contrib/wpa/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 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/aes_wrap.h"
  13 #include "crypto/crypto.h"
  14 #include "crypto/dh_group5.h"
  15 #include "crypto/sha256.h"
  16 #include "crypto/random.h"
  17 #include "common/ieee802_11_defs.h"
  18 #include "wps_i.h"
  19
  20
  21 int wps_build_public_key(struct wps_data *wps, struct wpabuf *msg)
  22 {
  23         struct wpabuf *pubkey;
  24
  25         wpa_printf(MSG_DEBUG, "WPS:  * Public Key");
  26         wpabuf_free(wps->dh_privkey);
  27         if (wps->dev_pw_id != DEV_PW_DEFAULT && wps->wps->dh_privkey) {
  28                 wpa_printf(MSG_DEBUG, "WPS: Using pre-configured DH keys");
  29                 wps->dh_privkey = wpabuf_dup(wps->wps->dh_privkey);
  30                 wps->dh_ctx = wps->wps->dh_ctx;
  31                 wps->wps->dh_ctx = NULL;
  32                 pubkey = wpabuf_dup(wps->wps->dh_pubkey);
  33 #ifdef CONFIG_WPS_NFC
  34         } else if (wps->dev_pw_id >= 0x10 && wps->wps->ap &&
  35                    wps->dev_pw_id == wps->wps->ap_nfc_dev_pw_id) {
  36                 wpa_printf(MSG_DEBUG, "WPS: Using NFC password token DH keys");
  37                 wps->dh_privkey = wpabuf_dup(wps->wps->ap_nfc_dh_privkey);
  38                 pubkey = wpabuf_dup(wps->wps->ap_nfc_dh_pubkey);
  39                 wps->dh_ctx = dh5_init_fixed(wps->dh_privkey, pubkey);
  40 #endif /* CONFIG_WPS_NFC */
  41         } else {
  42                 wpa_printf(MSG_DEBUG, "WPS: Generate new DH keys");
  43                 wps->dh_privkey = NULL;
  44                 dh5_free(wps->dh_ctx);
  45                 wps->dh_ctx = dh5_init(&wps->dh_privkey, &pubkey);
  46                 pubkey = wpabuf_zeropad(pubkey, 192);
  47         }
  48         if (wps->dh_ctx == NULL || wps->dh_privkey == NULL || pubkey == NULL) {
  49                 wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
  50                            "Diffie-Hellman handshake");
  51                 wpabuf_free(pubkey);
  52                 return -1;
  53         }
  54         wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH Private Key", wps->dh_privkey);
  55         wpa_hexdump_buf(MSG_DEBUG, "WPS: DH own Public Key", pubkey);
  56
  57         wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
  58         wpabuf_put_be16(msg, wpabuf_len(pubkey));
  59         wpabuf_put_buf(msg, pubkey);
  60
  61         if (wps->registrar) {
  62                 wpabuf_free(wps->dh_pubkey_r);
  63                 wps->dh_pubkey_r = pubkey;
  64         } else {
  65                 wpabuf_free(wps->dh_pubkey_e);
  66                 wps->dh_pubkey_e = pubkey;
  67         }
  68
  69         return 0;
  70 }
  71
  72
  73 int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
  74 {
  75         wpa_printf(MSG_DEBUG, "WPS:  * Request Type");
  76         wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
  77         wpabuf_put_be16(msg, 1);
  78         wpabuf_put_u8(msg, type);
  79         return 0;
  80 }
  81
  82
  83 int wps_build_resp_type(struct wpabuf *msg, enum wps_response_type type)
  84 {
  85         wpa_printf(MSG_DEBUG, "WPS:  * Response Type (%d)", type);
  86         wpabuf_put_be16(msg, ATTR_RESPONSE_TYPE);
  87         wpabuf_put_be16(msg, 1);
  88         wpabuf_put_u8(msg, type);
  89         return 0;
  90 }
  91
  92
  93 int wps_build_config_methods(struct wpabuf *msg, u16 methods)
  94 {
  95         wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
  96         wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
  97         wpabuf_put_be16(msg, 2);
  98         wpabuf_put_be16(msg, methods);
  99         return 0;
 100 }
 101
 102
 103 int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
 104 {
 105         wpa_printf(MSG_DEBUG, "WPS:  * UUID-E");
 106         wpabuf_put_be16(msg, ATTR_UUID_E);
 107         wpabuf_put_be16(msg, WPS_UUID_LEN);
 108         wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
 109         return 0;
 110 }
 111
 112
 113 int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
 114 {
 115         wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
 116         wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
 117         wpabuf_put_be16(msg, 2);
 118         wpabuf_put_be16(msg, id);
 119         return 0;
 120 }
 121
 122
 123 int wps_build_config_error(struct wpabuf *msg, u16 err)
 124 {
 125         wpa_printf(MSG_DEBUG, "WPS:  * Configuration Error (%d)", err);
 126         wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
 127         wpabuf_put_be16(msg, 2);
 128         wpabuf_put_be16(msg, err);
 129         return 0;
 130 }
 131
 132
 133 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
 134 {
 135         u8 hash[SHA256_MAC_LEN];
 136         const u8 *addr[2];
 137         size_t len[2];
 138
 139         if (wps->last_msg == NULL) {
 140                 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
 141                            "building authenticator");
 142                 return -1;
 143         }
 144
 145         /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
 146          * (M_curr* is M_curr without the Authenticator attribute)
 147          */
 148         addr[0] = wpabuf_head(wps->last_msg);
 149         len[0] = wpabuf_len(wps->last_msg);
 150         addr[1] = wpabuf_head(msg);
 151         len[1] = wpabuf_len(msg);
 152         hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
 153
 154         wpa_printf(MSG_DEBUG, "WPS:  * Authenticator");
 155         wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
 156         wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
 157         wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
 158
 159         return 0;
 160 }
 161
 162
 163 int wps_build_version(struct wpabuf *msg)
 164 {
 165         /*
 166          * Note: This attribute is deprecated and set to hardcoded 0x10 for
 167          * backwards compatibility reasons. The real version negotiation is
 168          * done with Version2.
 169          */
 170         wpa_printf(MSG_DEBUG, "WPS:  * Version (hardcoded 0x10)");
 171         wpabuf_put_be16(msg, ATTR_VERSION);
 172         wpabuf_put_be16(msg, 1);
 173         wpabuf_put_u8(msg, 0x10);
 174         return 0;
 175 }
 176
 177
 178 int wps_build_wfa_ext(struct wpabuf *msg, int req_to_enroll,
 179                       const u8 *auth_macs, size_t auth_macs_count)
 180 {
 181 #ifdef CONFIG_WPS2
 182         u8 *len;
 183
 184         wpabuf_put_be16(msg, ATTR_VENDOR_EXT);
 185         len = wpabuf_put(msg, 2); /* to be filled */
 186         wpabuf_put_be24(msg, WPS_VENDOR_ID_WFA);
 187
 188         wpa_printf(MSG_DEBUG, "WPS:  * Version2 (0x%x)", WPS_VERSION);
 189         wpabuf_put_u8(msg, WFA_ELEM_VERSION2);
 190         wpabuf_put_u8(msg, 1);
 191         wpabuf_put_u8(msg, WPS_VERSION);
 192
 193         if (req_to_enroll) {
 194                 wpa_printf(MSG_DEBUG, "WPS:  * Request to Enroll (1)");
 195                 wpabuf_put_u8(msg, WFA_ELEM_REQUEST_TO_ENROLL);
 196                 wpabuf_put_u8(msg, 1);
 197                 wpabuf_put_u8(msg, 1);
 198         }
 199
 200         if (auth_macs && auth_macs_count) {
 201                 size_t i;
 202                 wpa_printf(MSG_DEBUG, "WPS:  * AuthorizedMACs (count=%d)",
 203                            (int) auth_macs_count);
 204                 wpabuf_put_u8(msg, WFA_ELEM_AUTHORIZEDMACS);
 205                 wpabuf_put_u8(msg, auth_macs_count * ETH_ALEN);
 206                 wpabuf_put_data(msg, auth_macs, auth_macs_count * ETH_ALEN);
 207                 for (i = 0; i < auth_macs_count; i++)
 208                         wpa_printf(MSG_DEBUG, "WPS:    AuthorizedMAC: " MACSTR,
 209                                    MAC2STR(&auth_macs[i * ETH_ALEN]));
 210         }
 211
 212         WPA_PUT_BE16(len, (u8 *) wpabuf_put(msg, 0) - len - 2);
 213 #endif /* CONFIG_WPS2 */
 214
 215 #ifdef CONFIG_WPS_TESTING
 216         if (WPS_VERSION > 0x20) {
 217                 wpa_printf(MSG_DEBUG, "WPS:  * Extensibility Testing - extra "
 218                            "attribute");
 219                 wpabuf_put_be16(msg, ATTR_EXTENSIBILITY_TEST);
 220                 wpabuf_put_be16(msg, 1);
 221                 wpabuf_put_u8(msg, 42);
 222         }
 223 #endif /* CONFIG_WPS_TESTING */
 224         return 0;
 225 }
 226
 227
 228 int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
 229 {
 230         wpa_printf(MSG_DEBUG, "WPS:  * Message Type (%d)", msg_type);
 231         wpabuf_put_be16(msg, ATTR_MSG_TYPE);
 232         wpabuf_put_be16(msg, 1);
 233         wpabuf_put_u8(msg, msg_type);
 234         return 0;
 235 }
 236
 237
 238 int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
 239 {
 240         wpa_printf(MSG_DEBUG, "WPS:  * Enrollee Nonce");
 241         wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
 242         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 243         wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
 244         return 0;
 245 }
 246
 247
 248 int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
 249 {
 250         wpa_printf(MSG_DEBUG, "WPS:  * Registrar Nonce");
 251         wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
 252         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 253         wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
 254         return 0;
 255 }
 256
 257
 258 int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
 259 {
 260         u16 auth_types = WPS_AUTH_TYPES;
 261 #ifdef CONFIG_WPS2
 262         auth_types &= ~WPS_AUTH_SHARED;
 263 #endif /* CONFIG_WPS2 */
 264         wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type Flags");
 265         wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
 266         wpabuf_put_be16(msg, 2);
 267         wpabuf_put_be16(msg, auth_types);
 268         return 0;
 269 }
 270
 271
 272 int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
 273 {
 274         u16 encr_types = WPS_ENCR_TYPES;
 275 #ifdef CONFIG_WPS2
 276         encr_types &= ~WPS_ENCR_WEP;
 277 #endif /* CONFIG_WPS2 */
 278         wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type Flags");
 279         wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
 280         wpabuf_put_be16(msg, 2);
 281         wpabuf_put_be16(msg, encr_types);
 282         return 0;
 283 }
 284
 285
 286 int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
 287 {
 288         wpa_printf(MSG_DEBUG, "WPS:  * Connection Type Flags");
 289         wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
 290         wpabuf_put_be16(msg, 1);
 291         wpabuf_put_u8(msg, WPS_CONN_ESS);
 292         return 0;
 293 }
 294
 295
 296 int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
 297 {
 298         wpa_printf(MSG_DEBUG, "WPS:  * Association State");
 299         wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
 300         wpabuf_put_be16(msg, 2);
 301         wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
 302         return 0;
 303 }
 304
 305
 306 int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
 307 {
 308         u8 hash[SHA256_MAC_LEN];
 309
 310         wpa_printf(MSG_DEBUG, "WPS:  * Key Wrap Authenticator");
 311         hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
 312                     wpabuf_len(msg), hash);
 313
 314         wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
 315         wpabuf_put_be16(msg, WPS_KWA_LEN);
 316         wpabuf_put_data(msg, hash, WPS_KWA_LEN);
 317         return 0;
 318 }
 319
 320
 321 int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
 322                             struct wpabuf *plain)
 323 {
 324         size_t pad_len;
 325         const size_t block_size = 16;
 326         u8 *iv, *data;
 327
 328         wpa_printf(MSG_DEBUG, "WPS:  * Encrypted Settings");
 329
 330         /* PKCS#5 v2.0 pad */
 331         pad_len = block_size - wpabuf_len(plain) % block_size;
 332         os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
 333
 334         wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
 335         wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
 336
 337         iv = wpabuf_put(msg, block_size);
 338         if (random_get_bytes(iv, block_size) < 0)
 339                 return -1;
 340
 341         data = wpabuf_put(msg, 0);
 342         wpabuf_put_buf(msg, plain);
 343         if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
 344                 return -1;
 345
 346         return 0;
 347 }
 348
 349
 350 #ifdef CONFIG_WPS_OOB
 351 int wps_build_oob_dev_pw(struct wpabuf *msg, u16 dev_pw_id,
 352                          const struct wpabuf *pubkey, const u8 *dev_pw,
 353                          size_t dev_pw_len)
 354 {
 355         size_t hash_len;
 356         const u8 *addr[1];
 357         u8 pubkey_hash[WPS_HASH_LEN];
 358
 359         addr[0] = wpabuf_head(pubkey);
 360         hash_len = wpabuf_len(pubkey);
 361         sha256_vector(1, addr, &hash_len, pubkey_hash);
 362
 363         wpabuf_put_be16(msg, ATTR_OOB_DEVICE_PASSWORD);
 364         wpabuf_put_be16(msg, WPS_OOB_PUBKEY_HASH_LEN + 2 + dev_pw_len);
 365         wpabuf_put_data(msg, pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
 366         wpabuf_put_be16(msg, dev_pw_id);
 367         wpabuf_put_data(msg, dev_pw, dev_pw_len);
 368
 369         return 0;
 370 }
 371 #endif /* CONFIG_WPS_OOB */
 372
 373
 374 /* Encapsulate WPS IE data with one (or more, if needed) IE headers */
 375 struct wpabuf * wps_ie_encapsulate(struct wpabuf *data)
 376 {
 377         struct wpabuf *ie;
 378         const u8 *pos, *end;
 379
 380         ie = wpabuf_alloc(wpabuf_len(data) + 100);
 381         if (ie == NULL) {
 382                 wpabuf_free(data);
 383                 return NULL;
 384         }
 385
 386         pos = wpabuf_head(data);
 387         end = pos + wpabuf_len(data);
 388
 389         while (end > pos) {
 390                 size_t frag_len = end - pos;
 391                 if (frag_len > 251)
 392                         frag_len = 251;
 393                 wpabuf_put_u8(ie, WLAN_EID_VENDOR_SPECIFIC);
 394                 wpabuf_put_u8(ie, 4 + frag_len);
 395                 wpabuf_put_be32(ie, WPS_DEV_OUI_WFA);
 396                 wpabuf_put_data(ie, pos, frag_len);
 397                 pos += frag_len;
 398         }
 399
 400         wpabuf_free(data);
 401
 402         return ie;
 403 }