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 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, auth_response); 72 } else { 73 wpa_hexdump_ascii_key(MSG_DEBUG, "MSCHAPV2: password", 74 password, password_len); 75 generate_nt_response(auth_challenge, peer_challenge, 76 username, username_len, 77 password, password_len, nt_response); 78 generate_authenticator_response(password, password_len, 79 peer_challenge, auth_challenge, 80 username, username_len, 81 nt_response, auth_response); 82 } 83 wpa_hexdump(MSG_DEBUG, "MSCHAPV2: NT Response", 84 nt_response, MSCHAPV2_NT_RESPONSE_LEN); 85 wpa_hexdump(MSG_DEBUG, "MSCHAPV2: Auth Response", 86 auth_response, MSCHAPV2_AUTH_RESPONSE_LEN); 87 88 /* Generate master_key here since we have the needed data available. */ 89 if (pwhash) { 90 if (hash_nt_password_hash(password, password_hash_hash)) 91 return -1; 92 } else { 93 if (nt_password_hash(password, password_len, password_hash) || 94 hash_nt_password_hash(password_hash, password_hash_hash)) 95 return -1; 96 } 97 get_master_key(password_hash_hash, nt_response, master_key); 98 wpa_hexdump_key(MSG_DEBUG, "MSCHAPV2: Master Key", 99 master_key, MSCHAPV2_MASTER_KEY_LEN); 100 101 return 0; 102 } 103 104 105 int mschapv2_verify_auth_response(const u8 *auth_response, 106 const u8 *buf, size_t buf_len) 107 { 108 u8 recv_response[MSCHAPV2_AUTH_RESPONSE_LEN]; 109 if (buf_len < 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN || 110 buf[0] != 'S' || buf[1] != '=' || 111 hexstr2bin((char *) (buf + 2), recv_response, 112 MSCHAPV2_AUTH_RESPONSE_LEN) || 113 os_memcmp(auth_response, recv_response, 114 MSCHAPV2_AUTH_RESPONSE_LEN) != 0) 115 return -1; 116 return 0; 117 } 118
