src/lib/radius.c

   1 /*
   2  * radius.c     Functions to send/receive radius packets.
   3  *
   4  * Version:     $Id$
   5  *
   6  *   This library is free software; you can redistribute it and/or
   7  *   modify it under the terms of the GNU Lesser General Public
   8  *   License as published by the Free Software Foundation; either
   9  *   version 2.1 of the License, or (at your option) any later version.
  10  *
  11  *   This library 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 GNU
  14  *   Lesser General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU Lesser General Public
  17  *   License along with this library; if not, write to the Free Software
  18  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * Copyright 2000-2003,2006  The FreeRADIUS server project
  21  */
  22
  23 #include        <freeradius-devel/ident.h>
  24 RCSID("$Id$")
  25
  26 #include        <freeradius-devel/libradius.h>
  27 #include        <freeradius-devel/md5.h>
  28
  29 #include        <fcntl.h>
  30 #include        <ctype.h>
  31
  32 #ifdef WITH_UDPFROMTO
  33 #include        <freeradius-devel/udpfromto.h>
  34 #endif
  35
  36 #ifdef HAVE_MALLOC_H
  37 #include        <malloc.h>
  38 #endif
  39
  40 /*
  41  *  The RFC says 4096 octets max, and most packets are less than 256.
  42  */
  43 #define MAX_PACKET_LEN 4096
  44
  45 /*
  46  *      The maximum number of attributes which we allow in an incoming
  47  *      request.  If there are more attributes than this, the request
  48  *      is rejected.
  49  *
  50  *      This helps to minimize the potential for a DoS, when an
  51  *      attacker spoofs Access-Request packets, which don't have a
  52  *      Message-Authenticator attribute.  This means that the packet
  53  *      is unsigned, and the attacker can use resources on the server,
  54  *      even if the end request is rejected.
  55  */
  56 int librad_max_attributes = 0;
  57
  58 typedef struct radius_packet_t {
  59   uint8_t       code;
  60   uint8_t       id;
  61   uint8_t       length[2];
  62   uint8_t       vector[AUTH_VECTOR_LEN];
  63   uint8_t       data[1];
  64 } radius_packet_t;
  65
  66 static fr_randctx fr_rand_pool; /* across multiple calls */
  67 static int fr_rand_initialized = 0;
  68 static unsigned int salt_offset = 0;
  69
  70
  71 #define MAX_PACKET_CODE (52)
  72 static const char *packet_codes[] = {
  73   "",
  74   "Access-Request",
  75   "Access-Accept",
  76   "Access-Reject",
  77   "Accounting-Request",
  78   "Accounting-Response",
  79   "Accounting-Status",
  80   "Password-Request",
  81   "Password-Accept",
  82   "Password-Reject",
  83   "Accounting-Message",
  84   "Access-Challenge",
  85   "Status-Server",
  86   "Status-Client",
  87   "14",
  88   "15",
  89   "16",
  90   "17",
  91   "18",
  92   "19",
  93   "20",
  94   "Resource-Free-Request",
  95   "Resource-Free-Response",
  96   "Resource-Query-Request",
  97   "Resource-Query-Response",
  98   "Alternate-Resource-Reclaim-Request",
  99   "NAS-Reboot-Request",
 100   "NAS-Reboot-Response",
 101   "28",
 102   "Next-Passcode",
 103   "New-Pin",
 104   "Terminate-Session",
 105   "Password-Expired",
 106   "Event-Request",
 107   "Event-Response",
 108   "35",
 109   "36",
 110   "37",
 111   "38",
 112   "39",
 113   "Disconnect-Request",
 114   "Disconnect-ACK",
 115   "Disconnect-NAK",
 116   "CoA-Request",
 117   "CoA-ACK",
 118   "CoA-NAK",
 119   "46",
 120   "47",
 121   "48",
 122   "49",
 123   "IP-Address-Allocate",
 124   "IP-Address-Release"
 125 };
 126
 127
 128 /*
 129  *      Wrapper for sendto which handles sendfromto, IPv6, and all
 130  *      possible combinations.
 131  */
 132 static int rad_sendto(int sockfd, void *data, size_t data_len, int flags,
 133                       fr_ipaddr_t *src_ipaddr, int src_port,
 134                       fr_ipaddr_t *dst_ipaddr, int dst_port)
 135 {
 136         struct sockaddr_storage dst;
 137         socklen_t               sizeof_dst = sizeof(dst);
 138
 139 #ifdef WITH_UDPFROMTO
 140         struct sockaddr_storage src;
 141         socklen_t               sizeof_src = sizeof(src);
 142
 143         memset(&src, 0, sizeof(src));
 144 #endif
 145         memset(&dst, 0, sizeof(dst));
 146
 147         /*
 148          *      IPv4 is supported.
 149          */
 150         if (dst_ipaddr->af == AF_INET) {
 151                 struct sockaddr_in      *s4;
 152
 153                 s4 = (struct sockaddr_in *)&dst;
 154                 sizeof_dst = sizeof(struct sockaddr_in);
 155
 156                 s4->sin_family = AF_INET;
 157                 s4->sin_addr = dst_ipaddr->ipaddr.ip4addr;
 158                 s4->sin_port = htons(dst_port);
 159
 160 #ifdef WITH_UDPFROMTO
 161                 s4 = (struct sockaddr_in *)&src;
 162                 sizeof_src = sizeof(struct sockaddr_in);
 163
 164                 s4->sin_family = AF_INET;
 165                 s4->sin_addr = src_ipaddr->ipaddr.ip4addr;
 166                 s4->sin_port = htons(src_port);
 167 #else
 168                 src_port = src_port; /* -Wunused */
 169 #endif
 170
 171         /*
 172          *      IPv6 MAY be supported.
 173          */
 174 #ifdef HAVE_STRUCT_SOCKADDR_IN6
 175         } else if (dst_ipaddr->af == AF_INET6) {
 176                 struct sockaddr_in6     *s6;
 177
 178                 s6 = (struct sockaddr_in6 *)&dst;
 179                 sizeof_dst = sizeof(struct sockaddr_in6);
 180
 181                 s6->sin6_family = AF_INET6;
 182                 s6->sin6_addr = dst_ipaddr->ipaddr.ip6addr;
 183                 s6->sin6_port = htons(dst_port);
 184
 185 #ifdef WITH_UDPFROMTO
 186                 return -1;      /* UDPFROMTO && IPv6 are not supported */
 187 #if 0
 188                 s6 = (struct sockaddr_in6 *)&src;
 189                 sizeof_src = sizeof(struct sockaddr_in6);
 190
 191                 s6->sin6_family = AF_INET6;
 192                 s6->sin6_addr = src_ipaddr->ipaddr.ip6addr;
 193 #endif /* #if 0 */
 194 #endif /* WITH_UDPFROMTO */
 195 #endif /* HAVE_STRUCT_SOCKADDR_IN6 */
 196         } else return -1;   /* Unknown address family, Die Die Die! */
 197
 198 #ifdef WITH_UDPFROMTO
 199         /*
 200          *      Only IPv4 is supported for udpfromto.
 201          *
 202          *      And if they don't specify a source IP address, don't
 203          *      use udpfromto.
 204          */
 205         if ((dst_ipaddr->af == AF_INET) ||
 206             (src_ipaddr->af != AF_UNSPEC)) {
 207                 return sendfromto(sockfd, data, data_len, flags,
 208                                   (struct sockaddr *)&src, sizeof_src,
 209                                   (struct sockaddr *)&dst, sizeof_dst);
 210         }
 211 #else
 212         src_ipaddr = src_ipaddr; /* -Wunused */
 213 #endif
 214
 215         /*
 216          *      No udpfromto, OR an IPv6 socket, fail gracefully.
 217          */
 218         return sendto(sockfd, data, data_len, flags,
 219                       (struct sockaddr *)&dst, sizeof_dst);
 220 }
 221
 222
 223 void rad_recv_discard(int sockfd)
 224 {
 225         uint8_t                 header[4];
 226         struct sockaddr_storage src;
 227         socklen_t               sizeof_src = sizeof(src);
 228
 229         recvfrom(sockfd, header, sizeof(header), 0,
 230                  (struct sockaddr *)&src, &sizeof_src);
 231 }
 232
 233
 234 ssize_t rad_recv_header(int sockfd, fr_ipaddr_t *src_ipaddr, int *src_port,
 235                         int *code)
 236 {
 237         ssize_t                 data_len, packet_len;
 238         uint8_t                 header[4];
 239         struct sockaddr_storage src;
 240         socklen_t               sizeof_src = sizeof(src);
 241
 242         data_len = recvfrom(sockfd, header, sizeof(header), MSG_PEEK,
 243                             (struct sockaddr *)&src, &sizeof_src);
 244         if (data_len < 0) {
 245                 if ((errno == EAGAIN) || (errno == EINTR)) return 0;
 246                 return -1;
 247         }
 248
 249         /*
 250          *      Too little data is available, discard the packet.
 251          */
 252         if (data_len < 4) {
 253                 recvfrom(sockfd, header, sizeof(header), 0,
 254                          (struct sockaddr *)&src, &sizeof_src);
 255                 return 1;
 256
 257         } else {                /* we got 4 bytes of data. */
 258                 /*
 259                  *      See how long the packet says it is.
 260                  */
 261                 packet_len = (header[2] * 256) + header[3];
 262
 263                 /*
 264                  *      The length in the packet says it's less than
 265                  *      a RADIUS header length: discard it.
 266                  */
 267                 if (packet_len < AUTH_HDR_LEN) {
 268                         recvfrom(sockfd, header, sizeof(header), 0,
 269                                  (struct sockaddr *)&src, &sizeof_src);
 270                         return 1;
 271
 272                         /*
 273                          *      Enforce RFC requirements, for sanity.
 274                          *      Anything after 4k will be discarded.
 275                          */
 276                 } else if (packet_len > MAX_PACKET_LEN) {
 277                         recvfrom(sockfd, header, sizeof(header), 0,
 278                                  (struct sockaddr *)&src, &sizeof_src);
 279                         return 1;
 280                 }
 281         }
 282
 283         if (src.ss_family == AF_INET) {
 284                 struct sockaddr_in      *s4;
 285
 286                 s4 = (struct sockaddr_in *)&src;
 287                 src_ipaddr->af = AF_INET;
 288                 src_ipaddr->ipaddr.ip4addr = s4->sin_addr;
 289                 *src_port = ntohs(s4->sin_port);
 290
 291 #ifdef HAVE_STRUCT_SOCKADDR_IN6
 292         } else if (src.ss_family == AF_INET6) {
 293                 struct sockaddr_in6     *s6;
 294
 295                 s6 = (struct sockaddr_in6 *)&src;
 296                 src_ipaddr->af = AF_INET6;
 297                 src_ipaddr->ipaddr.ip6addr = s6->sin6_addr;
 298                 *src_port = ntohs(s6->sin6_port);
 299
 300 #endif
 301         } else {
 302                 recvfrom(sockfd, header, sizeof(header), 0,
 303                          (struct sockaddr *)&src, &sizeof_src);
 304                 return 1;
 305         }
 306
 307         *code = header[0];
 308
 309         /*
 310          *      The packet says it's this long, but the actual UDP
 311          *      size could still be smaller.
 312          */
 313         return packet_len;
 314 }
 315
 316
 317 /*
 318  *      wrapper for recvfrom, which handles recvfromto, IPv6, and all
 319  *      possible combinations.
 320  */
 321 static ssize_t rad_recvfrom(int sockfd, uint8_t **pbuf, int flags,
 322                             fr_ipaddr_t *src_ipaddr, uint16_t *src_port,
 323                             fr_ipaddr_t *dst_ipaddr, uint16_t *dst_port)
 324 {
 325         struct sockaddr_storage src;
 326         struct sockaddr_storage dst;
 327         socklen_t               sizeof_src = sizeof(src);
 328         socklen_t               sizeof_dst = sizeof(dst);
 329         ssize_t                 data_len;
 330         uint8_t                 header[4];
 331         void                    *buf;
 332         size_t                  len;
 333
 334         memset(&src, 0, sizeof_src);
 335         memset(&dst, 0, sizeof_dst);
 336
 337         /*
 338          *      Get address family, etc. first, so we know if we
 339          *      need to do udpfromto.
 340          *
 341          *      FIXME: udpfromto also does this, but it's not
 342          *      a critical problem.
 343          */
 344         if (getsockname(sockfd, (struct sockaddr *)&dst,
 345                         &sizeof_dst) < 0) return -1;
 346
 347         /*
 348          *      Read the length of the packet, from the packet.
 349          *      This lets us allocate the buffer to use for
 350          *      reading the rest of the packet.
 351          */
 352         data_len = recvfrom(sockfd, header, sizeof(header), MSG_PEEK,
 353                             (struct sockaddr *)&src, &sizeof_src);
 354         if (data_len < 0) {
 355                 if ((errno == EAGAIN) || (errno == EINTR)) return 0;
 356                 return -1;
 357         }
 358
 359         /*
 360          *      Too little data is available, discard the packet.
 361          */
 362         if (data_len < 4) {
 363                 recvfrom(sockfd, header, sizeof(header), flags,
 364                          (struct sockaddr *)&src, &sizeof_src);
 365                 return 0;
 366
 367         } else {                /* we got 4 bytes of data. */
 368                 /*
 369                  *      See how long the packet says it is.
 370                  */
 371                 len = (header[2] * 256) + header[3];
 372
 373                 /*
 374                  *      The length in the packet says it's less than
 375                  *      a RADIUS header length: discard it.
 376                  */
 377                 if (len < AUTH_HDR_LEN) {
 378                         recvfrom(sockfd, header, sizeof(header), flags,
 379                                  (struct sockaddr *)&src, &sizeof_src);
 380                         return 0;
 381
 382                         /*
 383                          *      Enforce RFC requirements, for sanity.
 384                          *      Anything after 4k will be discarded.
 385                          */
 386                 } else if (len > MAX_PACKET_LEN) {
 387                         recvfrom(sockfd, header, sizeof(header), flags,
 388                                  (struct sockaddr *)&src, &sizeof_src);
 389                         return len;
 390                 }
 391         }
 392
 393         buf = malloc(len);
 394         if (!buf) return -1;
 395
 396         /*
 397          *      Receive the packet.  The OS will discard any data in the
 398          *      packet after "len" bytes.
 399          */
 400 #ifdef WITH_UDPFROMTO
 401         if (dst.ss_family == AF_INET) {
 402                 data_len = recvfromto(sockfd, buf, len, flags,
 403                                       (struct sockaddr *)&src, &sizeof_src,
 404                                       (struct sockaddr *)&dst, &sizeof_dst);
 405         } else
 406 #endif
 407                 /*
 408                  *      No udpfromto, OR an IPv6 socket.  Fail gracefully.
 409                  */
 410                 data_len = recvfrom(sockfd, buf, len, flags,
 411                                     (struct sockaddr *)&src, &sizeof_src);
 412         if (data_len < 0) {
 413                 free(buf);
 414                 return data_len;
 415         }
 416
 417         /*
 418          *      Check address families, and update src/dst ports, etc.
 419          */
 420         if (src.ss_family == AF_INET) {
 421                 struct sockaddr_in      *s4;
 422
 423                 s4 = (struct sockaddr_in *)&src;
 424                 src_ipaddr->af = AF_INET;
 425                 src_ipaddr->ipaddr.ip4addr = s4->sin_addr;
 426                 *src_port = ntohs(s4->sin_port);
 427
 428                 s4 = (struct sockaddr_in *)&dst;
 429                 dst_ipaddr->af = AF_INET;
 430                 dst_ipaddr->ipaddr.ip4addr = s4->sin_addr;
 431                 *dst_port = ntohs(s4->sin_port);
 432
 433 #ifdef HAVE_STRUCT_SOCKADDR_IN6
 434         } else if (src.ss_family == AF_INET6) {
 435                 struct sockaddr_in6     *s6;
 436
 437                 s6 = (struct sockaddr_in6 *)&src;
 438                 src_ipaddr->af = AF_INET6;
 439                 src_ipaddr->ipaddr.ip6addr = s6->sin6_addr;
 440                 *src_port = ntohs(s6->sin6_port);
 441
 442                 s6 = (struct sockaddr_in6 *)&dst;
 443                 dst_ipaddr->af = AF_INET6;
 444                 dst_ipaddr->ipaddr.ip6addr = s6->sin6_addr;
 445                 *dst_port = ntohs(s6->sin6_port);
 446 #endif
 447         } else {
 448                 free(buf);
 449                 return -1;      /* Unknown address family, Die Die Die! */
 450         }
 451
 452         /*
 453          *      Different address families should never happen.
 454          */
 455         if (src.ss_family != dst.ss_family) {
 456                 free(buf);
 457                 return -1;
 458         }
 459
 460         /*
 461          *      Tell the caller about the data
 462          */
 463         *pbuf = buf;
 464
 465         return data_len;
 466 }
 467
 468
 469 #define AUTH_PASS_LEN (AUTH_VECTOR_LEN)
 470 /*************************************************************************
 471  *
 472  *      Function: make_secret
 473  *
 474  *      Purpose: Build an encrypted secret value to return in a reply
 475  *               packet.  The secret is hidden by xoring with a MD5 digest
 476  *               created from the shared secret and the authentication
 477  *               vector.  We put them into MD5 in the reverse order from
 478  *               that used when encrypting passwords to RADIUS.
 479  *
 480  *************************************************************************/
 481 static void make_secret(uint8_t *digest, const uint8_t *vector,
 482                         const char *secret, const uint8_t *value)
 483 {
 484         FR_MD5_CTX context;
 485         int             i;
 486
 487         fr_MD5Init(&context);
 488         fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
 489         fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
 490         fr_MD5Final(digest, &context);
 491
 492         for ( i = 0; i < AUTH_VECTOR_LEN; i++ ) {
 493                 digest[i] ^= value[i];
 494         }
 495 }
 496
 497 #define MAX_PASS_LEN (128)
 498 static void make_passwd(uint8_t *output, int *outlen,
 499                         const uint8_t *input, int inlen,
 500                         const char *secret, const uint8_t *vector)
 501 {
 502         FR_MD5_CTX context, old;
 503         uint8_t digest[AUTH_VECTOR_LEN];
 504         uint8_t passwd[MAX_PASS_LEN];
 505         int     i, n;
 506         int     len;
 507
 508         /*
 509          *      If the length is zero, round it up.
 510          */
 511         len = inlen;
 512         if (len == 0) {
 513                 len = AUTH_PASS_LEN;
 514         }
 515         else if (len > MAX_PASS_LEN) len = MAX_PASS_LEN;
 516
 517         else if ((len & 0x0f) != 0) {
 518                 len += 0x0f;
 519                 len &= ~0x0f;
 520         }
 521         *outlen = len;
 522
 523         memcpy(passwd, input, len);
 524         memset(passwd + len, 0, sizeof(passwd) - len);
 525
 526         fr_MD5Init(&context);
 527         fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
 528         old = context;
 529
 530         /*
 531          *      Do first pass.
 532          */
 533         fr_MD5Update(&context, vector, AUTH_PASS_LEN);
 534
 535         for (n = 0; n < len; n += AUTH_PASS_LEN) {
 536                 if (n > 0) {
 537                         context = old;
 538                         fr_MD5Update(&context,
 539                                        passwd + n - AUTH_PASS_LEN,
 540                                        AUTH_PASS_LEN);
 541                 }
 542
 543                 fr_MD5Final(digest, &context);
 544                 for (i = 0; i < AUTH_PASS_LEN; i++) {
 545                         passwd[i + n] ^= digest[i];
 546                 }
 547         }
 548
 549         memcpy(output, passwd, len);
 550 }
 551
 552 static void make_tunnel_passwd(uint8_t *output, int *outlen,
 553                                const uint8_t *input, int inlen, int room,
 554                                const char *secret, const uint8_t *vector)
 555 {
 556         FR_MD5_CTX context, old;
 557         uint8_t digest[AUTH_VECTOR_LEN];
 558         uint8_t passwd[MAX_STRING_LEN + AUTH_VECTOR_LEN];
 559         int     i, n;
 560         int     len;
 561
 562         /*
 563          *      Be paranoid.
 564          */
 565         if (room > 253) room = 253;
 566
 567         /*
 568          *      Account for 2 bytes of the salt, and round the room
 569          *      available down to the nearest multiple of 16.  Then,
 570          *      subtract one from that to account for the length byte,
 571          *      and the resulting number is the upper bound on the data
 572          *      to copy.
 573          *
 574          *      We could short-cut this calculation just be forcing
 575          *      inlen to be no more than 239.  It would work for all
 576          *      VSA's, as we don't pack multiple VSA's into one
 577          *      attribute.
 578          *
 579          *      However, this calculation is more general, if a little
 580          *      complex.  And it will work in the future for all possible
 581          *      kinds of weird attribute packing.
 582          */
 583         room -= 2;
 584         room -= (room & 0x0f);
 585         room--;
 586
 587         if (inlen > room) inlen = room;
 588
 589         /*
 590          *      Length of the encrypted data is password length plus
 591          *      one byte for the length of the password.
 592          */
 593         len = inlen + 1;
 594         if ((len & 0x0f) != 0) {
 595                 len += 0x0f;
 596                 len &= ~0x0f;
 597         }
 598         *outlen = len + 2;      /* account for the salt */
 599
 600         /*
 601          *      Copy the password over.
 602          */
 603         memcpy(passwd + 3, input, inlen);
 604         memset(passwd + 3 + inlen, 0, sizeof(passwd) - 3 - inlen);
 605
 606         /*
 607          *      Generate salt.  The RFC's say:
 608          *
 609          *      The high bit of salt[0] must be set, each salt in a
 610          *      packet should be unique, and they should be random
 611          *
 612          *      So, we set the high bit, add in a counter, and then
 613          *      add in some CSPRNG data.  should be OK..
 614          */
 615         passwd[0] = (0x80 | ( ((salt_offset++) & 0x0f) << 3) |
 616                      (fr_rand() & 0x07));
 617         passwd[1] = fr_rand();
 618         passwd[2] = inlen;      /* length of the password string */
 619
 620         fr_MD5Init(&context);
 621         fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
 622         old = context;
 623
 624         fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
 625         fr_MD5Update(&context, &passwd[0], 2);
 626
 627         for (n = 0; n < len; n += AUTH_PASS_LEN) {
 628                 if (n > 0) {
 629                         context = old;
 630                         fr_MD5Update(&context,
 631                                        passwd + 2 + n - AUTH_PASS_LEN,
 632                                        AUTH_PASS_LEN);
 633                 }
 634
 635                 fr_MD5Final(digest, &context);
 636                 for (i = 0; i < AUTH_PASS_LEN; i++) {
 637                         passwd[i + 2 + n] ^= digest[i];
 638                 }
 639         }
 640         memcpy(output, passwd, len + 2);
 641 }
 642
 643
 644 /*
 645  *      Parse a data structure into a RADIUS attribute.
 646  */
 647 int rad_vp2attr(const RADIUS_PACKET *packet, const RADIUS_PACKET *original,
 648                 const char *secret, const VALUE_PAIR *vp, uint8_t *ptr)
 649 {
 650         int             vendorcode;
 651         int             offset, len, total_length;
 652         uint32_t        lvalue;
 653         uint8_t         *length_ptr, *vsa_length_ptr;
 654         const uint8_t   *data = NULL;
 655         uint8_t         array[4];
 656
 657         vendorcode = total_length = 0;
 658         length_ptr = vsa_length_ptr = NULL;
 659
 660         /*
 661          *      For interoperability, always put vendor attributes
 662          *      into their own VSA.
 663          */
 664         if ((vendorcode = VENDOR(vp->attribute)) == 0) {
 665                 *(ptr++) = vp->attribute & 0xFF;
 666                 length_ptr = ptr;
 667                 *(ptr++) = 2;
 668                 total_length += 2;
 669
 670         } else {
 671                 int vsa_tlen = 1;
 672                 int vsa_llen = 1;
 673                 DICT_VENDOR *dv = dict_vendorbyvalue(vendorcode);
 674
 675                 /*
 676                  *      This must be an RFC-format attribute.  If it
 677                  *      wasn't, then the "decode" function would have
 678                  *      made a Vendor-Specific attribute (i.e. type
 679                  *      26), and we would have "vendorcode == 0" here.
 680                  */
 681                 if (dv) {
 682                         vsa_tlen = dv->type;
 683                         vsa_llen = dv->length;
 684                 }
 685
 686                 /*
 687                  *      Build a VSA header.
 688                  */
 689                 *ptr++ = PW_VENDOR_SPECIFIC;
 690                 vsa_length_ptr = ptr;
 691                 *ptr++ = 6;
 692                 lvalue = htonl(vendorcode);
 693                 memcpy(ptr, &lvalue, 4);
 694                 ptr += 4;
 695                 total_length += 6;
 696
 697                 switch (vsa_tlen) {
 698                 case 1:
 699                         ptr[0] = (vp->attribute & 0xFF);
 700                         break;
 701
 702                 case 2:
 703                         ptr[0] = ((vp->attribute >> 8) & 0xFF);
 704                         ptr[1] = (vp->attribute & 0xFF);
 705                         break;
 706
 707                 case 4:
 708                         ptr[0] = 0;
 709                         ptr[1] = 0;
 710                         ptr[2] = ((vp->attribute >> 8) & 0xFF);
 711                         ptr[3] = (vp->attribute & 0xFF);
 712                         break;
 713
 714                 default:
 715                         return 0; /* silently discard it */
 716                 }
 717                 ptr += vsa_tlen;
 718
 719                 switch (vsa_llen) {
 720                 case 0:
 721                         length_ptr = vsa_length_ptr;
 722                         vsa_length_ptr = NULL;
 723                         break;
 724                 case 1:
 725                         ptr[0] = 0;
 726                         length_ptr = ptr;
 727                         break;
 728                 case 2:
 729                         ptr[0] = 0;
 730                         ptr[1] = 0;
 731                         length_ptr = ptr + 1;
 732                         break;
 733
 734                 default:
 735                         return 0; /* silently discard it */
 736                 }
 737                 ptr += vsa_llen;
 738
 739                 total_length += vsa_tlen + vsa_llen;
 740                 if (vsa_length_ptr) *vsa_length_ptr += vsa_tlen + vsa_llen;
 741                 *length_ptr += vsa_tlen + vsa_llen;
 742         }
 743
 744         offset = 0;
 745         if (vp->flags.has_tag) {
 746                 if (TAG_VALID(vp->flags.tag)) {
 747                         ptr[0] = vp->flags.tag & 0xff;
 748                         offset = 1;
 749
 750                 } else if (vp->flags.encrypt == FLAG_ENCRYPT_TUNNEL_PASSWORD) {
 751                         /*
 752                          *      Tunnel passwords REQUIRE a tag, even
 753                          *      if don't have a valid tag.
 754                          */
 755                         ptr[0] = 0;
 756                         offset = 1;
 757                 } /* else don't write a tag */
 758         } /* else the attribute doesn't have a tag */
 759
 760         /*
 761          *      Set up the default sources for the data.
 762          */
 763         data = vp->vp_octets;
 764         len = vp->length;
 765
 766         switch(vp->type) {
 767         case PW_TYPE_STRING:
 768         case PW_TYPE_OCTETS:
 769         case PW_TYPE_IFID:
 770         case PW_TYPE_IPV6ADDR:
 771         case PW_TYPE_IPV6PREFIX:
 772         case PW_TYPE_ABINARY:
 773                 /* nothing more to do */
 774                 break;
 775
 776         case PW_TYPE_BYTE:
 777                 len = 1;        /* just in case */
 778                 array[0] = vp->vp_integer & 0xff;
 779                 data = array;
 780                 offset = 0;
 781                 break;
 782
 783
 784         case PW_TYPE_SHORT:
 785                 len = 2;        /* just in case */
 786                 array[0] = (vp->vp_integer >> 8) & 0xff;
 787                 array[1] = vp->vp_integer & 0xff;
 788                 data = array;
 789                 offset = 0;
 790                 break;
 791
 792         case PW_TYPE_INTEGER:
 793                 len = 4;        /* just in case */
 794                 lvalue = htonl(vp->vp_integer);
 795                 memcpy(array, &lvalue, sizeof(lvalue));
 796
 797                 /*
 798                  *      Perhaps discard the first octet.
 799                  */
 800                 data = &array[offset];
 801                 len -= offset;
 802                 break;
 803
 804         case PW_TYPE_IPADDR:
 805                 data = (const uint8_t *) &vp->vp_ipaddr;
 806                 len = 4;        /* just in case */
 807                 break;
 808
 809                 /*
 810                  *  There are no tagged date attributes.
 811                  */
 812         case PW_TYPE_DATE:
 813                 lvalue = htonl(vp->vp_date);
 814                 data = (const uint8_t *) &lvalue;
 815                 len = 4;        /* just in case */
 816                 break;
 817
 818         default:                /* unknown type: ignore it */
 819                 librad_log("ERROR: Unknown attribute type %d", vp->type);
 820                 return -1;
 821         }
 822
 823         /*
 824          *      Bound the data to 255 bytes.
 825          */
 826         if (len + offset + total_length > 255) {
 827                 len = 255 - offset - total_length;
 828         }
 829
 830         /*
 831          *      Encrypt the various password styles
 832          *
 833          *      Attributes with encrypted values MUST be less than
 834          *      128 bytes long.
 835          */
 836         switch (vp->flags.encrypt) {
 837         case FLAG_ENCRYPT_USER_PASSWORD:
 838                 make_passwd(ptr + offset, &len,
 839                             data, len,
 840                             secret, packet->vector);
 841                 break;
 842
 843         case FLAG_ENCRYPT_TUNNEL_PASSWORD:
 844                 /*
 845                  *      Check if 255 - offset - total_length is less
 846                  *      than 18.  If so, we can't fit the data into
 847                  *      the available space, and we discard the
 848                  *      attribute.
 849                  *
 850                  *      This is ONLY a problem if we have multiple VSA's
 851                  *      in one Vendor-Specific, though.
 852                  */
 853                 if ((255 - offset - total_length) < 18) return 0;
 854
 855                 switch (packet->code) {
 856                 case PW_AUTHENTICATION_ACK:
 857                 case PW_AUTHENTICATION_REJECT:
 858                 case PW_ACCESS_CHALLENGE:
 859                 default:
 860                         if (!original) {
 861                                 librad_log("ERROR: No request packet, cannot encrypt %s attribute in the vp.", vp->name);
 862                                 return -1;
 863                         }
 864                         make_tunnel_passwd(ptr + offset, &len,
 865                                            data, len, 255 - offset - total_length,
 866                                            secret, original->vector);
 867                         break;
 868                 case PW_ACCOUNTING_REQUEST:
 869                 case PW_DISCONNECT_REQUEST:
 870                 case PW_COA_REQUEST:
 871                         make_tunnel_passwd(ptr + offset, &len,
 872                                            data, len, 255 - offset - total_length,
 873                                            secret, packet->vector);
 874                         break;
 875                 }
 876                 break;
 877
 878                 /*
 879                  *      The code above ensures that this attribute
 880                  *      always fits.
 881                  */
 882         case FLAG_ENCRYPT_ASCEND_SECRET:
 883                 make_secret(ptr + offset, packet->vector,
 884                             secret, data);
 885                 len = AUTH_VECTOR_LEN;
 886                 break;
 887
 888
 889         default:
 890                 /*
 891                  *      Just copy the data over
 892                  */
 893                 memcpy(ptr + offset, data, len);
 894                 break;
 895         } /* switch over encryption flags */
 896
 897         /*
 898          *      Account for the tag (if any).
 899          */
 900         len += offset;
 901
 902         /*
 903          *      RFC 2865 section 5 says that zero-length attributes
 904          *      MUST NOT be sent.
 905          */
 906         if (len == 0) return 0;
 907
 908         /*
 909          *      Update the various lengths.
 910          */
 911         *length_ptr += len;
 912         if (vsa_length_ptr) *vsa_length_ptr += len;
 913         ptr += len;
 914         total_length += len;
 915
 916         return total_length;    /* of attribute */
 917 }
 918
 919
 920 /*
 921  *      Encode a packet.
 922  */
 923 int rad_encode(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
 924                const char *secret)
 925 {
 926         radius_packet_t *hdr;
 927         uint8_t         *ptr;
 928         uint16_t        total_length;
 929         int             len;
 930         VALUE_PAIR      *reply;
 931         const char      *what;
 932         char            ip_buffer[128];
 933
 934         /*
 935          *      For simplicity in the following logic, we allow
 936          *      the attributes to "overflow" the 4k maximum
 937          *      RADIUS packet size, by one attribute.
 938          *
 939          *      It's uint32_t, for alignment purposes.
 940          */
 941         uint32_t        data[(MAX_PACKET_LEN + 256) / 4];
 942
 943         if ((packet->code > 0) && (packet->code < MAX_PACKET_CODE)) {
 944                 what = packet_codes[packet->code];
 945         } else {
 946                 what = "Reply";
 947         }
 948
 949         DEBUG("Sending %s of id %d to %s port %d\n",
 950               what, packet->id,
 951               inet_ntop(packet->dst_ipaddr.af,
 952                         &packet->dst_ipaddr.ipaddr,
 953                         ip_buffer, sizeof(ip_buffer)),
 954               packet->dst_port);
 955
 956         /*
 957          *      Double-check some things based on packet code.
 958          */
 959         switch (packet->code) {
 960         case PW_AUTHENTICATION_ACK:
 961         case PW_AUTHENTICATION_REJECT:
 962         case PW_ACCESS_CHALLENGE:
 963                 if (!original) {
 964                         librad_log("ERROR: Cannot sign response packet without a request packet.");
 965                         return -1;
 966                 }
 967                 break;
 968
 969                 /*
 970                  *      These packet vectors start off as all zero.
 971                  */
 972         case PW_ACCOUNTING_REQUEST:
 973         case PW_DISCONNECT_REQUEST:
 974         case PW_COA_REQUEST:
 975                 memset(packet->vector, 0, sizeof(packet->vector));
 976                 break;
 977
 978         default:
 979                 break;
 980         }
 981
 982         /*
 983          *      Use memory on the stack, until we know how
 984          *      large the packet will be.
 985          */
 986         hdr = (radius_packet_t *) data;
 987
 988         /*
 989          *      Build standard header
 990          */
 991         hdr->code = packet->code;
 992         hdr->id = packet->id;
 993
 994         memcpy(hdr->vector, packet->vector, sizeof(hdr->vector));
 995
 996         total_length = AUTH_HDR_LEN;
 997
 998         /*
 999          *      Load up the configuration values for the user
1000          */
1001         ptr = hdr->data;
1002         packet->offset = 0;
1003
1004         /*
1005          *      FIXME: Loop twice over the reply list.  The first time,
1006          *      calculate the total length of data.  The second time,
1007          *      allocate the memory, and fill in the VP's.
1008          *
1009          *      Hmm... this may be slower than just doing a small
1010          *      memcpy.
1011          */
1012
1013         /*
1014          *      Loop over the reply attributes for the packet.
1015          */
1016         for (reply = packet->vps; reply; reply = reply->next) {
1017                 /*
1018                  *      Ignore non-wire attributes
1019                  */
1020                 if ((VENDOR(reply->attribute) == 0) &&
1021                     ((reply->attribute & 0xFFFF) > 0xff)) {
1022 #ifndef NDEBUG
1023                         /*
1024                          *      Permit the admin to send BADLY formatted
1025                          *      attributes with a debug build.
1026                          */
1027                         if (reply->attribute == PW_RAW_ATTRIBUTE) {
1028                                 memcpy(ptr, reply->vp_octets, reply->length);
1029                                 len = reply->length;
1030                                 goto next;
1031                         }
1032 #endif
1033                         continue;
1034                 }
1035
1036                 /*
1037                  *      Set the Message-Authenticator to the correct
1038                  *      length and initial value.
1039                  */
1040                 if (reply->attribute == PW_MESSAGE_AUTHENTICATOR) {
1041                         reply->length = AUTH_VECTOR_LEN;
1042                         memset(reply->vp_strvalue, 0, AUTH_VECTOR_LEN);
1043
1044                         /*
1045                          *      Cache the offset to the
1046                          *      Message-Authenticator
1047                          */
1048                         packet->offset = total_length;
1049                 }
1050
1051                 /*
1052                  *      Print out ONLY the attributes which
1053                  *      we're sending over the wire, and print
1054                  *      them out BEFORE they're encrypted.
1055                  */
1056                 debug_pair(reply);
1057
1058                 len = rad_vp2attr(packet, original, secret, reply, ptr);
1059
1060                 if (len < 0) return -1;
1061
1062                 /*
1063                  *      Check that the packet is no more than 4k in
1064                  *      size, AFTER writing the attribute past the 4k
1065                  *      boundary, but BEFORE deciding to increase the
1066                  *      size of the packet. Note that the 'data'
1067                  *      buffer, above, is one attribute longer than
1068                  *      necessary, in order to permit this overflow.
1069                  */
1070                 if ((total_length + len) > MAX_PACKET_LEN) {
1071                         break;
1072                 }
1073
1074         next:
1075                 ptr += len;
1076                 total_length += len;
1077         } /* done looping over all attributes */
1078
1079         /*
1080          *      Fill in the rest of the fields, and copy the data over
1081          *      from the local stack to the newly allocated memory.
1082          *
1083          *      Yes, all this 'memcpy' is slow, but it means
1084          *      that we only allocate the minimum amount of
1085          *      memory for a request.
1086          */
1087         packet->data_len = total_length;
1088         packet->data = (uint8_t *) malloc(packet->data_len);
1089         if (!packet->data) {
1090                 librad_log("Out of memory");
1091                 return -1;
1092         }
1093
1094         memcpy(packet->data, data, packet->data_len);
1095         hdr = (radius_packet_t *) packet->data;
1096
1097         total_length = htons(total_length);
1098         memcpy(hdr->length, &total_length, sizeof(total_length));
1099
1100         return 0;
1101 }
1102
1103
1104 /*
1105  *      Sign a previously encoded packet.
1106  */
1107 int rad_sign(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
1108              const char *secret)
1109 {
1110         radius_packet_t *hdr = (radius_packet_t *)packet->data;
1111
1112         /*
1113          *      It wasn't assigned an Id, this is bad!
1114          */
1115         if (packet->id < 0) {
1116                 librad_log("ERROR: RADIUS packets must be assigned an Id.");
1117                 return -1;
1118         }
1119
1120         if (!packet->data || (packet->data_len < AUTH_HDR_LEN) ||
1121             (packet->offset < 0)) {
1122                 librad_log("ERROR: You must call rad_encode() before rad_sign()");
1123                 return -1;
1124         }
1125
1126         /*
1127          *      If there's a Message-Authenticator, update it
1128          *      now, BEFORE updating the authentication vector.
1129          */
1130         if (packet->offset > 0) {
1131                 uint8_t calc_auth_vector[AUTH_VECTOR_LEN];
1132
1133                 switch (packet->code) {
1134                 case PW_ACCOUNTING_REQUEST:
1135                 case PW_ACCOUNTING_RESPONSE:
1136                 case PW_DISCONNECT_REQUEST:
1137                 case PW_DISCONNECT_ACK:
1138                 case PW_DISCONNECT_NAK:
1139                 case PW_COA_REQUEST:
1140                 case PW_COA_ACK:
1141                 case PW_COA_NAK:
1142                         memset(hdr->vector, 0, AUTH_VECTOR_LEN);
1143                         break;
1144
1145                 case PW_AUTHENTICATION_ACK:
1146                 case PW_AUTHENTICATION_REJECT:
1147                 case PW_ACCESS_CHALLENGE:
1148                         if (!original) {
1149                                 librad_log("ERROR: Cannot sign response packet without a request packet.");
1150                                 return -1;
1151                         }
1152                         memcpy(hdr->vector, original->vector,
1153                                AUTH_VECTOR_LEN);
1154                         break;
1155
1156                 default:        /* others have vector already set to zero */
1157                         break;
1158
1159                 }
1160
1161                 /*
1162                  *      Set the authentication vector to zero,
1163                  *      calculate the signature, and put it
1164                  *      into the Message-Authenticator
1165                  *      attribute.
1166                  */
1167                 fr_hmac_md5(packet->data, packet->data_len,
1168                             (const uint8_t *) secret, strlen(secret),
1169                             calc_auth_vector);
1170                 memcpy(packet->data + packet->offset + 2,
1171                        calc_auth_vector, AUTH_VECTOR_LEN);
1172
1173                 /*
1174                  *      Copy the original request vector back
1175                  *      to the raw packet.
1176                  */
1177                 memcpy(hdr->vector, packet->vector, AUTH_VECTOR_LEN);
1178         }
1179
1180         /*
1181          *      Switch over the packet code, deciding how to
1182          *      sign the packet.
1183          */
1184         switch (packet->code) {
1185                 /*
1186                  *      Request packets are not signed, bur
1187                  *      have a random authentication vector.
1188                  */
1189         case PW_AUTHENTICATION_REQUEST:
1190         case PW_STATUS_SERVER:
1191                 break;
1192
1193                 /*
1194                  *      Reply packets are signed with the
1195                  *      authentication vector of the request.
1196                  */
1197         default:
1198                 {
1199                         uint8_t digest[16];
1200
1201                         FR_MD5_CTX      context;
1202                         fr_MD5Init(&context);
1203                         fr_MD5Update(&context, packet->data, packet->data_len);
1204                         fr_MD5Update(&context, (const uint8_t *) secret,
1205                                      strlen(secret));
1206                         fr_MD5Final(digest, &context);
1207
1208                         memcpy(hdr->vector, digest, AUTH_VECTOR_LEN);
1209                         memcpy(packet->vector, digest, AUTH_VECTOR_LEN);
1210                         break;
1211                 }
1212         }/* switch over packet codes */
1213
1214         return 0;
1215 }
1216
1217 /*
1218  *      Reply to the request.  Also attach
1219  *      reply attribute value pairs and any user message provided.
1220  */
1221 int rad_send(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
1222              const char *secret)
1223 {
1224         VALUE_PAIR              *reply;
1225         const char              *what;
1226         char                    ip_buffer[128];
1227
1228         /*
1229          *      Maybe it's a fake packet.  Don't send it.
1230          */
1231         if (!packet || (packet->sockfd < 0)) {
1232                 return 0;
1233         }
1234
1235         if ((packet->code > 0) && (packet->code < MAX_PACKET_CODE)) {
1236                 what = packet_codes[packet->code];
1237         } else {
1238                 what = "Reply";
1239         }
1240
1241         /*
1242          *  First time through, allocate room for the packet
1243          */
1244         if (!packet->data) {
1245                 /*
1246                  *      Encode the packet.
1247                  */
1248                 if (rad_encode(packet, original, secret) < 0) {
1249                         return -1;
1250                 }
1251
1252                 /*
1253                  *      Re-sign it, including updating the
1254                  *      Message-Authenticator.
1255                  */
1256                 if (rad_sign(packet, original, secret) < 0) {
1257                         return -1;
1258                 }
1259
1260                 /*
1261                  *      If packet->data points to data, then we print out
1262                  *      the VP list again only for debugging.
1263                  */
1264         } else if (librad_debug) {
1265                 DEBUG("Sending %s of id %d to %s port %d\n", what, packet->id,
1266                       inet_ntop(packet->dst_ipaddr.af,
1267                                 &packet->dst_ipaddr.ipaddr,
1268                                 ip_buffer, sizeof(ip_buffer)),
1269                       packet->dst_port);
1270
1271                 for (reply = packet->vps; reply; reply = reply->next) {
1272                         /* FIXME: ignore attributes > 0xff */
1273                         debug_pair(reply);
1274                 }
1275         }
1276
1277         /*
1278          *      And send it on it's way.
1279          */
1280         return rad_sendto(packet->sockfd, packet->data, packet->data_len, 0,
1281                           &packet->src_ipaddr, packet->src_port,
1282                           &packet->dst_ipaddr, packet->dst_port);
1283 }
1284
1285
1286 /*
1287  *      Validates the requesting client NAS.  Calculates the
1288  *      signature based on the clients private key.
1289  */
1290 static int calc_acctdigest(RADIUS_PACKET *packet, const char *secret)
1291 {
1292         uint8_t         digest[AUTH_VECTOR_LEN];
1293         FR_MD5_CTX              context;
1294
1295         /*
1296          *      Zero out the auth_vector in the received packet.
1297          *      Then append the shared secret to the received packet,
1298          *      and calculate the MD5 sum. This must be the same
1299          *      as the original MD5 sum (packet->vector).
1300          */
1301         memset(packet->data + 4, 0, AUTH_VECTOR_LEN);
1302
1303         /*
1304          *  MD5(packet + secret);
1305          */
1306         fr_MD5Init(&context);
1307         fr_MD5Update(&context, packet->data, packet->data_len);
1308         fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
1309         fr_MD5Final(digest, &context);
1310
1311         /*
1312          *      Return 0 if OK, 2 if not OK.
1313          */
1314         if (memcmp(digest, packet->vector, AUTH_VECTOR_LEN) != 0) return 2;
1315         return 0;
1316 }
1317
1318
1319 /*
1320  *      Validates the requesting client NAS.  Calculates the
1321  *      signature based on the clients private key.
1322  */
1323 static int calc_replydigest(RADIUS_PACKET *packet, RADIUS_PACKET *original,
1324                             const char *secret)
1325 {
1326         uint8_t         calc_digest[AUTH_VECTOR_LEN];
1327         FR_MD5_CTX              context;
1328
1329         /*
1330          *      Very bad!
1331          */
1332         if (original == NULL) {
1333                 return 3;
1334         }
1335
1336         /*
1337          *  Copy the original vector in place.
1338          */
1339         memcpy(packet->data + 4, original->vector, AUTH_VECTOR_LEN);
1340
1341         /*
1342          *  MD5(packet + secret);
1343          */
1344         fr_MD5Init(&context);
1345         fr_MD5Update(&context, packet->data, packet->data_len);
1346         fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
1347         fr_MD5Final(calc_digest, &context);
1348
1349         /*
1350          *  Copy the packet's vector back to the packet.
1351          */
1352         memcpy(packet->data + 4, packet->vector, AUTH_VECTOR_LEN);
1353
1354         /*
1355          *      Return 0 if OK, 2 if not OK.
1356          */
1357         if (memcmp(packet->vector, calc_digest, AUTH_VECTOR_LEN) != 0) return 2;
1358         return 0;
1359 }
1360
1361
1362 /*
1363  *      See if the data pointed to by PTR is a valid RADIUS packet.
1364  *
1365  *      packet is not 'const * const' because we may update data_len,
1366  *      if there's more data in the UDP packet than in the RADIUS packet.
1367  */
1368 int rad_packet_ok(RADIUS_PACKET *packet, int flags)
1369 {
1370         uint8_t                 *attr;
1371         int                     totallen;
1372         int                     count;
1373         radius_packet_t         *hdr;
1374         char                    host_ipaddr[128];
1375         int                     require_ma = 0;
1376         int                     seen_ma = 0;
1377         int                     num_attributes;
1378
1379         /*
1380          *      Check for packets smaller than the packet header.
1381          *
1382          *      RFC 2865, Section 3., subsection 'length' says:
1383          *
1384          *      "The minimum length is 20 ..."
1385          */
1386         if (packet->data_len < AUTH_HDR_LEN) {
1387                 librad_log("WARNING: Malformed RADIUS packet from host %s: too short (received %d < minimum %d)",
1388                            inet_ntop(packet->src_ipaddr.af,
1389                                      &packet->src_ipaddr.ipaddr,
1390                                      host_ipaddr, sizeof(host_ipaddr)),
1391                            packet->data_len, AUTH_HDR_LEN);
1392                 return 0;
1393         }
1394
1395         /*
1396          *      RFC 2865, Section 3., subsection 'length' says:
1397          *
1398          *      " ... and maximum length is 4096."
1399          */
1400         if (packet->data_len > MAX_PACKET_LEN) {
1401                 librad_log("WARNING: Malformed RADIUS packet from host %s: too long (received %d > maximum %d)",
1402                            inet_ntop(packet->src_ipaddr.af,
1403                                      &packet->src_ipaddr.ipaddr,
1404                                      host_ipaddr, sizeof(host_ipaddr)),
1405                            packet->data_len, MAX_PACKET_LEN);
1406                 return 0;
1407         }
1408
1409         /*
1410          *      Check for packets with mismatched size.
1411          *      i.e. We've received 128 bytes, and the packet header
1412          *      says it's 256 bytes long.
1413          */
1414         totallen = (packet->data[2] << 8) | packet->data[3];
1415         hdr = (radius_packet_t *)packet->data;
1416
1417         /*
1418          *      Code of 0 is not understood.
1419          *      Code of 16 or greate is not understood.
1420          */
1421         if ((hdr->code == 0) ||
1422             (hdr->code >= MAX_PACKET_CODE)) {
1423                 librad_log("WARNING: Bad RADIUS packet from host %s: unknown packet code %d",
1424                            inet_ntop(packet->src_ipaddr.af,
1425                                      &packet->src_ipaddr.ipaddr,
1426                                      host_ipaddr, sizeof(host_ipaddr)),
1427                            hdr->code);
1428                 return 0;
1429         }
1430
1431         /*
1432          *      Message-Authenticator is required in Status-Server
1433          *      packets, otherwise they can be trivially forged.
1434          */
1435         if (hdr->code == PW_STATUS_SERVER) require_ma = 1;
1436
1437         /*
1438          *      It's also required if the caller asks for it.
1439          */
1440         if (flags) require_ma = 1;
1441
1442         /*
1443          *      Repeat the length checks.  This time, instead of
1444          *      looking at the data we received, look at the value
1445          *      of the 'length' field inside of the packet.
1446          *
1447          *      Check for packets smaller than the packet header.
1448          *
1449          *      RFC 2865, Section 3., subsection 'length' says:
1450          *
1451          *      "The minimum length is 20 ..."
1452          */
1453         if (totallen < AUTH_HDR_LEN) {
1454                 librad_log("WARNING: Malformed RADIUS packet from host %s: too short (length %d < minimum %d)",
1455                            inet_ntop(packet->src_ipaddr.af,
1456                                      &packet->src_ipaddr.ipaddr,
1457                                      host_ipaddr, sizeof(host_ipaddr)),
1458                            totallen, AUTH_HDR_LEN);
1459                 return 0;
1460         }
1461
1462         /*
1463          *      And again, for the value of the 'length' field.
1464          *
1465          *      RFC 2865, Section 3., subsection 'length' says:
1466          *
1467          *      " ... and maximum length is 4096."
1468          */
1469         if (totallen > MAX_PACKET_LEN) {
1470                 librad_log("WARNING: Malformed RADIUS packet from host %s: too long (length %d > maximum %d)",
1471                            inet_ntop(packet->src_ipaddr.af,
1472                                      &packet->src_ipaddr.ipaddr,
1473                                      host_ipaddr, sizeof(host_ipaddr)),
1474                            totallen, MAX_PACKET_LEN);
1475                 return 0;
1476         }
1477
1478         /*
1479          *      RFC 2865, Section 3., subsection 'length' says:
1480          *
1481          *      "If the packet is shorter than the Length field
1482          *      indicates, it MUST be silently discarded."
1483          *
1484          *      i.e. No response to the NAS.
1485          */
1486         if (packet->data_len < totallen) {
1487                 librad_log("WARNING: Malformed RADIUS packet from host %s: received %d octets, packet length says %d",
1488                            inet_ntop(packet->src_ipaddr.af,
1489                                      &packet->src_ipaddr.ipaddr,
1490                                      host_ipaddr, sizeof(host_ipaddr)),
1491                            packet->data_len, totallen);
1492                 return 0;
1493         }
1494
1495         /*
1496          *      RFC 2865, Section 3., subsection 'length' says:
1497          *
1498          *      "Octets outside the range of the Length field MUST be
1499          *      treated as padding and ignored on reception."
1500          */
1501         if (packet->data_len > totallen) {
1502                 /*
1503                  *      We're shortening the packet below, but just
1504                  *      to be paranoid, zero out the extra data.
1505                  */
1506                 memset(packet->data + totallen, 0, packet->data_len - totallen);
1507                 packet->data_len = totallen;
1508         }
1509
1510         /*
1511          *      Walk through the packet's attributes, ensuring that
1512          *      they add up EXACTLY to the size of the packet.
1513          *
1514          *      If they don't, then the attributes either under-fill
1515          *      or over-fill the packet.  Any parsing of the packet
1516          *      is impossible, and will result in unknown side effects.
1517          *
1518          *      This would ONLY happen with buggy RADIUS implementations,
1519          *      or with an intentional attack.  Either way, we do NOT want
1520          *      to be vulnerable to this problem.
1521          */
1522         attr = hdr->data;
1523         count = totallen - AUTH_HDR_LEN;
1524         num_attributes = 0;
1525
1526         while (count > 0) {
1527                 /*
1528                  *      Attribute number zero is NOT defined.
1529                  */
1530                 if (attr[0] == 0) {
1531                         librad_log("WARNING: Malformed RADIUS packet from host %s: Invalid attribute 0",
1532                                    inet_ntop(packet->src_ipaddr.af,
1533                                              &packet->src_ipaddr.ipaddr,
1534                                              host_ipaddr, sizeof(host_ipaddr)));
1535                         return 0;
1536                 }
1537
1538                 /*
1539                  *      Attributes are at LEAST as long as the ID & length
1540                  *      fields.  Anything shorter is an invalid attribute.
1541                  */
1542                 if (attr[1] < 2) {
1543                         librad_log("WARNING: Malformed RADIUS packet from host %s: attribute %d too short",
1544                                    inet_ntop(packet->src_ipaddr.af,
1545                                              &packet->src_ipaddr.ipaddr,
1546                                              host_ipaddr, sizeof(host_ipaddr)),
1547                                    attr[0]);
1548                         return 0;
1549                 }
1550
1551                 /*
1552                  *      Sanity check the attributes for length.
1553                  */
1554                 switch (attr[0]) {
1555                 default:        /* don't do anything by default */
1556                         break;
1557
1558                         /*
1559                          *      If there's an EAP-Message, we require
1560                          *      a Message-Authenticator.
1561                          */
1562                 case PW_EAP_MESSAGE:
1563                         require_ma = 1;
1564                         break;
1565
1566                 case PW_MESSAGE_AUTHENTICATOR:
1567                         if (attr[1] != 2 + AUTH_VECTOR_LEN) {
1568                                 librad_log("WARNING: Malformed RADIUS packet from host %s: Message-Authenticator has invalid length %d",
1569                                            inet_ntop(packet->src_ipaddr.af,
1570                                                      &packet->src_ipaddr.ipaddr,
1571                                                      host_ipaddr, sizeof(host_ipaddr)),
1572                                            attr[1] - 2);
1573                                 return 0;
1574                         }
1575                         seen_ma = 1;
1576                         break;
1577                 }
1578
1579                 /*
1580                  *      FIXME: Look up the base 255 attributes in the
1581                  *      dictionary, and switch over their type.  For
1582                  *      integer/date/ip, the attribute length SHOULD
1583                  *      be 6.
1584                  */
1585                 count -= attr[1];       /* grab the attribute length */
1586                 attr += attr[1];
1587                 num_attributes++;       /* seen one more attribute */
1588         }
1589
1590         /*
1591          *      If the attributes add up to a packet, it's allowed.
1592          *
1593          *      If not, we complain, and throw the packet away.
1594          */
1595         if (count != 0) {
1596                 librad_log("WARNING: Malformed RADIUS packet from host %s: packet attributes do NOT exactly fill the packet",
1597                            inet_ntop(packet->src_ipaddr.af,
1598                                      &packet->src_ipaddr.ipaddr,
1599                                      host_ipaddr, sizeof(host_ipaddr)));
1600                 return 0;
1601         }
1602
1603         /*
1604          *      If we're configured to look for a maximum number of
1605          *      attributes, and we've seen more than that maximum,
1606          *      then throw the packet away, as a possible DoS.
1607          */
1608         if ((librad_max_attributes > 0) &&
1609             (num_attributes > librad_max_attributes)) {
1610                 librad_log("WARNING: Possible DoS attack from host %s: Too many attributes in request (received %d, max %d are allowed).",
1611                            inet_ntop(packet->src_ipaddr.af,
1612                                      &packet->src_ipaddr.ipaddr,
1613                                      host_ipaddr, sizeof(host_ipaddr)),
1614                            num_attributes, librad_max_attributes);
1615                 return 0;
1616         }
1617
1618         /*
1619          *      http://www.freeradius.org/rfc/rfc2869.html#EAP-Message
1620          *
1621          *      A packet with an EAP-Message attribute MUST also have
1622          *      a Message-Authenticator attribute.
1623          *
1624          *      A Message-Authenticator all by itself is OK, though.
1625          *
1626          *      Similarly, Status-Server packets MUST contain
1627          *      Message-Authenticator attributes.
1628          */
1629         if (require_ma && ! seen_ma) {
1630                 librad_log("WARNING: Insecure packet from host %s:  Packet does not contain required Message-Authenticator attribute",
1631                            inet_ntop(packet->src_ipaddr.af,
1632                                      &packet->src_ipaddr.ipaddr,
1633                                      host_ipaddr, sizeof(host_ipaddr)));
1634                 return 0;
1635         }
1636
1637         /*
1638          *      Fill RADIUS header fields
1639          */
1640         packet->code = hdr->code;
1641         packet->id = hdr->id;
1642         memcpy(packet->vector, hdr->vector, AUTH_VECTOR_LEN);
1643
1644         return 1;
1645 }
1646
1647
1648 /*
1649  *      Receive UDP client requests, and fill in
1650  *      the basics of a RADIUS_PACKET structure.
1651  */
1652 RADIUS_PACKET *rad_recv(int fd, int flags)
1653 {
1654         RADIUS_PACKET           *packet;
1655
1656         /*
1657          *      Allocate the new request data structure
1658          */
1659         if ((packet = malloc(sizeof(*packet))) == NULL) {
1660                 librad_log("out of memory");
1661                 return NULL;
1662         }
1663         memset(packet, 0, sizeof(*packet));
1664
1665         packet->data_len = rad_recvfrom(fd, &packet->data, 0,
1666                                         &packet->src_ipaddr, &packet->src_port,
1667                                         &packet->dst_ipaddr, &packet->dst_port);
1668
1669         /*
1670          *      Check for socket errors.
1671          */
1672         if (packet->data_len < 0) {
1673                 librad_log("Error receiving packet: %s", strerror(errno));
1674                 /* packet->data is NULL */
1675                 free(packet);
1676                 return NULL;
1677         }
1678
1679         /*
1680          *      If the packet is too big, then rad_recvfrom did NOT
1681          *      allocate memory.  Instead, it just discarded the
1682          *      packet.
1683          */
1684         if (packet->data_len > MAX_PACKET_LEN) {
1685                 librad_log("Discarding packet: Larger than RFC limitation of 4096 bytes.");
1686                 /* packet->data is NULL */
1687                 free(packet);
1688                 return NULL;
1689         }
1690
1691         /*
1692          *      Read no data.  Continue.
1693          *      This check is AFTER the MAX_PACKET_LEN check above, because
1694          *      if the packet is larger than MAX_PACKET_LEN, we also have
1695          *      packet->data == NULL
1696          */
1697         if ((packet->data_len == 0) || !packet->data) {
1698                 librad_log("Empty packet: Socket is not ready.");
1699                 free(packet);
1700                 return NULL;
1701         }
1702
1703         /*
1704          *      See if it's a well-formed RADIUS packet.
1705          */
1706         if (!rad_packet_ok(packet, flags)) {
1707                 rad_free(&packet);
1708                 return NULL;
1709         }
1710
1711         /*
1712          *      Remember which socket we read the packet from.
1713          */
1714         packet->sockfd = fd;
1715
1716         /*
1717          *      FIXME: Do even more filtering by only permitting
1718          *      certain IP's.  The problem is that we don't know
1719          *      how to do this properly for all possible clients...
1720          */
1721
1722         /*
1723          *      Explicitely set the VP list to empty.
1724          */
1725         packet->vps = NULL;
1726
1727         if (librad_debug) {
1728                 char host_ipaddr[128];
1729
1730                 if ((packet->code > 0) && (packet->code < MAX_PACKET_CODE)) {
1731                         printf("rad_recv: %s packet from host %s port %d",
1732                                packet_codes[packet->code],
1733                                inet_ntop(packet->src_ipaddr.af,
1734                                          &packet->src_ipaddr.ipaddr,
1735                                          host_ipaddr, sizeof(host_ipaddr)),
1736                                packet->src_port);
1737                 } else {
1738                         printf("rad_recv: Packet from host %s port %d code=%d",
1739                                inet_ntop(packet->src_ipaddr.af,
1740                                          &packet->src_ipaddr.ipaddr,
1741                                          host_ipaddr, sizeof(host_ipaddr)),
1742                                packet->src_port,
1743                                packet->code);
1744                 }
1745                 printf(", id=%d, length=%d\n", packet->id, packet->data_len);
1746         }
1747
1748         return packet;
1749 }
1750
1751
1752 /*
1753  *      Verify the signature of a packet.
1754  */
1755 int rad_verify(RADIUS_PACKET *packet, RADIUS_PACKET *original,
1756                const char *secret)
1757 {
1758         uint8_t                 *ptr;
1759         int                     length;
1760         int                     attrlen;
1761
1762         if (!packet || !packet->data) return -1;
1763
1764         /*
1765          *      Before we allocate memory for the attributes, do more
1766          *      sanity checking.
1767          */
1768         ptr = packet->data + AUTH_HDR_LEN;
1769         length = packet->data_len - AUTH_HDR_LEN;
1770         while (length > 0) {
1771                 uint8_t msg_auth_vector[AUTH_VECTOR_LEN];
1772                 uint8_t calc_auth_vector[AUTH_VECTOR_LEN];
1773
1774                 attrlen = ptr[1];
1775
1776                 switch (ptr[0]) {
1777                 default:        /* don't do anything. */
1778                         break;
1779
1780                         /*
1781                          *      Note that more than one Message-Authenticator
1782                          *      attribute is invalid.
1783                          */
1784                 case PW_MESSAGE_AUTHENTICATOR:
1785                         memcpy(msg_auth_vector, &ptr[2], sizeof(msg_auth_vector));
1786                         memset(&ptr[2], 0, AUTH_VECTOR_LEN);
1787
1788                         switch (packet->code) {
1789                         default:
1790                                 break;
1791
1792                         case PW_ACCOUNTING_REQUEST:
1793                         case PW_ACCOUNTING_RESPONSE:
1794                         case PW_DISCONNECT_REQUEST:
1795                         case PW_DISCONNECT_ACK:
1796                         case PW_DISCONNECT_NAK:
1797                         case PW_COA_REQUEST:
1798                         case PW_COA_ACK:
1799                         case PW_COA_NAK:
1800                                 memset(packet->data + 4, 0, AUTH_VECTOR_LEN);
1801                                 break;
1802
1803                         case PW_AUTHENTICATION_ACK:
1804                         case PW_AUTHENTICATION_REJECT:
1805                         case PW_ACCESS_CHALLENGE:
1806                                 if (!original) {
1807                                         librad_log("ERROR: Cannot validate Message-Authenticator in response packet without a request packet.");
1808                                         return -1;
1809                                 }
1810                                 memcpy(packet->data + 4, original->vector, AUTH_VECTOR_LEN);
1811                                 break;
1812                         }
1813
1814                         fr_hmac_md5(packet->data, packet->data_len,
1815                                     (const uint8_t *) secret, strlen(secret),
1816                                     calc_auth_vector);
1817                         if (memcmp(calc_auth_vector, msg_auth_vector,
1818                                    sizeof(calc_auth_vector)) != 0) {
1819                                 char buffer[32];
1820                                 librad_log("Received packet from %s with invalid Message-Authenticator!  (Shared secret is incorrect.)",
1821                                            inet_ntop(packet->src_ipaddr.af,
1822                                                      &packet->src_ipaddr.ipaddr,
1823                                                      buffer, sizeof(buffer)));
1824                                 /* Silently drop packet, according to RFC 3579 */
1825                                 return -1;
1826                         } /* else the message authenticator was good */
1827
1828                         /*
1829                          *      Reinitialize Authenticators.
1830                          */
1831                         memcpy(&ptr[2], msg_auth_vector, AUTH_VECTOR_LEN);
1832                         memcpy(packet->data + 4, packet->vector, AUTH_VECTOR_LEN);
1833                         break;
1834                 } /* switch over the attributes */
1835
1836                 ptr += attrlen;
1837                 length -= attrlen;
1838         } /* loop over the packet, sanity checking the attributes */
1839
1840         /*
1841          *      It looks like a RADIUS packet, but we can't validate
1842          *      the signature.
1843          */
1844         if ((packet->code == 0) || packet->code >= MAX_PACKET_CODE) {
1845                 char buffer[32];
1846                 librad_log("Received Unknown packet code %d"
1847                            "from client %s port %d: Cannot validate signature",
1848                            packet->code,
1849                            inet_ntop(packet->src_ipaddr.af,
1850                                      &packet->src_ipaddr.ipaddr,
1851                                      buffer, sizeof(buffer)),
1852                            packet->src_port);
1853                 return -1;
1854         }
1855
1856         /*
1857          *      Calculate and/or verify digest.
1858          */
1859         switch(packet->code) {
1860                 int rcode;
1861                 char buffer[32];
1862
1863                 case PW_AUTHENTICATION_REQUEST:
1864                 case PW_STATUS_SERVER:
1865                 case PW_DISCONNECT_REQUEST:
1866                         /*
1867                          *      The authentication vector is random
1868                          *      nonsense, invented by the client.
1869                          */
1870                         break;
1871
1872                 case PW_ACCOUNTING_REQUEST:
1873                         if (calc_acctdigest(packet, secret) > 1) {
1874                                 librad_log("Received Accounting-Request packet "
1875                                            "from %s with invalid signature!  (Shared secret is incorrect.)",
1876                                            inet_ntop(packet->src_ipaddr.af,
1877                                                      &packet->src_ipaddr.ipaddr,
1878                                                      buffer, sizeof(buffer)));
1879                                 return -1;
1880                         }
1881                         break;
1882
1883                         /* Verify the reply digest */
1884                 case PW_AUTHENTICATION_ACK:
1885                 case PW_AUTHENTICATION_REJECT:
1886                 case PW_ACCESS_CHALLENGE:
1887                 case PW_ACCOUNTING_RESPONSE:
1888                 case PW_DISCONNECT_ACK:
1889                 case PW_DISCONNECT_NAK:
1890                 case PW_COA_ACK:
1891                 case PW_COA_NAK:
1892                         rcode = calc_replydigest(packet, original, secret);
1893                         if (rcode > 1) {
1894                                 librad_log("Received %s packet "
1895                                            "from client %s port %d with invalid signature (err=%d)!  (Shared secret is incorrect.)",
1896                                            packet_codes[packet->code],
1897                                            inet_ntop(packet->src_ipaddr.af,
1898                                                      &packet->src_ipaddr.ipaddr,
1899                                                      buffer, sizeof(buffer)),
1900                                            packet->src_port,
1901                                            rcode);
1902                                 return -1;
1903                         }
1904                         break;
1905
1906                 default:
1907                         librad_log("Received Unknown packet code %d"
1908                                    "from client %s port %d: Cannot validate signature",
1909                                    packet->code,
1910                                    inet_ntop(packet->src_ipaddr.af,
1911                                              &packet->src_ipaddr.ipaddr,
1912                                                      buffer, sizeof(buffer)),
1913                                    packet->src_port);
1914                         return -1;
1915         }
1916
1917         return 0;
1918 }
1919
1920
1921 /*
1922  *      Parse a RADIUS attribute into a data structure.
1923  */
1924 VALUE_PAIR *rad_attr2vp(const RADIUS_PACKET *packet, const RADIUS_PACKET *original,
1925                         const char *secret, int attribute, int length,
1926                         const uint8_t *data)
1927 {
1928         int offset = 0;
1929         VALUE_PAIR *vp;
1930
1931         if ((vp = paircreate(attribute, PW_TYPE_OCTETS)) == NULL) {
1932                 return NULL;
1933         }
1934
1935         /*
1936          *      If length is greater than 253, something is SERIOUSLY
1937          *      wrong.
1938          */
1939         if (length > 253) length = 253; /* paranoia (pair-anoia?) */
1940
1941         vp->length = length;
1942         vp->operator = T_OP_EQ;
1943         vp->next = NULL;
1944
1945         /*
1946          *      Handle tags.
1947          */
1948         if (vp->flags.has_tag) {
1949                 if (TAG_VALID(data[0]) ||
1950                     (vp->flags.encrypt == FLAG_ENCRYPT_TUNNEL_PASSWORD)) {
1951                         /*
1952                          *      Tunnel passwords REQUIRE a tag, even
1953                          *      if don't have a valid tag.
1954                          */
1955                         vp->flags.tag = data[0];
1956
1957                         if ((vp->type == PW_TYPE_STRING) ||
1958                             (vp->type == PW_TYPE_OCTETS)) offset = 1;
1959                 }
1960         }
1961
1962         /*
1963          *      Copy the data to be decrypted
1964          */
1965         memcpy(&vp->vp_octets[0], data + offset, length - offset);
1966         vp->length -= offset;
1967
1968         /*
1969          *      Decrypt the attribute.
1970          */
1971         switch (vp->flags.encrypt) {
1972                 /*
1973                  *  User-Password
1974                  */
1975         case FLAG_ENCRYPT_USER_PASSWORD:
1976                 if (original) {
1977                         rad_pwdecode((char *)vp->vp_strvalue,
1978                                      vp->length, secret,
1979                                      original->vector);
1980                 } else {
1981                         rad_pwdecode((char *)vp->vp_strvalue,
1982                                      vp->length, secret,
1983                                      packet->vector);
1984                 }
1985                 if (vp->attribute == PW_USER_PASSWORD) {
1986                         vp->length = strlen(vp->vp_strvalue);
1987                 }
1988                 break;
1989
1990                 /*
1991                  *      Tunnel-Password's may go ONLY
1992                  *      in response packets.
1993                  */
1994         case FLAG_ENCRYPT_TUNNEL_PASSWORD:
1995                 if (!original) goto raw;
1996
1997                 if (rad_tunnel_pwdecode(vp->vp_octets, &vp->length,
1998                                         secret, original->vector) < 0) {
1999                         goto raw;
2000                 }
2001                 break;
2002
2003                 /*
2004                  *  Ascend-Send-Secret
2005                  *  Ascend-Receive-Secret
2006                  */
2007         case FLAG_ENCRYPT_ASCEND_SECRET:
2008                 if (!original) {
2009                         goto raw;
2010                 } else {
2011                         uint8_t my_digest[AUTH_VECTOR_LEN];
2012                         make_secret(my_digest,
2013                                     original->vector,
2014                                     secret, data);
2015                         memcpy(vp->vp_strvalue, my_digest,
2016                                AUTH_VECTOR_LEN );
2017                         vp->vp_strvalue[AUTH_VECTOR_LEN] = '\0';
2018                         vp->length = strlen(vp->vp_strvalue);
2019                 }
2020                 break;
2021
2022         default:
2023                 break;
2024         } /* switch over encryption flags */
2025
2026
2027         switch (vp->type) {
2028         case PW_TYPE_STRING:
2029         case PW_TYPE_OCTETS:
2030         case PW_TYPE_ABINARY:
2031                 /* nothing more to do */
2032                 break;
2033
2034         case PW_TYPE_BYTE:
2035                 if (vp->length != 1) goto raw;
2036
2037                 vp->vp_integer = vp->vp_octets[0];
2038                 break;
2039
2040
2041         case PW_TYPE_SHORT:
2042                 if (vp->length != 2) goto raw;
2043
2044                 vp->vp_integer = (vp->vp_octets[0] << 8) | vp->vp_octets[1];
2045                 break;
2046
2047         case PW_TYPE_INTEGER:
2048                 if (vp->length != 4) goto raw;
2049
2050                 memcpy(&vp->vp_integer, vp->vp_octets, 4);
2051                 vp->vp_integer = ntohl(vp->vp_integer);
2052
2053                 if (vp->flags.has_tag) vp->vp_integer &= 0x00ffffff;
2054
2055                 /*
2056                  *      Try to get named VALUEs
2057                  */
2058                 {
2059                         DICT_VALUE *dval;
2060                         dval = dict_valbyattr(vp->attribute,
2061                                               vp->vp_integer);
2062                         if (dval) {
2063                                 strlcpy(vp->vp_strvalue,
2064                                         dval->name,
2065                                         sizeof(vp->vp_strvalue));
2066                         }
2067                 }
2068                 break;
2069
2070         case PW_TYPE_DATE:
2071                 if (vp->length != 4) goto raw;
2072
2073                 memcpy(&vp->vp_date, vp->vp_octets, 4);
2074                 vp->vp_date = ntohl(vp->vp_date);
2075                 break;
2076
2077
2078         case PW_TYPE_IPADDR:
2079                 if (vp->length != 4) goto raw;
2080
2081                 memcpy(&vp->vp_ipaddr, vp->vp_octets, 4);
2082                 break;
2083
2084                 /*
2085                  *      IPv6 interface ID is 8 octets long.
2086                  */
2087         case PW_TYPE_IFID:
2088                 if (vp->length != 8) goto raw;
2089                 /* vp->vp_ifid == vp->vp_octets */
2090                 break;
2091
2092                 /*
2093                  *      IPv6 addresses are 16 octets long
2094                  */
2095         case PW_TYPE_IPV6ADDR:
2096                 if (vp->length != 16) goto raw;
2097                 /* vp->vp_ipv6addr == vp->vp_octets */
2098                 break;
2099
2100                 /*
2101                  *      IPv6 prefixes are 2 to 18 octets long.
2102                  *
2103                  *      RFC 3162: The first octet is unused.
2104                  *      The second is the length of the prefix
2105                  *      the rest are the prefix data.
2106                  *
2107                  *      The prefix length can have value 0 to 128.
2108                  */
2109         case PW_TYPE_IPV6PREFIX:
2110                 if (vp->length < 2 || vp->length > 18) goto raw;
2111                 if (vp->vp_octets[1] > 128) goto raw;
2112
2113                 /*
2114                  *      FIXME: double-check that
2115                  *      (vp->vp_octets[1] >> 3) matches vp->length + 2
2116                  */
2117                 if (vp->length < 18) {
2118                         memset(vp->vp_octets + vp->length, 0,
2119                                18 - vp->length);
2120                 }
2121                 break;
2122
2123         default:
2124         raw:
2125                 vp->type = PW_TYPE_OCTETS;
2126                 vp->length = length;
2127                 memcpy(vp->vp_octets, data, length);
2128
2129
2130                 /*
2131                  *      Ensure there's no encryption or tag stuff,
2132                  *      we just pass the attribute as-is.
2133                  */
2134                 memset(&vp->flags, 0, sizeof(vp->flags));
2135         }
2136
2137         return vp;
2138 }
2139
2140
2141 /*
2142  *      Calculate/check digest, and decode radius attributes.
2143  *      Returns:
2144  *      -1 on decoding error
2145  *      0 on success
2146  */
2147 int rad_decode(RADIUS_PACKET *packet, RADIUS_PACKET *original,
2148                const char *secret)
2149 {
2150         uint32_t                lvalue;
2151         uint32_t                vendorcode;
2152         VALUE_PAIR              **tail;
2153         VALUE_PAIR              *pair;
2154         uint8_t                 *ptr;
2155         int                     packet_length;
2156         int                     attribute;
2157         int                     attrlen;
2158         int                     vendorlen;
2159         radius_packet_t         *hdr;
2160         int                     vsa_tlen, vsa_llen;
2161         DICT_VENDOR             *dv = NULL;
2162         int                     num_attributes = 0;
2163
2164         /*
2165          *      Extract attribute-value pairs
2166          */
2167         hdr = (radius_packet_t *)packet->data;
2168         ptr = hdr->data;
2169         packet_length = packet->data_len - AUTH_HDR_LEN;
2170
2171         /*
2172          *      There may be VP's already in the packet.  Don't
2173          *      destroy them.
2174          */
2175         for (tail = &packet->vps; *tail != NULL; tail = &((*tail)->next)) {
2176                 /* nothing */
2177         }
2178
2179         vendorcode = 0;
2180         vendorlen  = 0;
2181         vsa_tlen = vsa_llen = 1;
2182
2183         /*
2184          *      We have to read at least two bytes.
2185          *
2186          *      rad_recv() above ensures that this is OK.
2187          */
2188         while (packet_length > 0) {
2189                 attribute = -1;
2190                 attrlen = -1;
2191
2192                 /*
2193                  *      Normal attribute, handle it like normal.
2194                  */
2195                 if (vendorcode == 0) {
2196                         /*
2197                          *      No room to read attr/length,
2198                          *      or bad attribute, or attribute is
2199                          *      too short, or attribute is too long,
2200                          *      stop processing the packet.
2201                          */
2202                         if ((packet_length < 2) ||
2203                             (ptr[0] == 0) ||  (ptr[1] < 2) ||
2204                             (ptr[1] > packet_length)) break;
2205
2206                         attribute = *ptr++;
2207                         attrlen   = *ptr++;
2208
2209                         attrlen -= 2;
2210                         packet_length  -= 2;
2211
2212                         if (attribute != PW_VENDOR_SPECIFIC) goto create_pair;
2213
2214                         /*
2215                          *      No vendor code, or ONLY vendor code.
2216                          */
2217                         if (attrlen <= 4) goto create_pair;
2218
2219                         vendorlen = 0;
2220                 }
2221
2222                 /*
2223                  *      Handle Vendor-Specific
2224                  */
2225                 if (vendorlen == 0) {
2226                         uint8_t *subptr;
2227                         int sublen;
2228                         int myvendor;
2229
2230                         /*
2231                          *      attrlen was checked above.
2232                          */
2233                         memcpy(&lvalue, ptr, 4);
2234                         myvendor = ntohl(lvalue);
2235
2236                         /*
2237                          *      Zero isn't allowed.
2238                          */
2239                         if (myvendor == 0) goto create_pair;
2240
2241                         /*
2242                          *      This is an implementation issue.
2243                          *      We currently pack vendor into the upper
2244                          *      16 bits of a 32-bit attribute number,
2245                          *      so we can't handle vendor numbers larger
2246                          *      than 16 bits.
2247                          */
2248                         if (myvendor > 65535) goto create_pair;
2249
2250                         vsa_tlen = vsa_llen = 1;
2251                         dv = dict_vendorbyvalue(myvendor);
2252                         if (dv) {
2253                                 vsa_tlen = dv->type;
2254                                 vsa_llen = dv->length;
2255                         }
2256
2257                         /*
2258                          *      Sweep through the list of VSA's,
2259                          *      seeing if they exactly fill the
2260                          *      outer Vendor-Specific attribute.
2261                          *
2262                          *      If not, create a raw Vendor-Specific.
2263                          */
2264                         subptr = ptr + 4;
2265                         sublen = attrlen - 4;
2266
2267                         /*
2268                          *      See if we can parse it.
2269                          */
2270                         do {
2271                                 int myattr = 0;
2272
2273                                 /*
2274                                  *      Don't have a type, it's bad.
2275                                  */
2276                                 if (sublen < vsa_tlen) goto create_pair;
2277
2278                                 /*
2279                                  *      Ensure that the attribute number
2280                                  *      is OK.
2281                                  */
2282                                 switch (vsa_tlen) {
2283                                 case 1:
2284                                         myattr = subptr[0];
2285                                         break;
2286
2287                                 case 2:
2288                                         myattr = (subptr[0] << 8) | subptr[1];
2289                                         break;
2290
2291                                 case 4:
2292                                         if ((subptr[0] != 0) ||
2293                                             (subptr[1] != 0)) goto create_pair;
2294
2295                                         myattr = (subptr[2] << 8) | subptr[3];
2296                                         break;
2297
2298                                         /*
2299                                          *      Our dictionary is broken.
2300                                          */
2301                                 default:
2302                                         goto create_pair;
2303                                 }
2304
2305                                 /*
2306                                  *      Not enough room for one more
2307                                  *      attribute.  Die!
2308                                  */
2309                                 if (sublen < vsa_tlen + vsa_llen) goto create_pair;
2310                                 switch (vsa_llen) {
2311                                 case 0:
2312                                         attribute = (myvendor << 16) | myattr;
2313                                         ptr += 4 + vsa_tlen;
2314                                         attrlen -= (4 + vsa_tlen);
2315                                         packet_length -= 4 + vsa_tlen;
2316                                         goto create_pair;
2317
2318                                 case 1:
2319                                         if (subptr[vsa_tlen] < (vsa_tlen + vsa_llen))
2320                                                 goto create_pair;
2321
2322                                         if (subptr[vsa_tlen] > sublen)
2323                                                 goto create_pair;
2324                                         sublen -= subptr[vsa_tlen];
2325                                         subptr += subptr[vsa_tlen];
2326                                         break;
2327
2328                                 case 2:
2329                                         if (subptr[vsa_tlen] != 0) goto create_pair;
2330                                         if (subptr[vsa_tlen + 1] < (vsa_tlen + vsa_llen))
2331                                                 goto create_pair;
2332                                         if (subptr[vsa_tlen + 1] > sublen)
2333                                                 goto create_pair;
2334                                         sublen -= subptr[vsa_tlen + 1];
2335                                         subptr += subptr[vsa_tlen + 1];
2336                                         break;
2337
2338                                         /*
2339                                          *      Our dictionaries are
2340                                          *      broken.
2341                                          */
2342                                 default:
2343                                         goto create_pair;
2344                                 }
2345                         } while (sublen > 0);
2346
2347                         vendorcode = myvendor;
2348                         vendorlen = attrlen - 4;
2349                         packet_length -= 4;
2350
2351                         ptr += 4;
2352                 }
2353
2354                 /*
2355                  *      attrlen is the length of this attribute.
2356                  *      total_len is the length of the encompassing
2357                  *      attribute.
2358                  */
2359                 switch (vsa_tlen) {
2360                 case 1:
2361                         attribute = ptr[0];
2362                         break;
2363
2364                 case 2:
2365                         attribute = (ptr[0] << 8) | ptr[1];
2366                         break;
2367
2368                 default:        /* can't hit this. */
2369                         return -1;
2370                 }
2371                 attribute |= (vendorcode << 16);
2372                 ptr += vsa_tlen;
2373
2374                 switch (vsa_llen) {
2375                 case 1:
2376                         attrlen = ptr[0] - (vsa_tlen + vsa_llen);
2377                         break;
2378
2379                 case 2:
2380                         attrlen = ptr[1] - (vsa_tlen + vsa_llen);
2381                         break;
2382
2383                 default:        /* can't hit this. */
2384                         return -1;
2385                 }
2386                 ptr += vsa_llen;
2387                 vendorlen -= vsa_tlen + vsa_llen + attrlen;
2388                 if (vendorlen == 0) vendorcode = 0;
2389                 packet_length -= (vsa_tlen + vsa_llen);
2390
2391                 /*
2392                  *      Create the attribute, setting the default type
2393                  *      to 'octets'.  If the type in the dictionary
2394                  *      is different, then the dictionary type will
2395                  *      over-ride this one.
2396                  *
2397                  *      If the attribute has no data, then discard it.
2398                  */
2399         create_pair:
2400                 if (!attrlen) goto next;
2401
2402                 pair = rad_attr2vp(packet, original, secret,
2403                                    attribute, attrlen, ptr);
2404                 if (!pair) {
2405                         pairfree(&packet->vps);
2406                         librad_log("out of memory");
2407                         return -1;
2408                 }
2409
2410                 *tail = pair;
2411                 while (pair) {
2412                         num_attributes++;
2413                         debug_pair(pair);
2414                         tail = &pair->next;
2415                         pair = pair->next;
2416                 }
2417
2418                 /*
2419                  *      VSA's may not have been counted properly in
2420                  *      rad_packet_ok() above, as it is hard to count
2421                  *      then without using the dictionary.  We
2422                  *      therefore enforce the limits here, too.
2423                  */
2424                 if ((librad_max_attributes > 0) &&
2425                     (num_attributes > librad_max_attributes)) {
2426                         char host_ipaddr[128];
2427
2428                         pairfree(&packet->vps);
2429                         librad_log("WARNING: Possible DoS attack from host %s: Too many attributes in request (received %d, max %d are allowed).",
2430                                    inet_ntop(packet->src_ipaddr.af,
2431                                              &packet->src_ipaddr.ipaddr,
2432                                              host_ipaddr, sizeof(host_ipaddr)),
2433                                    num_attributes, librad_max_attributes);
2434                         return -1;
2435                 }
2436
2437                     next:
2438                 ptr += attrlen;
2439                 packet_length -= attrlen;
2440         }
2441
2442         /*
2443          *      Merge information from the outside world into our
2444          *      random pool.
2445          */
2446         fr_rand_seed(packet->data, AUTH_HDR_LEN);
2447
2448         return 0;
2449 }
2450
2451
2452 /*
2453  *      Encode password.
2454  *
2455  *      We assume that the passwd buffer passed is big enough.
2456  *      RFC2138 says the password is max 128 chars, so the size
2457  *      of the passwd buffer must be at least 129 characters.
2458  *      Preferably it's just MAX_STRING_LEN.
2459  *
2460  *      int *pwlen is updated to the new length of the encrypted
2461  *      password - a multiple of 16 bytes.
2462  */
2463 int rad_pwencode(char *passwd, size_t *pwlen, const char *secret,
2464                  const uint8_t *vector)
2465 {
2466         FR_MD5_CTX context, old;
2467         uint8_t digest[AUTH_VECTOR_LEN];
2468         int     i, n, secretlen;
2469         int     len;
2470
2471         /*
2472          *      RFC maximum is 128 bytes.
2473          *
2474          *      If length is zero, pad it out with zeros.
2475          *
2476          *      If the length isn't aligned to 16 bytes,
2477          *      zero out the extra data.
2478          */
2479         len = *pwlen;
2480
2481         if (len > 128) len = 128;
2482
2483         if (len == 0) {
2484                 memset(passwd, 0, AUTH_PASS_LEN);
2485                 len = AUTH_PASS_LEN;
2486         } else if ((len % AUTH_PASS_LEN) != 0) {
2487                 memset(&passwd[len], 0, AUTH_PASS_LEN - (len % AUTH_PASS_LEN));
2488                 len += AUTH_PASS_LEN - (len % AUTH_PASS_LEN);
2489         }
2490         *pwlen = len;
2491
2492         /*
2493          *      Use the secret to setup the decryption digest
2494          */
2495         secretlen = strlen(secret);
2496
2497         fr_MD5Init(&context);
2498         fr_MD5Update(&context, (const uint8_t *) secret, secretlen);
2499         old = context;          /* save intermediate work */
2500
2501         /*
2502          *      Encrypt it in place.  Don't bother checking
2503          *      len, as we've ensured above that it's OK.
2504          */
2505         for (n = 0; n < len; n += AUTH_PASS_LEN) {
2506                 if (n == 0) {
2507                         fr_MD5Update(&context, vector, AUTH_PASS_LEN);
2508                         fr_MD5Final(digest, &context);
2509                 } else {
2510                         context = old;
2511                         fr_MD5Update(&context,
2512                                      (uint8_t *) passwd + n - AUTH_PASS_LEN,
2513                                      AUTH_PASS_LEN);
2514                         fr_MD5Final(digest, &context);
2515                 }
2516
2517                 for (i = 0; i < AUTH_PASS_LEN; i++) {
2518                         passwd[i + n] ^= digest[i];
2519                 }
2520         }
2521
2522         return 0;
2523 }
2524
2525 /*
2526  *      Decode password.
2527  */
2528 int rad_pwdecode(char *passwd, size_t pwlen, const char *secret,
2529                  const uint8_t *vector)
2530 {
2531         FR_MD5_CTX context, old;
2532         uint8_t digest[AUTH_VECTOR_LEN];
2533         int     i;
2534         size_t  n, secretlen;
2535
2536         /*
2537          *      The RFC's say that the maximum is 128.
2538          *      The buffer we're putting it into above is 254, so
2539          *      we don't need to do any length checking.
2540          */
2541         if (pwlen > 128) pwlen = 128;
2542
2543         /*
2544          *      Catch idiots.
2545          */
2546         if (pwlen == 0) goto done;
2547
2548         /*
2549          *      Use the secret to setup the decryption digest
2550          */
2551         secretlen = strlen(secret);
2552
2553         fr_MD5Init(&context);
2554         fr_MD5Update(&context, (const uint8_t *) secret, secretlen);
2555         old = context;          /* save intermediate work */
2556
2557         /*
2558          *      The inverse of the code above.
2559          */
2560         for (n = 0; n < pwlen; n += AUTH_PASS_LEN) {
2561                 if (n == 0) {
2562                         fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
2563                         fr_MD5Final(digest, &context);
2564
2565                         context = old;
2566                         if (pwlen > AUTH_PASS_LEN) {
2567                                 fr_MD5Update(&context, (uint8_t *) passwd,
2568                                              AUTH_PASS_LEN);
2569                         }
2570                 } else {
2571                         fr_MD5Final(digest, &context);
2572
2573                         context = old;
2574                         if (pwlen > (n + AUTH_PASS_LEN)) {
2575                                 fr_MD5Update(&context, (uint8_t *) passwd + n,
2576                                              AUTH_PASS_LEN);
2577                         }
2578                 }
2579
2580                 for (i = 0; i < AUTH_PASS_LEN; i++) {
2581                         passwd[i + n] ^= digest[i];
2582                 }
2583         }
2584
2585  done:
2586         passwd[pwlen] = '\0';
2587         return strlen(passwd);
2588 }
2589
2590
2591 /*
2592  *      Encode Tunnel-Password attributes when sending them out on the wire.
2593  *
2594  *      int *pwlen is updated to the new length of the encrypted
2595  *      password - a multiple of 16 bytes.
2596  *
2597  *      This is per RFC-2868 which adds a two char SALT to the initial intermediate
2598  *      value MD5 hash.
2599  */
2600 int rad_tunnel_pwencode(char *passwd, size_t *pwlen, const char *secret,
2601                         const uint8_t *vector)
2602 {
2603         uint8_t buffer[AUTH_VECTOR_LEN + MAX_STRING_LEN + 3];
2604         unsigned char   digest[AUTH_VECTOR_LEN];
2605         char*   salt;
2606         int     i, n, secretlen;
2607         unsigned len, n2;
2608
2609         len = *pwlen;
2610
2611         if (len > 127) len = 127;
2612
2613         /*
2614          * Shift the password 3 positions right to place a salt and original
2615          * length, tag will be added automatically on packet send
2616          */
2617         for (n=len ; n>=0 ; n--) passwd[n+3] = passwd[n];
2618         salt = passwd;
2619         passwd += 2;
2620         /*
2621          * save original password length as first password character;
2622          */
2623         *passwd = len;
2624         len += 1;
2625
2626
2627         /*
2628          *      Generate salt.  The RFC's say:
2629          *
2630          *      The high bit of salt[0] must be set, each salt in a
2631          *      packet should be unique, and they should be random
2632          *
2633          *      So, we set the high bit, add in a counter, and then
2634          *      add in some CSPRNG data.  should be OK..
2635          */
2636         salt[0] = (0x80 | ( ((salt_offset++) & 0x0f) << 3) |
2637                    (fr_rand() & 0x07));
2638         salt[1] = fr_rand();
2639
2640         /*
2641          *      Padd password to multiple of AUTH_PASS_LEN bytes.
2642          */
2643         n = len % AUTH_PASS_LEN;
2644         if (n) {
2645                 n = AUTH_PASS_LEN - n;
2646                 for (; n > 0; n--, len++)
2647                         passwd[len] = 0;
2648         }
2649         /* set new password length */
2650         *pwlen = len + 2;
2651
2652         /*
2653          *      Use the secret to setup the decryption digest
2654          */
2655         secretlen = strlen(secret);
2656         memcpy(buffer, secret, secretlen);
2657
2658         for (n2 = 0; n2 < len; n2+=AUTH_PASS_LEN) {
2659                 if (!n2) {
2660                         memcpy(buffer + secretlen, vector, AUTH_VECTOR_LEN);
2661                         memcpy(buffer + secretlen + AUTH_VECTOR_LEN, salt, 2);
2662                         fr_md5_calc(digest, buffer, secretlen + AUTH_VECTOR_LEN + 2);
2663                 } else {
2664                         memcpy(buffer + secretlen, passwd + n2 - AUTH_PASS_LEN, AUTH_PASS_LEN);
2665                         fr_md5_calc(digest, buffer, secretlen + AUTH_PASS_LEN);
2666                 }
2667
2668                 for (i = 0; i < AUTH_PASS_LEN; i++) {
2669                         passwd[i + n2] ^= digest[i];
2670                 }
2671         }
2672         passwd[n2] = 0;
2673         return 0;
2674 }
2675
2676 /*
2677  *      Decode Tunnel-Password encrypted attributes.
2678  *
2679  *      Defined in RFC-2868, this uses a two char SALT along with the
2680  *      initial intermediate value, to differentiate it from the
2681  *      above.
2682  */
2683 int rad_tunnel_pwdecode(uint8_t *passwd, size_t *pwlen, const char *secret,
2684                         const uint8_t *vector)
2685 {
2686         FR_MD5_CTX  context, old;
2687         uint8_t         digest[AUTH_VECTOR_LEN];
2688         int             secretlen;
2689         unsigned        i, n, len, reallen;
2690
2691         len = *pwlen;
2692
2693         /*
2694          *      We need at least a salt.
2695          */
2696         if (len < 2) {
2697                 librad_log("tunnel password is too short");
2698                 return -1;
2699         }
2700
2701         /*
2702          *      There's a salt, but no password.  Or, there's a salt
2703          *      and a 'data_len' octet.  It's wrong, but at least we
2704          *      can figure out what it means: the password is empty.
2705          *
2706          *      Note that this means we ignore the 'data_len' field,
2707          *      if the attribute length tells us that there's no
2708          *      more data.  So the 'data_len' field may be wrong,
2709          *      but that's ok...
2710          */
2711         if (len <= 3) {
2712                 passwd[0] = 0;
2713                 *pwlen = 0;
2714                 return 0;
2715         }
2716
2717         len -= 2;               /* discount the salt */
2718
2719         /*
2720          *      Use the secret to setup the decryption digest
2721          */
2722         secretlen = strlen(secret);
2723
2724         fr_MD5Init(&context);
2725         fr_MD5Update(&context, (const uint8_t *) secret, secretlen);
2726         old = context;          /* save intermediate work */
2727
2728         /*
2729          *      Set up the initial key:
2730          *
2731          *       b(1) = MD5(secret + vector + salt)
2732          */
2733         fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
2734         fr_MD5Update(&context, passwd, 2);
2735
2736         reallen = 0;
2737         for (n = 0; n < len; n += AUTH_PASS_LEN) {
2738                 int base = 0;
2739
2740                 if (n == 0) {
2741                         fr_MD5Final(digest, &context);
2742
2743                         context = old;
2744
2745                         /*
2746                          *      A quick check: decrypt the first octet
2747                          *      of the password, which is the
2748                          *      'data_len' field.  Ensure it's sane.
2749                          */
2750                         reallen = passwd[2] ^ digest[0];
2751                         if (reallen >= len) {
2752                                 librad_log("tunnel password is too long for the attribute");
2753                                 return -1;
2754                         }
2755
2756                         fr_MD5Update(&context, passwd + 2, AUTH_PASS_LEN);
2757
2758                         base = 1;
2759                 } else {
2760                         fr_MD5Final(digest, &context);
2761
2762                         context = old;
2763                         fr_MD5Update(&context, passwd + n + 2, AUTH_PASS_LEN);
2764                 }
2765
2766                 for (i = base; i < AUTH_PASS_LEN; i++) {
2767                         passwd[n + i - 1] = passwd[n + i + 2] ^ digest[i];
2768                 }
2769         }
2770
2771         /*
2772          *      See make_tunnel_password, above.
2773          */
2774         if (reallen > 239) reallen = 239;
2775
2776         *pwlen = reallen;
2777         passwd[reallen] = 0;
2778
2779         return reallen;
2780 }
2781
2782 /*
2783  *      Encode a CHAP password
2784  *
2785  *      FIXME: might not work with Ascend because
2786  *      we use vp->length, and Ascend gear likes
2787  *      to send an extra '\0' in the string!
2788  */
2789 int rad_chap_encode(RADIUS_PACKET *packet, uint8_t *output, int id,
2790                     VALUE_PAIR *password)
2791 {
2792         int             i;
2793         uint8_t         *ptr;
2794         uint8_t         string[MAX_STRING_LEN * 2 + 1];
2795         VALUE_PAIR      *challenge;
2796
2797         /*
2798          *      Sanity check the input parameters
2799          */
2800         if ((packet == NULL) || (password == NULL)) {
2801                 return -1;
2802         }
2803
2804         /*
2805          *      Note that the password VP can be EITHER
2806          *      a User-Password attribute (from a check-item list),
2807          *      or a CHAP-Password attribute (the client asking
2808          *      the library to encode it).
2809          */
2810
2811         i = 0;
2812         ptr = string;
2813         *ptr++ = id;
2814
2815         i++;
2816         memcpy(ptr, password->vp_strvalue, password->length);
2817         ptr += password->length;
2818         i += password->length;
2819
2820         /*
2821          *      Use Chap-Challenge pair if present,
2822          *      Request-Authenticator otherwise.
2823          */
2824         challenge = pairfind(packet->vps, PW_CHAP_CHALLENGE);
2825         if (challenge) {
2826                 memcpy(ptr, challenge->vp_strvalue, challenge->length);
2827                 i += challenge->length;
2828         } else {
2829                 memcpy(ptr, packet->vector, AUTH_VECTOR_LEN);
2830                 i += AUTH_VECTOR_LEN;
2831         }
2832
2833         *output = id;
2834         fr_md5_calc((uint8_t *)output + 1, (uint8_t *)string, i);
2835
2836         return 0;
2837 }
2838
2839
2840 /*
2841  *      Seed the random number generator.
2842  *
2843  *      May be called any number of times.
2844  */
2845 void fr_rand_seed(const void *data, size_t size)
2846 {
2847         uint32_t hash;
2848
2849         /*
2850          *      Ensure that the pool is initialized.
2851          */
2852         if (!fr_rand_initialized) {
2853                 int fd;
2854
2855                 memset(&fr_rand_pool, 0, sizeof(fr_rand_pool));
2856
2857                 fd = open("/dev/urandom", O_RDONLY);
2858                 if (fd >= 0) {
2859                         size_t total;
2860                         ssize_t this;
2861
2862                         total = this = 0;
2863                         while (total < sizeof(fr_rand_pool.randrsl)) {
2864                                 this = read(fd, fr_rand_pool.randrsl,
2865                                             sizeof(fr_rand_pool.randrsl) - total);
2866                                 if ((this < 0) && (errno != EINTR)) break;
2867                                 if (this > 0) total += this;
2868                         }
2869                         close(fd);
2870                 } else {
2871                         fr_rand_pool.randrsl[0] = fd;
2872                         fr_rand_pool.randrsl[1] = time(NULL);
2873                         fr_rand_pool.randrsl[2] = errno;
2874                 }
2875
2876                 fr_randinit(&fr_rand_pool, 1);
2877                 fr_rand_pool.randcnt = 0;
2878                 fr_rand_initialized = 1;
2879         }
2880
2881         if (!data) return;
2882
2883         /*
2884          *      Hash the user data
2885          */
2886         hash = fr_rand();
2887         if (!hash) hash = fr_rand();
2888         hash = fr_hash_update(data, size, hash);
2889
2890         fr_rand_pool.randmem[fr_rand_pool.randcnt] ^= hash;
2891 }
2892
2893
2894 /*
2895  *      Return a 32-bit random number.
2896  */
2897 uint32_t fr_rand(void)
2898 {
2899         uint32_t num;
2900
2901         /*
2902          *      Ensure that the pool is initialized.
2903          */
2904         if (!fr_rand_initialized) {
2905                 fr_rand_seed(NULL, 0);
2906         }
2907
2908         num = fr_rand_pool.randrsl[fr_rand_pool.randcnt++];
2909         if (fr_rand_pool.randcnt == 256) {
2910                 fr_rand_pool.randcnt = 0;
2911                 fr_isaac(&fr_rand_pool);
2912         }
2913
2914         return num;
2915 }
2916
2917
2918 /*
2919  *      Allocate a new RADIUS_PACKET
2920  */
2921 RADIUS_PACKET *rad_alloc(int newvector)
2922 {
2923         RADIUS_PACKET   *rp;
2924
2925         if ((rp = malloc(sizeof(RADIUS_PACKET))) == NULL) {
2926                 librad_log("out of memory");
2927                 return NULL;
2928         }
2929         memset(rp, 0, sizeof(*rp));
2930         rp->id = -1;
2931         rp->offset = -1;
2932
2933         if (newvector) {
2934                 int i;
2935                 uint32_t hash, base;
2936
2937                 /*
2938                  *      Don't expose the actual contents of the random
2939                  *      pool.
2940                  */
2941                 base = fr_rand();
2942                 for (i = 0; i < AUTH_VECTOR_LEN; i += sizeof(uint32_t)) {
2943                         hash = fr_rand() ^ base;
2944                         memcpy(rp->vector + i, &hash, sizeof(hash));
2945                 }
2946         }
2947         fr_rand();              /* stir the pool again */
2948
2949         return rp;
2950 }
2951
2952 /*
2953  *      Free a RADIUS_PACKET
2954  */
2955 void rad_free(RADIUS_PACKET **radius_packet_ptr)
2956 {
2957         RADIUS_PACKET *radius_packet;
2958
2959         if (!radius_packet_ptr || !*radius_packet_ptr) return;
2960         radius_packet = *radius_packet_ptr;
2961
2962         free(radius_packet->data);
2963
2964         pairfree(&radius_packet->vps);
2965
2966         free(radius_packet);
2967
2968         *radius_packet_ptr = NULL;
2969 }