contrib/hostapd/src/eap_server/eap_tnc.c

   1 /*
   2  * EAP server method: EAP-TNC (Trusted Network Connect)
   3  * Copyright (c) 2007-2008, 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 "base64.h"
  19 #include "eap_i.h"
  20 #include "tncs.h"
  21
  22
  23 struct eap_tnc_data {
  24         enum { START, CONTINUE, RECOMMENDATION, FRAG_ACK, WAIT_FRAG_ACK, DONE,
  25                FAIL } state;
  26         enum { ALLOW, ISOLATE, NO_ACCESS, NO_RECOMMENDATION } recommendation;
  27         struct tncs_data *tncs;
  28         struct wpabuf *in_buf;
  29         struct wpabuf *out_buf;
  30         size_t out_used;
  31         size_t fragment_size;
  32 };
  33
  34
  35 /* EAP-TNC Flags */
  36 #define EAP_TNC_FLAGS_LENGTH_INCLUDED 0x80
  37 #define EAP_TNC_FLAGS_MORE_FRAGMENTS 0x40
  38 #define EAP_TNC_FLAGS_START 0x20
  39 #define EAP_TNC_VERSION_MASK 0x07
  40
  41 #define EAP_TNC_VERSION 1
  42
  43
  44 static void * eap_tnc_init(struct eap_sm *sm)
  45 {
  46         struct eap_tnc_data *data;
  47
  48         data = os_zalloc(sizeof(*data));
  49         if (data == NULL)
  50                 return NULL;
  51         data->state = START;
  52         data->tncs = tncs_init();
  53         if (data->tncs == NULL) {
  54                 os_free(data);
  55                 return NULL;
  56         }
  57
  58         data->fragment_size = 1300;
  59
  60         return data;
  61 }
  62
  63
  64 static void eap_tnc_reset(struct eap_sm *sm, void *priv)
  65 {
  66         struct eap_tnc_data *data = priv;
  67         wpabuf_free(data->in_buf);
  68         wpabuf_free(data->out_buf);
  69         tncs_deinit(data->tncs);
  70         os_free(data);
  71 }
  72
  73
  74 static struct wpabuf * eap_tnc_build_start(struct eap_sm *sm,
  75                                            struct eap_tnc_data *data, u8 id)
  76 {
  77         struct wpabuf *req;
  78
  79         req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, EAP_CODE_REQUEST,
  80                             id);
  81         if (req == NULL) {
  82                 wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory for "
  83                            "request");
  84                 data->state = FAIL;
  85                 return NULL;
  86         }
  87
  88         wpabuf_put_u8(req, EAP_TNC_FLAGS_START | EAP_TNC_VERSION);
  89
  90         data->state = CONTINUE;
  91
  92         return req;
  93 }
  94
  95
  96 static struct wpabuf * eap_tnc_build(struct eap_sm *sm,
  97                                      struct eap_tnc_data *data)
  98 {
  99         struct wpabuf *req;
 100         u8 *rpos, *rpos1;
 101         size_t rlen;
 102         char *start_buf, *end_buf;
 103         size_t start_len, end_len;
 104         size_t imv_len;
 105
 106         imv_len = tncs_total_send_len(data->tncs);
 107
 108         start_buf = tncs_if_tnccs_start(data->tncs);
 109         if (start_buf == NULL)
 110                 return NULL;
 111         start_len = os_strlen(start_buf);
 112         end_buf = tncs_if_tnccs_end();
 113         if (end_buf == NULL) {
 114                 os_free(start_buf);
 115                 return NULL;
 116         }
 117         end_len = os_strlen(end_buf);
 118
 119         rlen = start_len + imv_len + end_len;
 120         req = wpabuf_alloc(rlen);
 121         if (req == NULL) {
 122                 os_free(start_buf);
 123                 os_free(end_buf);
 124                 return NULL;
 125         }
 126
 127         wpabuf_put_data(req, start_buf, start_len);
 128         os_free(start_buf);
 129
 130         rpos1 = wpabuf_put(req, 0);
 131         rpos = tncs_copy_send_buf(data->tncs, rpos1);
 132         wpabuf_put(req, rpos - rpos1);
 133
 134         wpabuf_put_data(req, end_buf, end_len);
 135         os_free(end_buf);
 136
 137         wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Request",
 138                           wpabuf_head(req), wpabuf_len(req));
 139
 140         return req;
 141 }
 142
 143
 144 static struct wpabuf * eap_tnc_build_recommendation(struct eap_sm *sm,
 145                                                     struct eap_tnc_data *data)
 146 {
 147         switch (data->recommendation) {
 148         case ALLOW:
 149                 data->state = DONE;
 150                 break;
 151         case ISOLATE:
 152                 data->state = FAIL;
 153                 /* TODO: support assignment to a different VLAN */
 154                 break;
 155         case NO_ACCESS:
 156                 data->state = FAIL;
 157                 break;
 158         case NO_RECOMMENDATION:
 159                 data->state = DONE;
 160                 break;
 161         default:
 162                 wpa_printf(MSG_DEBUG, "EAP-TNC: Unknown recommendation");
 163                 return NULL;
 164         }
 165
 166         return eap_tnc_build(sm, data);
 167 }
 168
 169
 170 static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
 171 {
 172         struct wpabuf *msg;
 173
 174         msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 0, code, id);
 175         if (msg == NULL) {
 176                 wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
 177                            "for fragment ack");
 178                 return NULL;
 179         }
 180
 181         wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
 182
 183         return msg;
 184 }
 185
 186
 187 static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data, u8 id)
 188 {
 189         struct wpabuf *req;
 190         u8 flags;
 191         size_t send_len, plen;
 192
 193         wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Request");
 194
 195         flags = EAP_TNC_VERSION;
 196         send_len = wpabuf_len(data->out_buf) - data->out_used;
 197         if (1 + send_len > data->fragment_size) {
 198                 send_len = data->fragment_size - 1;
 199                 flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
 200                 if (data->out_used == 0) {
 201                         flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
 202                         send_len -= 4;
 203                 }
 204         }
 205
 206         plen = 1 + send_len;
 207         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 208                 plen += 4;
 209         req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
 210                             EAP_CODE_REQUEST, id);
 211         if (req == NULL)
 212                 return NULL;
 213
 214         wpabuf_put_u8(req, flags); /* Flags */
 215         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 216                 wpabuf_put_be32(req, wpabuf_len(data->out_buf));
 217
 218         wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
 219                         send_len);
 220         data->out_used += send_len;
 221
 222         if (data->out_used == wpabuf_len(data->out_buf)) {
 223                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 224                            "(message sent completely)",
 225                            (unsigned long) send_len);
 226                 wpabuf_free(data->out_buf);
 227                 data->out_buf = NULL;
 228                 data->out_used = 0;
 229         } else {
 230                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 231                            "(%lu more to send)", (unsigned long) send_len,
 232                            (unsigned long) wpabuf_len(data->out_buf) -
 233                            data->out_used);
 234                 data->state = WAIT_FRAG_ACK;
 235         }
 236
 237         return req;
 238 }
 239
 240
 241 static struct wpabuf * eap_tnc_buildReq(struct eap_sm *sm, void *priv, u8 id)
 242 {
 243         struct eap_tnc_data *data = priv;
 244
 245         switch (data->state) {
 246         case START:
 247                 tncs_init_connection(data->tncs);
 248                 return eap_tnc_build_start(sm, data, id);
 249         case CONTINUE:
 250                 if (data->out_buf == NULL) {
 251                         data->out_buf = eap_tnc_build(sm, data);
 252                         if (data->out_buf == NULL) {
 253                                 wpa_printf(MSG_DEBUG, "EAP-TNC: Failed to "
 254                                            "generate message");
 255                                 return NULL;
 256                         }
 257                         data->out_used = 0;
 258                 }
 259                 return eap_tnc_build_msg(data, id);
 260         case RECOMMENDATION:
 261                 if (data->out_buf == NULL) {
 262                         data->out_buf = eap_tnc_build_recommendation(sm, data);
 263                         if (data->out_buf == NULL) {
 264                                 wpa_printf(MSG_DEBUG, "EAP-TNC: Failed to "
 265                                            "generate recommendation message");
 266                                 return NULL;
 267                         }
 268                         data->out_used = 0;
 269                 }
 270                 return eap_tnc_build_msg(data, id);
 271         case WAIT_FRAG_ACK:
 272                 return eap_tnc_build_msg(data, id);
 273         case FRAG_ACK:
 274                 return eap_tnc_build_frag_ack(id, EAP_CODE_REQUEST);
 275         case DONE:
 276         case FAIL:
 277                 return NULL;
 278         }
 279
 280         return NULL;
 281 }
 282
 283
 284 static Boolean eap_tnc_check(struct eap_sm *sm, void *priv,
 285                              struct wpabuf *respData)
 286 {
 287         struct eap_tnc_data *data = priv;
 288         const u8 *pos;
 289         size_t len;
 290
 291         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, respData,
 292                                &len);
 293         if (pos == NULL) {
 294                 wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame");
 295                 return TRUE;
 296         }
 297
 298         if (len == 0 && data->state != WAIT_FRAG_ACK) {
 299                 wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (empty)");
 300                 return TRUE;
 301         }
 302
 303         if (len == 0)
 304                 return FALSE; /* Fragment ACK does not include flags */
 305
 306         if ((*pos & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
 307                 wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
 308                            *pos & EAP_TNC_VERSION_MASK);
 309                 return TRUE;
 310         }
 311
 312         if (*pos & EAP_TNC_FLAGS_START) {
 313                 wpa_printf(MSG_DEBUG, "EAP-TNC: Peer used Start flag");
 314                 return TRUE;
 315         }
 316
 317         return FALSE;
 318 }
 319
 320
 321 static void tncs_process(struct eap_tnc_data *data, struct wpabuf *inbuf)
 322 {
 323         enum tncs_process_res res;
 324
 325         res = tncs_process_if_tnccs(data->tncs, wpabuf_head(inbuf),
 326                                     wpabuf_len(inbuf));
 327         switch (res) {
 328         case TNCCS_RECOMMENDATION_ALLOW:
 329                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS allowed access");
 330                 data->state = RECOMMENDATION;
 331                 data->recommendation = ALLOW;
 332                 break;
 333         case TNCCS_RECOMMENDATION_NO_RECOMMENDATION:
 334                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS has no recommendation");
 335                 data->state = RECOMMENDATION;
 336                 data->recommendation = NO_RECOMMENDATION;
 337                 break;
 338         case TNCCS_RECOMMENDATION_ISOLATE:
 339                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS requested isolation");
 340                 data->state = RECOMMENDATION;
 341                 data->recommendation = ISOLATE;
 342                 break;
 343         case TNCCS_RECOMMENDATION_NO_ACCESS:
 344                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS rejected access");
 345                 data->state = RECOMMENDATION;
 346                 data->recommendation = NO_ACCESS;
 347                 break;
 348         case TNCCS_PROCESS_ERROR:
 349                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS processing error");
 350                 data->state = FAIL;
 351                 break;
 352         default:
 353                 break;
 354         }
 355 }
 356
 357
 358 static int eap_tnc_process_cont(struct eap_tnc_data *data,
 359                                 const u8 *buf, size_t len)
 360 {
 361         /* Process continuation of a pending message */
 362         if (len > wpabuf_tailroom(data->in_buf)) {
 363                 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
 364                 data->state = FAIL;
 365                 return -1;
 366         }
 367
 368         wpabuf_put_data(data->in_buf, buf, len);
 369         wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for %lu "
 370                    "bytes more", (unsigned long) len,
 371                    (unsigned long) wpabuf_tailroom(data->in_buf));
 372
 373         return 0;
 374 }
 375
 376
 377 static int eap_tnc_process_fragment(struct eap_tnc_data *data,
 378                                     u8 flags, u32 message_length,
 379                                     const u8 *buf, size_t len)
 380 {
 381         /* Process a fragment that is not the last one of the message */
 382         if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
 383                 wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
 384                            "fragmented packet");
 385                 return -1;
 386         }
 387
 388         if (data->in_buf == NULL) {
 389                 /* First fragment of the message */
 390                 data->in_buf = wpabuf_alloc(message_length);
 391                 if (data->in_buf == NULL) {
 392                         wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
 393                                    "message");
 394                         return -1;
 395                 }
 396                 wpabuf_put_data(data->in_buf, buf, len);
 397                 wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
 398                            "fragment, waiting for %lu bytes more",
 399                            (unsigned long) len,
 400                            (unsigned long) wpabuf_tailroom(data->in_buf));
 401         }
 402
 403         return 0;
 404 }
 405
 406
 407 static void eap_tnc_process(struct eap_sm *sm, void *priv,
 408                             struct wpabuf *respData)
 409 {
 410         struct eap_tnc_data *data = priv;
 411         const u8 *pos, *end;
 412         size_t len;
 413         u8 flags;
 414         u32 message_length = 0;
 415         struct wpabuf tmpbuf;
 416
 417         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, respData, &len);
 418         if (pos == NULL)
 419                 return; /* Should not happen; message already verified */
 420
 421         end = pos + len;
 422
 423         if (len == 1 && (data->state == DONE || data->state == FAIL)) {
 424                 wpa_printf(MSG_DEBUG, "EAP-TNC: Peer acknowledged the last "
 425                            "message");
 426                 return;
 427         }
 428
 429         if (len == 0) {
 430                 /* fragment ack */
 431                 flags = 0;
 432         } else
 433                 flags = *pos++;
 434
 435         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
 436                 if (end - pos < 4) {
 437                         wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
 438                         data->state = FAIL;
 439                         return;
 440                 }
 441                 message_length = WPA_GET_BE32(pos);
 442                 pos += 4;
 443
 444                 if (message_length < (u32) (end - pos)) {
 445                         wpa_printf(MSG_DEBUG, "EAP-TNC: Invalid Message "
 446                                    "Length (%d; %ld remaining in this msg)",
 447                                    message_length, (long) (end - pos));
 448                         data->state = FAIL;
 449                         return;
 450                 }
 451         }
 452         wpa_printf(MSG_DEBUG, "EAP-TNC: Received packet: Flags 0x%x "
 453                    "Message Length %u", flags, message_length);
 454
 455         if (data->state == WAIT_FRAG_ACK) {
 456                 if (len != 0) {
 457                         wpa_printf(MSG_DEBUG, "EAP-TNC: Unexpected payload "
 458                                    "in WAIT_FRAG_ACK state");
 459                         data->state = FAIL;
 460                         return;
 461                 }
 462                 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment acknowledged");
 463                 data->state = CONTINUE;
 464                 return;
 465         }
 466
 467         if (data->in_buf && eap_tnc_process_cont(data, pos, end - pos) < 0) {
 468                 data->state = FAIL;
 469                 return;
 470         }
 471
 472         if (flags & EAP_TNC_FLAGS_MORE_FRAGMENTS) {
 473                 if (eap_tnc_process_fragment(data, flags, message_length,
 474                                              pos, end - pos) < 0)
 475                         data->state = FAIL;
 476                 else
 477                         data->state = FRAG_ACK;
 478                 return;
 479         } else if (data->state == FRAG_ACK) {
 480                 wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
 481                 data->state = CONTINUE;
 482         }
 483
 484         if (data->in_buf == NULL) {
 485                 /* Wrap unfragmented messages as wpabuf without extra copy */
 486                 wpabuf_set(&tmpbuf, pos, end - pos);
 487                 data->in_buf = &tmpbuf;
 488         }
 489
 490         wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Received payload",
 491                           wpabuf_head(data->in_buf), wpabuf_len(data->in_buf));
 492         tncs_process(data, data->in_buf);
 493
 494         if (data->in_buf != &tmpbuf)
 495                 wpabuf_free(data->in_buf);
 496         data->in_buf = NULL;
 497 }
 498
 499
 500 static Boolean eap_tnc_isDone(struct eap_sm *sm, void *priv)
 501 {
 502         struct eap_tnc_data *data = priv;
 503         return data->state == DONE || data->state == FAIL;
 504 }
 505
 506
 507 static Boolean eap_tnc_isSuccess(struct eap_sm *sm, void *priv)
 508 {
 509         struct eap_tnc_data *data = priv;
 510         return data->state == DONE;
 511 }
 512
 513
 514 int eap_server_tnc_register(void)
 515 {
 516         struct eap_method *eap;
 517         int ret;
 518
 519         eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
 520                                       EAP_VENDOR_IETF, EAP_TYPE_TNC, "TNC");
 521         if (eap == NULL)
 522                 return -1;
 523
 524         eap->init = eap_tnc_init;
 525         eap->reset = eap_tnc_reset;
 526         eap->buildReq = eap_tnc_buildReq;
 527         eap->check = eap_tnc_check;
 528         eap->process = eap_tnc_process;
 529         eap->isDone = eap_tnc_isDone;
 530         eap->isSuccess = eap_tnc_isSuccess;
 531
 532         ret = eap_server_method_register(eap);
 533         if (ret)
 534                 eap_server_method_free(eap);
 535         return ret;
 536 }