1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1998 Juniper Networks, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/types.h> 33 #include <sys/socket.h> 34 #include <sys/time.h> 35 #include <netinet/in.h> 36 #include <arpa/inet.h> 37 #ifdef WITH_SSL 38 #include <openssl/hmac.h> 39 #include <openssl/md5.h> 40 #define MD5Init MD5_Init 41 #define MD5Update MD5_Update 42 #define MD5Final MD5_Final 43 #else 44 #define MD5_DIGEST_LENGTH 16 45 #include <md5.h> 46 #endif 47 48 #define MAX_FIELDS 7 49 50 /* We need the MPPE_KEY_LEN define */ 51 #include <netgraph/ng_mppc.h> 52 53 #include <errno.h> 54 #include <netdb.h> 55 #include <stdarg.h> 56 #include <stddef.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <unistd.h> 61 62 #include "radlib_private.h" 63 64 static void clear_password(struct rad_handle *); 65 static void generr(struct rad_handle *, const char *, ...) 66 __printflike(2, 3); 67 static void insert_scrambled_password(struct rad_handle *, int); 68 static void insert_request_authenticator(struct rad_handle *, int); 69 static void insert_message_authenticator(struct rad_handle *, int); 70 static int is_valid_response(struct rad_handle *, int, 71 const struct sockaddr_in *); 72 static int put_password_attr(struct rad_handle *, int, 73 const void *, size_t); 74 static int put_raw_attr(struct rad_handle *, int, 75 const void *, size_t); 76 static int split(char *, char *[], int, char *, size_t); 77 78 static void 79 clear_password(struct rad_handle *h) 80 { 81 if (h->pass_len != 0) { 82 memset(h->pass, 0, h->pass_len); 83 h->pass_len = 0; 84 } 85 h->pass_pos = 0; 86 } 87 88 static void 89 generr(struct rad_handle *h, const char *format, ...) 90 { 91 va_list ap; 92 93 va_start(ap, format); 94 vsnprintf(h->errmsg, ERRSIZE, format, ap); 95 va_end(ap); 96 } 97 98 static void 99 insert_scrambled_password(struct rad_handle *h, int srv) 100 { 101 MD5_CTX ctx; 102 unsigned char md5[MD5_DIGEST_LENGTH]; 103 const struct rad_server *srvp; 104 int padded_len; 105 int pos; 106 107 srvp = &h->servers[srv]; 108 padded_len = h->pass_len == 0 ? 16 : (h->pass_len+15) & ~0xf; 109 110 memcpy(md5, &h->out[POS_AUTH], LEN_AUTH); 111 for (pos = 0; pos < padded_len; pos += 16) { 112 int i; 113 114 /* Calculate the new scrambler */ 115 MD5Init(&ctx); 116 MD5Update(&ctx, srvp->secret, strlen(srvp->secret)); 117 MD5Update(&ctx, md5, 16); 118 MD5Final(md5, &ctx); 119 120 /* 121 * Mix in the current chunk of the password, and copy 122 * the result into the right place in the request. Also 123 * modify the scrambler in place, since we will use this 124 * in calculating the scrambler for next time. 125 */ 126 for (i = 0; i < 16; i++) 127 h->out[h->pass_pos + pos + i] = 128 md5[i] ^= h->pass[pos + i]; 129 } 130 } 131 132 static void 133 insert_request_authenticator(struct rad_handle *h, int resp) 134 { 135 MD5_CTX ctx; 136 const struct rad_server *srvp; 137 138 srvp = &h->servers[h->srv]; 139 140 /* Create the request authenticator */ 141 MD5Init(&ctx); 142 MD5Update(&ctx, &h->out[POS_CODE], POS_AUTH - POS_CODE); 143 if (resp) 144 MD5Update(&ctx, &h->in[POS_AUTH], LEN_AUTH); 145 else 146 MD5Update(&ctx, &h->out[POS_AUTH], LEN_AUTH); 147 MD5Update(&ctx, &h->out[POS_ATTRS], h->out_len - POS_ATTRS); 148 MD5Update(&ctx, srvp->secret, strlen(srvp->secret)); 149 MD5Final(&h->out[POS_AUTH], &ctx); 150 } 151 152 static void 153 insert_message_authenticator(struct rad_handle *h, int resp) 154 { 155 #ifdef WITH_SSL 156 u_char md[EVP_MAX_MD_SIZE]; 157 u_int md_len; 158 const struct rad_server *srvp; 159 HMAC_CTX ctx; 160 srvp = &h->servers[h->srv]; 161 162 if (h->authentic_pos != 0) { 163 HMAC_CTX_init(&ctx); 164 HMAC_Init(&ctx, srvp->secret, strlen(srvp->secret), EVP_md5()); 165 HMAC_Update(&ctx, &h->out[POS_CODE], POS_AUTH - POS_CODE); 166 if (resp) 167 HMAC_Update(&ctx, &h->in[POS_AUTH], LEN_AUTH); 168 else 169 HMAC_Update(&ctx, &h->out[POS_AUTH], LEN_AUTH); 170 HMAC_Update(&ctx, &h->out[POS_ATTRS], 171 h->out_len - POS_ATTRS); 172 HMAC_Final(&ctx, md, &md_len); 173 HMAC_CTX_cleanup(&ctx); 174 HMAC_cleanup(&ctx); 175 memcpy(&h->out[h->authentic_pos + 2], md, md_len); 176 } 177 #endif 178 } 179 180 /* 181 * Return true if the current response is valid for a request to the 182 * specified server. 183 */ 184 static int 185 is_valid_response(struct rad_handle *h, int srv, 186 const struct sockaddr_in *from) 187 { 188 MD5_CTX ctx; 189 unsigned char md5[MD5_DIGEST_LENGTH]; 190 const struct rad_server *srvp; 191 int len; 192 #ifdef WITH_SSL 193 HMAC_CTX hctx; 194 u_char resp[MSGSIZE], md[EVP_MAX_MD_SIZE]; 195 u_int md_len; 196 int pos; 197 #endif 198 199 srvp = &h->servers[srv]; 200 201 /* Check the source address */ 202 if (from->sin_family != srvp->addr.sin_family || 203 from->sin_addr.s_addr != srvp->addr.sin_addr.s_addr || 204 from->sin_port != srvp->addr.sin_port) 205 return 0; 206 207 /* Check the message length */ 208 if (h->in_len < POS_ATTRS) 209 return 0; 210 len = h->in[POS_LENGTH] << 8 | h->in[POS_LENGTH+1]; 211 if (len > h->in_len) 212 return 0; 213 214 /* Check the response authenticator */ 215 MD5Init(&ctx); 216 MD5Update(&ctx, &h->in[POS_CODE], POS_AUTH - POS_CODE); 217 MD5Update(&ctx, &h->out[POS_AUTH], LEN_AUTH); 218 MD5Update(&ctx, &h->in[POS_ATTRS], len - POS_ATTRS); 219 MD5Update(&ctx, srvp->secret, strlen(srvp->secret)); 220 MD5Final(md5, &ctx); 221 if (memcmp(&h->in[POS_AUTH], md5, sizeof md5) != 0) 222 return 0; 223 224 #ifdef WITH_SSL 225 /* 226 * For non accounting responses check the message authenticator, 227 * if any. 228 */ 229 if (h->in[POS_CODE] != RAD_ACCOUNTING_RESPONSE) { 230 231 memcpy(resp, h->in, MSGSIZE); 232 pos = POS_ATTRS; 233 234 /* Search and verify the Message-Authenticator */ 235 while (pos < len - 2) { 236 237 if (h->in[pos] == RAD_MESSAGE_AUTHENTIC) { 238 /* zero fill the Message-Authenticator */ 239 memset(&resp[pos + 2], 0, MD5_DIGEST_LENGTH); 240 241 HMAC_CTX_init(&hctx); 242 HMAC_Init(&hctx, srvp->secret, 243 strlen(srvp->secret), EVP_md5()); 244 HMAC_Update(&hctx, &h->in[POS_CODE], 245 POS_AUTH - POS_CODE); 246 HMAC_Update(&hctx, &h->out[POS_AUTH], 247 LEN_AUTH); 248 HMAC_Update(&hctx, &resp[POS_ATTRS], 249 h->in_len - POS_ATTRS); 250 HMAC_Final(&hctx, md, &md_len); 251 HMAC_CTX_cleanup(&hctx); 252 HMAC_cleanup(&hctx); 253 if (memcmp(md, &h->in[pos + 2], 254 MD5_DIGEST_LENGTH) != 0) 255 return 0; 256 break; 257 } 258 pos += h->in[pos + 1]; 259 } 260 } 261 #endif 262 return 1; 263 } 264 265 /* 266 * Return true if the current request is valid for the specified server. 267 */ 268 static int 269 is_valid_request(struct rad_handle *h) 270 { 271 MD5_CTX ctx; 272 unsigned char md5[MD5_DIGEST_LENGTH]; 273 const struct rad_server *srvp; 274 int len; 275 #ifdef WITH_SSL 276 HMAC_CTX hctx; 277 u_char resp[MSGSIZE], md[EVP_MAX_MD_SIZE]; 278 u_int md_len; 279 int pos; 280 #endif 281 282 srvp = &h->servers[h->srv]; 283 284 /* Check the message length */ 285 if (h->in_len < POS_ATTRS) 286 return (0); 287 len = h->in[POS_LENGTH] << 8 | h->in[POS_LENGTH+1]; 288 if (len > h->in_len) 289 return (0); 290 291 if (h->in[POS_CODE] != RAD_ACCESS_REQUEST) { 292 uint32_t zeroes[4] = { 0, 0, 0, 0 }; 293 /* Check the request authenticator */ 294 MD5Init(&ctx); 295 MD5Update(&ctx, &h->in[POS_CODE], POS_AUTH - POS_CODE); 296 MD5Update(&ctx, zeroes, LEN_AUTH); 297 MD5Update(&ctx, &h->in[POS_ATTRS], len - POS_ATTRS); 298 MD5Update(&ctx, srvp->secret, strlen(srvp->secret)); 299 MD5Final(md5, &ctx); 300 if (memcmp(&h->in[POS_AUTH], md5, sizeof md5) != 0) 301 return (0); 302 } 303 304 #ifdef WITH_SSL 305 /* Search and verify the Message-Authenticator */ 306 pos = POS_ATTRS; 307 while (pos < len - 2) { 308 if (h->in[pos] == RAD_MESSAGE_AUTHENTIC) { 309 memcpy(resp, h->in, MSGSIZE); 310 /* zero fill the Request-Authenticator */ 311 if (h->in[POS_CODE] != RAD_ACCESS_REQUEST) 312 memset(&resp[POS_AUTH], 0, LEN_AUTH); 313 /* zero fill the Message-Authenticator */ 314 memset(&resp[pos + 2], 0, MD5_DIGEST_LENGTH); 315 316 HMAC_CTX_init(&hctx); 317 HMAC_Init(&hctx, srvp->secret, 318 strlen(srvp->secret), EVP_md5()); 319 HMAC_Update(&hctx, resp, h->in_len); 320 HMAC_Final(&hctx, md, &md_len); 321 HMAC_CTX_cleanup(&hctx); 322 HMAC_cleanup(&hctx); 323 if (memcmp(md, &h->in[pos + 2], 324 MD5_DIGEST_LENGTH) != 0) 325 return (0); 326 break; 327 } 328 pos += h->in[pos + 1]; 329 } 330 #endif 331 return (1); 332 } 333 334 static int 335 put_password_attr(struct rad_handle *h, int type, const void *value, size_t len) 336 { 337 int padded_len; 338 int pad_len; 339 340 if (h->pass_pos != 0) { 341 generr(h, "Multiple User-Password attributes specified"); 342 return -1; 343 } 344 if (len > PASSSIZE) 345 len = PASSSIZE; 346 padded_len = len == 0 ? 16 : (len+15) & ~0xf; 347 pad_len = padded_len - len; 348 349 /* 350 * Put in a place-holder attribute containing all zeros, and 351 * remember where it is so we can fill it in later. 352 */ 353 clear_password(h); 354 put_raw_attr(h, type, h->pass, padded_len); 355 h->pass_pos = h->out_len - padded_len; 356 357 /* Save the cleartext password, padded as necessary */ 358 memcpy(h->pass, value, len); 359 h->pass_len = len; 360 memset(h->pass + len, 0, pad_len); 361 return 0; 362 } 363 364 static int 365 put_raw_attr(struct rad_handle *h, int type, const void *value, size_t len) 366 { 367 if (len > 253) { 368 generr(h, "Attribute too long"); 369 return -1; 370 } 371 if (h->out_len + 2 + len > MSGSIZE) { 372 generr(h, "Maximum message length exceeded"); 373 return -1; 374 } 375 h->out[h->out_len++] = type; 376 h->out[h->out_len++] = len + 2; 377 memcpy(&h->out[h->out_len], value, len); 378 h->out_len += len; 379 return 0; 380 } 381 382 int 383 rad_add_server(struct rad_handle *h, const char *host, int port, 384 const char *secret, int timeout, int tries) 385 { 386 struct in_addr bindto; 387 bindto.s_addr = INADDR_ANY; 388 389 return rad_add_server_ex(h, host, port, secret, timeout, tries, 390 DEAD_TIME, &bindto); 391 } 392 393 int 394 rad_add_server_ex(struct rad_handle *h, const char *host, int port, 395 const char *secret, int timeout, int tries, int dead_time, 396 struct in_addr *bindto) 397 { 398 struct rad_server *srvp; 399 400 if (h->num_servers >= MAXSERVERS) { 401 generr(h, "Too many RADIUS servers specified"); 402 return -1; 403 } 404 srvp = &h->servers[h->num_servers]; 405 406 memset(&srvp->addr, 0, sizeof srvp->addr); 407 srvp->addr.sin_len = sizeof srvp->addr; 408 srvp->addr.sin_family = AF_INET; 409 if (!inet_aton(host, &srvp->addr.sin_addr)) { 410 struct hostent *hent; 411 412 if ((hent = gethostbyname(host)) == NULL) { 413 generr(h, "%s: host not found", host); 414 return -1; 415 } 416 memcpy(&srvp->addr.sin_addr, hent->h_addr, 417 sizeof srvp->addr.sin_addr); 418 } 419 if (port != 0) 420 srvp->addr.sin_port = htons((u_short)port); 421 else { 422 struct servent *sent; 423 424 if (h->type == RADIUS_AUTH) 425 srvp->addr.sin_port = 426 (sent = getservbyname("radius", "udp")) != NULL ? 427 sent->s_port : htons(RADIUS_PORT); 428 else 429 srvp->addr.sin_port = 430 (sent = getservbyname("radacct", "udp")) != NULL ? 431 sent->s_port : htons(RADACCT_PORT); 432 } 433 if ((srvp->secret = strdup(secret)) == NULL) { 434 generr(h, "Out of memory"); 435 return -1; 436 } 437 srvp->timeout = timeout; 438 srvp->max_tries = tries; 439 srvp->num_tries = 0; 440 srvp->is_dead = 0; 441 srvp->dead_time = dead_time; 442 srvp->next_probe = 0; 443 srvp->bindto = bindto->s_addr; 444 h->num_servers++; 445 return 0; 446 } 447 448 void 449 rad_close(struct rad_handle *h) 450 { 451 int srv; 452 453 if (h->fd != -1) 454 close(h->fd); 455 for (srv = 0; srv < h->num_servers; srv++) { 456 memset(h->servers[srv].secret, 0, 457 strlen(h->servers[srv].secret)); 458 free(h->servers[srv].secret); 459 } 460 clear_password(h); 461 free(h); 462 } 463 464 void 465 rad_bind_to(struct rad_handle *h, in_addr_t addr) 466 { 467 468 h->bindto = addr; 469 } 470 471 int 472 rad_config(struct rad_handle *h, const char *path) 473 { 474 FILE *fp; 475 char buf[MAXCONFLINE]; 476 int linenum; 477 int retval; 478 479 if (path == NULL) 480 path = PATH_RADIUS_CONF; 481 if ((fp = fopen(path, "r")) == NULL) { 482 generr(h, "Cannot open \"%s\": %s", path, strerror(errno)); 483 return -1; 484 } 485 retval = 0; 486 linenum = 0; 487 while (fgets(buf, sizeof buf, fp) != NULL) { 488 int len; 489 char *fields[MAX_FIELDS]; 490 int nfields; 491 char msg[ERRSIZE]; 492 char *type; 493 char *host, *res; 494 char *port_str; 495 char *secret; 496 char *timeout_str; 497 char *maxtries_str; 498 char *dead_time_str; 499 char *bindto_str; 500 char *end; 501 char *wanttype; 502 unsigned long timeout; 503 unsigned long maxtries; 504 unsigned long dead_time; 505 int port; 506 struct in_addr bindto; 507 int i; 508 509 linenum++; 510 len = strlen(buf); 511 /* We know len > 0, else fgets would have returned NULL. */ 512 if (buf[len - 1] != '\n') { 513 if (len == sizeof buf - 1) 514 generr(h, "%s:%d: line too long", path, 515 linenum); 516 else 517 generr(h, "%s:%d: missing newline", path, 518 linenum); 519 retval = -1; 520 break; 521 } 522 buf[len - 1] = '\0'; 523 524 /* Extract the fields from the line. */ 525 nfields = split(buf, fields, MAX_FIELDS, msg, sizeof msg); 526 if (nfields == -1) { 527 generr(h, "%s:%d: %s", path, linenum, msg); 528 retval = -1; 529 break; 530 } 531 if (nfields == 0) 532 continue; 533 /* 534 * The first field should contain "auth" or "acct" for 535 * authentication or accounting, respectively. But older 536 * versions of the file didn't have that field. Default 537 * it to "auth" for backward compatibility. 538 */ 539 if (strcmp(fields[0], "auth") != 0 && 540 strcmp(fields[0], "acct") != 0) { 541 if (nfields >= MAX_FIELDS) { 542 generr(h, "%s:%d: invalid service type", path, 543 linenum); 544 retval = -1; 545 break; 546 } 547 nfields++; 548 for (i = nfields; --i > 0; ) 549 fields[i] = fields[i - 1]; 550 fields[0] = "auth"; 551 } 552 if (nfields < 3) { 553 generr(h, "%s:%d: missing shared secret", path, 554 linenum); 555 retval = -1; 556 break; 557 } 558 type = fields[0]; 559 host = fields[1]; 560 secret = fields[2]; 561 timeout_str = fields[3]; 562 maxtries_str = fields[4]; 563 dead_time_str = fields[5]; 564 bindto_str = fields[6]; 565 566 /* Ignore the line if it is for the wrong service type. */ 567 wanttype = h->type == RADIUS_AUTH ? "auth" : "acct"; 568 if (strcmp(type, wanttype) != 0) 569 continue; 570 571 /* Parse and validate the fields. */ 572 res = host; 573 host = strsep(&res, ":"); 574 port_str = strsep(&res, ":"); 575 if (port_str != NULL) { 576 port = strtoul(port_str, &end, 10); 577 if (*end != '\0') { 578 generr(h, "%s:%d: invalid port", path, 579 linenum); 580 retval = -1; 581 break; 582 } 583 } else 584 port = 0; 585 if (timeout_str != NULL) { 586 timeout = strtoul(timeout_str, &end, 10); 587 if (*end != '\0') { 588 generr(h, "%s:%d: invalid timeout", path, 589 linenum); 590 retval = -1; 591 break; 592 } 593 } else 594 timeout = TIMEOUT; 595 if (maxtries_str != NULL) { 596 maxtries = strtoul(maxtries_str, &end, 10); 597 if (*end != '\0') { 598 generr(h, "%s:%d: invalid maxtries", path, 599 linenum); 600 retval = -1; 601 break; 602 } 603 } else 604 maxtries = MAXTRIES; 605 606 if (dead_time_str != NULL) { 607 dead_time = strtoul(dead_time_str, &end, 10); 608 if (*end != '\0') { 609 generr(h, "%s:%d: invalid dead_time", path, 610 linenum); 611 retval = -1; 612 break; 613 } 614 } else 615 dead_time = DEAD_TIME; 616 617 if (bindto_str != NULL) { 618 bindto.s_addr = inet_addr(bindto_str); 619 if (bindto.s_addr == INADDR_NONE) { 620 generr(h, "%s:%d: invalid bindto", path, 621 linenum); 622 retval = -1; 623 break; 624 } 625 } else 626 bindto.s_addr = INADDR_ANY; 627 628 if (rad_add_server_ex(h, host, port, secret, timeout, maxtries, 629 dead_time, &bindto) == -1) { 630 strcpy(msg, h->errmsg); 631 generr(h, "%s:%d: %s", path, linenum, msg); 632 retval = -1; 633 break; 634 } 635 } 636 /* Clear out the buffer to wipe a possible copy of a shared secret */ 637 memset(buf, 0, sizeof buf); 638 fclose(fp); 639 return retval; 640 } 641 642 /* 643 * rad_init_send_request() must have previously been called. 644 * Returns: 645 * 0 The application should select on *fd with a timeout of tv before 646 * calling rad_continue_send_request again. 647 * < 0 Failure 648 * > 0 Success 649 */ 650 int 651 rad_continue_send_request(struct rad_handle *h, int selected, int *fd, 652 struct timeval *tv) 653 { 654 int n, cur_srv; 655 time_t now; 656 struct sockaddr_in sin; 657 658 if (h->type == RADIUS_SERVER) { 659 generr(h, "denied function call"); 660 return (-1); 661 } 662 if (selected) { 663 struct sockaddr_in from; 664 socklen_t fromlen; 665 666 fromlen = sizeof from; 667 h->in_len = recvfrom(h->fd, h->in, 668 MSGSIZE, MSG_WAITALL, (struct sockaddr *)&from, &fromlen); 669 if (h->in_len == -1) { 670 generr(h, "recvfrom: %s", strerror(errno)); 671 return -1; 672 } 673 if (is_valid_response(h, h->srv, &from)) { 674 h->in_len = h->in[POS_LENGTH] << 8 | 675 h->in[POS_LENGTH+1]; 676 h->in_pos = POS_ATTRS; 677 return h->in[POS_CODE]; 678 } 679 } 680 681 /* 682 * Scan round-robin to the next server that has some 683 * tries left. There is guaranteed to be one, or we 684 * would have exited this loop by now. 685 */ 686 cur_srv = h->srv; 687 now = time(NULL); 688 if (h->servers[h->srv].num_tries >= h->servers[h->srv].max_tries) { 689 /* Set next probe time for this server */ 690 if (h->servers[h->srv].dead_time) { 691 h->servers[h->srv].is_dead = 1; 692 h->servers[h->srv].next_probe = now + 693 h->servers[h->srv].dead_time; 694 } 695 do { 696 h->srv++; 697 if (h->srv >= h->num_servers) 698 h->srv = 0; 699 if (h->servers[h->srv].is_dead == 0) 700 break; 701 if (h->servers[h->srv].dead_time && 702 h->servers[h->srv].next_probe <= now) { 703 h->servers[h->srv].is_dead = 0; 704 h->servers[h->srv].num_tries = 0; 705 break; 706 } 707 } while (h->srv != cur_srv); 708 709 if (h->srv == cur_srv) { 710 generr(h, "No valid RADIUS responses received"); 711 return (-1); 712 } 713 } 714 715 /* Rebind */ 716 if (h->bindto != h->servers[h->srv].bindto) { 717 h->bindto = h->servers[h->srv].bindto; 718 close(h->fd); 719 if ((h->fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) { 720 generr(h, "Cannot create socket: %s", strerror(errno)); 721 return -1; 722 } 723 memset(&sin, 0, sizeof sin); 724 sin.sin_len = sizeof sin; 725 sin.sin_family = AF_INET; 726 sin.sin_addr.s_addr = h->bindto; 727 sin.sin_port = 0; 728 if (bind(h->fd, (const struct sockaddr *)&sin, 729 sizeof sin) == -1) { 730 generr(h, "bind: %s", strerror(errno)); 731 close(h->fd); 732 h->fd = -1; 733 return (-1); 734 } 735 } 736 737 if (h->out[POS_CODE] == RAD_ACCESS_REQUEST) { 738 /* Insert the scrambled password into the request */ 739 if (h->pass_pos != 0) 740 insert_scrambled_password(h, h->srv); 741 } 742 insert_message_authenticator(h, 0); 743 744 if (h->out[POS_CODE] != RAD_ACCESS_REQUEST) { 745 /* Insert the request authenticator into the request */ 746 memset(&h->out[POS_AUTH], 0, LEN_AUTH); 747 insert_request_authenticator(h, 0); 748 } 749 750 /* Send the request */ 751 n = sendto(h->fd, h->out, h->out_len, 0, 752 (const struct sockaddr *)&h->servers[h->srv].addr, 753 sizeof h->servers[h->srv].addr); 754 if (n != h->out_len) 755 tv->tv_sec = 1; /* Do not wait full timeout if send failed. */ 756 else 757 tv->tv_sec = h->servers[h->srv].timeout; 758 h->servers[h->srv].num_tries++; 759 tv->tv_usec = 0; 760 *fd = h->fd; 761 762 return 0; 763 } 764 765 int 766 rad_receive_request(struct rad_handle *h) 767 { 768 struct sockaddr_in from; 769 socklen_t fromlen; 770 int n; 771 772 if (h->type != RADIUS_SERVER) { 773 generr(h, "denied function call"); 774 return (-1); 775 } 776 h->srv = -1; 777 fromlen = sizeof(from); 778 h->in_len = recvfrom(h->fd, h->in, 779 MSGSIZE, MSG_WAITALL, (struct sockaddr *)&from, &fromlen); 780 if (h->in_len == -1) { 781 generr(h, "recvfrom: %s", strerror(errno)); 782 return (-1); 783 } 784 for (n = 0; n < h->num_servers; n++) { 785 if (h->servers[n].addr.sin_addr.s_addr == from.sin_addr.s_addr) { 786 h->servers[n].addr.sin_port = from.sin_port; 787 h->srv = n; 788 break; 789 } 790 } 791 if (h->srv == -1) 792 return (-2); 793 if (is_valid_request(h)) { 794 h->in_len = h->in[POS_LENGTH] << 8 | 795 h->in[POS_LENGTH+1]; 796 h->in_pos = POS_ATTRS; 797 return (h->in[POS_CODE]); 798 } 799 return (-3); 800 } 801 802 int 803 rad_send_response(struct rad_handle *h) 804 { 805 int n; 806 807 if (h->type != RADIUS_SERVER) { 808 generr(h, "denied function call"); 809 return (-1); 810 } 811 /* Fill in the length field in the message */ 812 h->out[POS_LENGTH] = h->out_len >> 8; 813 h->out[POS_LENGTH+1] = h->out_len; 814 815 insert_message_authenticator(h, 816 (h->in[POS_CODE] == RAD_ACCESS_REQUEST) ? 1 : 0); 817 insert_request_authenticator(h, 1); 818 819 /* Send the request */ 820 n = sendto(h->fd, h->out, h->out_len, 0, 821 (const struct sockaddr *)&h->servers[h->srv].addr, 822 sizeof h->servers[h->srv].addr); 823 if (n != h->out_len) { 824 if (n == -1) 825 generr(h, "sendto: %s", strerror(errno)); 826 else 827 generr(h, "sendto: short write"); 828 return -1; 829 } 830 831 return 0; 832 } 833 834 int 835 rad_create_request(struct rad_handle *h, int code) 836 { 837 int i; 838 839 if (h->type == RADIUS_SERVER) { 840 generr(h, "denied function call"); 841 return (-1); 842 } 843 if (h->num_servers == 0) { 844 generr(h, "No RADIUS servers specified"); 845 return (-1); 846 } 847 h->out[POS_CODE] = code; 848 h->out[POS_IDENT] = ++h->ident; 849 if (code == RAD_ACCESS_REQUEST) { 850 /* Create a random authenticator */ 851 for (i = 0; i < LEN_AUTH; i += 2) { 852 long r; 853 r = random(); 854 h->out[POS_AUTH+i] = (u_char)r; 855 h->out[POS_AUTH+i+1] = (u_char)(r >> 8); 856 } 857 } else 858 memset(&h->out[POS_AUTH], 0, LEN_AUTH); 859 h->out_len = POS_ATTRS; 860 clear_password(h); 861 h->authentic_pos = 0; 862 h->out_created = 1; 863 return 0; 864 } 865 866 int 867 rad_create_response(struct rad_handle *h, int code) 868 { 869 870 if (h->type != RADIUS_SERVER) { 871 generr(h, "denied function call"); 872 return (-1); 873 } 874 h->out[POS_CODE] = code; 875 h->out[POS_IDENT] = h->in[POS_IDENT]; 876 memset(&h->out[POS_AUTH], 0, LEN_AUTH); 877 h->out_len = POS_ATTRS; 878 clear_password(h); 879 h->authentic_pos = 0; 880 h->out_created = 1; 881 return 0; 882 } 883 884 struct in_addr 885 rad_cvt_addr(const void *data) 886 { 887 struct in_addr value; 888 889 memcpy(&value.s_addr, data, sizeof value.s_addr); 890 return value; 891 } 892 893 struct in6_addr 894 rad_cvt_addr6(const void *data) 895 { 896 struct in6_addr value; 897 898 memcpy(&value.s6_addr, data, sizeof value.s6_addr); 899 return value; 900 } 901 902 u_int32_t 903 rad_cvt_int(const void *data) 904 { 905 u_int32_t value; 906 907 memcpy(&value, data, sizeof value); 908 return ntohl(value); 909 } 910 911 char * 912 rad_cvt_string(const void *data, size_t len) 913 { 914 char *s; 915 916 s = malloc(len + 1); 917 if (s != NULL) { 918 memcpy(s, data, len); 919 s[len] = '\0'; 920 } 921 return s; 922 } 923 924 /* 925 * Returns the attribute type. If none are left, returns 0. On failure, 926 * returns -1. 927 */ 928 int 929 rad_get_attr(struct rad_handle *h, const void **value, size_t *len) 930 { 931 int type; 932 933 if (h->in_pos >= h->in_len) 934 return 0; 935 if (h->in_pos + 2 > h->in_len) { 936 generr(h, "Malformed attribute in response"); 937 return -1; 938 } 939 type = h->in[h->in_pos++]; 940 *len = h->in[h->in_pos++] - 2; 941 if (h->in_pos + (int)*len > h->in_len) { 942 generr(h, "Malformed attribute in response"); 943 return -1; 944 } 945 *value = &h->in[h->in_pos]; 946 h->in_pos += *len; 947 return type; 948 } 949 950 /* 951 * Returns -1 on error, 0 to indicate no event and >0 for success 952 */ 953 int 954 rad_init_send_request(struct rad_handle *h, int *fd, struct timeval *tv) 955 { 956 int srv; 957 time_t now; 958 struct sockaddr_in sin; 959 960 if (h->type == RADIUS_SERVER) { 961 generr(h, "denied function call"); 962 return (-1); 963 } 964 /* Make sure we have a socket to use */ 965 if (h->fd == -1) { 966 if ((h->fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) { 967 generr(h, "Cannot create socket: %s", strerror(errno)); 968 return -1; 969 } 970 memset(&sin, 0, sizeof sin); 971 sin.sin_len = sizeof sin; 972 sin.sin_family = AF_INET; 973 sin.sin_addr.s_addr = h->bindto; 974 sin.sin_port = htons(0); 975 if (bind(h->fd, (const struct sockaddr *)&sin, 976 sizeof sin) == -1) { 977 generr(h, "bind: %s", strerror(errno)); 978 close(h->fd); 979 h->fd = -1; 980 return -1; 981 } 982 } 983 984 if (h->out[POS_CODE] != RAD_ACCESS_REQUEST) { 985 /* Make sure no password given */ 986 if (h->pass_pos || h->chap_pass) { 987 generr(h, "User or Chap Password" 988 " in accounting request"); 989 return -1; 990 } 991 } else { 992 if (h->eap_msg == 0) { 993 /* Make sure the user gave us a password */ 994 if (h->pass_pos == 0 && !h->chap_pass) { 995 generr(h, "No User or Chap Password" 996 " attributes given"); 997 return -1; 998 } 999 if (h->pass_pos != 0 && h->chap_pass) { 1000 generr(h, "Both User and Chap Password" 1001 " attributes given"); 1002 return -1; 1003 } 1004 } 1005 } 1006 1007 /* Fill in the length field in the message */ 1008 h->out[POS_LENGTH] = h->out_len >> 8; 1009 h->out[POS_LENGTH+1] = h->out_len; 1010 1011 h->srv = 0; 1012 now = time(NULL); 1013 for (srv = 0; srv < h->num_servers; srv++) 1014 h->servers[srv].num_tries = 0; 1015 /* Find a first good server. */ 1016 for (srv = 0; srv < h->num_servers; srv++) { 1017 if (h->servers[srv].is_dead == 0) 1018 break; 1019 if (h->servers[srv].dead_time && 1020 h->servers[srv].next_probe <= now) { 1021 h->servers[srv].is_dead = 0; 1022 break; 1023 } 1024 h->srv++; 1025 } 1026 1027 /* If all servers was dead on the last probe, try from beginning */ 1028 if (h->srv == h->num_servers) { 1029 for (srv = 0; srv < h->num_servers; srv++) { 1030 h->servers[srv].is_dead = 0; 1031 h->servers[srv].next_probe = 0; 1032 } 1033 h->srv = 0; 1034 } 1035 1036 return rad_continue_send_request(h, 0, fd, tv); 1037 } 1038 1039 /* 1040 * Create and initialize a rad_handle structure, and return it to the 1041 * caller. Can fail only if the necessary memory cannot be allocated. 1042 * In that case, it returns NULL. 1043 */ 1044 struct rad_handle * 1045 rad_auth_open(void) 1046 { 1047 struct rad_handle *h; 1048 1049 h = (struct rad_handle *)malloc(sizeof(struct rad_handle)); 1050 if (h != NULL) { 1051 srandomdev(); 1052 h->fd = -1; 1053 h->num_servers = 0; 1054 h->ident = random(); 1055 h->errmsg[0] = '\0'; 1056 memset(h->pass, 0, sizeof h->pass); 1057 h->pass_len = 0; 1058 h->pass_pos = 0; 1059 h->chap_pass = 0; 1060 h->authentic_pos = 0; 1061 h->type = RADIUS_AUTH; 1062 h->out_created = 0; 1063 h->eap_msg = 0; 1064 h->bindto = INADDR_ANY; 1065 } 1066 return h; 1067 } 1068 1069 struct rad_handle * 1070 rad_acct_open(void) 1071 { 1072 struct rad_handle *h; 1073 1074 h = rad_open(); 1075 if (h != NULL) 1076 h->type = RADIUS_ACCT; 1077 return h; 1078 } 1079 1080 struct rad_handle * 1081 rad_server_open(int fd) 1082 { 1083 struct rad_handle *h; 1084 1085 h = rad_open(); 1086 if (h != NULL) { 1087 h->type = RADIUS_SERVER; 1088 h->fd = fd; 1089 } 1090 return h; 1091 } 1092 1093 struct rad_handle * 1094 rad_open(void) 1095 { 1096 return rad_auth_open(); 1097 } 1098 1099 int 1100 rad_put_addr(struct rad_handle *h, int type, struct in_addr addr) 1101 { 1102 return rad_put_attr(h, type, &addr.s_addr, sizeof addr.s_addr); 1103 } 1104 1105 int 1106 rad_put_addr6(struct rad_handle *h, int type, struct in6_addr addr) 1107 { 1108 1109 return rad_put_attr(h, type, &addr.s6_addr, sizeof addr.s6_addr); 1110 } 1111 1112 int 1113 rad_put_attr(struct rad_handle *h, int type, const void *value, size_t len) 1114 { 1115 int result; 1116 1117 if (!h->out_created) { 1118 generr(h, "Please call rad_create_request()" 1119 " before putting attributes"); 1120 return -1; 1121 } 1122 1123 if (h->out[POS_CODE] == RAD_ACCOUNTING_REQUEST) { 1124 if (type == RAD_EAP_MESSAGE) { 1125 generr(h, "EAP-Message attribute is not valid" 1126 " in accounting requests"); 1127 return -1; 1128 } 1129 } 1130 1131 /* 1132 * When proxying EAP Messages, the Message Authenticator 1133 * MUST be present; see RFC 3579. 1134 */ 1135 if (type == RAD_EAP_MESSAGE) { 1136 if (rad_put_message_authentic(h) == -1) 1137 return -1; 1138 } 1139 1140 if (type == RAD_USER_PASSWORD) { 1141 result = put_password_attr(h, type, value, len); 1142 } else if (type == RAD_MESSAGE_AUTHENTIC) { 1143 result = rad_put_message_authentic(h); 1144 } else { 1145 result = put_raw_attr(h, type, value, len); 1146 if (result == 0) { 1147 if (type == RAD_CHAP_PASSWORD) 1148 h->chap_pass = 1; 1149 else if (type == RAD_EAP_MESSAGE) 1150 h->eap_msg = 1; 1151 } 1152 } 1153 1154 return result; 1155 } 1156 1157 int 1158 rad_put_int(struct rad_handle *h, int type, u_int32_t value) 1159 { 1160 u_int32_t nvalue; 1161 1162 nvalue = htonl(value); 1163 return rad_put_attr(h, type, &nvalue, sizeof nvalue); 1164 } 1165 1166 int 1167 rad_put_string(struct rad_handle *h, int type, const char *str) 1168 { 1169 return rad_put_attr(h, type, str, strlen(str)); 1170 } 1171 1172 int 1173 rad_put_message_authentic(struct rad_handle *h) 1174 { 1175 #ifdef WITH_SSL 1176 u_char md_zero[MD5_DIGEST_LENGTH]; 1177 1178 if (h->out[POS_CODE] == RAD_ACCOUNTING_REQUEST) { 1179 generr(h, "Message-Authenticator is not valid" 1180 " in accounting requests"); 1181 return -1; 1182 } 1183 1184 if (h->authentic_pos == 0) { 1185 h->authentic_pos = h->out_len; 1186 memset(md_zero, 0, sizeof(md_zero)); 1187 return (put_raw_attr(h, RAD_MESSAGE_AUTHENTIC, md_zero, 1188 sizeof(md_zero))); 1189 } 1190 return 0; 1191 #else 1192 generr(h, "Message Authenticator not supported," 1193 " please recompile libradius with SSL support"); 1194 return -1; 1195 #endif 1196 } 1197 1198 /* 1199 * Returns the response type code on success, or -1 on failure. 1200 */ 1201 int 1202 rad_send_request(struct rad_handle *h) 1203 { 1204 struct timeval timelimit; 1205 struct timeval tv; 1206 int fd; 1207 int n; 1208 1209 n = rad_init_send_request(h, &fd, &tv); 1210 1211 if (n != 0) 1212 return n; 1213 1214 gettimeofday(&timelimit, NULL); 1215 timeradd(&tv, &timelimit, &timelimit); 1216 1217 for ( ; ; ) { 1218 fd_set readfds; 1219 1220 FD_ZERO(&readfds); 1221 FD_SET(fd, &readfds); 1222 1223 n = select(fd + 1, &readfds, NULL, NULL, &tv); 1224 1225 if (n == -1) { 1226 generr(h, "select: %s", strerror(errno)); 1227 return -1; 1228 } 1229 1230 if (!FD_ISSET(fd, &readfds)) { 1231 /* Compute a new timeout */ 1232 gettimeofday(&tv, NULL); 1233 timersub(&timelimit, &tv, &tv); 1234 if (tv.tv_sec > 0 || (tv.tv_sec == 0 && tv.tv_usec > 0)) 1235 /* Continue the select */ 1236 continue; 1237 } 1238 1239 n = rad_continue_send_request(h, n, &fd, &tv); 1240 1241 if (n != 0) 1242 return n; 1243 1244 gettimeofday(&timelimit, NULL); 1245 timeradd(&tv, &timelimit, &timelimit); 1246 } 1247 } 1248 1249 const char * 1250 rad_strerror(struct rad_handle *h) 1251 { 1252 return h->errmsg; 1253 } 1254 1255 /* 1256 * Destructively split a string into fields separated by white space. 1257 * `#' at the beginning of a field begins a comment that extends to the 1258 * end of the string. Fields may be quoted with `"'. Inside quoted 1259 * strings, the backslash escapes `\"' and `\\' are honored. 1260 * 1261 * Pointers to up to the first maxfields fields are stored in the fields 1262 * array. Missing fields get NULL pointers. 1263 * 1264 * The return value is the actual number of fields parsed, and is always 1265 * <= maxfields. 1266 * 1267 * On a syntax error, places a message in the msg string, and returns -1. 1268 */ 1269 static int 1270 split(char *str, char *fields[], int maxfields, char *msg, size_t msglen) 1271 { 1272 char *p; 1273 int i; 1274 static const char ws[] = " \t"; 1275 1276 for (i = 0; i < maxfields; i++) 1277 fields[i] = NULL; 1278 p = str; 1279 i = 0; 1280 while (*p != '\0') { 1281 p += strspn(p, ws); 1282 if (*p == '#' || *p == '\0') 1283 break; 1284 if (i >= maxfields) { 1285 snprintf(msg, msglen, "line has too many fields"); 1286 return -1; 1287 } 1288 if (*p == '"') { 1289 char *dst; 1290 1291 dst = ++p; 1292 fields[i] = dst; 1293 while (*p != '"') { 1294 if (*p == '\\') { 1295 p++; 1296 if (*p != '"' && *p != '\\' && 1297 *p != '\0') { 1298 snprintf(msg, msglen, 1299 "invalid `\\' escape"); 1300 return -1; 1301 } 1302 } 1303 if (*p == '\0') { 1304 snprintf(msg, msglen, 1305 "unterminated quoted string"); 1306 return -1; 1307 } 1308 *dst++ = *p++; 1309 } 1310 *dst = '\0'; 1311 p++; 1312 if (*fields[i] == '\0') { 1313 snprintf(msg, msglen, 1314 "empty quoted string not permitted"); 1315 return -1; 1316 } 1317 if (*p != '\0' && strspn(p, ws) == 0) { 1318 snprintf(msg, msglen, "quoted string not" 1319 " followed by white space"); 1320 return -1; 1321 } 1322 } else { 1323 fields[i] = p; 1324 p += strcspn(p, ws); 1325 if (*p != '\0') 1326 *p++ = '\0'; 1327 } 1328 i++; 1329 } 1330 return i; 1331 } 1332 1333 int 1334 rad_get_vendor_attr(u_int32_t *vendor, const void **data, size_t *len) 1335 { 1336 struct vendor_attribute *attr; 1337 1338 attr = (struct vendor_attribute *)*data; 1339 *vendor = ntohl(attr->vendor_value); 1340 *data = attr->attrib_data; 1341 *len = attr->attrib_len - 2; 1342 1343 return (attr->attrib_type); 1344 } 1345 1346 int 1347 rad_put_vendor_addr(struct rad_handle *h, int vendor, int type, 1348 struct in_addr addr) 1349 { 1350 return (rad_put_vendor_attr(h, vendor, type, &addr.s_addr, 1351 sizeof addr.s_addr)); 1352 } 1353 1354 int 1355 rad_put_vendor_addr6(struct rad_handle *h, int vendor, int type, 1356 struct in6_addr addr) 1357 { 1358 1359 return (rad_put_vendor_attr(h, vendor, type, &addr.s6_addr, 1360 sizeof addr.s6_addr)); 1361 } 1362 1363 int 1364 rad_put_vendor_attr(struct rad_handle *h, int vendor, int type, 1365 const void *value, size_t len) 1366 { 1367 struct vendor_attribute *attr; 1368 int res; 1369 1370 if (!h->out_created) { 1371 generr(h, "Please call rad_create_request()" 1372 " before putting attributes"); 1373 return -1; 1374 } 1375 1376 if ((attr = malloc(len + 6)) == NULL) { 1377 generr(h, "malloc failure (%zu bytes)", len + 6); 1378 return -1; 1379 } 1380 1381 attr->vendor_value = htonl(vendor); 1382 attr->attrib_type = type; 1383 attr->attrib_len = len + 2; 1384 memcpy(attr->attrib_data, value, len); 1385 1386 res = put_raw_attr(h, RAD_VENDOR_SPECIFIC, attr, len + 6); 1387 free(attr); 1388 if (res == 0 && vendor == RAD_VENDOR_MICROSOFT 1389 && (type == RAD_MICROSOFT_MS_CHAP_RESPONSE 1390 || type == RAD_MICROSOFT_MS_CHAP2_RESPONSE)) { 1391 h->chap_pass = 1; 1392 } 1393 return (res); 1394 } 1395 1396 int 1397 rad_put_vendor_int(struct rad_handle *h, int vendor, int type, u_int32_t i) 1398 { 1399 u_int32_t value; 1400 1401 value = htonl(i); 1402 return (rad_put_vendor_attr(h, vendor, type, &value, sizeof value)); 1403 } 1404 1405 int 1406 rad_put_vendor_string(struct rad_handle *h, int vendor, int type, 1407 const char *str) 1408 { 1409 return (rad_put_vendor_attr(h, vendor, type, str, strlen(str))); 1410 } 1411 1412 ssize_t 1413 rad_request_authenticator(struct rad_handle *h, char *buf, size_t len) 1414 { 1415 if (len < LEN_AUTH) 1416 return (-1); 1417 memcpy(buf, h->out + POS_AUTH, LEN_AUTH); 1418 if (len > LEN_AUTH) 1419 buf[LEN_AUTH] = '\0'; 1420 return (LEN_AUTH); 1421 } 1422 1423 u_char * 1424 rad_demangle(struct rad_handle *h, const void *mangled, size_t mlen) 1425 { 1426 char R[LEN_AUTH]; 1427 const char *S; 1428 int i, Ppos; 1429 MD5_CTX Context; 1430 u_char b[MD5_DIGEST_LENGTH], *C, *demangled; 1431 1432 if ((mlen % 16 != 0) || mlen > 128) { 1433 generr(h, "Cannot interpret mangled data of length %lu", 1434 (u_long)mlen); 1435 return NULL; 1436 } 1437 1438 C = (u_char *)mangled; 1439 1440 /* We need the shared secret as Salt */ 1441 S = rad_server_secret(h); 1442 1443 /* We need the request authenticator */ 1444 if (rad_request_authenticator(h, R, sizeof R) != LEN_AUTH) { 1445 generr(h, "Cannot obtain the RADIUS request authenticator"); 1446 return NULL; 1447 } 1448 1449 demangled = malloc(mlen); 1450 if (!demangled) 1451 return NULL; 1452 1453 MD5Init(&Context); 1454 MD5Update(&Context, S, strlen(S)); 1455 MD5Update(&Context, R, LEN_AUTH); 1456 MD5Final(b, &Context); 1457 Ppos = 0; 1458 while (mlen) { 1459 1460 mlen -= 16; 1461 for (i = 0; i < 16; i++) 1462 demangled[Ppos++] = C[i] ^ b[i]; 1463 1464 if (mlen) { 1465 MD5Init(&Context); 1466 MD5Update(&Context, S, strlen(S)); 1467 MD5Update(&Context, C, 16); 1468 MD5Final(b, &Context); 1469 } 1470 1471 C += 16; 1472 } 1473 1474 return demangled; 1475 } 1476 1477 u_char * 1478 rad_demangle_mppe_key(struct rad_handle *h, const void *mangled, 1479 size_t mlen, size_t *len) 1480 { 1481 char R[LEN_AUTH]; /* variable names as per rfc2548 */ 1482 const char *S; 1483 u_char b[MD5_DIGEST_LENGTH], *demangled; 1484 const u_char *A, *C; 1485 MD5_CTX Context; 1486 int Slen, i, Clen, Ppos; 1487 u_char *P; 1488 1489 if (mlen % 16 != SALT_LEN) { 1490 generr(h, "Cannot interpret mangled data of length %lu", 1491 (u_long)mlen); 1492 return NULL; 1493 } 1494 1495 /* We need the RADIUS Request-Authenticator */ 1496 if (rad_request_authenticator(h, R, sizeof R) != LEN_AUTH) { 1497 generr(h, "Cannot obtain the RADIUS request authenticator"); 1498 return NULL; 1499 } 1500 1501 A = (const u_char *)mangled; /* Salt comes first */ 1502 C = (const u_char *)mangled + SALT_LEN; /* Then the ciphertext */ 1503 Clen = mlen - SALT_LEN; 1504 S = rad_server_secret(h); /* We need the RADIUS secret */ 1505 Slen = strlen(S); 1506 P = alloca(Clen); /* We derive our plaintext */ 1507 1508 MD5Init(&Context); 1509 MD5Update(&Context, S, Slen); 1510 MD5Update(&Context, R, LEN_AUTH); 1511 MD5Update(&Context, A, SALT_LEN); 1512 MD5Final(b, &Context); 1513 Ppos = 0; 1514 1515 while (Clen) { 1516 Clen -= 16; 1517 1518 for (i = 0; i < 16; i++) 1519 P[Ppos++] = C[i] ^ b[i]; 1520 1521 if (Clen) { 1522 MD5Init(&Context); 1523 MD5Update(&Context, S, Slen); 1524 MD5Update(&Context, C, 16); 1525 MD5Final(b, &Context); 1526 } 1527 1528 C += 16; 1529 } 1530 1531 /* 1532 * The resulting plain text consists of a one-byte length, the text and 1533 * maybe some padding. 1534 */ 1535 *len = *P; 1536 if (*len > mlen - 1) { 1537 generr(h, "Mangled data seems to be garbage %zu %zu", 1538 *len, mlen-1); 1539 return NULL; 1540 } 1541 1542 if (*len > MPPE_KEY_LEN * 2) { 1543 generr(h, "Key to long (%zu) for me max. %d", 1544 *len, MPPE_KEY_LEN * 2); 1545 return NULL; 1546 } 1547 demangled = malloc(*len); 1548 if (!demangled) 1549 return NULL; 1550 1551 memcpy(demangled, P + 1, *len); 1552 return demangled; 1553 } 1554 1555 const char * 1556 rad_server_secret(struct rad_handle *h) 1557 { 1558 return (h->servers[h->srv].secret); 1559 } 1560