dist/wpa/src/eap_peer/mschapv2.c

   1 /*
   2  * MSCHAPV2 (RFC 2759)
   3  * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16
  17 #include "common.h"
  18 #include "ms_funcs.h"
  19 #include "mschapv2.h"
  20
  21 const u8 * mschapv2_remove_domain(const u8 *username, size_t *len)
  22 {
  23         size_t i;
  24
  25         /*
  26          * MSCHAPv2 does not include optional domain name in the
  27          * challenge-response calculation, so remove domain prefix
  28          * (if present).
  29          */
  30
  31         for (i = 0; i < *len; i++) {
  32                 if (username[i] == '\\') {
  33                         *len -= i + 1;
  34                         return username + i + 1;
  35                 }
  36         }
  37
  38         return username;
  39 }
  40
  41
  42 void mschapv2_derive_response(const u8 *identity, size_t identity_len,
  43                               const u8 *password, size_t password_len,
  44                               int pwhash,
  45                               const u8 *auth_challenge,
  46                               const u8 *peer_challenge,
  47                               u8 *nt_response, u8 *auth_response,
  48                               u8 *master_key)
  49 {
  50         const u8 *username;
  51         size_t username_len;
  52         u8 password_hash[16], password_hash_hash[16];
  53
  54         wpa_hexdump_ascii(MSG_DEBUG, "MSCHAPV2: Identity",
  55                           identity, identity_len);
  56         username_len = identity_len;
  57         username = mschapv2_remove_domain(identity, &username_len);
  58         wpa_hexdump_ascii(MSG_DEBUG, "MSCHAPV2: Username",
  59                           username, username_len);
  60
  61         wpa_hexdump(MSG_DEBUG, "MSCHAPV2: auth_challenge",
  62                     auth_challenge, MSCHAPV2_CHAL_LEN);
  63         wpa_hexdump(MSG_DEBUG, "MSCHAPV2: peer_challenge",
  64                     peer_challenge, MSCHAPV2_CHAL_LEN);
  65         wpa_hexdump_ascii(MSG_DEBUG, "MSCHAPV2: username",
  66                           username, username_len);
  67         /* Authenticator response is not really needed yet, but calculate it
  68          * here so that challenges need not be saved. */
  69         if (pwhash) {
  70                 wpa_hexdump_key(MSG_DEBUG, "MSCHAPV2: password hash",
  71                                 password, password_len);
  72                 generate_nt_response_pwhash(auth_challenge, peer_challenge,
  73                                             username, username_len,
  74                                             password, nt_response);
  75                 generate_authenticator_response_pwhash(
  76                         password, peer_challenge, auth_challenge,
  77                         username, username_len, nt_response, auth_response);
  78         } else {
  79                 wpa_hexdump_ascii_key(MSG_DEBUG, "MSCHAPV2: password",
  80                                       password, password_len);
  81                 generate_nt_response(auth_challenge, peer_challenge,
  82                                      username, username_len,
  83                                      password, password_len, nt_response);
  84                 generate_authenticator_response(password, password_len,
  85                                                 peer_challenge, auth_challenge,
  86                                                 username, username_len,
  87                                                 nt_response, auth_response);
  88         }
  89         wpa_hexdump(MSG_DEBUG, "MSCHAPV2: NT Response",
  90                     nt_response, MSCHAPV2_NT_RESPONSE_LEN);
  91         wpa_hexdump(MSG_DEBUG, "MSCHAPV2: Auth Response",
  92                     auth_response, MSCHAPV2_AUTH_RESPONSE_LEN);
  93
  94         /* Generate master_key here since we have the needed data available. */
  95         if (pwhash) {
  96                 hash_nt_password_hash(password, password_hash_hash);
  97         } else {
  98                 nt_password_hash(password, password_len, password_hash);
  99                 hash_nt_password_hash(password_hash, password_hash_hash);
 100         }
 101         get_master_key(password_hash_hash, nt_response, master_key);
 102         wpa_hexdump_key(MSG_DEBUG, "MSCHAPV2: Master Key",
 103                         master_key, MSCHAPV2_MASTER_KEY_LEN);
 104 }
 105
 106
 107 int mschapv2_verify_auth_response(const u8 *auth_response,
 108                                   const u8 *buf, size_t buf_len)
 109 {
 110         u8 recv_response[MSCHAPV2_AUTH_RESPONSE_LEN];
 111         if (buf_len < 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN ||
 112             buf[0] != 'S' || buf[1] != '=' ||
 113             hexstr2bin((char *) (buf + 2), recv_response,
 114                        MSCHAPV2_AUTH_RESPONSE_LEN) ||
 115             os_memcmp(auth_response, recv_response,
 116                       MSCHAPV2_AUTH_RESPONSE_LEN) != 0)
 117                 return -1;
 118         return 0;
 119 }