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