lib/pam_module/pam_opie/pam_opie.c

   1 /*-
   2  * Copyright 2000 James Bloom
   3  * All rights reserved.
   4  * Based upon code Copyright 1998 Juniper Networks, Inc.
   5  * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
   6  * All rights reserved.
   7  *
   8  * Portions of this software were developed for the FreeBSD Project by
   9  * ThinkSec AS and NAI Labs, the Security Research Division of Network
  10  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
  11  * ("CBOSS"), as part of the DARPA CHATS research program.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. The name of the author may not be used to endorse or promote
  22  *    products derived from this software without specific prior written
  23  *    permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  * $FreeBSD: src/lib/libpam/modules/pam_opie/pam_opie.c,v 1.26 2006/09/15 13:42:38 des Exp $
  38  * $DragonFly: src/lib/pam_module/pam_opie/pam_opie.c,v 1.1 2005/07/12 22:53:20 joerg Exp $
  39  */
  40
  41 #include <sys/types.h>
  42 #include <opie.h>
  43 #include <pwd.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48
  49 #define PAM_SM_AUTH
  50
  51 #include <security/pam_appl.h>
  52 #include <security/pam_modules.h>
  53 #include <security/pam_mod_misc.h>
  54
  55 #define PAM_OPT_NO_FAKE_PROMPTS "no_fake_prompts"
  56
  57 PAM_EXTERN int
  58 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
  59     int argc __unused, const char *argv[] __unused)
  60 {
  61         struct opie opie;
  62         struct passwd *pwd;
  63         int retval, i;
  64         const char *(promptstr[]) = { "%s\nPassword: ", "%s\nPassword [echo on]: "};
  65         char challenge[OPIE_CHALLENGE_MAX];
  66         char principal[OPIE_PRINCIPAL_MAX];
  67         const char *user;
  68         char *response;
  69         int style;
  70
  71         user = NULL;
  72         if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) {
  73                 if ((pwd = getpwnam(getlogin())) == NULL)
  74                         return (PAM_AUTH_ERR);
  75                 user = pwd->pw_name;
  76         }
  77         else {
  78                 retval = pam_get_user(pamh, &user, NULL);
  79                 if (retval != PAM_SUCCESS)
  80                         return (retval);
  81         }
  82
  83         PAM_LOG("Got user: %s", user);
  84
  85         /*
  86          * Watch out: libopie feels entitled to truncate the user name
  87          * passed to it if it's longer than OPIE_PRINCIPAL_MAX, which is
  88          * not uncommon in Windows environments.
  89          */
  90         if (strlen(user) >= sizeof(principal))
  91                 return (PAM_AUTH_ERR);
  92         strlcpy(principal, user, sizeof(principal));
  93
  94         /*
  95          * Don't call the OPIE atexit() handler when our program exits,
  96          * since the module has been unloaded and we will SEGV.
  97          */
  98         opiedisableaeh();
  99
 100         /*
 101          * If the no_fake_prompts option was given, and the user
 102          * doesn't have an OPIE key, just fail rather than present the
 103          * user with a bogus OPIE challenge.
 104          */
 105         if (opiechallenge(&opie, principal, challenge) != 0 &&
 106             openpam_get_option(pamh, PAM_OPT_NO_FAKE_PROMPTS))
 107                 return (PAM_AUTH_ERR);
 108
 109         /*
 110          * It doesn't make sense to use a password that has already been
 111          * typed in, since we haven't presented the challenge to the user
 112          * yet, so clear the stored password.
 113          */
 114         pam_set_item(pamh, PAM_AUTHTOK, NULL);
 115
 116         style = PAM_PROMPT_ECHO_OFF;
 117         for (i = 0; i < 2; i++) {
 118                 retval = pam_prompt(pamh, style, &response,
 119                     promptstr[i], challenge);
 120                 if (retval != PAM_SUCCESS) {
 121                         opieunlock();
 122                         return (retval);
 123                 }
 124
 125                 PAM_LOG("Completed challenge %d: %s", i, response);
 126
 127                 if (response[0] != '\0')
 128                         break;
 129
 130                 /* Second time round, echo the password */
 131                 style = PAM_PROMPT_ECHO_ON;
 132         }
 133
 134         pam_set_item(pamh, PAM_AUTHTOK, response);
 135
 136         /*
 137          * Opieverify is supposed to return -1 only if an error occurs.
 138          * But it returns -1 even if the response string isn't in the form
 139          * it expects.  Thus we can't log an error and can only check for
 140          * success or lack thereof.
 141          */
 142         retval = opieverify(&opie, response);
 143         free(response);
 144         return (retval == 0 ? PAM_SUCCESS : PAM_AUTH_ERR);
 145 }
 146
 147 PAM_EXTERN int
 148 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 149     int argc __unused, const char *argv[] __unused)
 150 {
 151
 152         return (PAM_SUCCESS);
 153 }
 154
 155 PAM_MODULE_ENTRY("pam_opie");