libeap/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 "eap_config.h"
  14 #include "tncc.h"
  15
  16
  17 struct eap_tnc_data {
  18         enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
  19         struct tncc_data *tncc;
  20         struct wpabuf *in_buf;
  21         struct wpabuf *out_buf;
  22         size_t out_used;
  23         size_t fragment_size;
  24 };
  25
  26
  27 /* EAP-TNC Flags */
  28 #define EAP_TNC_FLAGS_LENGTH_INCLUDED 0x80
  29 #define EAP_TNC_FLAGS_MORE_FRAGMENTS 0x40
  30 #define EAP_TNC_FLAGS_START 0x20
  31 #define EAP_TNC_VERSION_MASK 0x07
  32
  33 #define EAP_TNC_VERSION 1
  34
  35
  36 static void * eap_tnc_init(struct eap_sm *sm)
  37 {
  38         struct eap_tnc_data *data;
  39         struct eap_peer_config *config = eap_get_config(sm);
  40
  41         data = os_zalloc(sizeof(*data));
  42         if (data == NULL)
  43                 return NULL;
  44         data->state = WAIT_START;
  45         if (config && config->fragment_size)
  46                 data->fragment_size = config->fragment_size;
  47         else
  48                 data->fragment_size = 1300;
  49         data->tncc = tncc_init();
  50         if (data->tncc == NULL) {
  51                 os_free(data);
  52                 return NULL;
  53         }
  54
  55         return data;
  56 }
  57
  58
  59 static void eap_tnc_deinit(struct eap_sm *sm, void *priv)
  60 {
  61         struct eap_tnc_data *data = priv;
  62
  63         wpabuf_free(data->in_buf);
  64         wpabuf_free(data->out_buf);
  65         tncc_deinit(data->tncc);
  66         os_free(data);
  67 }
  68
  69
  70 static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
  71 {
  72         struct wpabuf *msg;
  73
  74         msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, code, id);
  75         if (msg == NULL) {
  76                 wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
  77                            "for fragment ack");
  78                 return NULL;
  79         }
  80         wpabuf_put_u8(msg, EAP_TNC_VERSION); /* Flags */
  81
  82         wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
  83
  84         return msg;
  85 }
  86
  87
  88 static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data,
  89                                          struct eap_method_ret *ret, u8 id)
  90 {
  91         struct wpabuf *resp;
  92         u8 flags;
  93         size_t send_len, plen;
  94
  95         ret->ignore = FALSE;
  96         wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Response");
  97         ret->allowNotifications = TRUE;
  98
  99         flags = EAP_TNC_VERSION;
 100         send_len = wpabuf_len(data->out_buf) - data->out_used;
 101         if (1 + send_len > data->fragment_size) {
 102                 send_len = data->fragment_size - 1;
 103                 flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
 104                 if (data->out_used == 0) {
 105                         flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
 106                         send_len -= 4;
 107                 }
 108         }
 109
 110         plen = 1 + send_len;
 111         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 112                 plen += 4;
 113         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
 114                              EAP_CODE_RESPONSE, id);
 115         if (resp == NULL)
 116                 return NULL;
 117
 118         wpabuf_put_u8(resp, flags); /* Flags */
 119         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
 120                 wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
 121
 122         wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
 123                         send_len);
 124         data->out_used += send_len;
 125
 126         ret->methodState = METHOD_MAY_CONT;
 127         ret->decision = DECISION_FAIL;
 128
 129         if (data->out_used == wpabuf_len(data->out_buf)) {
 130                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 131                            "(message sent completely)",
 132                            (unsigned long) send_len);
 133                 wpabuf_free(data->out_buf);
 134                 data->out_buf = NULL;
 135                 data->out_used = 0;
 136         } else {
 137                 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
 138                            "(%lu more to send)", (unsigned long) send_len,
 139                            (unsigned long) wpabuf_len(data->out_buf) -
 140                            data->out_used);
 141                 data->state = WAIT_FRAG_ACK;
 142         }
 143
 144         return resp;
 145 }
 146
 147
 148 static int eap_tnc_process_cont(struct eap_tnc_data *data,
 149                                 const u8 *buf, size_t len)
 150 {
 151         /* Process continuation of a pending message */
 152         if (len > wpabuf_tailroom(data->in_buf)) {
 153                 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
 154                 data->state = FAIL;
 155                 return -1;
 156         }
 157
 158         wpabuf_put_data(data->in_buf, buf, len);
 159         wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for "
 160                    "%lu bytes more", (unsigned long) len,
 161                    (unsigned long) wpabuf_tailroom(data->in_buf));
 162
 163         return 0;
 164 }
 165
 166
 167 static struct wpabuf * eap_tnc_process_fragment(struct eap_tnc_data *data,
 168                                                 struct eap_method_ret *ret,
 169                                                 u8 id, u8 flags,
 170                                                 u32 message_length,
 171                                                 const u8 *buf, size_t len)
 172 {
 173         /* Process a fragment that is not the last one of the message */
 174         if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
 175                 wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
 176                            "fragmented packet");
 177                 ret->ignore = TRUE;
 178                 return NULL;
 179         }
 180
 181         if (data->in_buf == NULL) {
 182                 /* First fragment of the message */
 183                 data->in_buf = wpabuf_alloc(message_length);
 184                 if (data->in_buf == NULL) {
 185                         wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
 186                                    "message");
 187                         ret->ignore = TRUE;
 188                         return NULL;
 189                 }
 190                 wpabuf_put_data(data->in_buf, buf, len);
 191                 wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
 192                            "fragment, waiting for %lu bytes more",
 193                            (unsigned long) len,
 194                            (unsigned long) wpabuf_tailroom(data->in_buf));
 195         }
 196
 197         return eap_tnc_build_frag_ack(id, EAP_CODE_RESPONSE);
 198 }
 199
 200
 201 static struct wpabuf * eap_tnc_process(struct eap_sm *sm, void *priv,
 202                                        struct eap_method_ret *ret,
 203                                        const struct wpabuf *reqData)
 204 {
 205         struct eap_tnc_data *data = priv;
 206         struct wpabuf *resp;
 207         const u8 *pos, *end;
 208         u8 *rpos, *rpos1;
 209         size_t len, rlen;
 210         size_t imc_len;
 211         char *start_buf, *end_buf;
 212         size_t start_len, end_len;
 213         int tncs_done = 0;
 214         u8 flags, id;
 215         u32 message_length = 0;
 216         struct wpabuf tmpbuf;
 217
 218         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, reqData, &len);
 219         if (pos == NULL) {
 220                 wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (pos=%p len=%lu)",
 221                            pos, (unsigned long) len);
 222                 ret->ignore = TRUE;
 223                 return NULL;
 224         }
 225
 226         id = eap_get_id(reqData);
 227
 228         end = pos + len;
 229
 230         if (len == 0)
 231                 flags = 0; /* fragment ack */
 232         else
 233                 flags = *pos++;
 234
 235         if (len > 0 && (flags & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
 236                 wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
 237                            flags & EAP_TNC_VERSION_MASK);
 238                 ret->ignore = TRUE;
 239                 return NULL;
 240         }
 241
 242         if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
 243                 if (end - pos < 4) {
 244                         wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
 245                         ret->ignore = TRUE;
 246                         return NULL;
 247                 }
 248                 message_length = WPA_GET_BE32(pos);
 249                 pos += 4;
 250
 251                 if (message_length < (u32) (end - pos) ||
 252                     message_length > 75000) {
 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 > 1) {
 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 (tncs_done) {
 354                 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1,
 355                                      EAP_CODE_RESPONSE, eap_get_id(reqData));
 356                 if (resp == NULL)
 357                         return NULL;
 358
 359                 wpabuf_put_u8(resp, EAP_TNC_VERSION);
 360                 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS done - reply with an "
 361                            "empty ACK message");
 362                 return resp;
 363         }
 364
 365         imc_len = tncc_total_send_len(data->tncc);
 366
 367         start_buf = tncc_if_tnccs_start(data->tncc);
 368         if (start_buf == NULL)
 369                 return NULL;
 370         start_len = os_strlen(start_buf);
 371         end_buf = tncc_if_tnccs_end();
 372         if (end_buf == NULL) {
 373                 os_free(start_buf);
 374                 return NULL;
 375         }
 376         end_len = os_strlen(end_buf);
 377
 378         rlen = start_len + imc_len + end_len;
 379         resp = wpabuf_alloc(rlen);
 380         if (resp == NULL) {
 381                 os_free(start_buf);
 382                 os_free(end_buf);
 383                 return NULL;
 384         }
 385
 386         wpabuf_put_data(resp, start_buf, start_len);
 387         os_free(start_buf);
 388
 389         rpos1 = wpabuf_put(resp, 0);
 390         rpos = tncc_copy_send_buf(data->tncc, rpos1);
 391         wpabuf_put(resp, rpos - rpos1);
 392
 393         wpabuf_put_data(resp, end_buf, end_len);
 394         os_free(end_buf);
 395
 396         wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Response",
 397                           wpabuf_head(resp), wpabuf_len(resp));
 398
 399         data->out_buf = resp;
 400         data->state = PROC_MSG;
 401         return eap_tnc_build_msg(data, ret, id);
 402
 403 fail:
 404         if (data->in_buf == &tmpbuf)
 405                 data->in_buf = NULL;
 406         return NULL;
 407 }
 408
 409
 410 int eap_peer_tnc_register(void)
 411 {
 412         struct eap_method *eap;
 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         return eap_peer_method_register(eap);
 424 }