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                 if (length < offset) {
 121                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too short (%d)to contain anything useful.", attr, length);
 122                         return 0;
 123                 }
 124
 125                 /*
 126                  *      EAP Messages cane be longer than MAX_STRING_LEN.
 127                  *      Other attributes cannot be.
 128                  */
 129                 if ((attr != PW_EAP_MESSAGE) &&
 130                     (length > (MAX_STRING_LEN + 8))) {
 131                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too long (%d) to pack into a RADIUS attribute.", attr, length);
 132                         return 0;
 133                 }
 134
 135                 if (length > data_left) {
 136                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is longer than room left in the packet (%d > %d).", attr, length, data_left);
 137                         return 0;
 138                 }
 139
 140                 /*
 141                  *      Check for broken implementations, which don't
 142                  *      pad the AVP to a 4-octet boundary.
 143                  */
 144                 if (data_left == length) break;
 145
 146                 /*
 147                  *      The length does NOT include the padding, so
 148                  *      we've got to account for it here by rounding up
 149                  *      to the nearest 4-byte boundary.
 150                  */
 151                 length += 0x03;
 152                 length &= ~0x03;
 153
 154                 /*
 155                  *      If the rest of the diameter packet is larger than
 156                  *      this attribute, continue.
 157                  *
 158                  *      Otherwise, if the attribute over-flows the end
 159                  *      of the packet, die.
 160                  */
 161                 if (data_left < length) {
 162                         DEBUG2("  rlm_eap_ttls: ERROR! Diameter attribute overflows packet!");
 163                         return 0;
 164                 }
 165
 166                 /*
 167                  *      Check again for equality, now that we're padded
 168                  *      length to a multiple of 4 octets.
 169                  */
 170                 if (data_left == length) break;
 171
 172                 /*
 173                  *      data_left > length, continue.
 174                  */
 175                 data_left -= length;
 176                 data += length - offset;
 177         }
 178
 179         /*
 180          *      We got this far.  It looks OK.
 181          */
 182         return 1;
 183 }
 184
 185
 186 /*
 187  *      Convert diameter attributes to our VALUE_PAIR's
 188  */
 189 static VALUE_PAIR *diameter2vp(SSL *ssl,
 190                                const uint8_t *data, size_t data_len)
 191 {
 192         uint32_t        attr;
 193         uint32_t        length;
 194         size_t          offset;
 195         size_t          size;
 196         size_t          data_left = data_len;
 197         VALUE_PAIR      *first = NULL;
 198         VALUE_PAIR      **last = &first;
 199         VALUE_PAIR      *vp;
 200
 201         while (data_left > 0) {
 202                 rad_assert(data_left <= data_len);
 203                 memcpy(&attr, data, sizeof(attr));
 204                 data += 4;
 205                 attr = ntohl(attr);
 206
 207                 memcpy(&length, data, sizeof(length));
 208                 data += 4;
 209                 length = ntohl(length);
 210
 211                 /*
 212                  *      A "vendor" flag, with a vendor ID of zero,
 213                  *      is equivalent to no vendor.  This is stupid.
 214                  */
 215                 offset = 8;
 216                 if ((length & (1 << 31)) != 0) {
 217                         uint32_t vendor;
 218
 219                         memcpy(&vendor, data, sizeof(vendor));
 220                         vendor = ntohl(vendor);
 221
 222                         if (attr > 65535) {
 223                                 DEBUG2("  rlm_eap_ttls: Cannot handle vendor attributes greater than 65535");
 224                                 pairfree(&first);
 225                                 return NULL;
 226                         }
 227
 228                         if (vendor > 32767) {
 229                                 DEBUG2("  rlm_eap_ttls: Cannot handle vendor Id greater than 32767");
 230                                 pairfree(&first);
 231                                 return NULL;
 232                         }
 233
 234                         attr |= (vendor << 16);
 235
 236                         data += 4; /* skip the vendor field, it's zero */
 237                         offset += 4; /* offset to value field */
 238                 }
 239
 240                 /*
 241                  *      Vendor attributes can be larger than 255.
 242                  *      Normal attributes cannot be.
 243                  */
 244                 if ((attr > 255) && (VENDOR(attr) == 0)) {
 245                         DEBUG2("  rlm_eap_ttls: Cannot handle Diameter attributes");
 246                         pairfree(&first);
 247                         return NULL;
 248                 }
 249
 250                 /*
 251                  *      FIXME: Handle the M bit.  For now, we assume that
 252                  *      some other module takes care of any attribute
 253                  *      with the M bit set.
 254                  */
 255
 256                 /*
 257                  *      Get the length.
 258                  */
 259                 length &= 0x00ffffff;
 260
 261                 /*
 262                  *      Get the size of the value portion of the
 263                  *      attribute.
 264                  */
 265                 size = length - offset;
 266
 267                 /*
 268                  *      Create it.
 269                  */
 270                 vp = paircreate(attr, PW_TYPE_OCTETS);
 271                 if (!vp) {
 272                         DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 273                         pairfree(&first);
 274                         return NULL;
 275                 }
 276
 277                 /*
 278                  *      If it's a type from our dictionary, then
 279                  *      we need to put the data in a relevant place.
 280                  */
 281                 switch (vp->type) {
 282                 case PW_TYPE_INTEGER:
 283                 case PW_TYPE_DATE:
 284                         if (size != vp->length) {
 285                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 286                                        attr);
 287                                 pairfree(&first);
 288                                 pairfree(&vp);
 289                                 return NULL;
 290                         }
 291                         memcpy(&vp->vp_integer, data, vp->length);
 292
 293                         /*
 294                          *      Stored in host byte order: change it.
 295                          */
 296                         vp->vp_integer = ntohl(vp->vp_integer);
 297                         break;
 298
 299                 case PW_TYPE_IPADDR:
 300                         if (size != vp->length) {
 301                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 302                                        attr);
 303                                 pairfree(&first);
 304                                 pairfree(&vp);
 305                                 return NULL;
 306                         }
 307                   memcpy(&vp->vp_ipaddr, data, vp->length);
 308
 309                   /*
 310                    *    Stored in network byte order: don't change it.
 311                    */
 312                   break;
 313
 314                   /*
 315                    *    String, octet, etc.  Copy the data from the
 316                    *    value field over verbatim.
 317                    *
 318                    *    FIXME: Ipv6 attributes ?
 319                    *
 320                    */
 321                 case PW_TYPE_OCTETS:
 322                         if (attr == PW_EAP_MESSAGE) {
 323                                 const uint8_t *eap_message = data;
 324
 325                                 /*
 326                                  *      vp exists the first time around.
 327                                  */
 328                                 while (1) {
 329                                         vp->length = size;
 330                                         if (vp->length > 253) vp->length = 253;
 331                                         memcpy(vp->vp_octets, eap_message,
 332                                                vp->length);
 333
 334                                         size -= vp->length;
 335                                         eap_message += vp->length;
 336
 337                                         *last = vp;
 338                                         last = &(vp->next);
 339
 340                                         if (size == 0) break;
 341
 342                                         vp = paircreate(attr, PW_TYPE_OCTETS);
 343                                         if (!vp) {
 344                                                 DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 345                                                 pairfree(&first);
 346                                                 return NULL;
 347                                         }
 348                                 }
 349
 350                                 goto next_attr;
 351                         } /* else it's another kind of attribute */
 352                         /* FALL-THROUGH */
 353
 354                 default:
 355                         vp->length = size;
 356                         memcpy(vp->vp_strvalue, data, vp->length);
 357                         break;
 358                 }
 359
 360                 /*
 361                  *      User-Password is NUL padded to a multiple
 362                  *      of 16 bytes.  Let's chop it to something
 363                  *      more reasonable.
 364                  *
 365                  *      NOTE: This means that the User-Password
 366                  *      attribute CANNOT EVER have embedded zeros in it!
 367                  */
 368                 switch (vp->attribute) {
 369                 case PW_USER_PASSWORD:
 370                         /*
 371                          *      If the password is exactly 16 octets,
 372                          *      it won't be zero-terminated.
 373                          */
 374                         vp->vp_strvalue[vp->length] = '\0';
 375                         vp->length = strlen(vp->vp_strvalue);
 376                         break;
 377
 378                         /*
 379                          *      Ensure that the client is using the
 380                          *      correct challenge.  This weirdness is
 381                          *      to protect against against replay
 382                          *      attacks, where anyone observing the
 383                          *      CHAP exchange could pose as that user,
 384                          *      by simply choosing to use the same
 385                          *      challenge.
 386                          *
 387                          *      By using a challenge based on
 388                          *      information from the current session,
 389                          *      we can guarantee that the client is
 390                          *      not *choosing* a challenge.
 391                          *
 392                          *      We're a little forgiving in that we
 393                          *      have loose checks on the length, and
 394                          *      we do NOT check the Id (first octet of
 395                          *      the response to the challenge)
 396                          *
 397                          *      But if the client gets the challenge correct,
 398                          *      we're not too worried about the Id.
 399                          */
 400                 case PW_CHAP_CHALLENGE:
 401                 case PW_MSCHAP_CHALLENGE:
 402                         if ((vp->length < 8) ||
 403                             (vp->length > 16)) {
 404                                 DEBUG2("  TTLS: Tunneled challenge has invalid length");
 405                                 pairfree(&first);
 406                                 pairfree(&vp);
 407                                 return NULL;
 408
 409                         } else {
 410                                 uint8_t challenge[16];
 411
 412                                 eapttls_gen_challenge(ssl, challenge,
 413                                                       sizeof(challenge));
 414
 415                                 if (memcmp(challenge, vp->vp_octets,
 416                                            vp->length) != 0) {
 417                                         DEBUG2("  TTLS: Tunneled challenge is incorrect");
 418                                         pairfree(&first);
 419                                         pairfree(&vp);
 420                                         return NULL;
 421                                 }
 422                         }
 423                         break;
 424
 425                 default:
 426                         break;
 427                 } /* switch over checking/re-writing of attributes. */
 428
 429                 /*
 430                  *      Update the list.
 431                  */
 432                 *last = vp;
 433                 last = &(vp->next);
 434
 435         next_attr:
 436                 /*
 437                  *      Catch non-aligned attributes.
 438                  */
 439                 if (data_left == length) break;
 440
 441                 /*
 442                  *      The length does NOT include the padding, so
 443                  *      we've got to account for it here by rounding up
 444                  *      to the nearest 4-byte boundary.
 445                  */
 446                 length += 0x03;
 447                 length &= ~0x03;
 448
 449                 rad_assert(data_left >= length);
 450                 data_left -= length;
 451                 data += length - offset; /* already updated */
 452         }
 453
 454         /*
 455          *      We got this far.  It looks OK.
 456          */
 457         return first;
 458 }
 459
 460 /*
 461  *      Convert VALUE_PAIR's to diameter attributes, and write them
 462  *      to an SSL session.
 463  *
 464  *      The ONLY VALUE_PAIR's which may be passed to this function
 465  *      are ones which can go inside of a RADIUS (i.e. diameter)
 466  *      packet.  So no server-configuration attributes, or the like.
 467  */
 468 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 469 {
 470         /*
 471          *      RADIUS packets are no more than 4k in size, so if
 472          *      we've got more than 4k of data to write, it's very
 473          *      bad.
 474          */
 475         uint8_t         buffer[4096];
 476         uint8_t         *p;
 477         uint32_t        attr;
 478         uint32_t        length;
 479         uint32_t        vendor;
 480         size_t          total;
 481         VALUE_PAIR      *vp;
 482
 483         p = buffer;
 484         total = 0;
 485
 486         for (vp = first; vp != NULL; vp = vp->next) {
 487                 /*
 488                  *      Too much data: die.
 489                  */
 490                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 491                         DEBUG2("  TTLS output buffer is full!");
 492                         return 0;
 493                 }
 494
 495                 /*
 496                  *      Hmm... we don't group multiple EAP-Messages
 497                  *      together.  Maybe we should...
 498                  */
 499
 500                 /*
 501                  *      Length is no more than 253, due to RADIUS
 502                  *      issues.
 503                  */
 504                 length = vp->length;
 505                 vendor = (vp->attribute >> 16) & 0xffff;
 506                 if (vendor != 0) {
 507                         attr = vp->attribute & 0xffff;
 508                         length |= (1 << 31);
 509                 } else {
 510                         attr = vp->attribute;
 511                 }
 512
 513                 /*
 514                  *      Hmm... set the M bit for all attributes?
 515                  */
 516                 length |= (1 << 30);
 517
 518                 attr = ntohl(attr);
 519
 520                 memcpy(p, &attr, sizeof(attr));
 521                 p += 4;
 522                 total += 4;
 523
 524                 length += 8;    /* includes 8 bytes of attr & length */
 525
 526                 if (vendor != 0) {
 527                         length += 4; /* include 4 bytes of vendor */
 528
 529                         length = ntohl(length);
 530                         memcpy(p, &length, sizeof(length));
 531                         p += 4;
 532                         total += 4;
 533
 534                         vendor = ntohl(vendor);
 535                         memcpy(p, &vendor, sizeof(vendor));
 536                         p += 4;
 537                         total += 4;
 538                 } else {
 539                         length = ntohl(length);
 540                         memcpy(p, &length, sizeof(length));
 541                         p += 4;
 542                         total += 4;
 543                 }
 544
 545                 switch (vp->type) {
 546                 case PW_TYPE_INTEGER:
 547                 case PW_TYPE_DATE:
 548                         attr = ntohl(vp->vp_integer); /* stored in host order */
 549                         memcpy(p, &attr, sizeof(attr));
 550                         length = 4;
 551                         break;
 552
 553                 case PW_TYPE_IPADDR:
 554                         memcpy(p, &vp->vp_ipaddr, 4); /* network order */
 555                         length = 4;
 556                         break;
 557
 558                 case PW_TYPE_STRING:
 559                 case PW_TYPE_OCTETS:
 560                 default:
 561                         memcpy(p, vp->vp_strvalue, vp->length);
 562                         length = vp->length;
 563                         break;
 564                 }
 565
 566                 /*
 567                  *      Skip to the end of the data.
 568                  */
 569                 p += length;
 570                 total += length;
 571
 572                 /*
 573                  *      Align the data to a multiple of 4 bytes.
 574                  */
 575                 if ((total & 0x03) != 0) {
 576                         size_t i;
 577
 578                         length = 4 - (total & 0x03);
 579                         for (i = 0; i < length; i++) {
 580                                 *p = '\0';
 581                                 p++;
 582                                 total++;
 583                         }
 584                 }
 585         } /* loop over the VP's to write. */
 586
 587         /*
 588          *      Write the data in the buffer to the SSL session.
 589          */
 590         if (total > 0) {
 591 #ifndef NDEBUG
 592                 size_t i;
 593
 594                 if (debug_flag > 2) {
 595                         for (i = 0; i < total; i++) {
 596                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 597
 598                                 printf("%02x ", buffer[i]);
 599
 600                                 if ((i & 0x0f) == 0x0f) printf("\n");
 601                         }
 602                         if ((total & 0x0f) != 0) printf("\n");
 603                 }
 604 #endif
 605
 606                 (tls_session->record_plus)(&tls_session->clean_in, buffer, total);
 607
 608                 /*
 609                  *      FIXME: Check the return code.
 610                  */
 611                 tls_handshake_send(tls_session);
 612         }
 613
 614         /*
 615          *      Everything's OK.
 616          */
 617         return 1;
 618 }
 619
 620 /*
 621  *      Use a reply packet to determine what to do.
 622  */
 623 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 624                          REQUEST *request, RADIUS_PACKET *reply)
 625 {
 626         int rcode = RLM_MODULE_REJECT;
 627         VALUE_PAIR *vp;
 628         ttls_tunnel_t *t = tls_session->opaque;
 629
 630         handler = handler;      /* -Wunused */
 631
 632         /*
 633          *      If the response packet was Access-Accept, then
 634          *      we're OK.  If not, die horribly.
 635          *
 636          *      FIXME: Take MS-CHAP2-Success attribute, and
 637          *      tunnel it back to the client, to authenticate
 638          *      ourselves to the client.
 639          *
 640          *      FIXME: If we have an Access-Challenge, then
 641          *      the Reply-Message is tunneled back to the client.
 642          *
 643          *      FIXME: If we have an EAP-Message, then that message
 644          *      must be tunneled back to the client.
 645          *
 646          *      FIXME: If we have an Access-Challenge with a State
 647          *      attribute, then do we tunnel that to the client, or
 648          *      keep track of it ourselves?
 649          *
 650          *      FIXME: EAP-Messages can only start with 'identity',
 651          *      NOT 'eap start', so we should check for that....
 652          */
 653         switch (reply->code) {
 654         case PW_AUTHENTICATION_ACK:
 655                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 656
 657                 rcode = RLM_MODULE_OK;
 658
 659                 /*
 660                  *      MS-CHAP2-Success means that we do NOT return
 661                  *      an Access-Accept, but instead tunnel that
 662                  *      attribute to the client, and keep going with
 663                  *      the TTLS session.  Once the client accepts
 664                  *      our identity, it will respond with an empty
 665                  *      packet, and we will send EAP-Success.
 666                  */
 667                 vp = NULL;
 668                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 669                 if (vp) {
 670                         DEBUG2("  TTLS: Got MS-CHAP2-Success, tunneling it to the client in a challenge.");
 671                         rcode = RLM_MODULE_HANDLED;
 672                         t->authenticated = TRUE;
 673
 674                         /*
 675                          *      Delete MPPE keys & encryption policy.  We don't
 676                          *      want these here.
 677                          */
 678                         pairdelete(&reply->vps, ((311 << 16) | 7));
 679                         pairdelete(&reply->vps, ((311 << 16) | 8));
 680                         pairdelete(&reply->vps, ((311 << 16) | 16));
 681                         pairdelete(&reply->vps, ((311 << 16) | 17));
 682
 683                         /*
 684                          *      Use the tunneled reply, but not now.
 685                          */
 686                         if (t->use_tunneled_reply) {
 687                                 t->reply = reply->vps;
 688                                 reply->vps = NULL;
 689                         }
 690
 691                 } else { /* no MS-CHAP2-Success */
 692                         /*
 693                          *      Can only have EAP-Message if there's
 694                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 695                          *
 696                          *      We also do NOT tunnel the EAP-Success
 697                          *      attribute back to the client, as the client
 698                          *      can figure it out, from the non-tunneled
 699                          *      EAP-Success packet.
 700                          */
 701                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 702                         pairfree(&vp);
 703                 }
 704
 705                 /*
 706                  *      Handle the ACK, by tunneling any necessary reply
 707                  *      VP's back to the client.
 708                  */
 709                 if (vp) {
 710                         vp2diameter(tls_session, vp);
 711                         pairfree(&vp);
 712                 }
 713
 714                 /*
 715                  *      If we've been told to use the attributes from
 716                  *      the reply, then do so.
 717                  *
 718                  *      WARNING: This may leak information about the
 719                  *      tunneled user!
 720                  */
 721                 if (t->use_tunneled_reply) {
 722                         pairdelete(&reply->vps, PW_PROXY_STATE);
 723                         pairadd(&request->reply->vps, reply->vps);
 724                         reply->vps = NULL;
 725                 }
 726                 break;
 727
 728
 729         case PW_AUTHENTICATION_REJECT:
 730                 DEBUG2("  TTLS: Got tunneled Access-Reject");
 731                 rcode = RLM_MODULE_REJECT;
 732                 break;
 733
 734                 /*
 735                  *      Handle Access-Challenge, but only if we
 736                  *      send tunneled reply data.  This is because
 737                  *      an Access-Challenge means that we MUST tunnel
 738                  *      a Reply-Message to the client.
 739                  */
 740         case PW_ACCESS_CHALLENGE:
 741                 DEBUG2("  TTLS: Got tunneled Access-Challenge");
 742
 743                 /*
 744                  *      Keep the State attribute, if necessary.
 745                  *
 746                  *      Get rid of the old State, too.
 747                  */
 748                 pairfree(&t->state);
 749                 pairmove2(&t->state, &reply->vps, PW_STATE);
 750
 751                 /*
 752                  *      We should really be a bit smarter about this,
 753                  *      and move over only those attributes which
 754                  *      are relevant to the authentication request,
 755                  *      but that's a lot more work, and this "dumb"
 756                  *      method works in 99.9% of the situations.
 757                  */
 758                 vp = NULL;
 759                 pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 760
 761                 /*
 762                  *      There MUST be a Reply-Message in the challenge,
 763                  *      which we tunnel back to the client.
 764                  *
 765                  *      If there isn't one in the reply VP's, then
 766                  *      we MUST create one, with an empty string as
 767                  *      it's value.
 768                  */
 769                 pairmove2(&vp, &reply->vps, PW_REPLY_MESSAGE);
 770
 771                 /*
 772                  *      Handle the ACK, by tunneling any necessary reply
 773                  *      VP's back to the client.
 774                  */
 775                 if (vp) {
 776                         vp2diameter(tls_session, vp);
 777                         pairfree(&vp);
 778                 }
 779                 rcode = RLM_MODULE_HANDLED;
 780                 break;
 781
 782         default:
 783                 DEBUG2("  TTLS: Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
 784                 rcode = RLM_MODULE_INVALID;
 785                 break;
 786         }
 787
 788         return rcode;
 789 }
 790
 791
 792 /*
 793  *      Do post-proxy processing,
 794  */
 795 static int eapttls_postproxy(EAP_HANDLER *handler, void *data)
 796 {
 797         int rcode;
 798         tls_session_t *tls_session = (tls_session_t *) data;
 799         REQUEST *fake;
 800
 801         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 802
 803         /*
 804          *      If there was a fake request associated with the proxied
 805          *      request, do more processing of it.
 806          */
 807         fake = (REQUEST *) request_data_get(handler->request,
 808                                             handler->request->proxy,
 809                                             REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);
 810
 811         /*
 812          *      Do the callback, if it exists, and if it was a success.
 813          */
 814         if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
 815                 VALUE_PAIR *vp;
 816                 REQUEST *request = handler->request;
 817
 818                 /*
 819                  *      Terrible hacks.
 820                  */
 821                 rad_assert(fake->packet == NULL);
 822                 fake->packet = request->proxy;
 823                 request->proxy = NULL;
 824
 825                 rad_assert(fake->reply == NULL);
 826                 fake->reply = request->proxy_reply;
 827                 request->proxy_reply = NULL;
 828
 829                 /*
 830                  *      Perform a post-auth stage for the tunneled
 831                  *      session.
 832                  */
 833                 fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
 834                 rcode = rad_postauth(fake);
 835                 DEBUG2("  POST-AUTH %d", rcode);
 836
 837 #ifndef NDEBUG
 838                 if (debug_flag > 0) {
 839                         printf("  TTLS: Final reply from tunneled session code %d\n",
 840                                fake->reply->code);
 841
 842                         for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
 843                                 putchar('\t');vp_print(stdout, vp);putchar('\n');
 844                         }
 845                 }
 846 #endif
 847
 848                 /*
 849                  *      Terrible hacks.
 850                  */
 851                 request->proxy = fake->packet;
 852                 fake->packet = NULL;
 853                 request->proxy_reply = fake->reply;
 854                 fake->reply = NULL;
 855
 856                 /*
 857                  *      And we're done with this request.
 858                  */
 859
 860                 switch (rcode) {
 861                 case RLM_MODULE_FAIL:
 862                         request_free(&fake);
 863                         eaptls_fail(handler->eap_ds, 0);
 864                         return 0;
 865                         break;
 866
 867                 default:  /* Don't Do Anything */
 868                         DEBUG2(" TTLS: Got reply %d",
 869                                request->proxy_reply->code);
 870                         break;
 871                 }
 872         }
 873         request_free(&fake);    /* robust if fake == NULL */
 874
 875         /*
 876          *      Process the reply from the home server.
 877          */
 878         rcode = process_reply(handler, tls_session, handler->request,
 879                               handler->request->proxy_reply);
 880
 881         /*
 882          *      The proxy code uses the reply from the home server as
 883          *      the basis for the reply to the NAS.  We don't want that,
 884          *      so we toss it, after we've had our way with it.
 885          */
 886         pairfree(&handler->request->proxy_reply->vps);
 887
 888         switch (rcode) {
 889         case RLM_MODULE_REJECT:
 890                 DEBUG2("  TTLS: Reply was rejected");
 891                 break;
 892
 893         case RLM_MODULE_HANDLED:
 894                 DEBUG2("  TTLS: Reply was handled");
 895                 eaptls_request(handler->eap_ds, tls_session);
 896                 return 1;
 897
 898         case RLM_MODULE_OK:
 899                 DEBUG2("  TTLS: Reply was OK");
 900                 eaptls_success(handler->eap_ds, 0);
 901                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 902                                      tls_session->ssl,
 903                                      "ttls keying material");
 904                 return 1;
 905
 906         default:
 907                 DEBUG2("  TTLS: Reply was unknown.");
 908                 break;
 909         }
 910
 911         eaptls_fail(handler->eap_ds, 0);
 912         return 0;
 913 }
 914
 915
 916 /*
 917  *      Free a request.
 918  */
 919 static void my_request_free(void *data)
 920 {
 921         REQUEST *request = (REQUEST *)data;
 922
 923         request_free(&request);
 924 }
 925
 926
 927 /*
 928  *      Process the "diameter" contents of the tunneled data.
 929  */
 930 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 931 {
 932         int err;
 933         int rcode = PW_AUTHENTICATION_REJECT;
 934         REQUEST *fake;
 935         VALUE_PAIR *vp;
 936         ttls_tunnel_t *t;
 937         const uint8_t *data;
 938         size_t data_len;
 939         REQUEST *request = handler->request;
 940
 941         /*
 942          *      FIXME: if the SSL session says "want read", or
 943          *      similar, leave the data in the clean_out buffer.  This
 944          *      lets the application data be sent across multiple
 945          *      fragments.
 946          */
 947         err = tls_handshake_recv(tls_session);
 948         if (!err) {
 949                 DEBUG2(" rlm_eap_peap: Failed in SSL");
 950                 return RLM_MODULE_REJECT;
 951         }
 952
 953         /*
 954          *      Just look at the buffer directly, without doing
 955          *      record_minus.
 956          */
 957         data_len = tls_session->clean_out.used;
 958         data = tls_session->clean_out.data;
 959
 960         t = (ttls_tunnel_t *) tls_session->opaque;
 961
 962         /*
 963          *      If there's no data, maybe this is an ACK to an
 964          *      MS-CHAP2-Success.
 965          */
 966         if (data_len == 0) {
 967                 if (t->authenticated) {
 968                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 969                         return PW_AUTHENTICATION_ACK;
 970                 } /* else no session, no data, die. */
 971
 972                 /*
 973                  *      FIXME: Call SSL_get_error() to see what went
 974                  *      wrong.
 975                  */
 976                 DEBUG2("rlm_eap_ttls: SSL_read Error");
 977                 return PW_AUTHENTICATION_REJECT;
 978         }
 979
 980 #ifndef NDEBUG
 981         if (debug_flag > 2) {
 982                 size_t i;
 983
 984                 for (i = 0; i < data_len; i++) {
 985                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 986
 987                         printf("%02x ", data[i]);
 988
 989                         if ((i & 0x0f) == 0x0f) printf("\n");
 990                 }
 991                 if ((data_len & 0x0f) != 0) printf("\n");
 992         }
 993 #endif
 994
 995         if (!diameter_verify(data, data_len)) {
 996                 return PW_AUTHENTICATION_REJECT;
 997         }
 998
 999         /*
1000          *      Allocate a fake REQUEST structe.
1001          */
1002         fake = request_alloc_fake(request);
1003
1004         rad_assert(fake->packet->vps == NULL);
1005
1006         /*
1007          *      Add the tunneled attributes to the fake request.
1008          */
1009         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
1010         if (!fake->packet->vps) {
1011                 request_free(&fake);
1012                 return PW_AUTHENTICATION_REJECT;
1013         }
1014
1015         /*
1016          *      Tell the request that it's a fake one.
1017          */
1018         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
1019         if (vp) {
1020                 pairadd(&fake->packet->vps, vp);
1021         }
1022
1023 #ifndef NDEBUG
1024         if (debug_flag > 0) {
1025                 printf("  TTLS: Got tunneled request\n");
1026
1027                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1028                         putchar('\t');vp_print(stdout, vp);putchar('\n');
1029                 }
1030         }
1031 #endif
1032
1033         /*
1034          *      Update other items in the REQUEST data structure.
1035          */
1036         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1037         fake->password = pairfind(fake->packet->vps, PW_USER_PASSWORD);
1038
1039         /*
1040          *      No User-Name, try to create one from stored data.
1041          */
1042         if (!fake->username) {
1043                 /*
1044                  *      No User-Name in the stored data, look for
1045                  *      an EAP-Identity, and pull it out of there.
1046                  */
1047                 if (!t->username) {
1048                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
1049                         if (vp &&
1050                             (vp->length >= EAP_HEADER_LEN + 2) &&
1051                             (vp->vp_strvalue[0] == PW_EAP_RESPONSE) &&
1052                             (vp->vp_strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
1053                             (vp->vp_strvalue[EAP_HEADER_LEN + 1] != 0)) {
1054                                 /*
1055                                  *      Create & remember a User-Name
1056                                  */
1057                                 t->username = pairmake("User-Name", "", T_OP_EQ);
1058                                 rad_assert(t->username != NULL);
1059
1060                                 memcpy(t->username->vp_strvalue, vp->vp_strvalue + 5,
1061                                        vp->length - 5);
1062                                 t->username->length = vp->length - 5;
1063                                 t->username->vp_strvalue[t->username->length] = 0;
1064
1065                                 DEBUG2("  TTLS: Got tunneled identity of %s",
1066                                        t->username->vp_strvalue);
1067
1068                                 /*
1069                                  *      If there's a default EAP type,
1070                                  *      set it here.
1071                                  */
1072                                 if (t->default_eap_type != 0) {
1073                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
1074                                         vp = paircreate(PW_EAP_TYPE,
1075                                                         PW_TYPE_INTEGER);
1076                                         rad_assert(vp != NULL);
1077                                         vp->vp_integer = t->default_eap_type;
1078                                         pairadd(&fake->config_items, vp);
1079                                 }
1080
1081                         } else {
1082                                 /*
1083                                  *      Don't reject the request outright,
1084                                  *      as it's permitted to do EAP without
1085                                  *      user-name.
1086                                  */
1087                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
1088                         }
1089                 } /* else there WAS a t->username */
1090
1091                 if (t->username) {
1092                         vp = paircopy(t->username);
1093                         pairadd(&fake->packet->vps, vp);
1094                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1095                 }
1096         } /* else the request ALREADY had a User-Name */
1097
1098         /*
1099          *      Add the State attribute, too, if it exists.
1100          */
1101         if (t->state) {
1102                 DEBUG2("  TTLS: Adding old state with %02x %02x",
1103                        t->state->vp_strvalue[0], t->state->vp_strvalue[1]);
1104                 vp = paircopy(t->state);
1105                 if (vp) pairadd(&fake->packet->vps, vp);
1106         }
1107
1108         /*
1109          *      If this is set, we copy SOME of the request attributes
1110          *      from outside of the tunnel to inside of the tunnel.
1111          *
1112          *      We copy ONLY those attributes which do NOT already
1113          *      exist in the tunneled request.
1114          */
1115         if (t->copy_request_to_tunnel) {
1116                 VALUE_PAIR *copy;
1117
1118                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
1119                         /*
1120                          *      The attribute is a server-side thingy,
1121                          *      don't copy it.
1122                          */
1123                         if ((vp->attribute > 255) &&
1124                             (((vp->attribute >> 16) & 0xffff) == 0)) {
1125                                 continue;
1126                         }
1127
1128                         /*
1129                          *      The outside attribute is already in the
1130                          *      tunnel, don't copy it.
1131                          *
1132                          *      This works for BOTH attributes which
1133                          *      are originally in the tunneled request,
1134                          *      AND attributes which are copied there
1135                          *      from below.
1136                          */
1137                         if (pairfind(fake->packet->vps, vp->attribute)) {
1138                                 continue;
1139                         }
1140
1141                         /*
1142                          *      Some attributes are handled specially.
1143                          */
1144                         switch (vp->attribute) {
1145                                 /*
1146                                  *      NEVER copy Message-Authenticator,
1147                                  *      EAP-Message, or State.  They're
1148                                  *      only for outside of the tunnel.
1149                                  */
1150                         case PW_USER_NAME:
1151                         case PW_USER_PASSWORD:
1152                         case PW_CHAP_PASSWORD:
1153                         case PW_CHAP_CHALLENGE:
1154                         case PW_PROXY_STATE:
1155                         case PW_MESSAGE_AUTHENTICATOR:
1156                         case PW_EAP_MESSAGE:
1157                         case PW_STATE:
1158                                 continue;
1159                                 break;
1160
1161                                 /*
1162                                  *      By default, copy it over.
1163                                  */
1164                         default:
1165                                 break;
1166                         }
1167
1168                         /*
1169                          *      Don't copy from the head, we've already
1170                          *      checked it.
1171                          */
1172                         copy = paircopy2(vp, vp->attribute);
1173                         pairadd(&fake->packet->vps, copy);
1174                 }
1175         }
1176
1177         if ((vp = pairfind(request->config_items, PW_VIRTUAL_SERVER)) != NULL) {
1178                 fake->server = vp->vp_strvalue;
1179
1180         } else if (t->virtual_server) {
1181                 fake->server = t->virtual_server;
1182
1183         } /* else fake->server == request->server */
1184
1185
1186 #ifndef NDEBUG
1187         if (debug_flag > 0) {
1188                 printf("  TTLS: Sending tunneled request\n");
1189
1190                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1191                         putchar('\t');vp_print(stdout, vp);putchar('\n');
1192                 }
1193
1194                 printf("server %s {\n", fake->server);
1195         }
1196 #endif
1197
1198         /*
1199          *      Call authentication recursively, which will
1200          *      do PAP, CHAP, MS-CHAP, etc.
1201          */
1202         rad_authenticate(fake);
1203
1204         /*
1205          *      Note that we don't do *anything* with the reply
1206          *      attributes.
1207          */
1208 #ifndef NDEBUG
1209         if (debug_flag > 0) {
1210                 printf("} # server %s\n", fake->server);
1211
1212                 printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1213                        fake->reply->code);
1214
1215                 for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1216                         putchar('\t');vp_print(stdout, vp);putchar('\n');
1217                 }
1218         }
1219 #endif
1220
1221         /*
1222          *      Decide what to do with the reply.
1223          */
1224         switch (fake->reply->code) {
1225         case 0:                 /* No reply code, must be proxied... */
1226                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1227                 if (vp) {
1228                         eap_tunnel_data_t *tunnel;
1229                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->vp_strvalue);
1230
1231                         /*
1232                          *      Tell the original request that it's going
1233                          *      to be proxied.
1234                          */
1235                         pairmove2(&(request->config_items),
1236                                   &(fake->config_items),
1237                                   PW_PROXY_TO_REALM);
1238
1239                         /*
1240                          *      Seed the proxy packet with the
1241                          *      tunneled request.
1242                          */
1243                         rad_assert(request->proxy == NULL);
1244                         request->proxy = fake->packet;
1245                         fake->packet = NULL;
1246                         rad_free(&fake->reply);
1247                         fake->reply = NULL;
1248
1249                         /*
1250                          *      Set up the callbacks for the tunnel
1251                          */
1252                         tunnel = rad_malloc(sizeof(*tunnel));
1253                         memset(tunnel, 0, sizeof(*tunnel));
1254
1255                         tunnel->tls_session = tls_session;
1256                         tunnel->callback = eapttls_postproxy;
1257
1258                         /*
1259                          *      Associate the callback with the request.
1260                          */
1261                         rcode = request_data_add(request,
1262                                                  request->proxy,
1263                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1264                                                  tunnel, free);
1265                         rad_assert(rcode == 0);
1266
1267                         /*
1268                          *      rlm_eap.c has taken care of associating
1269                          *      the handler with the fake request.
1270                          *
1271                          *      So we associate the fake request with
1272                          *      this request.
1273                          */
1274                         rcode = request_data_add(request,
1275                                                  request->proxy,
1276                                                  REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
1277                                                  fake, my_request_free);
1278                         rad_assert(rcode == 0);
1279                         fake = NULL;
1280
1281                         /*
1282                          *      Didn't authenticate the packet, but
1283                          *      we're proxying it.
1284                          */
1285                         rcode = PW_STATUS_CLIENT;
1286
1287                 } else {
1288                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1289                                request->number);
1290                         rcode = PW_AUTHENTICATION_REJECT;
1291                 }
1292                 break;
1293
1294         default:
1295                 /*
1296                  *      Returns RLM_MODULE_FOO, and we want to return
1297                  *      PW_FOO
1298                  */
1299                 rcode = process_reply(handler, tls_session, request,
1300                                       fake->reply);
1301                 switch (rcode) {
1302                 case RLM_MODULE_REJECT:
1303                         rcode = PW_AUTHENTICATION_REJECT;
1304                         break;
1305
1306                 case RLM_MODULE_HANDLED:
1307                         rcode = PW_ACCESS_CHALLENGE;
1308                         break;
1309
1310                 case RLM_MODULE_OK:
1311                         rcode = PW_AUTHENTICATION_ACK;
1312                         break;
1313
1314                 default:
1315                         rcode = PW_AUTHENTICATION_REJECT;
1316                         break;
1317                 }
1318                 break;
1319         }
1320
1321         request_free(&fake);
1322
1323         return rcode;
1324 }