1 /* $OpenBSD: auth-chall.c,v 1.14 2014/06/24 01:13:21 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 #include <stdarg.h>
30 #include <stdlib.h>
31 #include <stdio.h>
32
33 #include "xmalloc.h"
34 #include "key.h"
35 #include "hostfile.h"
36 #include "auth.h"
37 #include "log.h"
38 #include "misc.h"
39 #include "servconf.h"
40
41 /* limited protocol v1 interface to kbd-interactive authentication */
42
43 extern KbdintDevice *devices[];
44 static KbdintDevice *device;
45 extern ServerOptions options;
46
47 char *
get_challenge(Authctxt * authctxt)48 get_challenge(Authctxt *authctxt)
49 {
50 char *challenge, *name, *info, **prompts;
51 u_int i, numprompts;
52 u_int *echo_on;
53
54 #ifdef USE_PAM
55 if (!options.use_pam)
56 remove_kbdint_device("pam");
57 #endif
58
59 device = devices[0]; /* we always use the 1st device for protocol 1 */
60 if (device == NULL)
61 return NULL;
62 if ((authctxt->kbdintctxt = device->init_ctx(authctxt)) == NULL)
63 return NULL;
64 if (device->query(authctxt->kbdintctxt, &name, &info,
65 &numprompts, &prompts, &echo_on)) {
66 device->free_ctx(authctxt->kbdintctxt);
67 authctxt->kbdintctxt = NULL;
68 return NULL;
69 }
70 if (numprompts < 1)
71 fatal("get_challenge: numprompts < 1");
72 challenge = xstrdup(prompts[0]);
73 for (i = 0; i < numprompts; i++)
74 free(prompts[i]);
75 free(prompts);
76 free(name);
77 free(echo_on);
78 free(info);
79
80 return (challenge);
81 }
82 int
verify_response(Authctxt * authctxt,const char * response)83 verify_response(Authctxt *authctxt, const char *response)
84 {
85 char *resp[1], *name, *info, **prompts;
86 u_int i, numprompts, *echo_on;
87 int authenticated = 0;
88
89 if (device == NULL)
90 return 0;
91 if (authctxt->kbdintctxt == NULL)
92 return 0;
93 resp[0] = (char *)response;
94 switch (device->respond(authctxt->kbdintctxt, 1, resp)) {
95 case 0: /* Success */
96 authenticated = 1;
97 break;
98 case 1: /* Postponed - retry with empty query for PAM */
99 if ((device->query(authctxt->kbdintctxt, &name, &info,
100 &numprompts, &prompts, &echo_on)) != 0)
101 break;
102 if (numprompts == 0 &&
103 device->respond(authctxt->kbdintctxt, 0, resp) == 0)
104 authenticated = 1;
105
106 for (i = 0; i < numprompts; i++)
107 free(prompts[i]);
108 free(prompts);
109 free(name);
110 free(echo_on);
111 free(info);
112 break;
113 }
114 device->free_ctx(authctxt->kbdintctxt);
115 authctxt->kbdintctxt = NULL;
116 return authenticated;
117 }
118 void
abandon_challenge_response(Authctxt * authctxt)119 abandon_challenge_response(Authctxt *authctxt)
120 {
121 if (authctxt->kbdintctxt != NULL) {
122 device->free_ctx(authctxt->kbdintctxt);
123 authctxt->kbdintctxt = NULL;
124 }
125 }
126