1 /* 2 * MSCHAPV2 (RFC 2759) 3 * Copyright (c) 2004-2008, Jouni Malinen <j (at) 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 "crypto/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 } 120
