src/modules/rlm_eap/types/rlm_eap_ttls/ttls.c

   1 /*
   2  * rlm_eap_ttls.c  contains the interfaces that are called from eap
   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  *   Copyright 2003 Alan DeKok <aland@freeradius.org>
  21  */
  22 #include "eap_tls.h"
  23 #include "eap_ttls.h"
  24
  25 /*
  26  *    0                   1                   2                   3
  27  *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  28  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  29  *   |                           AVP Code                            |
  30  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  31  *   |V M r r r r r r|                  AVP Length                   |
  32  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  33  *   |                        Vendor-ID (opt)                        |
  34  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35  *   |    Data ...
  36  *   +-+-+-+-+-+-+-+-+
  37  */
  38
  39 /*
  40  *      Verify that the diameter packet is valid.
  41  */
  42 static int diameter_verify(const uint8_t *data, unsigned int data_len)
  43 {
  44         uint32_t attr;
  45         uint32_t length;
  46         unsigned int offset;
  47         unsigned int data_left = data_len;
  48
  49         while (data_left > 0) {
  50                 rad_assert(data_left <= data_len);
  51                 memcpy(&attr, data, sizeof(attr));
  52                 data += 4;
  53                 attr = ntohl(attr);
  54                 if (attr > 255) {
  55                         DEBUG2("  rlm_eap_ttls:  Non-RADIUS attribute in tunneled authentication is not supported");
  56                         return 0;
  57                 }
  58
  59                 memcpy(&length, data , sizeof(length));
  60                 data += 4;
  61                 length = ntohl(length);
  62
  63                 /*
  64                  *      A "vendor" flag, with a vendor ID of zero,
  65                  *      is equivalent to no vendor.  This is stupid.
  66                  */
  67                 offset = 8;
  68                 if ((length & (1 << 31)) != 0) {
  69                         int attribute;
  70                         uint32_t vendor;
  71                         DICT_ATTR *da;
  72
  73                         memcpy(&vendor, data, sizeof(vendor));
  74                         vendor = ntohl(vendor);
  75
  76                         if (vendor > 65535) {
  77                                 DEBUG2("  rlm_eap_ttls: Vendor codes larger than 65535 are not supported");
  78                                 return 0;
  79                         }
  80
  81                         attribute = (vendor << 16) | attr;
  82
  83                         da = dict_attrbyvalue(attribute);
  84
  85                         /*
  86                          *      SHOULD check ((length & (1 << 30)) != 0)
  87                          *      for the mandatory bit.
  88                          */
  89                         if (!da) {
  90                                 DEBUG2("  rlm_eap_ttls: Fatal! Vendor %u, Attribute %u was not found in our dictionary. ",
  91                                        vendor, attr);
  92                                 return 0;
  93                         }
  94
  95                         data += 4; /* skip the vendor field */
  96                         offset += 4; /* offset to value field */
  97                 }
  98
  99                 /*
 100                  *      Ignore the M bit.  We support all RADIUS attributes...
 101                  */
 102
 103                 /*
 104                  *      Get the length.  If it's too big, die.
 105                  */
 106                 length &= 0x00ffffff;
 107
 108                 /*
 109                  *      Too short or too long is bad.
 110                  *
 111                  *      FIXME: EAP-Message
 112                  */
 113                 if (length < offset) {
 114                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too short (%d)to contain anything useful.", attr, length);
 115                         return 0;
 116                 }
 117
 118                 if (length > (MAX_STRING_LEN + 8)) {
 119                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too long (%d) to pack into a RADIUS attribute.", attr, length);
 120                         return 0;
 121                 }
 122
 123                 if (length > data_left) {
 124                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is longer than room left in the packet (%d > %d).", attr, length, data_left);
 125                         return 0;
 126                 }
 127
 128                 /*
 129                  *      Check for broken implementations, which don't
 130                  *      pad the AVP to a 4-octet boundary.
 131                  */
 132                 if (data_left == length) break;
 133
 134                 /*
 135                  *      The length does NOT include the padding, so
 136                  *      we've got to account for it here by rounding up
 137                  *      to the nearest 4-byte boundary.
 138                  */
 139                 length += 0x03;
 140                 length &= ~0x03;
 141
 142                 /*
 143                  *      If the rest of the diameter packet is larger than
 144                  *      this attribute, continue.
 145                  *
 146                  *      Otherwise, if the attribute over-flows the end
 147                  *      of the packet, die.
 148                  */
 149                 if (data_left < length) {
 150                         DEBUG2("  rlm_eap_ttls: ERROR! Diameter attribute overflows packet!");
 151                         return 0;
 152                 }
 153
 154                 /*
 155                  *      Check again for equality, now that we're padded
 156                  *      length to a multiple of 4 octets.
 157                  */
 158                 if (data_left == length) break;
 159
 160                 /*
 161                  *      data_left > length, continue.
 162                  */
 163                 data_left -= length;
 164                 data += length - offset;
 165         }
 166
 167         /*
 168          *      We got this far.  It looks OK.
 169          */
 170         return 1;
 171 }
 172
 173
 174 /*
 175  *      Convert diameter attributes to our VALUE_PAIR's
 176  */
 177 static VALUE_PAIR *diameter2vp(SSL *ssl,
 178                                const uint8_t *data, unsigned int data_len)
 179 {
 180         uint32_t        attr;
 181         uint32_t        length;
 182         unsigned int    offset;
 183         int             size;
 184         unsigned int    data_left = data_len;
 185         VALUE_PAIR      *first = NULL;
 186         VALUE_PAIR      **last = &first;
 187         VALUE_PAIR      *vp;
 188
 189         while (data_left > 0) {
 190                 rad_assert(data_left <= data_len);
 191                 memcpy(&attr, data, sizeof(attr));
 192                 data += 4;
 193                 attr = ntohl(attr);
 194
 195                 memcpy(&length, data, sizeof(length));
 196                 data += 4;
 197                 length = ntohl(length);
 198
 199                 /*
 200                  *      Ignore the M bit.  We support all RADIUS attributes...
 201                  */
 202
 203                 /*
 204                  *      A "vendor" flag, with a vendor ID of zero,
 205                  *      is equivalent to no vendor.  This is stupid.
 206                  */
 207                 offset = 8;
 208                 if ((length & (1 << 31)) != 0) {
 209                         uint32_t vendor;
 210
 211                         memcpy(&vendor, data, sizeof(vendor));
 212                         vendor = ntohl(vendor);
 213
 214                         attr |= (vendor << 16);
 215
 216                         data += 4; /* skip the vendor field, it's zero */
 217                         offset += 4; /* offset to value field */
 218                 }
 219
 220                 /*
 221                  *      Get the length.
 222                  */
 223                 length &= 0x00ffffff;
 224
 225                 /*
 226                  *      diameter code + length, and it must fit in
 227                  *      a VALUE_PAIR.
 228                  */
 229                 rad_assert(length <= (offset + MAX_STRING_LEN));
 230
 231                 /*
 232                  *      Get the size of the value portion of the
 233                  *      attribute.
 234                  */
 235                 size = length - offset;
 236
 237                 /*
 238                  *      Create it.
 239                  */
 240                 vp = paircreate(attr, PW_TYPE_OCTETS);
 241                 if (!vp) {
 242                         DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 243                         pairfree(&first);
 244                         return NULL;
 245                 }
 246
 247                 /*
 248                  *      If it's a type from our dictionary, then
 249                  *      we need to put the data in a relevant place.
 250                  */
 251                 switch (vp->type) {
 252                 case PW_TYPE_INTEGER:
 253                 case PW_TYPE_DATE:
 254                         if (size != vp->length) {
 255                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 256                                        attr);
 257                                 pairfree(&first);
 258                                 return NULL;
 259                         }
 260                         memcpy(&vp->lvalue, data, vp->length);
 261
 262                         /*
 263                          *      Stored in host byte order: change it.
 264                          */
 265                         vp->lvalue = ntohl(vp->lvalue);
 266                         break;
 267
 268                 case PW_TYPE_IPADDR:
 269                         if (size != vp->length) {
 270                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 271                                        attr);
 272                                 pairfree(&first);
 273                                 return NULL;
 274                         }
 275                   memcpy(&vp->lvalue, data, vp->length);
 276
 277                   /*
 278                    *    Stored in network byte order: don't change it.
 279                    */
 280                   break;
 281
 282                   /*
 283                    *    String, octet, etc.  Copy the data from the
 284                    *    value field over verbatim.
 285                    *
 286                    *    FIXME: Ipv6 attributes ?
 287                    *
 288                    */
 289                 default:
 290                         vp->length = size;
 291                         memcpy(vp->strvalue, data, vp->length);
 292                         break;
 293                 }
 294
 295                 /*
 296                  *      User-Password is NUL padded to a multiple
 297                  *      of 16 bytes.  Let's chop it to something
 298                  *      more reasonable.
 299                  *
 300                  *      NOTE: This means that the User-Password
 301                  *      attribute CANNOT EVER have embedded zeros in it!
 302                  */
 303                 switch (vp->attribute) {
 304                 case PW_USER_PASSWORD:
 305                         rad_assert(vp->length <= 128); /* RFC requirements */
 306
 307                         /*
 308                          *      If the password is exactly 16 octets,
 309                          *      it won't be zero-terminated.
 310                          */
 311                         vp->strvalue[vp->length] = '\0';
 312                         vp->length = strlen(vp->strvalue);
 313                         break;
 314
 315                         /*
 316                          *      Ensure that the client is using the
 317                          *      correct challenge.  This weirdness is
 318                          *      to protect against against replay
 319                          *      attacks, where anyone observing the
 320                          *      CHAP exchange could pose as that user,
 321                          *      by simply choosing to use the same
 322                          *      challenge.
 323                          *
 324                          *      By using a challenge based on
 325                          *      information from the current session,
 326                          *      we can guarantee that the client is
 327                          *      not *choosing* a challenge.
 328                          *
 329                          *      We're a little forgiving in that we
 330                          *      have loose checks on the length, and
 331                          *      we do NOT check the Id (first octet of
 332                          *      the response to the challenge)
 333                          *
 334                          *      But if the client gets the challenge correct,
 335                          *      we're not too worried about the Id.
 336                          */
 337                 case PW_CHAP_CHALLENGE:
 338                 case PW_MSCHAP_CHALLENGE:
 339                         if ((vp->length < 8) ||
 340                             (vp->length > 16)) {
 341                                 DEBUG2("  TTLS: Tunneled challenge has invalid length");
 342                                 pairfree(&first);
 343                                 return NULL;
 344
 345                         } else {
 346                                 int i;
 347                                 uint8_t challenge[16];
 348
 349                                 eapttls_gen_challenge(ssl, challenge,
 350                                                       sizeof(challenge));
 351
 352                                 for (i = 0; i < vp->length; i++) {
 353                                         if (challenge[i] != vp->strvalue[i]) {
 354                                                 DEBUG2("  TTLS: Tunneled challenge is incorrect");
 355                                                 pairfree(&first);
 356                                                 return NULL;
 357                                         }
 358                                 }
 359                         }
 360                         break;
 361
 362                 default:
 363                         break;
 364                 } /* switch over checking/re-writing of attributes. */
 365
 366                 /*
 367                  *      Update the list.
 368                  */
 369                 *last = vp;
 370                 last = &(vp->next);
 371
 372                 /*
 373                  *      Catch non-aligned attributes.
 374                  */
 375                 if (data_left == length) break;
 376
 377                 /*
 378                  *      The length does NOT include the padding, so
 379                  *      we've got to account for it here by rounding up
 380                  *      to the nearest 4-byte boundary.
 381                  */
 382                 length += 0x03;
 383                 length &= ~0x03;
 384
 385                 rad_assert(data_left >= length);
 386                 data_left -= length;
 387                 data += length - offset; /* already updated */
 388         }
 389
 390         /*
 391          *      We got this far.  It looks OK.
 392          */
 393         return first;
 394 }
 395
 396 /*
 397  *      Convert VALUE_PAIR's to diameter attributes, and write them
 398  *      to an SSL session.
 399  *
 400  *      The ONLY VALUE_PAIR's which may be passed to this function
 401  *      are ones which can go inside of a RADIUS (i.e. diameter)
 402  *      packet.  So no server-configuration attributes, or the like.
 403  */
 404 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 405 {
 406         /*
 407          *      RADIUS packets are no more than 4k in size, so if
 408          *      we've got more than 4k of data to write, it's very
 409          *      bad.
 410          */
 411         uint8_t         buffer[4096];
 412         uint8_t         *p;
 413         uint32_t        attr;
 414         uint32_t        length;
 415         uint32_t        vendor;
 416         size_t          total;
 417         VALUE_PAIR      *vp;
 418
 419         p = buffer;
 420         total = 0;
 421
 422         for (vp = first; vp != NULL; vp = vp->next) {
 423                 /*
 424                  *      Too much data: die.
 425                  */
 426                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 427                         DEBUG2("  TTLS output buffer is full!");
 428                         return 0;
 429                 }
 430
 431                 /*
 432                  *      Hmm... we don't group multiple EAP-Messages
 433                  *      together.  Maybe we should...
 434                  */
 435
 436                 /*
 437                  *      Length is no more than 253, due to RADIUS
 438                  *      issues.
 439                  */
 440                 length = vp->length;
 441                 vendor = (vp->attribute >> 16) & 0xffff;
 442                 if (vendor != 0) {
 443                         attr = vp->attribute & 0xffff;
 444                         length |= (1 << 31);
 445                 } else {
 446                         attr = vp->attribute;
 447                 }
 448
 449                 /*
 450                  *      Hmm... set the M bit for all attributes?
 451                  */
 452                 length |= (1 << 30);
 453
 454                 attr = ntohl(attr);
 455
 456                 memcpy(p, &attr, sizeof(attr));
 457                 p += 4;
 458                 total += 4;
 459
 460                 length += 8;    /* includes 8 bytes of attr & length */
 461
 462                 if (vendor != 0) {
 463                         length += 4; /* include 4 bytes of vendor */
 464
 465                         length = ntohl(length);
 466                         memcpy(p, &length, sizeof(length));
 467                         p += 4;
 468                         total += 4;
 469
 470                         vendor = ntohl(vendor);
 471                         memcpy(p, &vendor, sizeof(vendor));
 472                         p += 4;
 473                         total += 4;
 474                 } else {
 475                         length = ntohl(length);
 476                         memcpy(p, &length, sizeof(length));
 477                         p += 4;
 478                         total += 4;
 479                 }
 480
 481                 switch (vp->type) {
 482                 case PW_TYPE_INTEGER:
 483                 case PW_TYPE_DATE:
 484                         attr = ntohl(vp->lvalue); /* stored in host order */
 485                         memcpy(p, &attr, sizeof(attr));
 486                         length = 4;
 487                         break;
 488
 489                 case PW_TYPE_IPADDR:
 490                         attr = vp->lvalue; /* stored in network order */
 491                         memcpy(p, &attr, sizeof(attr));
 492                         length = 4;
 493                         break;
 494
 495                 case PW_TYPE_STRING:
 496                 case PW_TYPE_OCTETS:
 497                 default:
 498                         memcpy(p, vp->strvalue, vp->length);
 499                         length = vp->length;
 500                         break;
 501                 }
 502
 503                 /*
 504                  *      Skip to the end of the data.
 505                  */
 506                 p += length;
 507                 total += length;
 508
 509                 /*
 510                  *      Align the data to a multiple of 4 bytes.
 511                  */
 512                 if ((total & 0x03) != 0) {
 513                         unsigned int i;
 514
 515                         length = total & 0x03;
 516                         for (i = 0; i < length; i++) {
 517                                 *p = '\0';
 518                                 p++;
 519                                 total++;
 520                         }
 521                 }
 522         } /* loop over the VP's to write. */
 523
 524         /*
 525          *      Write the data in the buffer to the SSL session.
 526          */
 527         if (total > 0) {
 528 #ifndef NDEBUG
 529                 unsigned int i;
 530
 531                 if (debug_flag > 2) {
 532                         for (i = 0; i < total; i++) {
 533                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 534
 535                                 printf("%02x ", buffer[i]);
 536
 537                                 if ((i & 0x0f) == 0x0f) printf("\n");
 538                         }
 539                         if ((total & 0x0f) != 0) printf("\n");
 540                 }
 541 #endif
 542
 543                 record_plus(&tls_session->clean_in, buffer, total);
 544
 545                 /*
 546                  *      FIXME: Check the return code.
 547                  */
 548                 tls_handshake_send(tls_session);
 549         }
 550
 551         /*
 552          *      Everything's OK.
 553          */
 554         return 1;
 555 }
 556
 557 /*
 558  *      Use a reply packet to determine what to do.
 559  */
 560 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 561                          REQUEST *request, RADIUS_PACKET *reply)
 562 {
 563         int rcode = RLM_MODULE_REJECT;
 564         VALUE_PAIR *vp;
 565         ttls_tunnel_t *t = tls_session->opaque;
 566
 567         handler = handler;      /* -Wunused */
 568
 569         /*
 570          *      If the response packet was Access-Accept, then
 571          *      we're OK.  If not, die horribly.
 572          *
 573          *      FIXME: Take MS-CHAP2-Success attribute, and
 574          *      tunnel it back to the client, to authenticate
 575          *      ourselves to the client.
 576          *
 577          *      FIXME: If we have an Access-Challenge, then
 578          *      the Reply-Message is tunneled back to the client.
 579          *
 580          *      FIXME: If we have an EAP-Message, then that message
 581          *      must be tunneled back to the client.
 582          *
 583          *      FIXME: If we have an Access-Challenge with a State
 584          *      attribute, then do we tunnel that to the client, or
 585          *      keep track of it ourselves?
 586          *
 587          *      FIXME: EAP-Messages can only start with 'identity',
 588          *      NOT 'eap start', so we should check for that....
 589          */
 590         switch (reply->code) {
 591         case PW_AUTHENTICATION_ACK:
 592                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 593
 594                 rcode = RLM_MODULE_OK;
 595
 596                 /*
 597                  *      MS-CHAP2-Success means that we do NOT return
 598                  *      an Access-Accept, but instead tunnel that
 599                  *      attribute to the client, and keep going with
 600                  *      the TTLS session.  Once the client accepts
 601                  *      our identity, it will respond with an empty
 602                  *      packet, and we will send EAP-Success.
 603                  */
 604                 vp = NULL;
 605                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 606                 if (vp) {
 607 #if 1
 608                         /*
 609                          *      FIXME: Tunneling MS-CHAP2-Success causes
 610                          *      the only client we have access to, to die.
 611                          *
 612                          *      We don't want that...
 613                          */
 614                         pairfree(&vp);
 615 #else
 616                         DEBUG2("  TTLS: Got MS-CHAP2-Success, tunneling it to the client in a challenge.");
 617                         rcode = RLM_MODULE_HANDLED;
 618                         t->authenticated = TRUE;
 619 #endif
 620                 } else { /* no MS-CHAP2-Success */
 621                         /*
 622                          *      Can only have EAP-Message if there's
 623                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 624                          *
 625                          *      We also do NOT tunnel the EAP-Success
 626                          *      attribute back to the client, as the client
 627                          *      can figure it out, from the non-tunneled
 628                          *      EAP-Success packet.
 629                          */
 630                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 631                         pairfree(&vp);
 632
 633                         /*
 634                          *      If we've been told to use the attributes from
 635                          *      the reply, then do so.
 636                          *
 637                          *      WARNING: This may leak information about the
 638                          *      tunneled user!
 639                          */
 640                         if (t->use_tunneled_reply) {
 641                                 pairadd(&request->reply->vps, reply->vps);
 642                                 reply->vps = NULL;
 643                         }
 644                 }
 645
 646                 /*
 647                  *      Handle the ACK, by tunneling any necessary reply
 648                  *      VP's back to the client.
 649                  */
 650                 if (vp) {
 651                         vp2diameter(tls_session, vp);
 652                         pairfree(&vp);
 653                 }
 654                 break;
 655
 656
 657         case PW_AUTHENTICATION_REJECT:
 658                 DEBUG2("  TTLS: Got tunneled Access-Reject");
 659                 rcode = RLM_MODULE_REJECT;
 660                 break;
 661
 662                 /*
 663                  *      Handle Access-Challenge, but only if we
 664                  *      send tunneled reply data.  This is because
 665                  *      an Access-Challenge means that we MUST tunnel
 666                  *      a Reply-Message to the client.
 667                  */
 668         case PW_ACCESS_CHALLENGE:
 669                 DEBUG2("  TTLS: Got tunneled Access-Challenge");
 670
 671                 /*
 672                  *      Keep the State attribute, if necessary.
 673                  *
 674                  *      Get rid of the old State, too.
 675                  */
 676                 pairfree(&t->state);
 677                 pairmove2(&t->state, &reply->vps, PW_STATE);
 678
 679                 /*
 680                  *      We should really be a bit smarter about this,
 681                  *      and move over only those attributes which
 682                  *      are relevant to the authentication request,
 683                  *      but that's a lot more work, and this "dumb"
 684                  *      method works in 99.9% of the situations.
 685                  */
 686                 vp = NULL;
 687                 pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 688
 689                 /*
 690                  *      There MUST be a Reply-Message in the challenge,
 691                  *      which we tunnel back to the client.
 692                  *
 693                  *      If there isn't one in the reply VP's, then
 694                  *      we MUST create one, with an empty string as
 695                  *      it's value.
 696                  */
 697                 pairmove2(&vp, &reply->vps, PW_REPLY_MESSAGE);
 698
 699                 /*
 700                  *      Handle the ACK, by tunneling any necessary reply
 701                  *      VP's back to the client.
 702                  */
 703                 if (vp) {
 704                         vp2diameter(tls_session, vp);
 705                         pairfree(&vp);
 706                 }
 707                 rcode = RLM_MODULE_HANDLED;
 708                 break;
 709
 710         default:
 711                 DEBUG2("  TTLS: Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
 712                 rcode = RLM_MODULE_REJECT;
 713                 break;
 714         }
 715
 716         return rcode;
 717 }
 718
 719
 720 /*
 721  *      Do post-proxy processing,
 722  */
 723 static int eapttls_postproxy(EAP_HANDLER *handler, void *data)
 724 {
 725         int rcode;
 726         tls_session_t *tls_session = (tls_session_t *) data;
 727
 728         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 729
 730         /*
 731          *      Process the reply from the home server.
 732          */
 733         rcode = process_reply(handler, tls_session, handler->request,
 734                               handler->request->proxy_reply);
 735
 736         /*
 737          *      The proxy code uses the reply from the home server as
 738          *      the basis for the reply to the NAS.  We don't want that,
 739          *      so we toss it, after we've had our way with it.
 740          */
 741         pairfree(&handler->request->proxy_reply->vps);
 742
 743         switch (rcode) {
 744         case RLM_MODULE_REJECT:
 745                 DEBUG2("  TTLS: Reply was rejected");
 746                 return 0;
 747
 748         case RLM_MODULE_HANDLED:
 749                 DEBUG2("  TTLS: Reply was handled");
 750                 eaptls_request(handler->eap_ds, tls_session);
 751                 return 1;
 752
 753         case RLM_MODULE_OK:
 754                 DEBUG2("  TTLS: Reply was OK");
 755                 eaptls_success(handler->eap_ds, 0);
 756                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 757                                      tls_session->ssl,
 758                                      "ttls keying material");
 759                 return 1;
 760
 761         default:
 762                 DEBUG2("  TTLS: Reply was unknown.");
 763                 break;
 764         }
 765
 766         eaptls_fail(handler->eap_ds, 0);
 767         return 0;
 768 }
 769
 770
 771 /*
 772  *      Process the "diameter" contents of the tunneled data.
 773  */
 774 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 775 {
 776         int err;
 777         int rcode = PW_AUTHENTICATION_REJECT;
 778         REQUEST *fake;
 779         VALUE_PAIR *vp;
 780         ttls_tunnel_t *t;
 781         const uint8_t *data;
 782         unsigned int data_len;
 783         char buffer[1024];
 784         REQUEST *request = handler->request;
 785
 786         /*
 787          *      Grab the dirty data, and copy it to our buffer.
 788          *
 789          *      I *really* don't like these 'record_t' things...
 790          */
 791         data_len = record_minus(&tls_session->dirty_in, buffer, sizeof(buffer));
 792         data = buffer;
 793
 794         /*
 795          *      Write the data from the dirty buffer (i.e. packet
 796          *      data) into the buffer which we will give to SSL for
 797          *      decoding.
 798          *
 799          *      Some of this code COULD technically go into the TLS
 800          *      module, in eaptls_process(), where it returns EAPTLS_OK.
 801          *
 802          *      Similarly, the writing of data to the SSL context could
 803          *      go there, too...
 804          */
 805         BIO_write(tls_session->into_ssl, buffer, data_len);
 806         record_init(&tls_session->clean_out);
 807
 808         /*
 809          *      Read (and decrypt) the tunneled data from the SSL session,
 810          *      and put it into the decrypted data buffer.
 811          */
 812         err = SSL_read(tls_session->ssl, tls_session->clean_out.data,
 813                        sizeof(tls_session->clean_out.data));
 814         if (err < 0) {
 815                 /*
 816                  *      FIXME: Call SSL_get_error() to see what went
 817                  *      wrong.
 818                  */
 819                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 820                 return PW_AUTHENTICATION_REJECT;
 821         }
 822
 823         t = (ttls_tunnel_t *) tls_session->opaque;
 824
 825         /*
 826          *      If there's no data, maybe this is an ACK to an
 827          *      MS-CHAP2-Success.
 828          */
 829         if (err == 0) {
 830                 if (t->authenticated) {
 831                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 832                         return PW_AUTHENTICATION_ACK;
 833                 } /* else no session, no data, die. */
 834
 835                 /*
 836                  *      FIXME: Call SSL_get_error() to see what went
 837                  *      wrong.
 838                  */
 839                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 840                 return PW_AUTHENTICATION_REJECT;
 841         }
 842
 843         data_len = tls_session->clean_out.used = err;
 844         data = tls_session->clean_out.data;
 845
 846 #ifndef NDEBUG
 847         if (debug_flag > 2) {
 848                 unsigned int i;
 849
 850                 for (i = 0; i < data_len; i++) {
 851                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 852
 853                         printf("%02x ", data[i]);
 854
 855                         if ((i & 0x0f) == 0x0f) printf("\n");
 856                 }
 857                 if ((data_len & 0x0f) != 0) printf("\n");
 858         }
 859 #endif
 860
 861         if (!diameter_verify(data, data_len)) {
 862                 return PW_AUTHENTICATION_REJECT;
 863         }
 864
 865         /*
 866          *      Allocate a fake REQUEST structe.
 867          */
 868         fake = request_alloc_fake(request);
 869
 870         rad_assert(fake->packet->vps == NULL);
 871
 872         /*
 873          *      Add the tunneled attributes to the fake request.
 874          */
 875         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
 876         if (!fake->packet->vps) {
 877                 return PW_AUTHENTICATION_REJECT;
 878         }
 879
 880         /*
 881          *      Tell the request that it's a fake one.
 882          */
 883         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
 884         if (vp) {
 885                 pairadd(&fake->packet->vps, vp);
 886         }
 887
 888 #ifndef NDEBUG
 889         if (debug_flag > 0) {
 890                 printf("  TTLS: Got tunneled request\n");
 891
 892                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
 893                         putchar('\t');vp_print(stdout, vp);putchar('\n');
 894                 }
 895         }
 896 #endif
 897
 898         /*
 899          *      Update other items in the REQUEST data structure.
 900          */
 901         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
 902         fake->password = pairfind(fake->packet->vps, PW_PASSWORD);
 903
 904         /*
 905          *      No User-Name, try to create one from stored data.
 906          */
 907         if (!fake->username) {
 908                 /*
 909                  *      No User-Name in the stored data, look for
 910                  *      an EAP-Identity, and pull it out of there.
 911                  */
 912                 if (!t->username) {
 913                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
 914                         if (vp &&
 915                             (vp->length >= EAP_HEADER_LEN + 2) &&
 916                             (vp->strvalue[0] == PW_EAP_RESPONSE) &&
 917                             (vp->strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
 918                             (vp->strvalue[EAP_HEADER_LEN + 1] != 0)) {
 919                                 /*
 920                                  *      Create & remember a User-Name
 921                                  */
 922                                 t->username = pairmake("User-Name", "", T_OP_EQ);
 923                                 rad_assert(t->username != NULL);
 924
 925                                 memcpy(t->username->strvalue, vp->strvalue + 5,
 926                                        vp->length - 5);
 927                                 t->username->length = vp->length - 5;
 928                                 t->username->strvalue[t->username->length] = 0;
 929
 930                                 DEBUG2("  TTLS: Got tunneled identity of %s",
 931                                        t->username->strvalue);
 932
 933                                 /*
 934                                  *      If there's a default EAP type,
 935                                  *      set it here.
 936                                  */
 937                                 if (t->default_eap_type != 0) {
 938                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
 939                                         vp = paircreate(PW_EAP_TYPE,
 940                                                         PW_TYPE_INTEGER);
 941                                         rad_assert(vp != NULL);
 942                                         vp->lvalue = t->default_eap_type;
 943                                         pairadd(&fake->config_items, vp);
 944                                 }
 945
 946                         } else {
 947                                 /*
 948                                  *      Don't reject the request outright,
 949                                  *      as it's permitted to do EAP without
 950                                  *      user-name.
 951                                  */
 952                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
 953                         }
 954                 } /* else there WAS a t->username */
 955
 956                 if (t->username) {
 957                         vp = paircopy(t->username);
 958                         pairadd(&fake->packet->vps, vp);
 959                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
 960                 }
 961         } /* else the request ALREADY had a User-Name */
 962
 963         /*
 964          *      Add the State attribute, too, if it exists.
 965          */
 966         if (t->state) {
 967                 DEBUG2("  TTLS: Adding old state with %02x %02x",
 968                        t->state->strvalue[0], t->state->strvalue[1]);
 969                 vp = paircopy(t->state);
 970                 if (vp) pairadd(&fake->packet->vps, vp);
 971         }
 972
 973         /*
 974          *      If this is set, we copy SOME of the request attributes
 975          *      from outside of the tunnel to inside of the tunnel.
 976          *
 977          *      We copy ONLY those attributes which do NOT already
 978          *      exist in the tunneled request.
 979          */
 980         if (t->copy_request_to_tunnel) {
 981                 VALUE_PAIR *copy;
 982
 983                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
 984                         /*
 985                          *      The attribute is a server-side thingy,
 986                          *      don't copy it.
 987                          */
 988                         if ((vp->attribute > 255) &&
 989                             (((vp->attribute >> 16) & 0xffff) == 0)) {
 990                                 continue;
 991                         }
 992
 993                         /*
 994                          *      The outside attribute is already in the
 995                          *      tunnel, don't copy it.
 996                          *
 997                          *      This works for BOTH attributes which
 998                          *      are originally in the tunneled request,
 999                          *      AND attributes which are copied there
1000                          *      from below.
1001                          */
1002                         if (pairfind(fake->packet->vps, vp->attribute)) {
1003                                 continue;
1004                         }
1005
1006                         /*
1007                          *      Some attributes are handled specially.
1008                          */
1009                         switch (vp->attribute) {
1010                                 /*
1011                                  *      NEVER copy Message-Authenticator,
1012                                  *      EAP-Message, or State.  They're
1013                                  *      only for outside of the tunnel.
1014                                  */
1015                         case PW_USER_NAME:
1016                         case PW_USER_PASSWORD:
1017                         case PW_CHAP_PASSWORD:
1018                         case PW_CHAP_CHALLENGE:
1019                         case PW_PROXY_STATE:
1020                         case PW_MESSAGE_AUTHENTICATOR:
1021                         case PW_EAP_MESSAGE:
1022                         case PW_STATE:
1023                                 continue;
1024                                 break;
1025
1026                                 /*
1027                                  *      By default, copy it over.
1028                                  */
1029                         default:
1030                                 break;
1031                         }
1032
1033                         /*
1034                          *      Don't copy from the head, we've already
1035                          *      checked it.
1036                          */
1037                         copy = paircopy2(vp, vp->attribute);
1038                         pairadd(&fake->packet->vps, copy);
1039                 }
1040         }
1041
1042 #ifndef NDEBUG
1043         if (debug_flag > 0) {
1044           printf("  TTLS: Sending tunneled request\n");
1045
1046           for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1047             putchar('\t');vp_print(stdout, vp);putchar('\n');
1048           }
1049         }
1050 #endif
1051
1052         /*
1053          *      Call authentication recursively, which will
1054          *      do PAP, CHAP, MS-CHAP, etc.
1055          */
1056         rad_authenticate(fake);
1057
1058         /*
1059          *      Note that we don't do *anything* with the reply
1060          *      attributes.
1061          */
1062 #ifndef NDEBUG
1063         if (debug_flag > 0) {
1064           printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1065                  fake->reply->code);
1066
1067           for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1068             putchar('\t');vp_print(stdout, vp);putchar('\n');
1069           }
1070         }
1071 #endif
1072
1073         /*
1074          *      Decide what to do with the reply.
1075          */
1076         switch (fake->reply->code) {
1077         case 0:                 /* No reply code, must be proxied... */
1078                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1079                 if (vp) {
1080                         eap_tunnel_data_t *tunnel;
1081                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->strvalue);
1082
1083                         /*
1084                          *      Tell the original request that it's going
1085                          *      to be proxied.
1086                          */
1087                         pairmove2(&(request->config_items),
1088                                   &(fake->config_items),
1089                                   PW_PROXY_TO_REALM);
1090
1091                         /*
1092                          *      Seed the proxy packet with the
1093                          *      tunneled request.
1094                          */
1095                         rad_assert(request->proxy == NULL);
1096                         request->proxy = fake->packet;
1097                         fake->packet = NULL;
1098
1099                         /*
1100                          *      Set up the callbacks for the tunnel
1101                          */
1102                         tunnel = rad_malloc(sizeof(*tunnel));
1103                         memset(tunnel, 0, sizeof(*tunnel));
1104
1105                         tunnel->tls_session = tls_session;
1106                         tunnel->callback = eapttls_postproxy;
1107
1108                         /*
1109                          *      Associate the callback with the request.
1110                          */
1111                         rcode = request_data_add(request,
1112                                                  request->proxy,
1113                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1114                                                  tunnel, free);
1115                         rad_assert(rcode == 0);
1116
1117                         /*
1118                          *      Didn't authenticate the packet, but
1119                          *      we're proxying it.
1120                          */
1121                         rcode = RLM_MODULE_UPDATED;
1122
1123                 } else {
1124                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1125                                request->number);
1126                         rcode = RLM_MODULE_REJECT;
1127                 }
1128                 break;
1129
1130         default:
1131                 rcode = process_reply(handler, tls_session, request,
1132                                       fake->reply);
1133                 break;
1134         }
1135
1136         request_free(&fake);
1137
1138         return rcode;
1139 }
1140