contrib/hostapd/src/wps/wps_attr_build.c

   1 /*
   2  * Wi-Fi Protected Setup - attribute building
   3  * Copyright (c) 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 "dh_groups.h"
  19 #include "sha256.h"
  20 #include "aes_wrap.h"
  21 #include "wps_i.h"
  22
  23
  24 int wps_build_public_key(struct wps_data *wps, struct wpabuf *msg)
  25 {
  26         struct wpabuf *pubkey;
  27
  28         wpa_printf(MSG_DEBUG, "WPS:  * Public Key");
  29         pubkey = dh_init(dh_groups_get(WPS_DH_GROUP), &wps->dh_privkey);
  30         pubkey = wpabuf_zeropad(pubkey, 192);
  31         if (pubkey == NULL) {
  32                 wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
  33                            "Diffie-Hellman handshake");
  34                 return -1;
  35         }
  36
  37         wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
  38         wpabuf_put_be16(msg, wpabuf_len(pubkey));
  39         wpabuf_put_buf(msg, pubkey);
  40
  41         if (wps->registrar) {
  42                 wpabuf_free(wps->dh_pubkey_r);
  43                 wps->dh_pubkey_r = pubkey;
  44         } else {
  45                 wpabuf_free(wps->dh_pubkey_e);
  46                 wps->dh_pubkey_e = pubkey;
  47         }
  48
  49         return 0;
  50 }
  51
  52
  53 int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
  54 {
  55         wpa_printf(MSG_DEBUG, "WPS:  * Request Type");
  56         wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
  57         wpabuf_put_be16(msg, 1);
  58         wpabuf_put_u8(msg, type);
  59         return 0;
  60 }
  61
  62
  63 int wps_build_config_methods(struct wpabuf *msg, u16 methods)
  64 {
  65         wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
  66         wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
  67         wpabuf_put_be16(msg, 2);
  68         wpabuf_put_be16(msg, methods);
  69         return 0;
  70 }
  71
  72
  73 int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
  74 {
  75         wpa_printf(MSG_DEBUG, "WPS:  * UUID-E");
  76         wpabuf_put_be16(msg, ATTR_UUID_E);
  77         wpabuf_put_be16(msg, WPS_UUID_LEN);
  78         wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
  79         return 0;
  80 }
  81
  82
  83 int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
  84 {
  85         wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
  86         wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
  87         wpabuf_put_be16(msg, 2);
  88         wpabuf_put_be16(msg, id);
  89         return 0;
  90 }
  91
  92
  93 int wps_build_config_error(struct wpabuf *msg, u16 err)
  94 {
  95         wpa_printf(MSG_DEBUG, "WPS:  * Configuration Error (%d)", err);
  96         wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
  97         wpabuf_put_be16(msg, 2);
  98         wpabuf_put_be16(msg, err);
  99         return 0;
 100 }
 101
 102
 103 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
 104 {
 105         u8 hash[SHA256_MAC_LEN];
 106         const u8 *addr[2];
 107         size_t len[2];
 108
 109         if (wps->last_msg == NULL) {
 110                 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
 111                            "building authenticator");
 112                 return -1;
 113         }
 114
 115         /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
 116          * (M_curr* is M_curr without the Authenticator attribute)
 117          */
 118         addr[0] = wpabuf_head(wps->last_msg);
 119         len[0] = wpabuf_len(wps->last_msg);
 120         addr[1] = wpabuf_head(msg);
 121         len[1] = wpabuf_len(msg);
 122         hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
 123
 124         wpa_printf(MSG_DEBUG, "WPS:  * Authenticator");
 125         wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
 126         wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
 127         wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
 128
 129         return 0;
 130 }
 131
 132
 133 int wps_build_version(struct wpabuf *msg)
 134 {
 135         wpa_printf(MSG_DEBUG, "WPS:  * Version");
 136         wpabuf_put_be16(msg, ATTR_VERSION);
 137         wpabuf_put_be16(msg, 1);
 138         wpabuf_put_u8(msg, WPS_VERSION);
 139         return 0;
 140 }
 141
 142
 143 int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
 144 {
 145         wpa_printf(MSG_DEBUG, "WPS:  * Message Type (%d)", msg_type);
 146         wpabuf_put_be16(msg, ATTR_MSG_TYPE);
 147         wpabuf_put_be16(msg, 1);
 148         wpabuf_put_u8(msg, msg_type);
 149         return 0;
 150 }
 151
 152
 153 int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
 154 {
 155         wpa_printf(MSG_DEBUG, "WPS:  * Enrollee Nonce");
 156         wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
 157         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 158         wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
 159         return 0;
 160 }
 161
 162
 163 int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
 164 {
 165         wpa_printf(MSG_DEBUG, "WPS:  * Registrar Nonce");
 166         wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
 167         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 168         wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
 169         return 0;
 170 }
 171
 172
 173 int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
 174 {
 175         wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type Flags");
 176         wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
 177         wpabuf_put_be16(msg, 2);
 178         wpabuf_put_be16(msg, WPS_AUTH_TYPES);
 179         return 0;
 180 }
 181
 182
 183 int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
 184 {
 185         wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type Flags");
 186         wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
 187         wpabuf_put_be16(msg, 2);
 188         wpabuf_put_be16(msg, WPS_ENCR_TYPES);
 189         return 0;
 190 }
 191
 192
 193 int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
 194 {
 195         wpa_printf(MSG_DEBUG, "WPS:  * Connection Type Flags");
 196         wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
 197         wpabuf_put_be16(msg, 1);
 198         wpabuf_put_u8(msg, WPS_CONN_ESS);
 199         return 0;
 200 }
 201
 202
 203 int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
 204 {
 205         wpa_printf(MSG_DEBUG, "WPS:  * Association State");
 206         wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
 207         wpabuf_put_be16(msg, 2);
 208         wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
 209         return 0;
 210 }
 211
 212
 213 int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
 214 {
 215         u8 hash[SHA256_MAC_LEN];
 216
 217         wpa_printf(MSG_DEBUG, "WPS:  * Key Wrap Authenticator");
 218         hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
 219                     wpabuf_len(msg), hash);
 220
 221         wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
 222         wpabuf_put_be16(msg, WPS_KWA_LEN);
 223         wpabuf_put_data(msg, hash, WPS_KWA_LEN);
 224         return 0;
 225 }
 226
 227
 228 int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
 229                             struct wpabuf *plain)
 230 {
 231         size_t pad_len;
 232         const size_t block_size = 16;
 233         u8 *iv, *data;
 234
 235         wpa_printf(MSG_DEBUG, "WPS:  * Encrypted Settings");
 236
 237         /* PKCS#5 v2.0 pad */
 238         pad_len = block_size - wpabuf_len(plain) % block_size;
 239         os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
 240
 241         wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
 242         wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
 243
 244         iv = wpabuf_put(msg, block_size);
 245         if (os_get_random(iv, block_size) < 0)
 246                 return -1;
 247
 248         data = wpabuf_put(msg, 0);
 249         wpabuf_put_buf(msg, plain);
 250         if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
 251                 return -1;
 252
 253         return 0;
 254 }