1 /* $OpenBSD: auth-chall.c,v 1.12 2006/08/03 03:34:41 deraadt 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
41 extern KbdintDevice *devices[];
42 static KbdintDevice *device;
43 extern ServerOptions options;
44
45 char *
get_challenge(Authctxt * authctxt)46 get_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 xfree(prompts[i]);
73 xfree(prompts);
74 xfree(name);
75 xfree(echo_on);
76 xfree(info);
77
78 return (challenge);
79 }
80 int
verify_response(Authctxt * authctxt,const char * response)81 verify_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 xfree(prompts[i]);
106 xfree(prompts);
107 xfree(name);
108 xfree(echo_on);
109 xfree(info);
110 break;
111 }
112 device->free_ctx(authctxt->kbdintctxt);
113 authctxt->kbdintctxt = NULL;
114 return authenticated;
115 }
116 void
abandon_challenge_response(Authctxt * authctxt)117 abandon_challenge_response(Authctxt *authctxt)
118 {
119 if (authctxt->kbdintctxt != NULL) {
120 device->free_ctx(authctxt->kbdintctxt);
121 authctxt->kbdintctxt = NULL;
122 }
123 }
124