src/modules/rlm_eap/libeap/tls.c

   1 /*
   2  * tls.c
   3  *
   4  * Version:     $Id$
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * Copyright 2001  hereUare Communications, Inc. <raghud@hereuare.com>
  21  * Copyright 2003  Alan DeKok <aland@freeradius.org>
  22  * Copyright 2006  The FreeRADIUS server project
  23  */
  24
  25 #include <freeradius-devel/ident.h>
  26 RCSID("$Id$")
  27
  28 #include "eap_tls.h"
  29
  30 /* record */
  31 static void             record_init(record_t *buf);
  32 static void             record_close(record_t *buf);
  33 static unsigned int     record_plus(record_t *buf, const void *ptr,
  34                                     unsigned int size);
  35 static unsigned int     record_minus(record_t *buf, void *ptr,
  36                                      unsigned int size);
  37
  38 tls_session_t *eaptls_new_session(SSL_CTX *ssl_ctx, int client_cert)
  39 {
  40         tls_session_t *state = NULL;
  41         SSL *new_tls = NULL;
  42
  43         client_cert = client_cert; /* -Wunused.  See bug #350 */
  44
  45         if ((new_tls = SSL_new(ssl_ctx)) == NULL) {
  46                 radlog(L_ERR, "SSL: Error creating new SSL: %s",
  47                        ERR_error_string(ERR_get_error(), NULL));
  48                 return NULL;
  49         }
  50
  51         /* We use the SSL's "app_data" to indicate a call-back */
  52         SSL_set_app_data(new_tls, NULL);
  53
  54         state = (tls_session_t *)malloc(sizeof(*state));
  55         memset(state, 0, sizeof(*state));
  56         session_init(state);
  57
  58         state->ctx = ssl_ctx;
  59         state->ssl = new_tls;
  60
  61         /*
  62          *      Initialize callbacks
  63          */
  64         state->record_init = record_init;
  65         state->record_close = record_close;
  66         state->record_plus = record_plus;
  67         state->record_minus = record_minus;
  68
  69         /*
  70          *      Create & hook the BIOs to handle the dirty side of the
  71          *      SSL.  This is *very important* as we want to handle
  72          *      the transmission part.  Now the only IO interface
  73          *      that SSL is aware of, is our defined BIO buffers.
  74          *
  75          *      This means that all SSL IO is done to/from memory,
  76          *      and we can update those BIOs from the EAP packets we've
  77          *      received.
  78          */
  79         state->into_ssl = BIO_new(BIO_s_mem());
  80         state->from_ssl = BIO_new(BIO_s_mem());
  81         SSL_set_bio(state->ssl, state->into_ssl, state->from_ssl);
  82
  83         /*
  84          *      Add the message callback to identify what type of
  85          *      message/handshake is passed
  86          */
  87         SSL_set_msg_callback(new_tls, cbtls_msg);
  88         SSL_set_msg_callback_arg(new_tls, state);
  89         SSL_set_info_callback(new_tls, cbtls_info);
  90
  91         /*
  92          *      In Server mode we only accept.
  93          */
  94         SSL_set_accept_state(state->ssl);
  95
  96         return state;
  97 }
  98
  99 /*
 100  *      Print out some text describing the error.
 101  */
 102 static int int_ssl_check(SSL *s, int ret, const char *text)
 103 {
 104         int e;
 105         unsigned long l;
 106
 107         if ((l = ERR_get_error()) != 0) {
 108                 radlog(L_ERR, "rlm_eap: SSL error %s",
 109                        ERR_error_string(l, NULL));
 110         }
 111         e = SSL_get_error(s, ret);
 112
 113         switch(e) {
 114                 /*
 115                  *      These seem to be harmless and already "dealt
 116                  *      with" by our non-blocking environment. NB:
 117                  *      "ZERO_RETURN" is the clean "error"
 118                  *      indicating a successfully closed SSL
 119                  *      tunnel. We let this happen because our IO
 120                  *      loop should not appear to have broken on
 121                  *      this condition - and outside the IO loop, the
 122                  *      "shutdown" state is checked.
 123                  *
 124                  *      Don't print anything if we ignore the error.
 125                  */
 126         case SSL_ERROR_NONE:
 127         case SSL_ERROR_WANT_READ:
 128         case SSL_ERROR_WANT_WRITE:
 129         case SSL_ERROR_WANT_X509_LOOKUP:
 130         case SSL_ERROR_ZERO_RETURN:
 131                 break;
 132
 133                 /*
 134                  *      These seem to be indications of a genuine
 135                  *      error that should result in the SSL tunnel
 136                  *      being regarded as "dead".
 137                  */
 138         case SSL_ERROR_SYSCALL:
 139                 radlog(L_ERR, "SSL: %s failed in a system call (%d), TLS session fails.",
 140                        text, ret);
 141                 return 0;
 142
 143         case SSL_ERROR_SSL:
 144                 radlog(L_ERR, "SSL: %s failed inside of TLS (%d), TLS session fails.",
 145                        text, ret);
 146                 return 0;
 147
 148         default:
 149                 /*
 150                  *      For any other errors that (a) exist, and (b)
 151                  *      crop up - we need to interpret what to do with
 152                  *      them - so "politely inform" the caller that
 153                  *      the code needs updating here.
 154                  */
 155                 radlog(L_ERR, "SSL: FATAL SSL error ..... %d\n", e);
 156                 return 0;
 157         }
 158
 159         return 1;
 160 }
 161
 162 /*
 163  * We are the server, we always get the dirty data
 164  * (Handshake data is also considered as dirty data)
 165  * During handshake, since SSL API handles itself,
 166  * After clean-up, dirty_out will be filled with
 167  * the data required for handshaking. So we check
 168  * if dirty_out is empty then we simply send it back.
 169  * As of now, if handshake is successful, then it is EAP-Success
 170  * or else EAP-failure should be sent
 171  *
 172  * Fill the Bio with the dirty data to clean it
 173  * Get the cleaned data from SSL, if it is not Handshake data
 174  */
 175 int tls_handshake_recv(tls_session_t *ssn)
 176 {
 177         int err;
 178
 179         BIO_write(ssn->into_ssl, ssn->dirty_in.data, ssn->dirty_in.used);
 180
 181         err = SSL_read(ssn->ssl, ssn->clean_out.data + ssn->clean_out.used,
 182                        sizeof(ssn->clean_out.data) - ssn->clean_out.used);
 183         if (err > 0) {
 184                 ssn->clean_out.used += err;
 185                 record_init(&ssn->dirty_in);
 186                 return 1;
 187         }
 188
 189         if (!int_ssl_check(ssn->ssl, err, "SSL_read")) {
 190                 return 0;
 191         }
 192
 193         /* Some Extra STATE information for easy debugging */
 194         if (SSL_is_init_finished(ssn->ssl)) {
 195                 DEBUG2("SSL Connection Established\n");
 196         }
 197         if (SSL_in_init(ssn->ssl)) {
 198                 DEBUG2("In SSL Handshake Phase\n");
 199         }
 200         if (SSL_in_before(ssn->ssl)) {
 201                 DEBUG2("Before SSL Handshake Phase\n");
 202         }
 203         if (SSL_in_accept_init(ssn->ssl)) {
 204                 DEBUG2("In SSL Accept mode \n");
 205         }
 206         if (SSL_in_connect_init(ssn->ssl)) {
 207                 DEBUG2("In SSL Connect mode \n");
 208         }
 209
 210         err = BIO_ctrl_pending(ssn->from_ssl);
 211         if (err > 0) {
 212                 err = BIO_read(ssn->from_ssl, ssn->dirty_out.data,
 213                                sizeof(ssn->dirty_out.data));
 214                 if (err > 0) {
 215                         ssn->dirty_out.used = err;
 216
 217                 } else if (BIO_should_retry(ssn->from_ssl)) {
 218                         record_init(&ssn->dirty_in);
 219                         DEBUG2("  tls: Asking for more data in tunnel");
 220                         return 1;
 221
 222                 } else {
 223                         int_ssl_check(ssn->ssl, err, "BIO_read");
 224                         record_init(&ssn->dirty_in);
 225                         return 0;
 226                 }
 227         } else {
 228                 DEBUG2("SSL Application Data");
 229                 /* Its clean application data, do whatever we want */
 230                 record_init(&ssn->clean_out);
 231         }
 232
 233         /* We are done with dirty_in, reinitialize it */
 234         record_init(&ssn->dirty_in);
 235         return 1;
 236 }
 237
 238 /*
 239  *      Take clear-text user data, and encrypt it into the output buffer,
 240  *      to send to the client at the other end of the SSL connection.
 241  */
 242 int tls_handshake_send(tls_session_t *ssn)
 243 {
 244         int err;
 245
 246         /*
 247          *      If there's un-encrypted data in 'clean_in', then write
 248          *      that data to the SSL session, and then call the BIO function
 249          *      to get that encrypted data from the SSL session, into
 250          *      a buffer which we can then package into an EAP packet.
 251          *
 252          *      Based on Server's logic this clean_in is expected to
 253          *      contain the data to send to the client.
 254          */
 255         if (ssn->clean_in.used > 0) {
 256                 int written;
 257
 258                 written = SSL_write(ssn->ssl, ssn->clean_in.data, ssn->clean_in.used);
 259                 record_minus(&ssn->clean_in, NULL, written);
 260
 261                 /* Get the dirty data from Bio to send it */
 262                 err = BIO_read(ssn->from_ssl, ssn->dirty_out.data,
 263                                sizeof(ssn->dirty_out.data));
 264                 if (err > 0) {
 265                         ssn->dirty_out.used = err;
 266                 } else {
 267                         int_ssl_check(ssn->ssl, err, "handshake_send");
 268                 }
 269         }
 270
 271         return 1;
 272 }
 273
 274 void session_init(tls_session_t *ssn)
 275 {
 276         ssn->ssl = NULL;
 277         ssn->into_ssl = ssn->from_ssl = NULL;
 278         record_init(&ssn->clean_in);
 279         record_init(&ssn->clean_out);
 280         record_init(&ssn->dirty_in);
 281         record_init(&ssn->dirty_out);
 282
 283         memset(&ssn->info, 0, sizeof(ssn->info));
 284
 285         ssn->offset = 0;
 286         ssn->fragment = 0;
 287         ssn->tls_msg_len = 0;
 288         ssn->length_flag = 0;
 289         ssn->opaque = NULL;
 290         ssn->free_opaque = NULL;
 291 }
 292
 293 void session_close(tls_session_t *ssn)
 294 {
 295         SSL_set_quiet_shutdown(ssn->ssl, 1);
 296         SSL_shutdown(ssn->ssl);
 297
 298         if(ssn->ssl)
 299                 SSL_free(ssn->ssl);
 300 #if 0
 301 /*
 302  * WARNING: SSL_free seems to decrement the reference counts already,
 303  *      so doing this might crash the application.
 304  */
 305         if(ssn->into_ssl)
 306                 BIO_free(ssn->into_ssl);
 307         if(ssn->from_ssl)
 308                 BIO_free(ssn->from_ssl);
 309 #endif
 310         record_close(&ssn->clean_in);
 311         record_close(&ssn->clean_out);
 312         record_close(&ssn->dirty_in);
 313         record_close(&ssn->dirty_out);
 314         session_init(ssn);
 315 }
 316
 317 void session_free(void *ssn)
 318 {
 319         tls_session_t *sess = (tls_session_t *)ssn;
 320
 321         if (!ssn) return;
 322
 323         /*
 324          *      Free any opaque TTLS or PEAP data.
 325          */
 326         if ((sess->opaque) && (sess->free_opaque)) {
 327                 sess->free_opaque(sess->opaque);
 328                 sess->opaque = NULL;
 329         }
 330
 331         session_close(sess);
 332
 333         free(sess);
 334 }
 335
 336 static void record_init(record_t *rec)
 337 {
 338         rec->used = 0;
 339 }
 340
 341 static void record_close(record_t *rec)
 342 {
 343         rec->used = 0;
 344 }
 345
 346
 347 /*
 348  *      Copy data to the intermediate buffer, before we send
 349  *      it somewhere.
 350  */
 351 static unsigned int record_plus(record_t *rec, const void *ptr,
 352                                 unsigned int size)
 353 {
 354         unsigned int added = MAX_RECORD_SIZE - rec->used;
 355
 356         if(added > size)
 357                 added = size;
 358         if(added == 0)
 359                 return 0;
 360         memcpy(rec->data + rec->used, ptr, added);
 361         rec->used += added;
 362         return added;
 363 }
 364
 365 /*
 366  *      Take data from the buffer, and give it to the caller.
 367  */
 368 static unsigned int record_minus(record_t *rec, void *ptr,
 369                                  unsigned int size)
 370 {
 371         unsigned int taken = rec->used;
 372
 373         if(taken > size)
 374                 taken = size;
 375         if(taken == 0)
 376                 return 0;
 377         if(ptr)
 378                 memcpy(ptr, rec->data, taken);
 379         rec->used -= taken;
 380
 381         /*
 382          *      This is pretty bad...
 383          */
 384         if(rec->used > 0)
 385                 memmove(rec->data, rec->data + taken, rec->used);
 386         return taken;
 387 }
 388
 389 void tls_session_information(tls_session_t *tls_session)
 390 {
 391         const char *str_write_p, *str_version, *str_content_type = "";
 392         const char *str_details1 = "", *str_details2= "";
 393         EAP_HANDLER *handler;
 394         REQUEST *request;
 395
 396         /*
 397          *      Don't print this out in the normal course of
 398          *      operations.
 399          */
 400         if (debug_flag == 0) {
 401                 return;
 402         }
 403
 404         str_write_p = tls_session->info.origin ? ">>>" : "<<<";
 405
 406         switch (tls_session->info.version)
 407         {
 408         case SSL2_VERSION:
 409                 str_version = "SSL 2.0";
 410                 break;
 411         case SSL3_VERSION:
 412                 str_version = "SSL 3.0 ";
 413                 break;
 414         case TLS1_VERSION:
 415                 str_version = "TLS 1.0 ";
 416                 break;
 417         default:
 418                 str_version = "Unknown TLS version";
 419                 break;
 420         }
 421
 422         if (tls_session->info.version == SSL3_VERSION ||
 423             tls_session->info.version == TLS1_VERSION) {
 424                 switch (tls_session->info.content_type) {
 425                 case SSL3_RT_CHANGE_CIPHER_SPEC:
 426                         str_content_type = "ChangeCipherSpec";
 427                         break;
 428                 case SSL3_RT_ALERT:
 429                         str_content_type = "Alert";
 430                         break;
 431                 case SSL3_RT_HANDSHAKE:
 432                         str_content_type = "Handshake";
 433                         break;
 434                 case SSL3_RT_APPLICATION_DATA:
 435                         str_content_type = "ApplicationData";
 436                         break;
 437                 default:
 438                         str_content_type = "UnknownContentType";
 439                         break;
 440                 }
 441
 442                 if (tls_session->info.content_type == SSL3_RT_ALERT) {
 443                         str_details1 = ", ???";
 444
 445                         if (tls_session->info.record_len == 2) {
 446
 447                                 switch (tls_session->info.alert_level) {
 448                                 case SSL3_AL_WARNING:
 449                                         str_details1 = ", warning";
 450                                         break;
 451                                 case SSL3_AL_FATAL:
 452                                         str_details1 = ", fatal";
 453                                         break;
 454                                 }
 455
 456                                 str_details2 = " ???";
 457                                 switch (tls_session->info.alert_description) {
 458                                 case SSL3_AD_CLOSE_NOTIFY:
 459                                         str_details2 = " close_notify";
 460                                         break;
 461                                 case SSL3_AD_UNEXPECTED_MESSAGE:
 462                                         str_details2 = " unexpected_message";
 463                                         break;
 464                                 case SSL3_AD_BAD_RECORD_MAC:
 465                                         str_details2 = " bad_record_mac";
 466                                         break;
 467                                 case TLS1_AD_DECRYPTION_FAILED:
 468                                         str_details2 = " decryption_failed";
 469                                         break;
 470                                 case TLS1_AD_RECORD_OVERFLOW:
 471                                         str_details2 = " record_overflow";
 472                                         break;
 473                                 case SSL3_AD_DECOMPRESSION_FAILURE:
 474                                         str_details2 = " decompression_failure";
 475                                         break;
 476                                 case SSL3_AD_HANDSHAKE_FAILURE:
 477                                         str_details2 = " handshake_failure";
 478                                         break;
 479                                 case SSL3_AD_BAD_CERTIFICATE:
 480                                         str_details2 = " bad_certificate";
 481                                         break;
 482                                 case SSL3_AD_UNSUPPORTED_CERTIFICATE:
 483                                         str_details2 = " unsupported_certificate";
 484                                         break;
 485                                 case SSL3_AD_CERTIFICATE_REVOKED:
 486                                         str_details2 = " certificate_revoked";
 487                                         break;
 488                                 case SSL3_AD_CERTIFICATE_EXPIRED:
 489                                         str_details2 = " certificate_expired";
 490                                         break;
 491                                 case SSL3_AD_CERTIFICATE_UNKNOWN:
 492                                         str_details2 = " certificate_unknown";
 493                                         break;
 494                                 case SSL3_AD_ILLEGAL_PARAMETER:
 495                                         str_details2 = " illegal_parameter";
 496                                         break;
 497                                 case TLS1_AD_UNKNOWN_CA:
 498                                         str_details2 = " unknown_ca";
 499                                         break;
 500                                 case TLS1_AD_ACCESS_DENIED:
 501                                         str_details2 = " access_denied";
 502                                         break;
 503                                 case TLS1_AD_DECODE_ERROR:
 504                                         str_details2 = " decode_error";
 505                                         break;
 506                                 case TLS1_AD_DECRYPT_ERROR:
 507                                         str_details2 = " decrypt_error";
 508                                         break;
 509                                 case TLS1_AD_EXPORT_RESTRICTION:
 510                                         str_details2 = " export_restriction";
 511                                         break;
 512                                 case TLS1_AD_PROTOCOL_VERSION:
 513                                         str_details2 = " protocol_version";
 514                                         break;
 515                                 case TLS1_AD_INSUFFICIENT_SECURITY:
 516                                         str_details2 = " insufficient_security";
 517                                         break;
 518                                 case TLS1_AD_INTERNAL_ERROR:
 519                                         str_details2 = " internal_error";
 520                                         break;
 521                                 case TLS1_AD_USER_CANCELLED:
 522                                         str_details2 = " user_canceled";
 523                                         break;
 524                                 case TLS1_AD_NO_RENEGOTIATION:
 525                                         str_details2 = " no_renegotiation";
 526                                         break;
 527                                 }
 528                         }
 529                 }
 530
 531                 if (tls_session->info.content_type == SSL3_RT_HANDSHAKE) {
 532                         str_details1 = "???";
 533
 534                         if (tls_session->info.record_len > 0)
 535                         switch (tls_session->info.handshake_type)
 536                         {
 537                         case SSL3_MT_HELLO_REQUEST:
 538                                 str_details1 = ", HelloRequest";
 539                                 break;
 540                         case SSL3_MT_CLIENT_HELLO:
 541                                 str_details1 = ", ClientHello";
 542                                 break;
 543                         case SSL3_MT_SERVER_HELLO:
 544                                 str_details1 = ", ServerHello";
 545                                 break;
 546                         case SSL3_MT_CERTIFICATE:
 547                                 str_details1 = ", Certificate";
 548                                 break;
 549                         case SSL3_MT_SERVER_KEY_EXCHANGE:
 550                                 str_details1 = ", ServerKeyExchange";
 551                                 break;
 552                         case SSL3_MT_CERTIFICATE_REQUEST:
 553                                 str_details1 = ", CertificateRequest";
 554                                 break;
 555                         case SSL3_MT_SERVER_DONE:
 556                                 str_details1 = ", ServerHelloDone";
 557                                 break;
 558                         case SSL3_MT_CERTIFICATE_VERIFY:
 559                                 str_details1 = ", CertificateVerify";
 560                                 break;
 561                         case SSL3_MT_CLIENT_KEY_EXCHANGE:
 562                                 str_details1 = ", ClientKeyExchange";
 563                                 break;
 564                         case SSL3_MT_FINISHED:
 565                                 str_details1 = ", Finished";
 566                                 break;
 567                         }
 568                 }
 569         }
 570
 571         snprintf(tls_session->info.info_description,
 572                  sizeof(tls_session->info.info_description),
 573                  "%s %s%s [length %04lx]%s%s\n",
 574                  str_write_p, str_version, str_content_type,
 575                  (unsigned long)tls_session->info.record_len,
 576                  str_details1, str_details2);
 577
 578         handler = (EAP_HANDLER *)SSL_get_ex_data(tls_session->ssl, 0);
 579         if (handler) {
 580                 request = handler->request;
 581         } else {
 582                 request = NULL;
 583         }
 584
 585         RDEBUG2("%s\n", tls_session->info.info_description);
 586 }