auth-chall.c revision 120405 
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 1.8 2001/05/18 14:13:28 markus Exp $");
27RCSID("$FreeBSD: head/crypto/openssh/auth-chall.c 120405 2003-09-24 18:24:27Z des $");
28
29#include "auth.h"
30#include "log.h"
31#include "xmalloc.h"
32
33/* limited protocol v1 interface to kbd-interactive authentication */
34
35extern KbdintDevice *devices[];
36static KbdintDevice *device;
37
38char *
39get_challenge(Authctxt *authctxt)
40{
41	char *challenge, *name, *info, **prompts;
42	u_int i, numprompts;
43	u_int *echo_on;
44
45	device = devices[0]; /* we always use the 1st device for protocol 1 */
46	if (device == NULL)
47		return NULL;
48	if ((authctxt->kbdintctxt = device->init_ctx(authctxt)) == NULL)
49		return NULL;
50	if (device->query(authctxt->kbdintctxt, &name, &info,
51	    &numprompts, &prompts, &echo_on)) {
52		device->free_ctx(authctxt->kbdintctxt);
53		authctxt->kbdintctxt = NULL;
54		return NULL;
55	}
56	if (numprompts < 1)
57		fatal("get_challenge: numprompts < 1");
58	challenge = xstrdup(prompts[0]);
59	for (i = 0; i < numprompts; i++)
60		xfree(prompts[i]);
61	xfree(prompts);
62	xfree(name);
63	xfree(echo_on);
64	xfree(info);
65
66	return (challenge);
67}
68int
69verify_response(Authctxt *authctxt, const char *response)
70{
71	char *resp[1];
72	int res;
73
74	if (device == NULL)
75		return 0;
76	if (authctxt->kbdintctxt == NULL)
77		return 0;
78	resp[0] = (char *)response;
79	res = device->respond(authctxt->kbdintctxt, 1, resp);
80	if (res == 1) {
81		/* postponed - send a null query just in case */
82		char *name, *info, **prompts;
83		u_int i, numprompts, *echo_on;
84
85		res = device->query(authctxt->kbdintctxt, &name, &info,
86		    &numprompts, &prompts, &echo_on);
87		if (res == 0) {
88			for (i = 0; i < numprompts; i++)
89				xfree(prompts[i]);
90			xfree(prompts);
91			xfree(name);
92			xfree(echo_on);
93			xfree(info);
94		}
95		/* if we received more prompts, we're screwed */
96		res = (res == 0 && numprompts == 0) ? 0 : -1;
97	}
98	device->free_ctx(authctxt->kbdintctxt);
99	authctxt->kbdintctxt = NULL;
100	return res ? 0 : 1;
101}
102void
103abandon_challenge_response(Authctxt *authctxt)
104{
105	if (authctxt->kbdintctxt != NULL) {
106		device->free_ctx(authctxt->kbdintctxt);
107		authctxt->kbdintctxt = NULL;
108	}
109}
110