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