lib/libradius/radlib.c

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