contrib/hostapd/eap_tls.c

   1 /*
   2  * hostapd / EAP-TLS (RFC 2716)
   3  * Copyright (c) 2004-2007, 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 "hostapd.h"
  18 #include "common.h"
  19 #include "eap_i.h"
  20 #include "eap_tls_common.h"
  21 #include "tls.h"
  22
  23
  24 static void eap_tls_reset(struct eap_sm *sm, void *priv);
  25
  26
  27 struct eap_tls_data {
  28         struct eap_ssl_data ssl;
  29         enum { START, CONTINUE, SUCCESS, FAILURE } state;
  30 };
  31
  32
  33 static void * eap_tls_init(struct eap_sm *sm)
  34 {
  35         struct eap_tls_data *data;
  36
  37         data = wpa_zalloc(sizeof(*data));
  38         if (data == NULL)
  39                 return NULL;
  40         data->state = START;
  41
  42         if (eap_tls_ssl_init(sm, &data->ssl, 1)) {
  43                 wpa_printf(MSG_INFO, "EAP-TLS: Failed to initialize SSL.");
  44                 eap_tls_reset(sm, data);
  45                 return NULL;
  46         }
  47
  48         return data;
  49 }
  50
  51
  52 static void eap_tls_reset(struct eap_sm *sm, void *priv)
  53 {
  54         struct eap_tls_data *data = priv;
  55         if (data == NULL)
  56                 return;
  57         eap_tls_ssl_deinit(sm, &data->ssl);
  58         free(data);
  59 }
  60
  61
  62 static u8 * eap_tls_build_start(struct eap_sm *sm, struct eap_tls_data *data,
  63                                 int id, size_t *reqDataLen)
  64 {
  65         struct eap_hdr *req;
  66         u8 *pos;
  67
  68         *reqDataLen = sizeof(*req) + 2;
  69         req = malloc(*reqDataLen);
  70         if (req == NULL) {
  71                 wpa_printf(MSG_ERROR, "EAP-TLS: Failed to allocate memory for "
  72                            "request");
  73                 data->state = FAILURE;
  74                 return NULL;
  75         }
  76
  77         req->code = EAP_CODE_REQUEST;
  78         req->identifier = id;
  79         req->length = htons(*reqDataLen);
  80         pos = (u8 *) (req + 1);
  81         *pos++ = EAP_TYPE_TLS;
  82         *pos = EAP_TLS_FLAGS_START;
  83
  84         data->state = CONTINUE;
  85
  86         return (u8 *) req;
  87 }
  88
  89
  90 static u8 * eap_tls_build_req(struct eap_sm *sm, struct eap_tls_data *data,
  91                               int id, size_t *reqDataLen)
  92 {
  93         int res;
  94         u8 *req;
  95
  96         res = eap_tls_buildReq_helper(sm, &data->ssl, EAP_TYPE_TLS, 0, id,
  97                                       &req, reqDataLen);
  98
  99         if (tls_connection_established(sm->ssl_ctx, data->ssl.conn)) {
 100                 wpa_printf(MSG_DEBUG, "EAP-TLS: Done");
 101                 data->state = SUCCESS;
 102         }
 103
 104         if (res == 1)
 105                 return eap_tls_build_ack(reqDataLen, id, EAP_TYPE_TLS, 0);
 106         return req;
 107 }
 108
 109
 110 static u8 * eap_tls_buildReq(struct eap_sm *sm, void *priv, int id,
 111                              size_t *reqDataLen)
 112 {
 113         struct eap_tls_data *data = priv;
 114
 115         switch (data->state) {
 116         case START:
 117                 return eap_tls_build_start(sm, data, id, reqDataLen);
 118         case CONTINUE:
 119                 return eap_tls_build_req(sm, data, id, reqDataLen);
 120         default:
 121                 wpa_printf(MSG_DEBUG, "EAP-TLS: %s - unexpected state %d",
 122                            __func__, data->state);
 123                 return NULL;
 124         }
 125 }
 126
 127
 128 static Boolean eap_tls_check(struct eap_sm *sm, void *priv,
 129                              u8 *respData, size_t respDataLen)
 130 {
 131         struct eap_hdr *resp;
 132         u8 *pos;
 133
 134         resp = (struct eap_hdr *) respData;
 135         pos = (u8 *) (resp + 1);
 136         if (respDataLen < sizeof(*resp) + 2 || *pos != EAP_TYPE_TLS ||
 137             (ntohs(resp->length)) > respDataLen) {
 138                 wpa_printf(MSG_INFO, "EAP-TLS: Invalid frame");
 139                 return TRUE;
 140         }
 141
 142         return FALSE;
 143 }
 144
 145
 146 static void eap_tls_process(struct eap_sm *sm, void *priv,
 147                             u8 *respData, size_t respDataLen)
 148 {
 149         struct eap_tls_data *data = priv;
 150         struct eap_hdr *resp;
 151         u8 *pos, flags;
 152         int left;
 153         unsigned int tls_msg_len;
 154
 155         resp = (struct eap_hdr *) respData;
 156         pos = (u8 *) (resp + 1);
 157         pos++;
 158         flags = *pos++;
 159         left = htons(resp->length) - sizeof(struct eap_hdr) - 2;
 160         wpa_printf(MSG_DEBUG, "EAP-TLS: Received packet(len=%lu) - "
 161                    "Flags 0x%02x", (unsigned long) respDataLen, flags);
 162         if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) {
 163                 if (left < 4) {
 164                         wpa_printf(MSG_INFO, "EAP-TLS: Short frame with TLS "
 165                                    "length");
 166                         data->state = FAILURE;
 167                         return;
 168                 }
 169                 tls_msg_len = (pos[0] << 24) | (pos[1] << 16) | (pos[2] << 8) |
 170                         pos[3];
 171                 wpa_printf(MSG_DEBUG, "EAP-TLS: TLS Message Length: %d",
 172                            tls_msg_len);
 173                 if (data->ssl.tls_in_left == 0) {
 174                         data->ssl.tls_in_total = tls_msg_len;
 175                         data->ssl.tls_in_left = tls_msg_len;
 176                         free(data->ssl.tls_in);
 177                         data->ssl.tls_in = NULL;
 178                         data->ssl.tls_in_len = 0;
 179                 }
 180                 pos += 4;
 181                 left -= 4;
 182         }
 183
 184         if (eap_tls_process_helper(sm, &data->ssl, pos, left) < 0) {
 185                 wpa_printf(MSG_INFO, "EAP-TLS: TLS processing failed");
 186                 data->state = FAILURE;
 187                 return;
 188         }
 189
 190         if (tls_connection_get_write_alerts(sm->ssl_ctx, data->ssl.conn) > 1) {
 191                 wpa_printf(MSG_INFO, "EAP-TLS: Locally detected fatal error "
 192                            "in TLS processing");
 193                 data->state = FAILURE;
 194                 return;
 195         }
 196 }
 197
 198
 199 static Boolean eap_tls_isDone(struct eap_sm *sm, void *priv)
 200 {
 201         struct eap_tls_data *data = priv;
 202         return data->state == SUCCESS || data->state == FAILURE;
 203 }
 204
 205
 206 static u8 * eap_tls_getKey(struct eap_sm *sm, void *priv, size_t *len)
 207 {
 208         struct eap_tls_data *data = priv;
 209         u8 *eapKeyData;
 210
 211         if (data->state != SUCCESS)
 212                 return NULL;
 213
 214         eapKeyData = eap_tls_derive_key(sm, &data->ssl,
 215                                         "client EAP encryption",
 216                                         EAP_TLS_KEY_LEN);
 217         if (eapKeyData) {
 218                 *len = EAP_TLS_KEY_LEN;
 219                 wpa_hexdump(MSG_DEBUG, "EAP-TLS: Derived key",
 220                             eapKeyData, EAP_TLS_KEY_LEN);
 221         } else {
 222                 wpa_printf(MSG_DEBUG, "EAP-TLS: Failed to derive key");
 223         }
 224
 225         return eapKeyData;
 226 }
 227
 228
 229 static u8 * eap_tls_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 230 {
 231         struct eap_tls_data *data = priv;
 232         u8 *eapKeyData, *emsk;
 233
 234         if (data->state != SUCCESS)
 235                 return NULL;
 236
 237         eapKeyData = eap_tls_derive_key(sm, &data->ssl,
 238                                         "client EAP encryption",
 239                                         EAP_TLS_KEY_LEN + EAP_EMSK_LEN);
 240         if (eapKeyData) {
 241                 emsk = malloc(EAP_EMSK_LEN);
 242                 if (emsk)
 243                         memcpy(emsk, eapKeyData + EAP_TLS_KEY_LEN,
 244                                EAP_EMSK_LEN);
 245                 free(eapKeyData);
 246         } else
 247                 emsk = NULL;
 248
 249         if (emsk) {
 250                 *len = EAP_EMSK_LEN;
 251                 wpa_hexdump(MSG_DEBUG, "EAP-TLS: Derived EMSK",
 252                             emsk, EAP_EMSK_LEN);
 253         } else {
 254                 wpa_printf(MSG_DEBUG, "EAP-TLS: Failed to derive EMSK");
 255         }
 256
 257         return emsk;
 258 }
 259
 260
 261 static Boolean eap_tls_isSuccess(struct eap_sm *sm, void *priv)
 262 {
 263         struct eap_tls_data *data = priv;
 264         return data->state == SUCCESS;
 265 }
 266
 267
 268 int eap_server_tls_register(void)
 269 {
 270         struct eap_method *eap;
 271         int ret;
 272
 273         eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
 274                                       EAP_VENDOR_IETF, EAP_TYPE_TLS, "TLS");
 275         if (eap == NULL)
 276                 return -1;
 277
 278         eap->init = eap_tls_init;
 279         eap->reset = eap_tls_reset;
 280         eap->buildReq = eap_tls_buildReq;
 281         eap->check = eap_tls_check;
 282         eap->process = eap_tls_process;
 283         eap->isDone = eap_tls_isDone;
 284         eap->getKey = eap_tls_getKey;
 285         eap->isSuccess = eap_tls_isSuccess;
 286         eap->get_emsk = eap_tls_get_emsk;
 287
 288         ret = eap_server_method_register(eap);
 289         if (ret)
 290                 eap_server_method_free(eap);
 291         return ret;
 292 }