1 /* 2 * MSCHAPV2 (RFC 2759) 3 * Copyright (c) 2004-2008, Jouni Malinen <j (at) w1.fi> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "includes.h" 10 11 #include "common.h" 12 #include "crypto/ms_funcs.h" 13 #include "mschapv2.h" 14 15 const u8 * mschapv2_remove_domain(const u8 *username, size_t *len) 16 { 17 size_t i; 18 19 /* 20 * MSCHAPv2 does not include optional domain name in the 21 * challenge-response calculation, so remove domain prefix 22 * (if present). 23 */ 24 25 for (i = 0; i < *len; i++) { 26 if (username[i] == '\\') { 27 *len -= i + 1; 28 return username + i + 1; 29 } 30 } 31 32 return username; 33 } 34 35 36 int mschapv2_derive_response(const u8 *identity, size_t identity_len, 37 const u8 *password, size_t password_len, 38 int pwhash, 39 const u8 *auth_challenge, 40 const u8 *peer_challenge, 41 u8 *nt_response, u8 *auth_response, 42 u8 *master_key) 43 { 44 const u8 *username; 45 size_t username_len; 46 u8 password_hash[16], password_hash_hash[16]; 47 48 wpa_hexdump_ascii(MSG_DEBUG, "MSCHAPV2: Identity", 49 identity, identity_len); 50 username_len = identity_len; 51 username = mschapv2_remove_domain(identity, &username_len); 52 wpa_hexdump_ascii(MSG_DEBUG, "MSCHAPV2: Username", 53 username, username_len); 54 55 wpa_hexdump(MSG_DEBUG, "MSCHAPV2: auth_challenge", 56 auth_challenge, MSCHAPV2_CHAL_LEN); 57 wpa_hexdump(MSG_DEBUG, "MSCHAPV2: peer_challenge", 58 peer_challenge, MSCHAPV2_CHAL_LEN); 59 wpa_hexdump_ascii(MSG_DEBUG, "MSCHAPV2: username", 60 username, username_len); 61 /* Authenticator response is not really needed yet, but calculate it 62 * here so that challenges need not be saved. */ 63 if (pwhash) { 64 wpa_hexdump_key(MSG_DEBUG, "MSCHAPV2: password hash", 65 password, password_len); 66 if (generate_nt_response_pwhash(auth_challenge, peer_challenge, 67 username, username_len, 68 password, nt_response) || 69 generate_authenticator_response_pwhash( 70 password, peer_challenge, auth_challenge, 71 username, username_len, nt_response, 72 auth_response)) 73 return -1; 74 } else { 75 wpa_hexdump_ascii_key(MSG_DEBUG, "MSCHAPV2: password", 76 password, password_len); 77 if (generate_nt_response(auth_challenge, peer_challenge, 78 username, username_len, 79 password, password_len, 80 nt_response) || 81 generate_authenticator_response(password, password_len, 82 peer_challenge, 83 auth_challenge, 84 username, username_len, 85 nt_response, 86 auth_response)) 87 return -1; 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 if (hash_nt_password_hash(password, password_hash_hash)) 97 return -1; 98 } else { 99 if (nt_password_hash(password, password_len, password_hash) || 100 hash_nt_password_hash(password_hash, password_hash_hash)) 101 return -1; 102 } 103 if (get_master_key(password_hash_hash, nt_response, master_key)) 104 return -1; 105 wpa_hexdump_key(MSG_DEBUG, "MSCHAPV2: Master Key", 106 master_key, MSCHAPV2_MASTER_KEY_LEN); 107 108 return 0; 109 } 110 111 112 int mschapv2_verify_auth_response(const u8 *auth_response, 113 const u8 *buf, size_t buf_len) 114 { 115 u8 recv_response[MSCHAPV2_AUTH_RESPONSE_LEN]; 116 if (buf_len < 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN || 117 buf[0] != 'S' || buf[1] != '=' || 118 hexstr2bin((char *) (buf + 2), recv_response, 119 MSCHAPV2_AUTH_RESPONSE_LEN) || 120 os_memcmp_const(auth_response, recv_response, 121 MSCHAPV2_AUTH_RESPONSE_LEN) != 0) 122 return -1; 123 return 0; 124 } 125
