auth-chall.c revision 149753 
1/*
2 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
26RCSID("$OpenBSD: auth-chall.c,v 1.9 2003/11/03 09:03:37 djm Exp $");
27RCSID("$FreeBSD: head/crypto/openssh/auth-chall.c 147005 2005-06-05 15:46:09Z des $");
28
29#include "auth.h"
30#include "log.h"
31#include "xmalloc.h"
32#include "servconf.h"
33
34/* limited protocol v1 interface to kbd-interactive authentication */
35
36extern KbdintDevice *devices[];
37static KbdintDevice *device;
38extern ServerOptions options;
39
40char *
41get_challenge(Authctxt *authctxt)
42{
43	char *challenge, *name, *info, **prompts;
44	u_int i, numprompts;
45	u_int *echo_on;
46
47#ifdef USE_PAM
48	if (!options.use_pam)
49		remove_kbdint_device("pam");
50#endif
51
52	device = devices[0]; /* we always use the 1st device for protocol 1 */
53	if (device == NULL)
54		return NULL;
55	if ((authctxt->kbdintctxt = device->init_ctx(authctxt)) == NULL)
56		return NULL;
57	if (device->query(authctxt->kbdintctxt, &name, &info,
58	    &numprompts, &prompts, &echo_on)) {
59		device->free_ctx(authctxt->kbdintctxt);
60		authctxt->kbdintctxt = NULL;
61		return NULL;
62	}
63	if (numprompts < 1)
64		fatal("get_challenge: numprompts < 1");
65	challenge = xstrdup(prompts[0]);
66	for (i = 0; i < numprompts; i++)
67		xfree(prompts[i]);
68	xfree(prompts);
69	xfree(name);
70	xfree(echo_on);
71	xfree(info);
72
73	return (challenge);
74}
75int
76verify_response(Authctxt *authctxt, const char *response)
77{
78	char *resp[1], *name, *info, **prompts;
79	u_int i, numprompts, *echo_on;
80	int authenticated = 0;
81
82	if (device == NULL)
83		return 0;
84	if (authctxt->kbdintctxt == NULL)
85		return 0;
86	resp[0] = (char *)response;
87	switch (device->respond(authctxt->kbdintctxt, 1, resp)) {
88	case 0: /* Success */
89		authenticated = 1;
90		break;
91	case 1: /* Postponed - retry with empty query for PAM */
92		if ((device->query(authctxt->kbdintctxt, &name, &info,
93		    &numprompts, &prompts, &echo_on)) != 0)
94			break;
95		if (numprompts == 0 &&
96		    device->respond(authctxt->kbdintctxt, 0, resp) == 0)
97			authenticated = 1;
98
99		for (i = 0; i < numprompts; i++)
100			xfree(prompts[i]);
101		xfree(prompts);
102		xfree(name);
103		xfree(echo_on);
104		xfree(info);
105		break;
106	}
107	device->free_ctx(authctxt->kbdintctxt);
108	authctxt->kbdintctxt = NULL;
109	return authenticated;
110}
111void
112abandon_challenge_response(Authctxt *authctxt)
113{
114	if (authctxt->kbdintctxt != NULL) {
115		device->free_ctx(authctxt->kbdintctxt);
116		authctxt->kbdintctxt = NULL;
117	}
118}
119