 0; i < numprompts; i++)
105			free(prompts[i]);
106		free(prompts);
107		free(name);
108		free(echo_on);
109		free(info);
110		break;
111	}
112	device->free_ctx(authctxt->kbdintctxt);
113	authctxt->kbdintctxt = NULL;
114	return authenticated;
115}
116void
117abandon_challenge_response(Authctxt *authctxt)
118{
119	if (authctxt->kbdintctxt != NULL) {
120		device->free_ctx(authctxt->kbdintctxt);
121		authctxt->kbdintctxt = NULL;
122	}
123}
124