crypto/openssh-3.8.1p1/auth-chall.c

   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"
  26 RCSID("$OpenBSD: auth-chall.c,v 1.9 2003/11/03 09:03:37 djm Exp $");
  27
  28 #include "auth.h"
  29 #include "log.h"
  30 #include "xmalloc.h"
  31
  32 /* limited protocol v1 interface to kbd-interactive authentication */
  33
  34 extern KbdintDevice *devices[];
  35 static KbdintDevice *device;
  36
  37 char *
  38 get_challenge(Authctxt *authctxt)
  39 {
  40         char *challenge, *name, *info, **prompts;
  41         u_int i, numprompts;
  42         u_int *echo_on;
  43
  44         device = devices[0]; /* we always use the 1st device for protocol 1 */
  45         if (device == NULL)
  46                 return NULL;
  47         if ((authctxt->kbdintctxt = device->init_ctx(authctxt)) == NULL)
  48                 return NULL;
  49         if (device->query(authctxt->kbdintctxt, &name, &info,
  50             &numprompts, &prompts, &echo_on)) {
  51                 device->free_ctx(authctxt->kbdintctxt);
  52                 authctxt->kbdintctxt = NULL;
  53                 return NULL;
  54         }
  55         if (numprompts < 1)
  56                 fatal("get_challenge: numprompts < 1");
  57         challenge = xstrdup(prompts[0]);
  58         for (i = 0; i < numprompts; i++)
  59                 xfree(prompts[i]);
  60         xfree(prompts);
  61         xfree(name);
  62         xfree(echo_on);
  63         xfree(info);
  64
  65         return (challenge);
  66 }
  67 int
  68 verify_response(Authctxt *authctxt, const char *response)
  69 {
  70         char *resp[1], *name, *info, **prompts;
  71         u_int i, numprompts, *echo_on;
  72         int authenticated = 0;
  73
  74         if (device == NULL)
  75                 return 0;
  76         if (authctxt->kbdintctxt == NULL)
  77                 return 0;
  78         resp[0] = (char *)response;
  79         switch (device->respond(authctxt->kbdintctxt, 1, resp)) {
  80         case 0: /* Success */
  81                 authenticated = 1;
  82                 break;
  83         case 1: /* Postponed - retry with empty query for PAM */
  84                 if ((device->query(authctxt->kbdintctxt, &name, &info,
  85                     &numprompts, &prompts, &echo_on)) != 0)
  86                         break;
  87                 if (numprompts == 0 &&
  88                     device->respond(authctxt->kbdintctxt, 0, resp) == 0)
  89                         authenticated = 1;
  90
  91                 for (i = 0; i < numprompts; i++)
  92                         xfree(prompts[i]);
  93                 xfree(prompts);
  94                 xfree(name);
  95                 xfree(echo_on);
  96                 xfree(info);
  97                 break;
  98         }
  99         device->free_ctx(authctxt->kbdintctxt);
 100         authctxt->kbdintctxt = NULL;
 101         return authenticated;
 102 }
 103 void
 104 abandon_challenge_response(Authctxt *authctxt)
 105 {
 106         if (authctxt->kbdintctxt != NULL) {
 107                 device->free_ctx(authctxt->kbdintctxt);
 108                 authctxt->kbdintctxt = NULL;
 109         }
 110 }