contrib/hostapd/src/eap_peer/eap_tnc.c

   1 /*
   2  * EAP peer method: EAP-TNC (Trusted Network Connect)
   3  * Copyright (c) 2007, 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 "eap_i.h"
  13 #include "tncc.h"
  14
  15
  16 struct eap_tnc_data {
  17         enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
  18         struct tncc_data *tncc;
  19         struct wpabuf *in_buf;
  20         struct wpabuf *out_buf;
  21         size_t out_used;
  22         size_t fragment_size;
  23 };
  24
  25
  26 /* EAP-TNC Flags */
  27 #define EAP_TNC_FLAGS_LENGTH_INCLUDED 0x80
  28 #define EAP_TNC_FLAGS_MORE_FRAGMENTS 0x40
  29 #define EAP_TNC_FLAGS_START 0x20
  30 #define EAP_TNC_VERSION_MASK 0x07
  31
  32 #define EAP_TNC_VERSION 1
  33
  34
  35 static void * eap_tnc_init(struct eap_sm *sm)
  36 {
  37         struct eap_tnc_data *data;
  38
  39         data = os_zalloc(sizeof(*data));
  40         if (data == NULL)
  41                 return NULL;
  42         data->state = WAIT_START;
  43         data->fragment_size = 1300;
  44         data->tncc = tncc_init();
  45         if (data->tncc == NULL) {
  46                 os_free(data);
  47                 return NULL;
  48         }
  49
  50         return data;
  51 }
  52
  53
  54 static void eap_tnc_deinit(struct eap_sm *sm, void *priv)
  55 {
  56         struct eap_tnc_data *data = priv;
  57
  58         wpabuf_free(data->in_buf);
  59         wpabuf_free(data->out_buf);
  60         tncc_deinit(data->tncc);
  61         os_free(data);
  62 }
  63
  64
  65 static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
  66 {
  67         struct wpabuf *msg;
  68
  69         msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, code, id);
  70         if (msg == NULL) {
  71                 wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
  72                            "for fragment ack");
  73                 return NULL;
  74         }
  75         wpabuf_put_u8(msg, EAP_TNC_VERSION); /* Flags */
  76
  77         wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
  78
  79         return msg;
  80 }
  81
  82
  83 static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data,
  84                                          struct eap_method_ret *ret, u8 id)
  85 {
  86         struct wpabuf *resp;
  87         u8 flags;
  88         size_t send_len, plen;
  89
  90         ret->ignore = FALSE;
  91         wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Response");
  92         ret->allowNotifications = TRUE;
  93
  94         flags = EAP_TNC_VERSION;
  95         send_len = wpabuf_len(data->out_buf) - data->out_used;
  96         if (1 + send_len > data->fragment_size) {
  97                 send_len = data->fragment_size - 1;
  98                 flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
  99                 if (data->out_used == 0) {
 100                         flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
 101                         send_len -= 4;
 102                 }
 103         }
 104
 105         plen = 1 + send_len;
 106         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 107                 plen += 4;
 108         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
 109                              EAP_CODE_RESPONSE, id);
 110         if (resp == NULL)
 111                 return NULL;
 112
 113         wpabuf_put_u8(resp, flags); /* Flags */
 114         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 115                 wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
 116
 117         wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
 118                         send_len);
 119         data->out_used += send_len;
 120
 121         ret->methodState = METHOD_MAY_CONT;
 122         ret->decision = DECISION_FAIL;
 123
 124         if (data->out_used == wpabuf_len(data->out_buf)) {
 125                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 126                            "(message sent completely)",
 127                            (unsigned long) send_len);
 128                 wpabuf_free(data->out_buf);
 129                 data->out_buf = NULL;
 130                 data->out_used = 0;
 131         } else {
 132                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 133                            "(%lu more to send)", (unsigned long) send_len,
 134                            (unsigned long) wpabuf_len(data->out_buf) -
 135                            data->out_used);
 136                 data->state = WAIT_FRAG_ACK;
 137         }
 138
 139         return resp;
 140 }
 141
 142
 143 static int eap_tnc_process_cont(struct eap_tnc_data *data,
 144                                 const u8 *buf, size_t len)
 145 {
 146         /* Process continuation of a pending message */
 147         if (len > wpabuf_tailroom(data->in_buf)) {
 148                 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
 149                 data->state = FAIL;
 150                 return -1;
 151         }
 152
 153         wpabuf_put_data(data->in_buf, buf, len);
 154         wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for "
 155                    "%lu bytes more", (unsigned long) len,
 156                    (unsigned long) wpabuf_tailroom(data->in_buf));
 157
 158         return 0;
 159 }
 160
 161
 162 static struct wpabuf * eap_tnc_process_fragment(struct eap_tnc_data *data,
 163                                                 struct eap_method_ret *ret,
 164                                                 u8 id, u8 flags,
 165                                                 u32 message_length,
 166                                                 const u8 *buf, size_t len)
 167 {
 168         /* Process a fragment that is not the last one of the message */
 169         if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
 170                 wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
 171                            "fragmented packet");
 172                 ret->ignore = TRUE;
 173                 return NULL;
 174         }
 175
 176         if (data->in_buf == NULL) {
 177                 /* First fragment of the message */
 178                 data->in_buf = wpabuf_alloc(message_length);
 179                 if (data->in_buf == NULL) {
 180                         wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
 181                                    "message");
 182                         ret->ignore = TRUE;
 183                         return NULL;
 184                 }
 185                 wpabuf_put_data(data->in_buf, buf, len);
 186                 wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
 187                            "fragment, waiting for %lu bytes more",
 188                            (unsigned long) len,
 189                            (unsigned long) wpabuf_tailroom(data->in_buf));
 190         }
 191
 192         return eap_tnc_build_frag_ack(id, EAP_CODE_RESPONSE);
 193 }
 194
 195
 196 static struct wpabuf * eap_tnc_process(struct eap_sm *sm, void *priv,
 197                                        struct eap_method_ret *ret,
 198                                        const struct wpabuf *reqData)
 199 {
 200         struct eap_tnc_data *data = priv;
 201         struct wpabuf *resp;
 202         const u8 *pos, *end;
 203         u8 *rpos, *rpos1;
 204         size_t len, rlen;
 205         size_t imc_len;
 206         char *start_buf, *end_buf;
 207         size_t start_len, end_len;
 208         int tncs_done = 0;
 209         u8 flags, id;
 210         u32 message_length = 0;
 211         struct wpabuf tmpbuf;
 212
 213         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, reqData, &len);
 214         if (pos == NULL) {
 215                 wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (pos=%p len=%lu)",
 216                            pos, (unsigned long) len);
 217                 ret->ignore = TRUE;
 218                 return NULL;
 219         }
 220
 221         id = eap_get_id(reqData);
 222
 223         end = pos + len;
 224
 225         if (len == 0)
 226                 flags = 0; /* fragment ack */
 227         else
 228                 flags = *pos++;
 229
 230         if (len > 0 && (flags & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
 231                 wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
 232                            flags & EAP_TNC_VERSION_MASK);
 233                 ret->ignore = TRUE;
 234                 return NULL;
 235         }
 236
 237         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
 238                 if (end - pos < 4) {
 239                         wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
 240                         ret->ignore = TRUE;
 241                         return NULL;
 242                 }
 243                 message_length = WPA_GET_BE32(pos);
 244                 pos += 4;
 245
 246                 if (message_length < (u32) (end - pos)) {
 247                         wpa_printf(MSG_DEBUG, "EAP-TNC: Invalid Message "
 248                                    "Length (%d; %ld remaining in this msg)",
 249                                    message_length, (long) (end - pos));
 250                         ret->ignore = TRUE;
 251                         return NULL;
 252                 }
 253         }
 254
 255         wpa_printf(MSG_DEBUG, "EAP-TNC: Received packet: Flags 0x%x "
 256                    "Message Length %u", flags, message_length);
 257
 258         if (data->state == WAIT_FRAG_ACK) {
 259                 if (len > 1) {
 260                         wpa_printf(MSG_DEBUG, "EAP-TNC: Unexpected payload in "
 261                                    "WAIT_FRAG_ACK state");
 262                         ret->ignore = TRUE;
 263                         return NULL;
 264                 }
 265                 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment acknowledged");
 266                 data->state = PROC_MSG;
 267                 return eap_tnc_build_msg(data, ret, id);
 268         }
 269
 270         if (data->in_buf && eap_tnc_process_cont(data, pos, end - pos) < 0) {
 271                 ret->ignore = TRUE;
 272                 return NULL;
 273         }
 274
 275         if (flags & EAP_TNC_FLAGS_MORE_FRAGMENTS) {
 276                 return eap_tnc_process_fragment(data, ret, id, flags,
 277                                                 message_length, pos,
 278                                                 end - pos);
 279         }
 280
 281         if (data->in_buf == NULL) {
 282                 /* Wrap unfragmented messages as wpabuf without extra copy */
 283                 wpabuf_set(&tmpbuf, pos, end - pos);
 284                 data->in_buf = &tmpbuf;
 285         }
 286
 287         if (data->state == WAIT_START) {
 288                 if (!(flags & EAP_TNC_FLAGS_START)) {
 289                         wpa_printf(MSG_DEBUG, "EAP-TNC: Server did not use "
 290                                    "start flag in the first message");
 291                         ret->ignore = TRUE;
 292                         goto fail;
 293                 }
 294
 295                 tncc_init_connection(data->tncc);
 296
 297                 data->state = PROC_MSG;
 298         } else {
 299                 enum tncc_process_res res;
 300
 301                 if (flags & EAP_TNC_FLAGS_START) {
 302                         wpa_printf(MSG_DEBUG, "EAP-TNC: Server used start "
 303                                    "flag again");
 304                         ret->ignore = TRUE;
 305                         goto fail;
 306                 }
 307
 308                 res = tncc_process_if_tnccs(data->tncc,
 309                                             wpabuf_head(data->in_buf),
 310                                             wpabuf_len(data->in_buf));
 311                 switch (res) {
 312                 case TNCCS_PROCESS_ERROR:
 313                         ret->ignore = TRUE;
 314                         goto fail;
 315                 case TNCCS_PROCESS_OK_NO_RECOMMENDATION:
 316                 case TNCCS_RECOMMENDATION_ERROR:
 317                         wpa_printf(MSG_DEBUG, "EAP-TNC: No "
 318                                    "TNCCS-Recommendation received");
 319                         break;
 320                 case TNCCS_RECOMMENDATION_ALLOW:
 321                         wpa_msg(sm->msg_ctx, MSG_INFO,
 322                                 "TNC: Recommendation = allow");
 323                         tncs_done = 1;
 324                         break;
 325                 case TNCCS_RECOMMENDATION_NONE:
 326                         wpa_msg(sm->msg_ctx, MSG_INFO,
 327                                 "TNC: Recommendation = none");
 328                         tncs_done = 1;
 329                         break;
 330                 case TNCCS_RECOMMENDATION_ISOLATE:
 331                         wpa_msg(sm->msg_ctx, MSG_INFO,
 332                                 "TNC: Recommendation = isolate");
 333                         tncs_done = 1;
 334                         break;
 335                 }
 336         }
 337
 338         if (data->in_buf != &tmpbuf)
 339                 wpabuf_free(data->in_buf);
 340         data->in_buf = NULL;
 341
 342         ret->ignore = FALSE;
 343         ret->methodState = METHOD_MAY_CONT;
 344         ret->decision = DECISION_UNCOND_SUCC;
 345         ret->allowNotifications = TRUE;
 346
 347         if (data->out_buf) {
 348                 data->state = PROC_MSG;
 349                 return eap_tnc_build_msg(data, ret, id);
 350         }
 351
 352         if (tncs_done) {
 353                 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1,
 354                                      EAP_CODE_RESPONSE, eap_get_id(reqData));
 355                 if (resp == NULL)
 356                         return NULL;
 357
 358                 wpabuf_put_u8(resp, EAP_TNC_VERSION);
 359                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS done - reply with an "
 360                            "empty ACK message");
 361                 return resp;
 362         }
 363
 364         imc_len = tncc_total_send_len(data->tncc);
 365
 366         start_buf = tncc_if_tnccs_start(data->tncc);
 367         if (start_buf == NULL)
 368                 return NULL;
 369         start_len = os_strlen(start_buf);
 370         end_buf = tncc_if_tnccs_end();
 371         if (end_buf == NULL) {
 372                 os_free(start_buf);
 373                 return NULL;
 374         }
 375         end_len = os_strlen(end_buf);
 376
 377         rlen = start_len + imc_len + end_len;
 378         resp = wpabuf_alloc(rlen);
 379         if (resp == NULL) {
 380                 os_free(start_buf);
 381                 os_free(end_buf);
 382                 return NULL;
 383         }
 384
 385         wpabuf_put_data(resp, start_buf, start_len);
 386         os_free(start_buf);
 387
 388         rpos1 = wpabuf_put(resp, 0);
 389         rpos = tncc_copy_send_buf(data->tncc, rpos1);
 390         wpabuf_put(resp, rpos - rpos1);
 391
 392         wpabuf_put_data(resp, end_buf, end_len);
 393         os_free(end_buf);
 394
 395         wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Response",
 396                           wpabuf_head(resp), wpabuf_len(resp));
 397
 398         data->out_buf = resp;
 399         data->state = PROC_MSG;
 400         return eap_tnc_build_msg(data, ret, id);
 401
 402 fail:
 403         if (data->in_buf == &tmpbuf)
 404                 data->in_buf = NULL;
 405         return NULL;
 406 }
 407
 408
 409 int eap_peer_tnc_register(void)
 410 {
 411         struct eap_method *eap;
 412         int ret;
 413
 414         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 415                                     EAP_VENDOR_IETF, EAP_TYPE_TNC, "TNC");
 416         if (eap == NULL)
 417                 return -1;
 418
 419         eap->init = eap_tnc_init;
 420         eap->deinit = eap_tnc_deinit;
 421         eap->process = eap_tnc_process;
 422
 423         ret = eap_peer_method_register(eap);
 424         if (ret)
 425                 eap_peer_method_free(eap);
 426         return ret;
 427 }