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 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 "tncc.h"
  21
  22
  23 struct eap_tnc_data {
  24         enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
  25         struct tncc_data *tncc;
  26         struct wpabuf *in_buf;
  27         struct wpabuf *out_buf;
  28         size_t out_used;
  29         size_t fragment_size;
  30 };
  31
  32
  33 /* EAP-TNC Flags */
  34 #define EAP_TNC_FLAGS_LENGTH_INCLUDED 0x80
  35 #define EAP_TNC_FLAGS_MORE_FRAGMENTS 0x40
  36 #define EAP_TNC_FLAGS_START 0x20
  37 #define EAP_TNC_VERSION_MASK 0x07
  38
  39 #define EAP_TNC_VERSION 1
  40
  41
  42 static void * eap_tnc_init(struct eap_sm *sm)
  43 {
  44         struct eap_tnc_data *data;
  45
  46         data = os_zalloc(sizeof(*data));
  47         if (data == NULL)
  48                 return NULL;
  49         data->state = WAIT_START;
  50         data->fragment_size = 1300;
  51         data->tncc = tncc_init();
  52         if (data->tncc == NULL) {
  53                 os_free(data);
  54                 return NULL;
  55         }
  56
  57         return data;
  58 }
  59
  60
  61 static void eap_tnc_deinit(struct eap_sm *sm, void *priv)
  62 {
  63         struct eap_tnc_data *data = priv;
  64
  65         wpabuf_free(data->in_buf);
  66         wpabuf_free(data->out_buf);
  67         tncc_deinit(data->tncc);
  68         os_free(data);
  69 }
  70
  71
  72 static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
  73 {
  74         struct wpabuf *msg;
  75
  76         msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 0, code, id);
  77         if (msg == NULL) {
  78                 wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
  79                            "for fragment ack");
  80                 return NULL;
  81         }
  82
  83         wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
  84
  85         return msg;
  86 }
  87
  88
  89 static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data,
  90                                          struct eap_method_ret *ret, u8 id)
  91 {
  92         struct wpabuf *resp;
  93         u8 flags;
  94         size_t send_len, plen;
  95
  96         ret->ignore = FALSE;
  97         wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Response");
  98         ret->allowNotifications = TRUE;
  99
 100         flags = EAP_TNC_VERSION;
 101         send_len = wpabuf_len(data->out_buf) - data->out_used;
 102         if (1 + send_len > data->fragment_size) {
 103                 send_len = data->fragment_size - 1;
 104                 flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
 105                 if (data->out_used == 0) {
 106                         flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
 107                         send_len -= 4;
 108                 }
 109         }
 110
 111         plen = 1 + send_len;
 112         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 113                 plen += 4;
 114         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
 115                              EAP_CODE_RESPONSE, id);
 116         if (resp == NULL)
 117                 return NULL;
 118
 119         wpabuf_put_u8(resp, flags); /* Flags */
 120         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 121                 wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
 122
 123         wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
 124                         send_len);
 125         data->out_used += send_len;
 126
 127         ret->methodState = METHOD_MAY_CONT;
 128         ret->decision = DECISION_FAIL;
 129
 130         if (data->out_used == wpabuf_len(data->out_buf)) {
 131                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 132                            "(message sent completely)",
 133                            (unsigned long) send_len);
 134                 wpabuf_free(data->out_buf);
 135                 data->out_buf = NULL;
 136                 data->out_used = 0;
 137         } else {
 138                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 139                            "(%lu more to send)", (unsigned long) send_len,
 140                            (unsigned long) wpabuf_len(data->out_buf) -
 141                            data->out_used);
 142                 data->state = WAIT_FRAG_ACK;
 143         }
 144
 145         return resp;
 146 }
 147
 148
 149 static int eap_tnc_process_cont(struct eap_tnc_data *data,
 150                                 const u8 *buf, size_t len)
 151 {
 152         /* Process continuation of a pending message */
 153         if (len > wpabuf_tailroom(data->in_buf)) {
 154                 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
 155                 data->state = FAIL;
 156                 return -1;
 157         }
 158
 159         wpabuf_put_data(data->in_buf, buf, len);
 160         wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for "
 161                    "%lu bytes more", (unsigned long) len,
 162                    (unsigned long) wpabuf_tailroom(data->in_buf));
 163
 164         return 0;
 165 }
 166
 167
 168 static struct wpabuf * eap_tnc_process_fragment(struct eap_tnc_data *data,
 169                                                 struct eap_method_ret *ret,
 170                                                 u8 id, u8 flags,
 171                                                 u32 message_length,
 172                                                 const u8 *buf, size_t len)
 173 {
 174         /* Process a fragment that is not the last one of the message */
 175         if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
 176                 wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
 177                            "fragmented packet");
 178                 ret->ignore = TRUE;
 179                 return NULL;
 180         }
 181
 182         if (data->in_buf == NULL) {
 183                 /* First fragment of the message */
 184                 data->in_buf = wpabuf_alloc(message_length);
 185                 if (data->in_buf == NULL) {
 186                         wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
 187                                    "message");
 188                         ret->ignore = TRUE;
 189                         return NULL;
 190                 }
 191                 wpabuf_put_data(data->in_buf, buf, len);
 192                 wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
 193                            "fragment, waiting for %lu bytes more",
 194                            (unsigned long) len,
 195                            (unsigned long) wpabuf_tailroom(data->in_buf));
 196         }
 197
 198         return eap_tnc_build_frag_ack(id, EAP_CODE_RESPONSE);
 199 }
 200
 201
 202 static struct wpabuf * eap_tnc_process(struct eap_sm *sm, void *priv,
 203                                        struct eap_method_ret *ret,
 204                                        const struct wpabuf *reqData)
 205 {
 206         struct eap_tnc_data *data = priv;
 207         struct wpabuf *resp;
 208         const u8 *pos, *end;
 209         u8 *rpos, *rpos1;
 210         size_t len, rlen;
 211         size_t imc_len;
 212         char *start_buf, *end_buf;
 213         size_t start_len, end_len;
 214         int tncs_done = 0;
 215         u8 flags, id;
 216         u32 message_length = 0;
 217         struct wpabuf tmpbuf;
 218
 219         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, reqData, &len);
 220         if (pos == NULL) {
 221                 wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (pos=%p len=%lu)",
 222                            pos, (unsigned long) len);
 223                 ret->ignore = TRUE;
 224                 return NULL;
 225         }
 226
 227         id = eap_get_id(reqData);
 228
 229         end = pos + len;
 230
 231         if (len == 0)
 232                 flags = 0; /* fragment ack */
 233         else
 234                 flags = *pos++;
 235
 236         if (len > 0 && (flags & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
 237                 wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
 238                            flags & EAP_TNC_VERSION_MASK);
 239                 ret->ignore = TRUE;
 240                 return NULL;
 241         }
 242
 243         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
 244                 if (end - pos < 4) {
 245                         wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
 246                         ret->ignore = TRUE;
 247                         return NULL;
 248                 }
 249                 message_length = WPA_GET_BE32(pos);
 250                 pos += 4;
 251
 252                 if (message_length < (u32) (end - pos)) {
 253                         wpa_printf(MSG_DEBUG, "EAP-TNC: Invalid Message "
 254                                    "Length (%d; %ld remaining in this msg)",
 255                                    message_length, (long) (end - pos));
 256                         ret->ignore = TRUE;
 257                         return NULL;
 258                 }
 259         }
 260
 261         wpa_printf(MSG_DEBUG, "EAP-TNC: Received packet: Flags 0x%x "
 262                    "Message Length %u", flags, message_length);
 263
 264         if (data->state == WAIT_FRAG_ACK) {
 265                 if (len != 0) {
 266                         wpa_printf(MSG_DEBUG, "EAP-TNC: Unexpected payload in "
 267                                    "WAIT_FRAG_ACK state");
 268                         ret->ignore = TRUE;
 269                         return NULL;
 270                 }
 271                 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment acknowledged");
 272                 data->state = PROC_MSG;
 273                 return eap_tnc_build_msg(data, ret, id);
 274         }
 275
 276         if (data->in_buf && eap_tnc_process_cont(data, pos, end - pos) < 0) {
 277                 ret->ignore = TRUE;
 278                 return NULL;
 279         }
 280
 281         if (flags & EAP_TNC_FLAGS_MORE_FRAGMENTS) {
 282                 return eap_tnc_process_fragment(data, ret, id, flags,
 283                                                 message_length, pos,
 284                                                 end - pos);
 285         }
 286
 287         if (data->in_buf == NULL) {
 288                 /* Wrap unfragmented messages as wpabuf without extra copy */
 289                 wpabuf_set(&tmpbuf, pos, end - pos);
 290                 data->in_buf = &tmpbuf;
 291         }
 292
 293         if (data->state == WAIT_START) {
 294                 if (!(flags & EAP_TNC_FLAGS_START)) {
 295                         wpa_printf(MSG_DEBUG, "EAP-TNC: Server did not use "
 296                                    "start flag in the first message");
 297                         ret->ignore = TRUE;
 298                         goto fail;
 299                 }
 300
 301                 tncc_init_connection(data->tncc);
 302
 303                 data->state = PROC_MSG;
 304         } else {
 305                 enum tncc_process_res res;
 306
 307                 if (flags & EAP_TNC_FLAGS_START) {
 308                         wpa_printf(MSG_DEBUG, "EAP-TNC: Server used start "
 309                                    "flag again");
 310                         ret->ignore = TRUE;
 311                         goto fail;
 312                 }
 313
 314                 res = tncc_process_if_tnccs(data->tncc,
 315                                             wpabuf_head(data->in_buf),
 316                                             wpabuf_len(data->in_buf));
 317                 switch (res) {
 318                 case TNCCS_PROCESS_ERROR:
 319                         ret->ignore = TRUE;
 320                         goto fail;
 321                 case TNCCS_PROCESS_OK_NO_RECOMMENDATION:
 322                 case TNCCS_RECOMMENDATION_ERROR:
 323                         wpa_printf(MSG_DEBUG, "EAP-TNC: No "
 324                                    "TNCCS-Recommendation received");
 325                         break;
 326                 case TNCCS_RECOMMENDATION_ALLOW:
 327                         wpa_msg(sm->msg_ctx, MSG_INFO,
 328                                 "TNC: Recommendation = allow");
 329                         tncs_done = 1;
 330                         break;
 331                 case TNCCS_RECOMMENDATION_NONE:
 332                         wpa_msg(sm->msg_ctx, MSG_INFO,
 333                                 "TNC: Recommendation = none");
 334                         tncs_done = 1;
 335                         break;
 336                 case TNCCS_RECOMMENDATION_ISOLATE:
 337                         wpa_msg(sm->msg_ctx, MSG_INFO,
 338                                 "TNC: Recommendation = isolate");
 339                         tncs_done = 1;
 340                         break;
 341                 }
 342         }
 343
 344         if (data->in_buf != &tmpbuf)
 345                 wpabuf_free(data->in_buf);
 346         data->in_buf = NULL;
 347
 348         ret->ignore = FALSE;
 349         ret->methodState = METHOD_MAY_CONT;
 350         ret->decision = DECISION_UNCOND_SUCC;
 351         ret->allowNotifications = TRUE;
 352
 353         if (data->out_buf) {
 354                 data->state = PROC_MSG;
 355                 return eap_tnc_build_msg(data, ret, id);
 356         }
 357
 358         if (tncs_done) {
 359                 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1,
 360                                      EAP_CODE_RESPONSE, eap_get_id(reqData));
 361                 if (resp == NULL)
 362                         return NULL;
 363
 364                 wpabuf_put_u8(resp, EAP_TNC_VERSION);
 365                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS done - reply with an "
 366                            "empty ACK message");
 367                 return resp;
 368         }
 369
 370         imc_len = tncc_total_send_len(data->tncc);
 371
 372         start_buf = tncc_if_tnccs_start(data->tncc);
 373         if (start_buf == NULL)
 374                 return NULL;
 375         start_len = os_strlen(start_buf);
 376         end_buf = tncc_if_tnccs_end();
 377         if (end_buf == NULL) {
 378                 os_free(start_buf);
 379                 return NULL;
 380         }
 381         end_len = os_strlen(end_buf);
 382
 383         rlen = start_len + imc_len + end_len;
 384         resp = wpabuf_alloc(rlen);
 385         if (resp == NULL) {
 386                 os_free(start_buf);
 387                 os_free(end_buf);
 388                 return NULL;
 389         }
 390
 391         wpabuf_put_data(resp, start_buf, start_len);
 392         os_free(start_buf);
 393
 394         rpos1 = wpabuf_put(resp, 0);
 395         rpos = tncc_copy_send_buf(data->tncc, rpos1);
 396         wpabuf_put(resp, rpos - rpos1);
 397
 398         wpabuf_put_data(resp, end_buf, end_len);
 399         os_free(end_buf);
 400
 401         wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Response",
 402                           wpabuf_head(resp), wpabuf_len(resp));
 403
 404         data->out_buf = resp;
 405         data->state = PROC_MSG;
 406         return eap_tnc_build_msg(data, ret, id);
 407
 408 fail:
 409         if (data->in_buf == &tmpbuf)
 410                 data->in_buf = NULL;
 411         return NULL;
 412 }
 413
 414
 415 int eap_peer_tnc_register(void)
 416 {
 417         struct eap_method *eap;
 418         int ret;
 419
 420         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 421                                     EAP_VENDOR_IETF, EAP_TYPE_TNC, "TNC");
 422         if (eap == NULL)
 423                 return -1;
 424
 425         eap->init = eap_tnc_init;
 426         eap->deinit = eap_tnc_deinit;
 427         eap->process = eap_tnc_process;
 428
 429         ret = eap_peer_method_register(eap);
 430         if (ret)
 431                 eap_peer_method_free(eap);
 432         return ret;
 433 }