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_group5.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                 wps->dh_ctx = wps->wps->dh_ctx;
  35                 wps->wps->dh_ctx = NULL;
  36                 pubkey = wpabuf_dup(wps->wps->dh_pubkey);
  37         } else {
  38                 wpa_printf(MSG_DEBUG, "WPS: Generate new DH keys");
  39                 wps->dh_privkey = NULL;
  40                 dh5_free(wps->dh_ctx);
  41                 wps->dh_ctx = dh5_init(&wps->dh_privkey, &pubkey);
  42                 pubkey = wpabuf_zeropad(pubkey, 192);
  43         }
  44         if (wps->dh_ctx == NULL || wps->dh_privkey == NULL || pubkey == NULL) {
  45                 wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
  46                            "Diffie-Hellman handshake");
  47                 wpabuf_free(pubkey);
  48                 return -1;
  49         }
  50
  51         wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
  52         wpabuf_put_be16(msg, wpabuf_len(pubkey));
  53         wpabuf_put_buf(msg, pubkey);
  54
  55         if (wps->registrar) {
  56                 wpabuf_free(wps->dh_pubkey_r);
  57                 wps->dh_pubkey_r = pubkey;
  58         } else {
  59                 wpabuf_free(wps->dh_pubkey_e);
  60                 wps->dh_pubkey_e = pubkey;
  61         }
  62
  63         return 0;
  64 }
  65
  66
  67 int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
  68 {
  69         wpa_printf(MSG_DEBUG, "WPS:  * Request Type");
  70         wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
  71         wpabuf_put_be16(msg, 1);
  72         wpabuf_put_u8(msg, type);
  73         return 0;
  74 }
  75
  76
  77 int wps_build_config_methods(struct wpabuf *msg, u16 methods)
  78 {
  79         wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
  80         wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
  81         wpabuf_put_be16(msg, 2);
  82         wpabuf_put_be16(msg, methods);
  83         return 0;
  84 }
  85
  86
  87 int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
  88 {
  89         wpa_printf(MSG_DEBUG, "WPS:  * UUID-E");
  90         wpabuf_put_be16(msg, ATTR_UUID_E);
  91         wpabuf_put_be16(msg, WPS_UUID_LEN);
  92         wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
  93         return 0;
  94 }
  95
  96
  97 int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
  98 {
  99         wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
 100         wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
 101         wpabuf_put_be16(msg, 2);
 102         wpabuf_put_be16(msg, id);
 103         return 0;
 104 }
 105
 106
 107 int wps_build_config_error(struct wpabuf *msg, u16 err)
 108 {
 109         wpa_printf(MSG_DEBUG, "WPS:  * Configuration Error (%d)", err);
 110         wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
 111         wpabuf_put_be16(msg, 2);
 112         wpabuf_put_be16(msg, err);
 113         return 0;
 114 }
 115
 116
 117 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
 118 {
 119         u8 hash[SHA256_MAC_LEN];
 120         const u8 *addr[2];
 121         size_t len[2];
 122
 123         if (wps->last_msg == NULL) {
 124                 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
 125                            "building authenticator");
 126                 return -1;
 127         }
 128
 129         /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
 130          * (M_curr* is M_curr without the Authenticator attribute)
 131          */
 132         addr[0] = wpabuf_head(wps->last_msg);
 133         len[0] = wpabuf_len(wps->last_msg);
 134         addr[1] = wpabuf_head(msg);
 135         len[1] = wpabuf_len(msg);
 136         hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
 137
 138         wpa_printf(MSG_DEBUG, "WPS:  * Authenticator");
 139         wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
 140         wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
 141         wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
 142
 143         return 0;
 144 }
 145
 146
 147 int wps_build_version(struct wpabuf *msg)
 148 {
 149         wpa_printf(MSG_DEBUG, "WPS:  * Version");
 150         wpabuf_put_be16(msg, ATTR_VERSION);
 151         wpabuf_put_be16(msg, 1);
 152         wpabuf_put_u8(msg, WPS_VERSION);
 153         return 0;
 154 }
 155
 156
 157 int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
 158 {
 159         wpa_printf(MSG_DEBUG, "WPS:  * Message Type (%d)", msg_type);
 160         wpabuf_put_be16(msg, ATTR_MSG_TYPE);
 161         wpabuf_put_be16(msg, 1);
 162         wpabuf_put_u8(msg, msg_type);
 163         return 0;
 164 }
 165
 166
 167 int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
 168 {
 169         wpa_printf(MSG_DEBUG, "WPS:  * Enrollee Nonce");
 170         wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
 171         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 172         wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
 173         return 0;
 174 }
 175
 176
 177 int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
 178 {
 179         wpa_printf(MSG_DEBUG, "WPS:  * Registrar Nonce");
 180         wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
 181         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 182         wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
 183         return 0;
 184 }
 185
 186
 187 int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
 188 {
 189         wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type Flags");
 190         wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
 191         wpabuf_put_be16(msg, 2);
 192         wpabuf_put_be16(msg, WPS_AUTH_TYPES);
 193         return 0;
 194 }
 195
 196
 197 int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
 198 {
 199         wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type Flags");
 200         wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
 201         wpabuf_put_be16(msg, 2);
 202         wpabuf_put_be16(msg, WPS_ENCR_TYPES);
 203         return 0;
 204 }
 205
 206
 207 int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
 208 {
 209         wpa_printf(MSG_DEBUG, "WPS:  * Connection Type Flags");
 210         wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
 211         wpabuf_put_be16(msg, 1);
 212         wpabuf_put_u8(msg, WPS_CONN_ESS);
 213         return 0;
 214 }
 215
 216
 217 int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
 218 {
 219         wpa_printf(MSG_DEBUG, "WPS:  * Association State");
 220         wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
 221         wpabuf_put_be16(msg, 2);
 222         wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
 223         return 0;
 224 }
 225
 226
 227 int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
 228 {
 229         u8 hash[SHA256_MAC_LEN];
 230
 231         wpa_printf(MSG_DEBUG, "WPS:  * Key Wrap Authenticator");
 232         hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
 233                     wpabuf_len(msg), hash);
 234
 235         wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
 236         wpabuf_put_be16(msg, WPS_KWA_LEN);
 237         wpabuf_put_data(msg, hash, WPS_KWA_LEN);
 238         return 0;
 239 }
 240
 241
 242 int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
 243                             struct wpabuf *plain)
 244 {
 245         size_t pad_len;
 246         const size_t block_size = 16;
 247         u8 *iv, *data;
 248
 249         wpa_printf(MSG_DEBUG, "WPS:  * Encrypted Settings");
 250
 251         /* PKCS#5 v2.0 pad */
 252         pad_len = block_size - wpabuf_len(plain) % block_size;
 253         os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
 254
 255         wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
 256         wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
 257
 258         iv = wpabuf_put(msg, block_size);
 259         if (os_get_random(iv, block_size) < 0)
 260                 return -1;
 261
 262         data = wpabuf_put(msg, 0);
 263         wpabuf_put_buf(msg, plain);
 264         if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
 265                 return -1;
 266
 267         return 0;
 268 }
 269
 270
 271 #ifdef CONFIG_WPS_OOB
 272 int wps_build_oob_dev_password(struct wpabuf *msg, struct wps_context *wps)
 273 {
 274         size_t hash_len;
 275         const u8 *addr[1];
 276         u8 pubkey_hash[WPS_HASH_LEN];
 277         u8 dev_password_bin[WPS_OOB_DEVICE_PASSWORD_LEN];
 278
 279         wpa_printf(MSG_DEBUG, "WPS:  * OOB Device Password");
 280
 281         addr[0] = wpabuf_head(wps->dh_pubkey);
 282         hash_len = wpabuf_len(wps->dh_pubkey);
 283         sha256_vector(1, addr, &hash_len, pubkey_hash);
 284
 285         if (os_get_random((u8 *) &wps->oob_dev_pw_id, sizeof(u16)) < 0) {
 286                 wpa_printf(MSG_ERROR, "WPS: device password id "
 287                            "generation error");
 288                 return -1;
 289         }
 290         wps->oob_dev_pw_id |= 0x0010;
 291
 292         if (os_get_random(dev_password_bin, WPS_OOB_DEVICE_PASSWORD_LEN) < 0) {
 293                 wpa_printf(MSG_ERROR, "WPS: OOB device password "
 294                            "generation error");
 295                 return -1;
 296         }
 297
 298         wpabuf_put_be16(msg, ATTR_OOB_DEVICE_PASSWORD);
 299         wpabuf_put_be16(msg, WPS_OOB_DEVICE_PASSWORD_ATTR_LEN);
 300         wpabuf_put_data(msg, pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
 301         wpabuf_put_be16(msg, wps->oob_dev_pw_id);
 302         wpabuf_put_data(msg, dev_password_bin, WPS_OOB_DEVICE_PASSWORD_LEN);
 303
 304         wpa_snprintf_hex_uppercase(
 305                 wpabuf_put(wps->oob_conf.dev_password,
 306                            wpabuf_size(wps->oob_conf.dev_password)),
 307                 wpabuf_size(wps->oob_conf.dev_password),
 308                 dev_password_bin, WPS_OOB_DEVICE_PASSWORD_LEN);
 309
 310         return 0;
 311 }
 312 #endif /* CONFIG_WPS_OOB */