src/wps/wps_attr_process.c

   1 /*
   2  * Wi-Fi Protected Setup - attribute processing
   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 "crypto/sha256.h"
  19 #include "wps_i.h"
  20
  21
  22 int wps_process_authenticator(struct wps_data *wps, const u8 *authenticator,
  23                               const struct wpabuf *msg)
  24 {
  25         u8 hash[SHA256_MAC_LEN];
  26         const u8 *addr[2];
  27         size_t len[2];
  28
  29         if (authenticator == NULL) {
  30                 wpa_printf(MSG_DEBUG, "WPS: No Authenticator attribute "
  31                            "included");
  32                 return -1;
  33         }
  34
  35         if (wps->last_msg == NULL) {
  36                 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
  37                            "validating authenticator");
  38                 return -1;
  39         }
  40
  41         /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
  42          * (M_curr* is M_curr without the Authenticator attribute)
  43          */
  44         addr[0] = wpabuf_head(wps->last_msg);
  45         len[0] = wpabuf_len(wps->last_msg);
  46         addr[1] = wpabuf_head(msg);
  47         len[1] = wpabuf_len(msg) - 4 - WPS_AUTHENTICATOR_LEN;
  48         hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
  49
  50         if (os_memcmp(hash, authenticator, WPS_AUTHENTICATOR_LEN) != 0) {
  51                 wpa_printf(MSG_DEBUG, "WPS: Incorrect Authenticator");
  52                 return -1;
  53         }
  54
  55         return 0;
  56 }
  57
  58
  59 int wps_process_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg,
  60                               const u8 *key_wrap_auth)
  61 {
  62         u8 hash[SHA256_MAC_LEN];
  63         const u8 *head;
  64         size_t len;
  65
  66         if (key_wrap_auth == NULL) {
  67                 wpa_printf(MSG_DEBUG, "WPS: No KWA in decrypted attribute");
  68                 return -1;
  69         }
  70
  71         head = wpabuf_head(msg);
  72         len = wpabuf_len(msg) - 4 - WPS_KWA_LEN;
  73         if (head + len != key_wrap_auth - 4) {
  74                 wpa_printf(MSG_DEBUG, "WPS: KWA not in the end of the "
  75                            "decrypted attribute");
  76                 return -1;
  77         }
  78
  79         hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, head, len, hash);
  80         if (os_memcmp(hash, key_wrap_auth, WPS_KWA_LEN) != 0) {
  81                 wpa_printf(MSG_DEBUG, "WPS: Invalid KWA");
  82                 return -1;
  83         }
  84
  85         return 0;
  86 }
  87
  88
  89 static int wps_process_cred_network_idx(struct wps_credential *cred,
  90                                         const u8 *idx)
  91 {
  92         if (idx == NULL) {
  93                 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
  94                            "Network Index");
  95                 return -1;
  96         }
  97
  98         wpa_printf(MSG_DEBUG, "WPS: Network Index: %d", *idx);
  99
 100         return 0;
 101 }
 102
 103
 104 static int wps_process_cred_ssid(struct wps_credential *cred, const u8 *ssid,
 105                                  size_t ssid_len)
 106 {
 107         if (ssid == NULL) {
 108                 wpa_printf(MSG_DEBUG, "WPS: Credential did not include SSID");
 109                 return -1;
 110         }
 111
 112         /* Remove zero-padding since some Registrar implementations seem to use
 113          * hardcoded 32-octet length for this attribute */
 114         while (ssid_len > 0 && ssid[ssid_len - 1] == 0)
 115                 ssid_len--;
 116
 117         wpa_hexdump_ascii(MSG_DEBUG, "WPS: SSID", ssid, ssid_len);
 118         if (ssid_len <= sizeof(cred->ssid)) {
 119                 os_memcpy(cred->ssid, ssid, ssid_len);
 120                 cred->ssid_len = ssid_len;
 121         }
 122
 123         return 0;
 124 }
 125
 126
 127 static int wps_process_cred_auth_type(struct wps_credential *cred,
 128                                       const u8 *auth_type)
 129 {
 130         if (auth_type == NULL) {
 131                 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
 132                            "Authentication Type");
 133                 return -1;
 134         }
 135
 136         cred->auth_type = WPA_GET_BE16(auth_type);
 137         wpa_printf(MSG_DEBUG, "WPS: Authentication Type: 0x%x",
 138                    cred->auth_type);
 139
 140         return 0;
 141 }
 142
 143
 144 static int wps_process_cred_encr_type(struct wps_credential *cred,
 145                                       const u8 *encr_type)
 146 {
 147         if (encr_type == NULL) {
 148                 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
 149                            "Encryption Type");
 150                 return -1;
 151         }
 152
 153         cred->encr_type = WPA_GET_BE16(encr_type);
 154         wpa_printf(MSG_DEBUG, "WPS: Encryption Type: 0x%x",
 155                    cred->encr_type);
 156
 157         return 0;
 158 }
 159
 160
 161 static int wps_process_cred_network_key_idx(struct wps_credential *cred,
 162                                             const u8 *key_idx)
 163 {
 164         if (key_idx == NULL)
 165                 return 0; /* optional attribute */
 166
 167         wpa_printf(MSG_DEBUG, "WPS: Network Key Index: %d", *key_idx);
 168         cred->key_idx = *key_idx;
 169
 170         return 0;
 171 }
 172
 173
 174 static int wps_process_cred_network_key(struct wps_credential *cred,
 175                                         const u8 *key, size_t key_len)
 176 {
 177         if (key == NULL) {
 178                 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
 179                            "Network Key");
 180                 return -1;
 181         }
 182
 183         wpa_hexdump_key(MSG_DEBUG, "WPS: Network Key", key, key_len);
 184         if (key_len <= sizeof(cred->key)) {
 185                 os_memcpy(cred->key, key, key_len);
 186                 cred->key_len = key_len;
 187         }
 188
 189         return 0;
 190 }
 191
 192
 193 static int wps_process_cred_mac_addr(struct wps_credential *cred,
 194                                      const u8 *mac_addr)
 195 {
 196         if (mac_addr == NULL) {
 197                 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
 198                            "MAC Address");
 199                 return -1;
 200         }
 201
 202         wpa_printf(MSG_DEBUG, "WPS: MAC Address " MACSTR, MAC2STR(mac_addr));
 203         os_memcpy(cred->mac_addr, mac_addr, ETH_ALEN);
 204
 205         return 0;
 206 }
 207
 208
 209 static int wps_process_cred_eap_type(struct wps_credential *cred,
 210                                      const u8 *eap_type, size_t eap_type_len)
 211 {
 212         if (eap_type == NULL)
 213                 return 0; /* optional attribute */
 214
 215         wpa_hexdump(MSG_DEBUG, "WPS: EAP Type", eap_type, eap_type_len);
 216
 217         return 0;
 218 }
 219
 220
 221 static int wps_process_cred_eap_identity(struct wps_credential *cred,
 222                                          const u8 *identity,
 223                                          size_t identity_len)
 224 {
 225         if (identity == NULL)
 226                 return 0; /* optional attribute */
 227
 228         wpa_hexdump_ascii(MSG_DEBUG, "WPS: EAP Identity",
 229                           identity, identity_len);
 230
 231         return 0;
 232 }
 233
 234
 235 static int wps_process_cred_key_prov_auto(struct wps_credential *cred,
 236                                           const u8 *key_prov_auto)
 237 {
 238         if (key_prov_auto == NULL)
 239                 return 0; /* optional attribute */
 240
 241         wpa_printf(MSG_DEBUG, "WPS: Key Provided Automatically: %d",
 242                    *key_prov_auto);
 243
 244         return 0;
 245 }
 246
 247
 248 static int wps_process_cred_802_1x_enabled(struct wps_credential *cred,
 249                                            const u8 *dot1x_enabled)
 250 {
 251         if (dot1x_enabled == NULL)
 252                 return 0; /* optional attribute */
 253
 254         wpa_printf(MSG_DEBUG, "WPS: 802.1X Enabled: %d", *dot1x_enabled);
 255
 256         return 0;
 257 }
 258
 259
 260 static void wps_workaround_cred_key(struct wps_credential *cred)
 261 {
 262         if (cred->auth_type & (WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK) &&
 263             cred->key_len > 8 && cred->key_len < 64 &&
 264             cred->key[cred->key_len - 1] == 0) {
 265                 /*
 266                  * A deployed external registrar is known to encode ASCII
 267                  * passphrases incorrectly. Remove the extra NULL termination
 268                  * to fix the encoding.
 269                  */
 270                 wpa_printf(MSG_DEBUG, "WPS: Workaround - remove NULL "
 271                            "termination from ASCII passphrase");
 272                 cred->key_len--;
 273         }
 274 }
 275
 276
 277 int wps_process_cred(struct wps_parse_attr *attr,
 278                      struct wps_credential *cred)
 279 {
 280         wpa_printf(MSG_DEBUG, "WPS: Process Credential");
 281
 282         /* TODO: support multiple Network Keys */
 283         if (wps_process_cred_network_idx(cred, attr->network_idx) ||
 284             wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
 285             wps_process_cred_auth_type(cred, attr->auth_type) ||
 286             wps_process_cred_encr_type(cred, attr->encr_type) ||
 287             wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
 288             wps_process_cred_network_key(cred, attr->network_key,
 289                                          attr->network_key_len) ||
 290             wps_process_cred_mac_addr(cred, attr->mac_addr) ||
 291             wps_process_cred_eap_type(cred, attr->eap_type,
 292                                       attr->eap_type_len) ||
 293             wps_process_cred_eap_identity(cred, attr->eap_identity,
 294                                           attr->eap_identity_len) ||
 295             wps_process_cred_key_prov_auto(cred, attr->key_prov_auto) ||
 296             wps_process_cred_802_1x_enabled(cred, attr->dot1x_enabled))
 297                 return -1;
 298
 299         wps_workaround_cred_key(cred);
 300
 301         return 0;
 302 }
 303
 304
 305 int wps_process_ap_settings(struct wps_parse_attr *attr,
 306                             struct wps_credential *cred)
 307 {
 308         wpa_printf(MSG_DEBUG, "WPS: Processing AP Settings");
 309         os_memset(cred, 0, sizeof(*cred));
 310         /* TODO: optional attributes New Password and Device Password ID */
 311         if (wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
 312             wps_process_cred_auth_type(cred, attr->auth_type) ||
 313             wps_process_cred_encr_type(cred, attr->encr_type) ||
 314             wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
 315             wps_process_cred_network_key(cred, attr->network_key,
 316                                          attr->network_key_len) ||
 317             wps_process_cred_mac_addr(cred, attr->mac_addr))
 318                 return -1;
 319
 320         wps_workaround_cred_key(cred);
 321
 322         return 0;
 323 }