crypto/dist/heimdal/lib/krb5/send_to_kdc.c

   1 /*
   2  * Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35
  36 __RCSID("$Heimdal: send_to_kdc.c 21934 2007-08-27 14:21:04Z lha $"
  37         "$NetBSD$");
  38
  39 struct send_to_kdc {
  40     krb5_send_to_kdc_func func;
  41     void *data;
  42 };
  43
  44 /*
  45  * send the data in `req' on the socket `fd' (which is datagram iff udp)
  46  * waiting `tmout' for a reply and returning the reply in `rep'.
  47  * iff limit read up to this many bytes
  48  * returns 0 and data in `rep' if succesful, otherwise -1
  49  */
  50
  51 static int
  52 recv_loop (int fd,
  53            time_t tmout,
  54            int udp,
  55            size_t limit,
  56            krb5_data *rep)
  57 {
  58      fd_set fdset;
  59      struct timeval timeout;
  60      int ret;
  61      int nbytes;
  62
  63      if (fd >= FD_SETSIZE) {
  64          return -1;
  65      }
  66
  67      krb5_data_zero(rep);
  68      do {
  69          FD_ZERO(&fdset);
  70          FD_SET(fd, &fdset);
  71          timeout.tv_sec  = tmout;
  72          timeout.tv_usec = 0;
  73          ret = select (fd + 1, &fdset, NULL, NULL, &timeout);
  74          if (ret < 0) {
  75              if (errno == EINTR)
  76                  continue;
  77              return -1;
  78          } else if (ret == 0) {
  79              return 0;
  80          } else {
  81              void *tmp;
  82
  83              if (ioctl (fd, FIONREAD, &nbytes) < 0) {
  84                  krb5_data_free (rep);
  85                  return -1;
  86              }
  87              if(nbytes <= 0)
  88                  return 0;
  89
  90              if (limit)
  91                  nbytes = min(nbytes, limit - rep->length);
  92
  93              tmp = realloc (rep->data, rep->length + nbytes);
  94              if (tmp == NULL) {
  95                  krb5_data_free (rep);
  96                  return -1;
  97              }
  98              rep->data = tmp;
  99              ret = recv (fd, (char*)tmp + rep->length, nbytes, 0);
 100              if (ret < 0) {
 101                  krb5_data_free (rep);
 102                  return -1;
 103              }
 104              rep->length += ret;
 105          }
 106      } while(!udp && (limit == 0 || rep->length < limit));
 107      return 0;
 108 }
 109
 110 /*
 111  * Send kerberos requests and receive a reply on a udp or any other kind
 112  * of a datagram socket.  See `recv_loop'.
 113  */
 114
 115 static int
 116 send_and_recv_udp(int fd,
 117                   time_t tmout,
 118                   const krb5_data *req,
 119                   krb5_data *rep)
 120 {
 121     if (send (fd, req->data, req->length, 0) < 0)
 122         return -1;
 123
 124     return recv_loop(fd, tmout, 1, 0, rep);
 125 }
 126
 127 /*
 128  * `send_and_recv' for a TCP (or any other stream) socket.
 129  * Since there are no record limits on a stream socket the protocol here
 130  * is to prepend the request with 4 bytes of its length and the reply
 131  * is similarly encoded.
 132  */
 133
 134 static int
 135 send_and_recv_tcp(int fd,
 136                   time_t tmout,
 137                   const krb5_data *req,
 138                   krb5_data *rep)
 139 {
 140     unsigned char len[4];
 141     unsigned long rep_len;
 142     krb5_data len_data;
 143
 144     _krb5_put_int(len, req->length, 4);
 145     if(net_write(fd, len, sizeof(len)) < 0)
 146         return -1;
 147     if(net_write(fd, req->data, req->length) < 0)
 148         return -1;
 149     if (recv_loop (fd, tmout, 0, 4, &len_data) < 0)
 150         return -1;
 151     if (len_data.length != 4) {
 152         krb5_data_free (&len_data);
 153         return -1;
 154     }
 155     _krb5_get_int(len_data.data, &rep_len, 4);
 156     krb5_data_free (&len_data);
 157     if (recv_loop (fd, tmout, 0, rep_len, rep) < 0)
 158         return -1;
 159     if(rep->length != rep_len) {
 160         krb5_data_free (rep);
 161         return -1;
 162     }
 163     return 0;
 164 }
 165
 166 int
 167 _krb5_send_and_recv_tcp(int fd,
 168                         time_t tmout,
 169                         const krb5_data *req,
 170                         krb5_data *rep)
 171 {
 172     return send_and_recv_tcp(fd, tmout, req, rep);
 173 }
 174
 175 /*
 176  * `send_and_recv' tailored for the HTTP protocol.
 177  */
 178
 179 static int
 180 send_and_recv_http(int fd,
 181                    time_t tmout,
 182                    const char *prefix,
 183                    const krb5_data *req,
 184                    krb5_data *rep)
 185 {
 186     char *request;
 187     char *str;
 188     int ret;
 189     int len = base64_encode(req->data, req->length, &str);
 190
 191     if(len < 0)
 192         return -1;
 193     asprintf(&request, "GET %s%s HTTP/1.0\r\n\r\n", prefix, str);
 194     free(str);
 195     if (request == NULL)
 196         return -1;
 197     ret = net_write (fd, request, strlen(request));
 198     free (request);
 199     if (ret < 0)
 200         return ret;
 201     ret = recv_loop(fd, tmout, 0, 0, rep);
 202     if(ret)
 203         return ret;
 204     {
 205         unsigned long rep_len;
 206         char *s, *p;
 207
 208         s = realloc(rep->data, rep->length + 1);
 209         if (s == NULL) {
 210             krb5_data_free (rep);
 211             return -1;
 212         }
 213         s[rep->length] = 0;
 214         p = strstr(s, "\r\n\r\n");
 215         if(p == NULL) {
 216             krb5_data_zero(rep);
 217             free(s);
 218             return -1;
 219         }
 220         p += 4;
 221         rep->data = s;
 222         rep->length -= p - s;
 223         if(rep->length < 4) { /* remove length */
 224             krb5_data_zero(rep);
 225             free(s);
 226             return -1;
 227         }
 228         rep->length -= 4;
 229         _krb5_get_int(p, &rep_len, 4);
 230         if (rep_len != rep->length) {
 231             krb5_data_zero(rep);
 232             free(s);
 233             return -1;
 234         }
 235         memmove(rep->data, p + 4, rep->length);
 236     }
 237     return 0;
 238 }
 239
 240 static int
 241 init_port(const char *s, int fallback)
 242 {
 243     if (s) {
 244         int tmp;
 245
 246         sscanf (s, "%d", &tmp);
 247         return htons(tmp);
 248     } else
 249         return fallback;
 250 }
 251
 252 /*
 253  * Return 0 if succesful, otherwise 1
 254  */
 255
 256 static int
 257 send_via_proxy (krb5_context context,
 258                 const krb5_krbhst_info *hi,
 259                 const krb5_data *send_data,
 260                 krb5_data *receive)
 261 {
 262     char *proxy2 = strdup(context->http_proxy);
 263     char *proxy  = proxy2;
 264     char *prefix;
 265     char *colon;
 266     struct addrinfo hints;
 267     struct addrinfo *ai, *a;
 268     int ret;
 269     int s = -1;
 270     char portstr[NI_MAXSERV];
 271
 272     if (proxy == NULL)
 273         return ENOMEM;
 274     if (strncmp (proxy, "http://", 7) == 0)
 275         proxy += 7;
 276
 277     colon = strchr(proxy, ':');
 278     if(colon != NULL)
 279         *colon++ = '\0';
 280     memset (&hints, 0, sizeof(hints));
 281     hints.ai_family   = PF_UNSPEC;
 282     hints.ai_socktype = SOCK_STREAM;
 283     snprintf (portstr, sizeof(portstr), "%d",
 284               ntohs(init_port (colon, htons(80))));
 285     ret = getaddrinfo (proxy, portstr, &hints, &ai);
 286     free (proxy2);
 287     if (ret)
 288         return krb5_eai_to_heim_errno(ret, errno);
 289
 290     for (a = ai; a != NULL; a = a->ai_next) {
 291         s = socket (a->ai_family, a->ai_socktype, a->ai_protocol);
 292         if (s < 0)
 293             continue;
 294         if (connect (s, a->ai_addr, a->ai_addrlen) < 0) {
 295             close (s);
 296             continue;
 297         }
 298         break;
 299     }
 300     if (a == NULL) {
 301         freeaddrinfo (ai);
 302         return 1;
 303     }
 304     freeaddrinfo (ai);
 305
 306     asprintf(&prefix, "http://%s/", hi->hostname);
 307     if(prefix == NULL) {
 308         close(s);
 309         return 1;
 310     }
 311     ret = send_and_recv_http(s, context->kdc_timeout,
 312                              prefix, send_data, receive);
 313     close (s);
 314     free(prefix);
 315     if(ret == 0 && receive->length != 0)
 316         return 0;
 317     return 1;
 318 }
 319
 320 /*
 321  * Send the data `send' to one host from `handle` and get back the reply
 322  * in `receive'.
 323  */
 324
 325 krb5_error_code KRB5_LIB_FUNCTION
 326 krb5_sendto (krb5_context context,
 327              const krb5_data *send_data,
 328              krb5_krbhst_handle handle,
 329              krb5_data *receive)
 330 {
 331      krb5_error_code ret;
 332      int fd;
 333      int i;
 334
 335      krb5_data_zero(receive);
 336
 337      for (i = 0; i < context->max_retries; ++i) {
 338          krb5_krbhst_info *hi;
 339
 340          while (krb5_krbhst_next(context, handle, &hi) == 0) {
 341              struct addrinfo *ai, *a;
 342
 343              if (context->send_to_kdc) {
 344                  struct send_to_kdc *s = context->send_to_kdc;
 345
 346                  ret = (*s->func)(context, s->data,
 347                                   hi, send_data, receive);
 348                  if (ret == 0 && receive->length != 0)
 349                      goto out;
 350                  continue;
 351              }
 352
 353              if(hi->proto == KRB5_KRBHST_HTTP && context->http_proxy) {
 354                  if (send_via_proxy (context, hi, send_data, receive) == 0) {
 355                      ret = 0;
 356                      goto out;
 357                  }
 358                  continue;
 359              }
 360
 361              ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 362              if (ret)
 363                  continue;
 364
 365              for (a = ai; a != NULL; a = a->ai_next) {
 366                  fd = socket (a->ai_family, a->ai_socktype, a->ai_protocol);
 367                  if (fd < 0)
 368                      continue;
 369                  if (connect (fd, a->ai_addr, a->ai_addrlen) < 0) {
 370                      close (fd);
 371                      continue;
 372                  }
 373                  switch (hi->proto) {
 374                  case KRB5_KRBHST_HTTP :
 375                      ret = send_and_recv_http(fd, context->kdc_timeout,
 376                                               "", send_data, receive);
 377                      break;
 378                  case KRB5_KRBHST_TCP :
 379                      ret = send_and_recv_tcp (fd, context->kdc_timeout,
 380                                               send_data, receive);
 381                      break;
 382                  case KRB5_KRBHST_UDP :
 383                      ret = send_and_recv_udp (fd, context->kdc_timeout,
 384                                               send_data, receive);
 385                      break;
 386                  }
 387                  close (fd);
 388                  if(ret == 0 && receive->length != 0)
 389                      goto out;
 390              }
 391          }
 392          krb5_krbhst_reset(context, handle);
 393      }
 394      krb5_clear_error_string (context);
 395      ret = KRB5_KDC_UNREACH;
 396 out:
 397      return ret;
 398 }
 399
 400 krb5_error_code KRB5_LIB_FUNCTION
 401 krb5_sendto_kdc(krb5_context context,
 402                 const krb5_data *send_data,
 403                 const krb5_realm *realm,
 404                 krb5_data *receive)
 405 {
 406     return krb5_sendto_kdc_flags(context, send_data, realm, receive, 0);
 407 }
 408
 409 krb5_error_code KRB5_LIB_FUNCTION
 410 krb5_sendto_kdc_flags(krb5_context context,
 411                       const krb5_data *send_data,
 412                       const krb5_realm *realm,
 413                       krb5_data *receive,
 414                       int flags)
 415 {
 416     krb5_error_code ret;
 417     krb5_sendto_ctx ctx;
 418
 419     ret = krb5_sendto_ctx_alloc(context, &ctx);
 420     if (ret)
 421         return ret;
 422     krb5_sendto_ctx_add_flags(ctx, flags);
 423     krb5_sendto_ctx_set_func(ctx, _krb5_kdc_retry, NULL);
 424
 425     ret = krb5_sendto_context(context, ctx, send_data, *realm, receive);
 426     krb5_sendto_ctx_free(context, ctx);
 427     return ret;
 428 }
 429
 430 krb5_error_code KRB5_LIB_FUNCTION
 431 krb5_set_send_to_kdc_func(krb5_context context,
 432                           krb5_send_to_kdc_func func,
 433                           void *data)
 434 {
 435     free(context->send_to_kdc);
 436     if (func == NULL) {
 437         context->send_to_kdc = NULL;
 438         return 0;
 439     }
 440
 441     context->send_to_kdc = malloc(sizeof(*context->send_to_kdc));
 442     if (context->send_to_kdc == NULL) {
 443         krb5_set_error_string(context, "Out of memory");
 444         return ENOMEM;
 445     }
 446
 447     context->send_to_kdc->func = func;
 448     context->send_to_kdc->data = data;
 449     return 0;
 450 }
 451
 452 struct krb5_sendto_ctx_data {
 453     int flags;
 454     int type;
 455     krb5_sendto_ctx_func func;
 456     void *data;
 457 };
 458
 459 krb5_error_code KRB5_LIB_FUNCTION
 460 krb5_sendto_ctx_alloc(krb5_context context, krb5_sendto_ctx *ctx)
 461 {
 462     *ctx = calloc(1, sizeof(**ctx));
 463     if (*ctx == NULL) {
 464         krb5_set_error_string(context, "out of memory");
 465         return ENOMEM;
 466     }
 467     return 0;
 468 }
 469
 470 void KRB5_LIB_FUNCTION
 471 krb5_sendto_ctx_add_flags(krb5_sendto_ctx ctx, int flags)
 472 {
 473     ctx->flags |= flags;
 474 }
 475
 476 int KRB5_LIB_FUNCTION
 477 krb5_sendto_ctx_get_flags(krb5_sendto_ctx ctx)
 478 {
 479     return ctx->flags;
 480 }
 481
 482 void KRB5_LIB_FUNCTION
 483 krb5_sendto_ctx_set_type(krb5_sendto_ctx ctx, int type)
 484 {
 485     ctx->type = type;
 486 }
 487
 488
 489 void KRB5_LIB_FUNCTION
 490 krb5_sendto_ctx_set_func(krb5_sendto_ctx ctx,
 491                          krb5_sendto_ctx_func func,
 492                          void *data)
 493 {
 494     ctx->func = func;
 495     ctx->data = data;
 496 }
 497
 498 void KRB5_LIB_FUNCTION
 499 krb5_sendto_ctx_free(krb5_context context, krb5_sendto_ctx ctx)
 500 {
 501     memset(ctx, 0, sizeof(*ctx));
 502     free(ctx);
 503 }
 504
 505 krb5_error_code KRB5_LIB_FUNCTION
 506 krb5_sendto_context(krb5_context context,
 507                     krb5_sendto_ctx ctx,
 508                     const krb5_data *send_data,
 509                     const krb5_realm realm,
 510                     krb5_data *receive)
 511 {
 512     krb5_error_code ret;
 513     krb5_krbhst_handle handle = NULL;
 514     int type, freectx = 0;
 515     int action;
 516
 517     krb5_data_zero(receive);
 518
 519     if (ctx == NULL) {
 520         freectx = 1;
 521         ret = krb5_sendto_ctx_alloc(context, &ctx);
 522         if (ret)
 523             return ret;
 524     }
 525
 526     type = ctx->type;
 527     if (type == 0) {
 528         if ((ctx->flags & KRB5_KRBHST_FLAGS_MASTER) || context->use_admin_kdc)
 529             type = KRB5_KRBHST_ADMIN;
 530         else
 531             type = KRB5_KRBHST_KDC;
 532     }
 533
 534     if (send_data->length > context->large_msg_size)
 535         ctx->flags |= KRB5_KRBHST_FLAGS_LARGE_MSG;
 536
 537     /* loop until we get back a appropriate response */
 538
 539     do {
 540         action = KRB5_SENDTO_DONE;
 541
 542         krb5_data_free(receive);
 543
 544         if (handle == NULL) {
 545             ret = krb5_krbhst_init_flags(context, realm, type,
 546                                          ctx->flags, &handle);
 547             if (ret) {
 548                 if (freectx)
 549                     krb5_sendto_ctx_free(context, ctx);
 550                 return ret;
 551             }
 552         }
 553
 554         ret = krb5_sendto(context, send_data, handle, receive);
 555         if (ret)
 556             break;
 557         if (ctx->func) {
 558             ret = (*ctx->func)(context, ctx, ctx->data, receive, &action);
 559             if (ret)
 560                 break;
 561         }
 562         if (action != KRB5_SENDTO_CONTINUE) {
 563             krb5_krbhst_free(context, handle);
 564             handle = NULL;
 565         }
 566     } while (action != KRB5_SENDTO_DONE);
 567     if (handle)
 568         krb5_krbhst_free(context, handle);
 569     if (ret == KRB5_KDC_UNREACH)
 570         krb5_set_error_string(context,
 571                               "unable to reach any KDC in realm %s", realm);
 572     if (ret)
 573         krb5_data_free(receive);
 574     if (freectx)
 575         krb5_sendto_ctx_free(context, ctx);
 576     return ret;
 577 }
 578
 579 krb5_error_code
 580 _krb5_kdc_retry(krb5_context context, krb5_sendto_ctx ctx, void *data,
 581                 const krb5_data *reply, int *action)
 582 {
 583     krb5_error_code ret;
 584     KRB_ERROR error;
 585
 586     if(krb5_rd_error(context, reply, &error))
 587         return 0;
 588
 589     ret = krb5_error_from_rd_error(context, &error, NULL);
 590     krb5_free_error_contents(context, &error);
 591
 592     switch(ret) {
 593     case KRB5KRB_ERR_RESPONSE_TOO_BIG: {
 594         if (krb5_sendto_ctx_get_flags(ctx) & KRB5_KRBHST_FLAGS_LARGE_MSG)
 595             break;
 596         krb5_sendto_ctx_add_flags(ctx, KRB5_KRBHST_FLAGS_LARGE_MSG);
 597         *action = KRB5_SENDTO_RESTART;
 598         break;
 599     }
 600     case KRB5KDC_ERR_SVC_UNAVAILABLE:
 601         *action = KRB5_SENDTO_CONTINUE;
 602         break;
 603     }
 604     return 0;
 605 }