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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  *   Copyright 2003 Alan DeKok <aland@freeradius.org>
  21  *   Copyright 2006 The FreeRADIUS server project
  22  */
  23
  24 #include <freeradius-devel/ident.h>
  25 RCSID("$Id$")
  26
  27 #include "eap_ttls.h"
  28
  29 /*
  30  *    0                   1                   2                   3
  31  *    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
  32  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  33  *   |                           AVP Code                            |
  34  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35  *   |V M r r r r r r|                  AVP Length                   |
  36  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37  *   |                        Vendor-ID (opt)                        |
  38  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  39  *   |    Data ...
  40  *   +-+-+-+-+-+-+-+-+
  41  */
  42
  43 /*
  44  *      Verify that the diameter packet is valid.
  45  */
  46 static int diameter_verify(const uint8_t *data, unsigned int data_len)
  47 {
  48         uint32_t attr;
  49         uint32_t length;
  50         unsigned int offset;
  51         unsigned int data_left = data_len;
  52
  53         while (data_left > 0) {
  54                 if (data_len < 12) {
  55                         DEBUG2("  rlm_eap_ttls:  Diameter attribute is too small to contain a Diameter header");
  56                         return 0;
  57                 }
  58
  59                 rad_assert(data_left <= data_len);
  60                 memcpy(&attr, data, sizeof(attr));
  61                 data += 4;
  62                 attr = ntohl(attr);
  63                 if (attr > 255) {
  64                         DEBUG2("  rlm_eap_ttls:  Non-RADIUS attribute in tunneled authentication is not supported");
  65                         return 0;
  66                 }
  67
  68                 memcpy(&length, data , sizeof(length));
  69                 data += 4;
  70                 length = ntohl(length);
  71
  72                 /*
  73                  *      A "vendor" flag, with a vendor ID of zero,
  74                  *      is equivalent to no vendor.  This is stupid.
  75                  */
  76                 offset = 8;
  77                 if ((length & (1 << 31)) != 0) {
  78                         int attribute;
  79                         uint32_t vendor;
  80                         DICT_ATTR *da;
  81
  82                         memcpy(&vendor, data, sizeof(vendor));
  83                         vendor = ntohl(vendor);
  84
  85                         if (vendor > 65535) {
  86                                 DEBUG2("  rlm_eap_ttls: Vendor codes larger than 65535 are not supported");
  87                                 return 0;
  88                         }
  89
  90                         attribute = (vendor << 16) | attr;
  91
  92                         da = dict_attrbyvalue(attribute);
  93
  94                         /*
  95                          *      SHOULD check ((length & (1 << 30)) != 0)
  96                          *      for the mandatory bit.
  97                          */
  98                         if (!da) {
  99                                 DEBUG2("  rlm_eap_ttls: Fatal! Vendor %u, Attribute %u was not found in our dictionary. ",
 100                                        vendor, attr);
 101                                 return 0;
 102                         }
 103
 104                         data += 4; /* skip the vendor field */
 105                         offset += 4; /* offset to value field */
 106                 }
 107
 108                 /*
 109                  *      Ignore the M bit.  We support all RADIUS attributes...
 110                  */
 111
 112                 /*
 113                  *      Get the length.  If it's too big, die.
 114                  */
 115                 length &= 0x00ffffff;
 116
 117                 /*
 118                  *      Too short or too long is bad.
 119                  *
 120                  *      FIXME: EAP-Message
 121                  */
 122                 if (length < offset) {
 123                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too short (%d)to contain anything useful.", attr, length);
 124                         return 0;
 125                 }
 126
 127                 if (length > (MAX_STRING_LEN + 8)) {
 128                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too long (%d) to pack into a RADIUS attribute.", attr, length);
 129                         return 0;
 130                 }
 131
 132                 if (length > data_left) {
 133                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is longer than room left in the packet (%d > %d).", attr, length, data_left);
 134                         return 0;
 135                 }
 136
 137                 /*
 138                  *      Check for broken implementations, which don't
 139                  *      pad the AVP to a 4-octet boundary.
 140                  */
 141                 if (data_left == length) break;
 142
 143                 /*
 144                  *      The length does NOT include the padding, so
 145                  *      we've got to account for it here by rounding up
 146                  *      to the nearest 4-byte boundary.
 147                  */
 148                 length += 0x03;
 149                 length &= ~0x03;
 150
 151                 /*
 152                  *      If the rest of the diameter packet is larger than
 153                  *      this attribute, continue.
 154                  *
 155                  *      Otherwise, if the attribute over-flows the end
 156                  *      of the packet, die.
 157                  */
 158                 if (data_left < length) {
 159                         DEBUG2("  rlm_eap_ttls: ERROR! Diameter attribute overflows packet!");
 160                         return 0;
 161                 }
 162
 163                 /*
 164                  *      Check again for equality, now that we're padded
 165                  *      length to a multiple of 4 octets.
 166                  */
 167                 if (data_left == length) break;
 168
 169                 /*
 170                  *      data_left > length, continue.
 171                  */
 172                 data_left -= length;
 173                 data += length - offset;
 174         }
 175
 176         /*
 177          *      We got this far.  It looks OK.
 178          */
 179         return 1;
 180 }
 181
 182
 183 /*
 184  *      Convert diameter attributes to our VALUE_PAIR's
 185  */
 186 static VALUE_PAIR *diameter2vp(SSL *ssl,
 187                                const uint8_t *data, unsigned int data_len)
 188 {
 189         uint32_t        attr;
 190         uint32_t        length;
 191         unsigned int    offset;
 192         int             size;
 193         unsigned int    data_left = data_len;
 194         VALUE_PAIR      *first = NULL;
 195         VALUE_PAIR      **last = &first;
 196         VALUE_PAIR      *vp;
 197
 198         while (data_left > 0) {
 199                 rad_assert(data_left <= data_len);
 200                 memcpy(&attr, data, sizeof(attr));
 201                 data += 4;
 202                 attr = ntohl(attr);
 203
 204                 memcpy(&length, data, sizeof(length));
 205                 data += 4;
 206                 length = ntohl(length);
 207
 208                 /*
 209                  *      Ignore the M bit.  We support all RADIUS attributes...
 210                  */
 211
 212                 /*
 213                  *      A "vendor" flag, with a vendor ID of zero,
 214                  *      is equivalent to no vendor.  This is stupid.
 215                  */
 216                 offset = 8;
 217                 if ((length & (1 << 31)) != 0) {
 218                         uint32_t vendor;
 219
 220                         memcpy(&vendor, data, sizeof(vendor));
 221                         vendor = ntohl(vendor);
 222
 223                         attr |= (vendor << 16);
 224
 225                         data += 4; /* skip the vendor field, it's zero */
 226                         offset += 4; /* offset to value field */
 227                 }
 228
 229                 /*
 230                  *      Get the length.
 231                  */
 232                 length &= 0x00ffffff;
 233
 234                 /*
 235                  *      diameter code + length, and it must fit in
 236                  *      a VALUE_PAIR.
 237                  */
 238                 rad_assert(length <= (offset + MAX_STRING_LEN));
 239
 240                 /*
 241                  *      Get the size of the value portion of the
 242                  *      attribute.
 243                  */
 244                 size = length - offset;
 245
 246                 /*
 247                  *      Create it.
 248                  */
 249                 vp = paircreate(attr, PW_TYPE_OCTETS);
 250                 if (!vp) {
 251                         DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 252                         pairfree(&first);
 253                         return NULL;
 254                 }
 255
 256                 /*
 257                  *      If it's a type from our dictionary, then
 258                  *      we need to put the data in a relevant place.
 259                  */
 260                 switch (vp->type) {
 261                 case PW_TYPE_INTEGER:
 262                 case PW_TYPE_DATE:
 263                         if (size != vp->length) {
 264                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 265                                        attr);
 266                                 pairfree(&first);
 267                                 return NULL;
 268                         }
 269                         memcpy(&vp->lvalue, data, vp->length);
 270
 271                         /*
 272                          *      Stored in host byte order: change it.
 273                          */
 274                         vp->lvalue = ntohl(vp->lvalue);
 275                         break;
 276
 277                 case PW_TYPE_IPADDR:
 278                         if (size != vp->length) {
 279                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 280                                        attr);
 281                                 pairfree(&first);
 282                                 return NULL;
 283                         }
 284                   memcpy(&vp->lvalue, data, vp->length);
 285
 286                   /*
 287                    *    Stored in network byte order: don't change it.
 288                    */
 289                   break;
 290
 291                   /*
 292                    *    String, octet, etc.  Copy the data from the
 293                    *    value field over verbatim.
 294                    *
 295                    *    FIXME: Ipv6 attributes ?
 296                    *
 297                    */
 298                 default:
 299                         vp->length = size;
 300                         memcpy(vp->vp_strvalue, data, vp->length);
 301                         break;
 302                 }
 303
 304                 /*
 305                  *      User-Password is NUL padded to a multiple
 306                  *      of 16 bytes.  Let's chop it to something
 307                  *      more reasonable.
 308                  *
 309                  *      NOTE: This means that the User-Password
 310                  *      attribute CANNOT EVER have embedded zeros in it!
 311                  */
 312                 switch (vp->attribute) {
 313                 case PW_USER_PASSWORD:
 314                         rad_assert(vp->length <= 128); /* RFC requirements */
 315
 316                         /*
 317                          *      If the password is exactly 16 octets,
 318                          *      it won't be zero-terminated.
 319                          */
 320                         vp->vp_strvalue[vp->length] = '\0';
 321                         vp->length = strlen(vp->vp_strvalue);
 322                         break;
 323
 324                         /*
 325                          *      Ensure that the client is using the
 326                          *      correct challenge.  This weirdness is
 327                          *      to protect against against replay
 328                          *      attacks, where anyone observing the
 329                          *      CHAP exchange could pose as that user,
 330                          *      by simply choosing to use the same
 331                          *      challenge.
 332                          *
 333                          *      By using a challenge based on
 334                          *      information from the current session,
 335                          *      we can guarantee that the client is
 336                          *      not *choosing* a challenge.
 337                          *
 338                          *      We're a little forgiving in that we
 339                          *      have loose checks on the length, and
 340                          *      we do NOT check the Id (first octet of
 341                          *      the response to the challenge)
 342                          *
 343                          *      But if the client gets the challenge correct,
 344                          *      we're not too worried about the Id.
 345                          */
 346                 case PW_CHAP_CHALLENGE:
 347                 case PW_MSCHAP_CHALLENGE:
 348                         if ((vp->length < 8) ||
 349                             (vp->length > 16)) {
 350                                 DEBUG2("  TTLS: Tunneled challenge has invalid length");
 351                                 pairfree(&first);
 352                                 return NULL;
 353
 354                         } else {
 355                                 int i;
 356                                 uint8_t challenge[16];
 357
 358                                 eapttls_gen_challenge(ssl, challenge,
 359                                                       sizeof(challenge));
 360
 361                                 for (i = 0; i < vp->length; i++) {
 362                                         if (challenge[i] != vp->vp_strvalue[i]) {
 363                                                 DEBUG2("  TTLS: Tunneled challenge is incorrect");
 364                                                 pairfree(&first);
 365                                                 return NULL;
 366                                         }
 367                                 }
 368                         }
 369                         break;
 370
 371                 default:
 372                         break;
 373                 } /* switch over checking/re-writing of attributes. */
 374
 375                 /*
 376                  *      Update the list.
 377                  */
 378                 *last = vp;
 379                 last = &(vp->next);
 380
 381                 /*
 382                  *      Catch non-aligned attributes.
 383                  */
 384                 if (data_left == length) break;
 385
 386                 /*
 387                  *      The length does NOT include the padding, so
 388                  *      we've got to account for it here by rounding up
 389                  *      to the nearest 4-byte boundary.
 390                  */
 391                 length += 0x03;
 392                 length &= ~0x03;
 393
 394                 rad_assert(data_left >= length);
 395                 data_left -= length;
 396                 data += length - offset; /* already updated */
 397         }
 398
 399         /*
 400          *      We got this far.  It looks OK.
 401          */
 402         return first;
 403 }
 404
 405 /*
 406  *      Convert VALUE_PAIR's to diameter attributes, and write them
 407  *      to an SSL session.
 408  *
 409  *      The ONLY VALUE_PAIR's which may be passed to this function
 410  *      are ones which can go inside of a RADIUS (i.e. diameter)
 411  *      packet.  So no server-configuration attributes, or the like.
 412  */
 413 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 414 {
 415         /*
 416          *      RADIUS packets are no more than 4k in size, so if
 417          *      we've got more than 4k of data to write, it's very
 418          *      bad.
 419          */
 420         uint8_t         buffer[4096];
 421         uint8_t         *p;
 422         uint32_t        attr;
 423         uint32_t        length;
 424         uint32_t        vendor;
 425         size_t          total;
 426         VALUE_PAIR      *vp;
 427
 428         p = buffer;
 429         total = 0;
 430
 431         for (vp = first; vp != NULL; vp = vp->next) {
 432                 /*
 433                  *      Too much data: die.
 434                  */
 435                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 436                         DEBUG2("  TTLS output buffer is full!");
 437                         return 0;
 438                 }
 439
 440                 /*
 441                  *      Hmm... we don't group multiple EAP-Messages
 442                  *      together.  Maybe we should...
 443                  */
 444
 445                 /*
 446                  *      Length is no more than 253, due to RADIUS
 447                  *      issues.
 448                  */
 449                 length = vp->length;
 450                 vendor = (vp->attribute >> 16) & 0xffff;
 451                 if (vendor != 0) {
 452                         attr = vp->attribute & 0xffff;
 453                         length |= (1 << 31);
 454                 } else {
 455                         attr = vp->attribute;
 456                 }
 457
 458                 /*
 459                  *      Hmm... set the M bit for all attributes?
 460                  */
 461                 length |= (1 << 30);
 462
 463                 attr = ntohl(attr);
 464
 465                 memcpy(p, &attr, sizeof(attr));
 466                 p += 4;
 467                 total += 4;
 468
 469                 length += 8;    /* includes 8 bytes of attr & length */
 470
 471                 if (vendor != 0) {
 472                         length += 4; /* include 4 bytes of vendor */
 473
 474                         length = ntohl(length);
 475                         memcpy(p, &length, sizeof(length));
 476                         p += 4;
 477                         total += 4;
 478
 479                         vendor = ntohl(vendor);
 480                         memcpy(p, &vendor, sizeof(vendor));
 481                         p += 4;
 482                         total += 4;
 483                 } else {
 484                         length = ntohl(length);
 485                         memcpy(p, &length, sizeof(length));
 486                         p += 4;
 487                         total += 4;
 488                 }
 489
 490                 switch (vp->type) {
 491                 case PW_TYPE_INTEGER:
 492                 case PW_TYPE_DATE:
 493                         attr = ntohl(vp->lvalue); /* stored in host order */
 494                         memcpy(p, &attr, sizeof(attr));
 495                         length = 4;
 496                         break;
 497
 498                 case PW_TYPE_IPADDR:
 499                         attr = vp->lvalue; /* stored in network order */
 500                         memcpy(p, &attr, sizeof(attr));
 501                         length = 4;
 502                         break;
 503
 504                 case PW_TYPE_STRING:
 505                 case PW_TYPE_OCTETS:
 506                 default:
 507                         memcpy(p, vp->vp_strvalue, vp->length);
 508                         length = vp->length;
 509                         break;
 510                 }
 511
 512                 /*
 513                  *      Skip to the end of the data.
 514                  */
 515                 p += length;
 516                 total += length;
 517
 518                 /*
 519                  *      Align the data to a multiple of 4 bytes.
 520                  */
 521                 if ((total & 0x03) != 0) {
 522                         unsigned int i;
 523
 524                         length = 4 - (total & 0x03);
 525                         for (i = 0; i < length; i++) {
 526                                 *p = '\0';
 527                                 p++;
 528                                 total++;
 529                         }
 530                 }
 531         } /* loop over the VP's to write. */
 532
 533         /*
 534          *      Write the data in the buffer to the SSL session.
 535          */
 536         if (total > 0) {
 537 #ifndef NDEBUG
 538                 unsigned int i;
 539
 540                 if (debug_flag > 2) {
 541                         for (i = 0; i < total; i++) {
 542                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 543
 544                                 printf("%02x ", buffer[i]);
 545
 546                                 if ((i & 0x0f) == 0x0f) printf("\n");
 547                         }
 548                         if ((total & 0x0f) != 0) printf("\n");
 549                 }
 550 #endif
 551
 552                 (tls_session->record_plus)(&tls_session->clean_in, buffer, total);
 553
 554                 /*
 555                  *      FIXME: Check the return code.
 556                  */
 557                 tls_handshake_send(tls_session);
 558         }
 559
 560         /*
 561          *      Everything's OK.
 562          */
 563         return 1;
 564 }
 565
 566 /*
 567  *      Use a reply packet to determine what to do.
 568  */
 569 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 570                          REQUEST *request, RADIUS_PACKET *reply)
 571 {
 572         int rcode = RLM_MODULE_REJECT;
 573         VALUE_PAIR *vp;
 574         ttls_tunnel_t *t = tls_session->opaque;
 575
 576         handler = handler;      /* -Wunused */
 577
 578         /*
 579          *      If the response packet was Access-Accept, then
 580          *      we're OK.  If not, die horribly.
 581          *
 582          *      FIXME: Take MS-CHAP2-Success attribute, and
 583          *      tunnel it back to the client, to authenticate
 584          *      ourselves to the client.
 585          *
 586          *      FIXME: If we have an Access-Challenge, then
 587          *      the Reply-Message is tunneled back to the client.
 588          *
 589          *      FIXME: If we have an EAP-Message, then that message
 590          *      must be tunneled back to the client.
 591          *
 592          *      FIXME: If we have an Access-Challenge with a State
 593          *      attribute, then do we tunnel that to the client, or
 594          *      keep track of it ourselves?
 595          *
 596          *      FIXME: EAP-Messages can only start with 'identity',
 597          *      NOT 'eap start', so we should check for that....
 598          */
 599         switch (reply->code) {
 600         case PW_AUTHENTICATION_ACK:
 601                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 602
 603                 rcode = RLM_MODULE_OK;
 604
 605                 /*
 606                  *      MS-CHAP2-Success means that we do NOT return
 607                  *      an Access-Accept, but instead tunnel that
 608                  *      attribute to the client, and keep going with
 609                  *      the TTLS session.  Once the client accepts
 610                  *      our identity, it will respond with an empty
 611                  *      packet, and we will send EAP-Success.
 612                  */
 613                 vp = NULL;
 614                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 615                 if (vp) {
 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                 } else { /* no MS-CHAP2-Success */
 620                         /*
 621                          *      Can only have EAP-Message if there's
 622                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 623                          *
 624                          *      We also do NOT tunnel the EAP-Success
 625                          *      attribute back to the client, as the client
 626                          *      can figure it out, from the non-tunneled
 627                          *      EAP-Success packet.
 628                          */
 629                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 630                         pairfree(&vp);
 631                 }
 632
 633                 /*
 634                  *      Handle the ACK, by tunneling any necessary reply
 635                  *      VP's back to the client.
 636                  */
 637                 if (vp) {
 638                         vp2diameter(tls_session, vp);
 639                         pairfree(&vp);
 640                 }
 641
 642                 /*
 643                  *      If we've been told to use the attributes from
 644                  *      the reply, then do so.
 645                  *
 646                  *      WARNING: This may leak information about the
 647                  *      tunneled user!
 648                  */
 649                 if (t->use_tunneled_reply) {
 650                         pairdelete(&reply->vps, PW_PROXY_STATE);
 651                         pairadd(&request->reply->vps, reply->vps);
 652                         reply->vps = NULL;
 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_INVALID;
 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         REQUEST *fake;
 728
 729         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 730
 731         /*
 732          *      If there was a fake request associated with the proxied
 733          *      request, do more processing of it.
 734          */
 735         fake = (REQUEST *) request_data_get(handler->request,
 736                                             handler->request->proxy,
 737                                             REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);
 738
 739         /*
 740          *      Do the callback, if it exists, and if it was a success.
 741          */
 742         if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
 743                 VALUE_PAIR *vp;
 744                 REQUEST *request = handler->request;
 745
 746                 /*
 747                  *      Terrible hacks.
 748                  */
 749                 rad_assert(fake->packet == NULL);
 750                 fake->packet = request->proxy;
 751                 request->proxy = NULL;
 752
 753                 rad_assert(fake->reply == NULL);
 754                 fake->reply = request->proxy_reply;
 755                 request->proxy_reply = NULL;
 756
 757                 /*
 758                  *      Perform a post-auth stage for the tunneled
 759                  *      session.
 760                  */
 761                 fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
 762                 rcode = rad_postauth(fake);
 763                 DEBUG2("  POST-AUTH %d", rcode);
 764
 765 #ifndef NDEBUG
 766                 if (debug_flag > 0) {
 767                         printf("  TTLS: Final reply from tunneled session code %d\n",
 768                                fake->reply->code);
 769
 770                         for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
 771                                 putchar('\t');vp_print(stdout, vp);putchar('\n');
 772                         }
 773                 }
 774 #endif
 775
 776                 /*
 777                  *      Terrible hacks.
 778                  */
 779                 request->proxy = fake->packet;
 780                 fake->packet = NULL;
 781                 request->proxy_reply = fake->reply;
 782                 fake->reply = NULL;
 783
 784                 /*
 785                  *      And we're done with this request.
 786                  */
 787
 788                 switch (rcode) {
 789                 case RLM_MODULE_FAIL:
 790                         request_free(&fake);
 791                         eaptls_fail(handler->eap_ds, 0);
 792                         return 0;
 793                         break;
 794
 795                 default:  /* Don't Do Anything */
 796                         DEBUG2(" TTLS: Got reply %d",
 797                                request->proxy_reply->code);
 798                         break;
 799                 }
 800         }
 801         request_free(&fake);    /* robust if fake == NULL */
 802
 803         /*
 804          *      Process the reply from the home server.
 805          */
 806         rcode = process_reply(handler, tls_session, handler->request,
 807                               handler->request->proxy_reply);
 808
 809         /*
 810          *      The proxy code uses the reply from the home server as
 811          *      the basis for the reply to the NAS.  We don't want that,
 812          *      so we toss it, after we've had our way with it.
 813          */
 814         pairfree(&handler->request->proxy_reply->vps);
 815
 816         switch (rcode) {
 817         case RLM_MODULE_REJECT:
 818                 DEBUG2("  TTLS: Reply was rejected");
 819                 break;
 820
 821         case RLM_MODULE_HANDLED:
 822                 DEBUG2("  TTLS: Reply was handled");
 823                 eaptls_request(handler->eap_ds, tls_session);
 824                 return 1;
 825
 826         case RLM_MODULE_OK:
 827                 DEBUG2("  TTLS: Reply was OK");
 828                 eaptls_success(handler->eap_ds, 0);
 829                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 830                                      tls_session->ssl,
 831                                      "ttls keying material");
 832                 return 1;
 833
 834         default:
 835                 DEBUG2("  TTLS: Reply was unknown.");
 836                 break;
 837         }
 838
 839         eaptls_fail(handler->eap_ds, 0);
 840         return 0;
 841 }
 842
 843
 844 /*
 845  *      Free a request.
 846  */
 847 static void my_request_free(void *data)
 848 {
 849         REQUEST *request = (REQUEST *)data;
 850
 851         request_free(&request);
 852 }
 853
 854
 855 /*
 856  *      Process the "diameter" contents of the tunneled data.
 857  */
 858 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 859 {
 860         int err;
 861         int rcode = PW_AUTHENTICATION_REJECT;
 862         REQUEST *fake;
 863         VALUE_PAIR *vp;
 864         ttls_tunnel_t *t;
 865         const uint8_t *data;
 866         unsigned int data_len;
 867         char buffer[1024];
 868         REQUEST *request = handler->request;
 869
 870         /*
 871          *      Grab the dirty data, and copy it to our buffer.
 872          *
 873          *      I *really* don't like these 'record_t' things...
 874          */
 875         data_len = (tls_session->record_minus)(&tls_session->dirty_in, buffer, sizeof(buffer));
 876         data = buffer;
 877
 878         /*
 879          *      Write the data from the dirty buffer (i.e. packet
 880          *      data) into the buffer which we will give to SSL for
 881          *      decoding.
 882          *
 883          *      Some of this code COULD technically go into the TLS
 884          *      module, in eaptls_process(), where it returns EAPTLS_OK.
 885          *
 886          *      Similarly, the writing of data to the SSL context could
 887          *      go there, too...
 888          */
 889         BIO_write(tls_session->into_ssl, buffer, data_len);
 890         (tls_session->record_init)(&tls_session->clean_out);
 891
 892         /*
 893          *      Read (and decrypt) the tunneled data from the SSL session,
 894          *      and put it into the decrypted data buffer.
 895          */
 896         err = SSL_read(tls_session->ssl, tls_session->clean_out.data,
 897                        sizeof(tls_session->clean_out.data));
 898         if (err < 0) {
 899                 /*
 900                  *      FIXME: Call SSL_get_error() to see what went
 901                  *      wrong.
 902                  */
 903                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 904                 return PW_AUTHENTICATION_REJECT;
 905         }
 906
 907         t = (ttls_tunnel_t *) tls_session->opaque;
 908
 909         /*
 910          *      If there's no data, maybe this is an ACK to an
 911          *      MS-CHAP2-Success.
 912          */
 913         if (err == 0) {
 914                 if (t->authenticated) {
 915                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 916                         return PW_AUTHENTICATION_ACK;
 917                 } /* else no session, no data, die. */
 918
 919                 /*
 920                  *      FIXME: Call SSL_get_error() to see what went
 921                  *      wrong.
 922                  */
 923                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 924                 return PW_AUTHENTICATION_REJECT;
 925         }
 926
 927         data_len = tls_session->clean_out.used = err;
 928         data = tls_session->clean_out.data;
 929
 930 #ifndef NDEBUG
 931         if (debug_flag > 2) {
 932                 unsigned int i;
 933
 934                 for (i = 0; i < data_len; i++) {
 935                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 936
 937                         printf("%02x ", data[i]);
 938
 939                         if ((i & 0x0f) == 0x0f) printf("\n");
 940                 }
 941                 if ((data_len & 0x0f) != 0) printf("\n");
 942         }
 943 #endif
 944
 945         if (!diameter_verify(data, data_len)) {
 946                 return PW_AUTHENTICATION_REJECT;
 947         }
 948
 949         /*
 950          *      Allocate a fake REQUEST structe.
 951          */
 952         fake = request_alloc_fake(request);
 953
 954         rad_assert(fake->packet->vps == NULL);
 955
 956         /*
 957          *      Add the tunneled attributes to the fake request.
 958          */
 959         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
 960         if (!fake->packet->vps) {
 961                 return PW_AUTHENTICATION_REJECT;
 962         }
 963
 964         /*
 965          *      Tell the request that it's a fake one.
 966          */
 967         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
 968         if (vp) {
 969                 pairadd(&fake->packet->vps, vp);
 970         }
 971
 972 #ifndef NDEBUG
 973         if (debug_flag > 0) {
 974                 printf("  TTLS: Got tunneled request\n");
 975
 976                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
 977                         putchar('\t');vp_print(stdout, vp);putchar('\n');
 978                 }
 979         }
 980 #endif
 981
 982         /*
 983          *      Update other items in the REQUEST data structure.
 984          */
 985         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
 986         fake->password = pairfind(fake->packet->vps, PW_USER_PASSWORD);
 987
 988         /*
 989          *      No User-Name, try to create one from stored data.
 990          */
 991         if (!fake->username) {
 992                 /*
 993                  *      No User-Name in the stored data, look for
 994                  *      an EAP-Identity, and pull it out of there.
 995                  */
 996                 if (!t->username) {
 997                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
 998                         if (vp &&
 999                             (vp->length >= EAP_HEADER_LEN + 2) &&
1000                             (vp->vp_strvalue[0] == PW_EAP_RESPONSE) &&
1001                             (vp->vp_strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
1002                             (vp->vp_strvalue[EAP_HEADER_LEN + 1] != 0)) {
1003                                 /*
1004                                  *      Create & remember a User-Name
1005                                  */
1006                                 t->username = pairmake("User-Name", "", T_OP_EQ);
1007                                 rad_assert(t->username != NULL);
1008
1009                                 memcpy(t->username->vp_strvalue, vp->vp_strvalue + 5,
1010                                        vp->length - 5);
1011                                 t->username->length = vp->length - 5;
1012                                 t->username->vp_strvalue[t->username->length] = 0;
1013
1014                                 DEBUG2("  TTLS: Got tunneled identity of %s",
1015                                        t->username->vp_strvalue);
1016
1017                                 /*
1018                                  *      If there's a default EAP type,
1019                                  *      set it here.
1020                                  */
1021                                 if (t->default_eap_type != 0) {
1022                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
1023                                         vp = paircreate(PW_EAP_TYPE,
1024                                                         PW_TYPE_INTEGER);
1025                                         rad_assert(vp != NULL);
1026                                         vp->lvalue = t->default_eap_type;
1027                                         pairadd(&fake->config_items, vp);
1028                                 }
1029
1030                         } else {
1031                                 /*
1032                                  *      Don't reject the request outright,
1033                                  *      as it's permitted to do EAP without
1034                                  *      user-name.
1035                                  */
1036                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
1037                         }
1038                 } /* else there WAS a t->username */
1039
1040                 if (t->username) {
1041                         vp = paircopy(t->username);
1042                         pairadd(&fake->packet->vps, vp);
1043                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1044                 }
1045         } /* else the request ALREADY had a User-Name */
1046
1047         /*
1048          *      Add the State attribute, too, if it exists.
1049          */
1050         if (t->state) {
1051                 DEBUG2("  TTLS: Adding old state with %02x %02x",
1052                        t->state->vp_strvalue[0], t->state->vp_strvalue[1]);
1053                 vp = paircopy(t->state);
1054                 if (vp) pairadd(&fake->packet->vps, vp);
1055         }
1056
1057         /*
1058          *      If this is set, we copy SOME of the request attributes
1059          *      from outside of the tunnel to inside of the tunnel.
1060          *
1061          *      We copy ONLY those attributes which do NOT already
1062          *      exist in the tunneled request.
1063          */
1064         if (t->copy_request_to_tunnel) {
1065                 VALUE_PAIR *copy;
1066
1067                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
1068                         /*
1069                          *      The attribute is a server-side thingy,
1070                          *      don't copy it.
1071                          */
1072                         if ((vp->attribute > 255) &&
1073                             (((vp->attribute >> 16) & 0xffff) == 0)) {
1074                                 continue;
1075                         }
1076
1077                         /*
1078                          *      The outside attribute is already in the
1079                          *      tunnel, don't copy it.
1080                          *
1081                          *      This works for BOTH attributes which
1082                          *      are originally in the tunneled request,
1083                          *      AND attributes which are copied there
1084                          *      from below.
1085                          */
1086                         if (pairfind(fake->packet->vps, vp->attribute)) {
1087                                 continue;
1088                         }
1089
1090                         /*
1091                          *      Some attributes are handled specially.
1092                          */
1093                         switch (vp->attribute) {
1094                                 /*
1095                                  *      NEVER copy Message-Authenticator,
1096                                  *      EAP-Message, or State.  They're
1097                                  *      only for outside of the tunnel.
1098                                  */
1099                         case PW_USER_NAME:
1100                         case PW_USER_PASSWORD:
1101                         case PW_CHAP_PASSWORD:
1102                         case PW_CHAP_CHALLENGE:
1103                         case PW_PROXY_STATE:
1104                         case PW_MESSAGE_AUTHENTICATOR:
1105                         case PW_EAP_MESSAGE:
1106                         case PW_STATE:
1107                                 continue;
1108                                 break;
1109
1110                                 /*
1111                                  *      By default, copy it over.
1112                                  */
1113                         default:
1114                                 break;
1115                         }
1116
1117                         /*
1118                          *      Don't copy from the head, we've already
1119                          *      checked it.
1120                          */
1121                         copy = paircopy2(vp, vp->attribute);
1122                         pairadd(&fake->packet->vps, copy);
1123                 }
1124         }
1125
1126 #ifndef NDEBUG
1127         if (debug_flag > 0) {
1128           printf("  TTLS: Sending tunneled request\n");
1129
1130           for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1131             putchar('\t');vp_print(stdout, vp);putchar('\n');
1132           }
1133         }
1134 #endif
1135
1136         /*
1137          *      Call authentication recursively, which will
1138          *      do PAP, CHAP, MS-CHAP, etc.
1139          */
1140         rad_authenticate(fake);
1141
1142         /*
1143          *      Note that we don't do *anything* with the reply
1144          *      attributes.
1145          */
1146 #ifndef NDEBUG
1147         if (debug_flag > 0) {
1148           printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1149                  fake->reply->code);
1150
1151           for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1152             putchar('\t');vp_print(stdout, vp);putchar('\n');
1153           }
1154         }
1155 #endif
1156
1157         /*
1158          *      Decide what to do with the reply.
1159          */
1160         switch (fake->reply->code) {
1161         case 0:                 /* No reply code, must be proxied... */
1162                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1163                 if (vp) {
1164                         eap_tunnel_data_t *tunnel;
1165                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->vp_strvalue);
1166
1167                         /*
1168                          *      Tell the original request that it's going
1169                          *      to be proxied.
1170                          */
1171                         pairmove2(&(request->config_items),
1172                                   &(fake->config_items),
1173                                   PW_PROXY_TO_REALM);
1174
1175                         /*
1176                          *      Seed the proxy packet with the
1177                          *      tunneled request.
1178                          */
1179                         rad_assert(request->proxy == NULL);
1180                         request->proxy = fake->packet;
1181                         fake->packet = NULL;
1182                         rad_free(&fake->reply);
1183                         fake->reply = NULL;
1184
1185                         /*
1186                          *      Set up the callbacks for the tunnel
1187                          */
1188                         tunnel = rad_malloc(sizeof(*tunnel));
1189                         memset(tunnel, 0, sizeof(*tunnel));
1190
1191                         tunnel->tls_session = tls_session;
1192                         tunnel->callback = eapttls_postproxy;
1193
1194                         /*
1195                          *      Associate the callback with the request.
1196                          */
1197                         rcode = request_data_add(request,
1198                                                  request->proxy,
1199                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1200                                                  tunnel, free);
1201                         rad_assert(rcode == 0);
1202
1203                         /*
1204                          *      rlm_eap.c has taken care of associating
1205                          *      the handler with the fake request.
1206                          *
1207                          *      So we associate the fake request with
1208                          *      this request.
1209                          */
1210                         rcode = request_data_add(request,
1211                                                  request->proxy,
1212                                                  REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
1213                                                  fake, my_request_free);
1214                         rad_assert(rcode == 0);
1215                         fake = NULL;
1216
1217                         /*
1218                          *      Didn't authenticate the packet, but
1219                          *      we're proxying it.
1220                          */
1221                         rcode = PW_STATUS_CLIENT;
1222
1223                 } else {
1224                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1225                                request->number);
1226                         rcode = PW_AUTHENTICATION_REJECT;
1227                 }
1228                 break;
1229
1230         default:
1231                 /*
1232                  *      Returns RLM_MODULE_FOO, and we want to return
1233                  *      PW_FOO
1234                  */
1235                 rcode = process_reply(handler, tls_session, request,
1236                                       fake->reply);
1237                 switch (rcode) {
1238                 case RLM_MODULE_REJECT:
1239                         rcode = PW_AUTHENTICATION_REJECT;
1240                         break;
1241
1242                 case RLM_MODULE_HANDLED:
1243                         rcode = PW_ACCESS_CHALLENGE;
1244                         break;
1245
1246                 case RLM_MODULE_OK:
1247                         rcode = PW_AUTHENTICATION_ACK;
1248                         break;
1249
1250                 default:
1251                         rcode = PW_AUTHENTICATION_REJECT;
1252                         break;
1253                 }
1254                 break;
1255         }
1256
1257         request_free(&fake);
1258
1259         return rcode;
1260 }