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 "crypto.h"
  20 #include "sha256.h"
  21 #include "aes_wrap.h"
  22 #include "wps_i.h"
  23
  24
  25 int wps_build_public_key(struct wps_data *wps, struct wpabuf *msg)
  26 {
  27         struct wpabuf *pubkey;
  28
  29         wpa_printf(MSG_DEBUG, "WPS:  * Public Key");
  30         wpabuf_free(wps->dh_privkey);
  31         if (wps->dev_pw_id != DEV_PW_DEFAULT && wps->wps->dh_privkey) {
  32                 wpa_printf(MSG_DEBUG, "WPS: Using pre-configured DH keys");
  33                 wps->dh_privkey = wpabuf_dup(wps->wps->dh_privkey);
  34                 pubkey = wpabuf_dup(wps->wps->dh_pubkey);
  35         } else {
  36                 wpa_printf(MSG_DEBUG, "WPS: Generate new DH keys");
  37                 wps->dh_privkey = NULL;
  38                 pubkey = dh_init(dh_groups_get(WPS_DH_GROUP),
  39                                  &wps->dh_privkey);
  40                 pubkey = wpabuf_zeropad(pubkey, 192);
  41         }
  42         if (wps->dh_privkey == NULL || pubkey == NULL) {
  43                 wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
  44                            "Diffie-Hellman handshake");
  45                 wpabuf_free(pubkey);
  46                 return -1;
  47         }
  48
  49         wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
  50         wpabuf_put_be16(msg, wpabuf_len(pubkey));
  51         wpabuf_put_buf(msg, pubkey);
  52
  53         if (wps->registrar) {
  54                 wpabuf_free(wps->dh_pubkey_r);
  55                 wps->dh_pubkey_r = pubkey;
  56         } else {
  57                 wpabuf_free(wps->dh_pubkey_e);
  58                 wps->dh_pubkey_e = pubkey;
  59         }
  60
  61         return 0;
  62 }
  63
  64
  65 int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
  66 {
  67         wpa_printf(MSG_DEBUG, "WPS:  * Request Type");
  68         wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
  69         wpabuf_put_be16(msg, 1);
  70         wpabuf_put_u8(msg, type);
  71         return 0;
  72 }
  73
  74
  75 int wps_build_config_methods(struct wpabuf *msg, u16 methods)
  76 {
  77         wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
  78         wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
  79         wpabuf_put_be16(msg, 2);
  80         wpabuf_put_be16(msg, methods);
  81         return 0;
  82 }
  83
  84
  85 int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
  86 {
  87         wpa_printf(MSG_DEBUG, "WPS:  * UUID-E");
  88         wpabuf_put_be16(msg, ATTR_UUID_E);
  89         wpabuf_put_be16(msg, WPS_UUID_LEN);
  90         wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
  91         return 0;
  92 }
  93
  94
  95 int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
  96 {
  97         wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
  98         wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
  99         wpabuf_put_be16(msg, 2);
 100         wpabuf_put_be16(msg, id);
 101         return 0;
 102 }
 103
 104
 105 int wps_build_config_error(struct wpabuf *msg, u16 err)
 106 {
 107         wpa_printf(MSG_DEBUG, "WPS:  * Configuration Error (%d)", err);
 108         wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
 109         wpabuf_put_be16(msg, 2);
 110         wpabuf_put_be16(msg, err);
 111         return 0;
 112 }
 113
 114
 115 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
 116 {
 117         u8 hash[SHA256_MAC_LEN];
 118         const u8 *addr[2];
 119         size_t len[2];
 120
 121         if (wps->last_msg == NULL) {
 122                 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
 123                            "building authenticator");
 124                 return -1;
 125         }
 126
 127         /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
 128          * (M_curr* is M_curr without the Authenticator attribute)
 129          */
 130         addr[0] = wpabuf_head(wps->last_msg);
 131         len[0] = wpabuf_len(wps->last_msg);
 132         addr[1] = wpabuf_head(msg);
 133         len[1] = wpabuf_len(msg);
 134         hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
 135
 136         wpa_printf(MSG_DEBUG, "WPS:  * Authenticator");
 137         wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
 138         wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
 139         wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
 140
 141         return 0;
 142 }
 143
 144
 145 int wps_build_version(struct wpabuf *msg)
 146 {
 147         wpa_printf(MSG_DEBUG, "WPS:  * Version");
 148         wpabuf_put_be16(msg, ATTR_VERSION);
 149         wpabuf_put_be16(msg, 1);
 150         wpabuf_put_u8(msg, WPS_VERSION);
 151         return 0;
 152 }
 153
 154
 155 int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
 156 {
 157         wpa_printf(MSG_DEBUG, "WPS:  * Message Type (%d)", msg_type);
 158         wpabuf_put_be16(msg, ATTR_MSG_TYPE);
 159         wpabuf_put_be16(msg, 1);
 160         wpabuf_put_u8(msg, msg_type);
 161         return 0;
 162 }
 163
 164
 165 int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
 166 {
 167         wpa_printf(MSG_DEBUG, "WPS:  * Enrollee Nonce");
 168         wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
 169         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 170         wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
 171         return 0;
 172 }
 173
 174
 175 int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
 176 {
 177         wpa_printf(MSG_DEBUG, "WPS:  * Registrar Nonce");
 178         wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
 179         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 180         wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
 181         return 0;
 182 }
 183
 184
 185 int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
 186 {
 187         wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type Flags");
 188         wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
 189         wpabuf_put_be16(msg, 2);
 190         wpabuf_put_be16(msg, WPS_AUTH_TYPES);
 191         return 0;
 192 }
 193
 194
 195 int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
 196 {
 197         wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type Flags");
 198         wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
 199         wpabuf_put_be16(msg, 2);
 200         wpabuf_put_be16(msg, WPS_ENCR_TYPES);
 201         return 0;
 202 }
 203
 204
 205 int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
 206 {
 207         wpa_printf(MSG_DEBUG, "WPS:  * Connection Type Flags");
 208         wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
 209         wpabuf_put_be16(msg, 1);
 210         wpabuf_put_u8(msg, WPS_CONN_ESS);
 211         return 0;
 212 }
 213
 214
 215 int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
 216 {
 217         wpa_printf(MSG_DEBUG, "WPS:  * Association State");
 218         wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
 219         wpabuf_put_be16(msg, 2);
 220         wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
 221         return 0;
 222 }
 223
 224
 225 int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
 226 {
 227         u8 hash[SHA256_MAC_LEN];
 228
 229         wpa_printf(MSG_DEBUG, "WPS:  * Key Wrap Authenticator");
 230         hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
 231                     wpabuf_len(msg), hash);
 232
 233         wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
 234         wpabuf_put_be16(msg, WPS_KWA_LEN);
 235         wpabuf_put_data(msg, hash, WPS_KWA_LEN);
 236         return 0;
 237 }
 238
 239
 240 int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
 241                             struct wpabuf *plain)
 242 {
 243         size_t pad_len;
 244         const size_t block_size = 16;
 245         u8 *iv, *data;
 246
 247         wpa_printf(MSG_DEBUG, "WPS:  * Encrypted Settings");
 248
 249         /* PKCS#5 v2.0 pad */
 250         pad_len = block_size - wpabuf_len(plain) % block_size;
 251         os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
 252
 253         wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
 254         wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
 255
 256         iv = wpabuf_put(msg, block_size);
 257         if (os_get_random(iv, block_size) < 0)
 258                 return -1;
 259
 260         data = wpabuf_put(msg, 0);
 261         wpabuf_put_buf(msg, plain);
 262         if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
 263                 return -1;
 264
 265         return 0;
 266 }
 267
 268
 269 int wps_build_oob_dev_password(struct wpabuf *msg, struct wps_context *wps)
 270 {
 271         size_t hash_len;
 272         const u8 *addr[1];
 273         u8 pubkey_hash[WPS_HASH_LEN];
 274         u8 dev_password_bin[WPS_OOB_DEVICE_PASSWORD_LEN];
 275
 276         wpa_printf(MSG_DEBUG, "WPS:  * OOB Device Password");
 277
 278         addr[0] = wpabuf_head(wps->dh_pubkey);
 279         hash_len = wpabuf_len(wps->dh_pubkey);
 280         sha256_vector(1, addr, &hash_len, pubkey_hash);
 281
 282         if (os_get_random((u8 *) &wps->oob_dev_pw_id, sizeof(u16)) < 0) {
 283                 wpa_printf(MSG_ERROR, "WPS: device password id "
 284                            "generation error");
 285                 return -1;
 286         }
 287         wps->oob_dev_pw_id |= 0x0010;
 288
 289         if (os_get_random(dev_password_bin, WPS_OOB_DEVICE_PASSWORD_LEN) < 0) {
 290                 wpa_printf(MSG_ERROR, "WPS: OOB device password "
 291                            "generation error");
 292                 return -1;
 293         }
 294
 295         wpabuf_put_be16(msg, ATTR_OOB_DEVICE_PASSWORD);
 296         wpabuf_put_be16(msg, WPS_OOB_DEVICE_PASSWORD_ATTR_LEN);
 297         wpabuf_put_data(msg, pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
 298         wpabuf_put_be16(msg, wps->oob_dev_pw_id);
 299         wpabuf_put_data(msg, dev_password_bin, WPS_OOB_DEVICE_PASSWORD_LEN);
 300
 301         wpa_snprintf_hex_uppercase(
 302                 wpabuf_put(wps->oob_conf.dev_password,
 303                            wpabuf_size(wps->oob_conf.dev_password)),
 304                 wpabuf_size(wps->oob_conf.dev_password),
 305                 dev_password_bin, WPS_OOB_DEVICE_PASSWORD_LEN);
 306
 307         return 0;
 308 }