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("$Id$");
  37
  38 /*
  39  * send the data in `req' on the socket `fd' (which is datagram iff udp)
  40  * waiting `tmout' for a reply and returning the reply in `rep'.
  41  * iff limit read up to this many bytes
  42  * returns 0 and data in `rep' if succesful, otherwise -1
  43  */
  44
  45 static int
  46 recv_loop (int fd,
  47            time_t tmout,
  48            int udp,
  49            size_t limit,
  50            krb5_data *rep)
  51 {
  52      fd_set fdset;
  53      struct timeval timeout;
  54      int ret;
  55      int nbytes;
  56
  57      if (fd >= FD_SETSIZE) {
  58          return -1;
  59      }
  60
  61      krb5_data_zero(rep);
  62      do {
  63          FD_ZERO(&fdset);
  64          FD_SET(fd, &fdset);
  65          timeout.tv_sec  = tmout;
  66          timeout.tv_usec = 0;
  67          ret = select (fd + 1, &fdset, NULL, NULL, &timeout);
  68          if (ret < 0) {
  69              if (errno == EINTR)
  70                  continue;
  71              return -1;
  72          } else if (ret == 0) {
  73              return 0;
  74          } else {
  75              void *tmp;
  76
  77              if (ioctl (fd, FIONREAD, &nbytes) < 0) {
  78                  krb5_data_free (rep);
  79                  return -1;
  80              }
  81              if(nbytes == 0)
  82                  return 0;
  83
  84              if (limit)
  85                  nbytes = min(nbytes, limit - rep->length);
  86
  87              tmp = realloc (rep->data, rep->length + nbytes);
  88              if (tmp == NULL) {
  89                  krb5_data_free (rep);
  90                  return -1;
  91              }
  92              rep->data = tmp;
  93              ret = recv (fd, (char*)tmp + rep->length, nbytes, 0);
  94              if (ret < 0) {
  95                  krb5_data_free (rep);
  96                  return -1;
  97              }
  98              rep->length += ret;
  99          }
 100      } while(!udp && (limit == 0 || rep->length < limit));
 101      return 0;
 102 }
 103
 104 /*
 105  * Send kerberos requests and receive a reply on a udp or any other kind
 106  * of a datagram socket.  See `recv_loop'.
 107  */
 108
 109 static int
 110 send_and_recv_udp(int fd,
 111                   time_t tmout,
 112                   const krb5_data *req,
 113                   krb5_data *rep)
 114 {
 115     if (send (fd, req->data, req->length, 0) < 0)
 116         return -1;
 117
 118     return recv_loop(fd, tmout, 1, 0, rep);
 119 }
 120
 121 /*
 122  * `send_and_recv' for a TCP (or any other stream) socket.
 123  * Since there are no record limits on a stream socket the protocol here
 124  * is to prepend the request with 4 bytes of its length and the reply
 125  * is similarly encoded.
 126  */
 127
 128 static int
 129 send_and_recv_tcp(int fd,
 130                   time_t tmout,
 131                   const krb5_data *req,
 132                   krb5_data *rep)
 133 {
 134     unsigned char len[4];
 135     unsigned long rep_len;
 136     krb5_data len_data;
 137
 138     _krb5_put_int(len, req->length, 4);
 139     if(net_write(fd, len, sizeof(len)) < 0)
 140         return -1;
 141     if(net_write(fd, req->data, req->length) < 0)
 142         return -1;
 143     if (recv_loop (fd, tmout, 0, 4, &len_data) < 0)
 144         return -1;
 145     if (len_data.length != 4) {
 146         krb5_data_free (&len_data);
 147         return -1;
 148     }
 149     _krb5_get_int(len_data.data, &rep_len, 4);
 150     krb5_data_free (&len_data);
 151     if (recv_loop (fd, tmout, 0, rep_len, rep) < 0)
 152         return -1;
 153     if(rep->length != rep_len) {
 154         krb5_data_free (rep);
 155         return -1;
 156     }
 157     return 0;
 158 }
 159
 160 /*
 161  * `send_and_recv' tailored for the HTTP protocol.
 162  */
 163
 164 static int
 165 send_and_recv_http(int fd,
 166                    time_t tmout,
 167                    const char *prefix,
 168                    const krb5_data *req,
 169                    krb5_data *rep)
 170 {
 171     char *request;
 172     char *str;
 173     int ret;
 174     int len = base64_encode(req->data, req->length, &str);
 175
 176     if(len < 0)
 177         return -1;
 178     asprintf(&request, "GET %s%s HTTP/1.0\r\n\r\n", prefix, str);
 179     free(str);
 180     if (request == NULL)
 181         return -1;
 182     ret = net_write (fd, request, strlen(request));
 183     free (request);
 184     if (ret < 0)
 185         return ret;
 186     ret = recv_loop(fd, tmout, 0, 0, rep);
 187     if(ret)
 188         return ret;
 189     {
 190         unsigned long rep_len;
 191         char *s, *p;
 192
 193         s = realloc(rep->data, rep->length + 1);
 194         if (s == NULL) {
 195             krb5_data_free (rep);
 196             return -1;
 197         }
 198         s[rep->length] = 0;
 199         p = strstr(s, "\r\n\r\n");
 200         if(p == NULL) {
 201             free(s);
 202             return -1;
 203         }
 204         p += 4;
 205         rep->data = s;
 206         rep->length -= p - s;
 207         if(rep->length < 4) { /* remove length */
 208             free(s);
 209             return -1;
 210         }
 211         rep->length -= 4;
 212         _krb5_get_int(p, &rep_len, 4);
 213         if (rep_len != rep->length) {
 214             free(s);
 215             return -1;
 216         }
 217         memmove(rep->data, p + 4, rep->length);
 218     }
 219     return 0;
 220 }
 221
 222 static int
 223 init_port(const char *s, int fallback)
 224 {
 225     if (s) {
 226         int tmp;
 227
 228         sscanf (s, "%d", &tmp);
 229         return htons(tmp);
 230     } else
 231         return fallback;
 232 }
 233
 234 /*
 235  * Return 0 if succesful, otherwise 1
 236  */
 237
 238 static int
 239 send_via_proxy (krb5_context context,
 240                 const krb5_krbhst_info *hi,
 241                 const krb5_data *send_data,
 242                 krb5_data *receive)
 243 {
 244     char *proxy2 = strdup(context->http_proxy);
 245     char *proxy  = proxy2;
 246     char *prefix;
 247     char *colon;
 248     struct addrinfo hints;
 249     struct addrinfo *ai, *a;
 250     int ret;
 251     int s = -1;
 252     char portstr[NI_MAXSERV];
 253
 254     if (proxy == NULL)
 255         return ENOMEM;
 256     if (strncmp (proxy, "http://", 7) == 0)
 257         proxy += 7;
 258
 259     colon = strchr(proxy, ':');
 260     if(colon != NULL)
 261         *colon++ = '\0';
 262     memset (&hints, 0, sizeof(hints));
 263     hints.ai_family   = PF_UNSPEC;
 264     hints.ai_socktype = SOCK_STREAM;
 265     snprintf (portstr, sizeof(portstr), "%d",
 266               ntohs(init_port (colon, htons(80))));
 267     ret = getaddrinfo (proxy, portstr, &hints, &ai);
 268     free (proxy2);
 269     if (ret)
 270         return krb5_eai_to_heim_errno(ret, errno);
 271
 272     for (a = ai; a != NULL; a = a->ai_next) {
 273         s = socket (a->ai_family, a->ai_socktype, a->ai_protocol);
 274         if (s < 0)
 275             continue;
 276         if (connect (s, a->ai_addr, a->ai_addrlen) < 0) {
 277             close (s);
 278             continue;
 279         }
 280         break;
 281     }
 282     if (a == NULL) {
 283         freeaddrinfo (ai);
 284         return 1;
 285     }
 286     freeaddrinfo (ai);
 287
 288     asprintf(&prefix, "http://%s/", hi->hostname);
 289     if(prefix == NULL) {
 290         close(s);
 291         return 1;
 292     }
 293     ret = send_and_recv_http(s, context->kdc_timeout,
 294                              prefix, send_data, receive);
 295     close (s);
 296     free(prefix);
 297     if(ret == 0 && receive->length != 0)
 298         return 0;
 299     return 1;
 300 }
 301
 302 /*
 303  * Send the data `send' to one host from `handle` and get back the reply
 304  * in `receive'.
 305  */
 306
 307 krb5_error_code
 308 krb5_sendto (krb5_context context,
 309              const krb5_data *send_data,
 310              krb5_krbhst_handle handle,
 311              krb5_data *receive)
 312 {
 313      krb5_error_code ret = 0;
 314      int fd;
 315      int i;
 316
 317      for (i = 0; i < context->max_retries; ++i) {
 318          krb5_krbhst_info *hi;
 319
 320          while (krb5_krbhst_next(context, handle, &hi) == 0) {
 321              int ret;
 322              struct addrinfo *ai, *a;
 323
 324              if(hi->proto == KRB5_KRBHST_HTTP && context->http_proxy) {
 325                  if (send_via_proxy (context, hi, send_data, receive))
 326                      continue;
 327                  else
 328                      goto out;
 329              }
 330
 331              ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 332              if (ret)
 333                  continue;
 334
 335              for (a = ai; a != NULL; a = a->ai_next) {
 336                  fd = socket (a->ai_family, a->ai_socktype, a->ai_protocol);
 337                  if (fd < 0)
 338                      continue;
 339                  if (connect (fd, a->ai_addr, a->ai_addrlen) < 0) {
 340                      close (fd);
 341                      continue;
 342                  }
 343                  switch (hi->proto) {
 344                  case KRB5_KRBHST_HTTP :
 345                      ret = send_and_recv_http(fd, context->kdc_timeout,
 346                                               "", send_data, receive);
 347                      break;
 348                  case KRB5_KRBHST_TCP :
 349                      ret = send_and_recv_tcp (fd, context->kdc_timeout,
 350                                               send_data, receive);
 351                      break;
 352                  case KRB5_KRBHST_UDP :
 353                      ret = send_and_recv_udp (fd, context->kdc_timeout,
 354                                               send_data, receive);
 355                      break;
 356                  }
 357                  close (fd);
 358                  if(ret == 0 && receive->length != 0)
 359                      goto out;
 360              }
 361          }
 362          krb5_krbhst_reset(context, handle);
 363      }
 364      krb5_clear_error_string (context);
 365      ret = KRB5_KDC_UNREACH;
 366 out:
 367      return ret;
 368 }
 369
 370 krb5_error_code
 371 krb5_sendto_kdc(krb5_context context,
 372                 const krb5_data *send_data,
 373                 const krb5_realm *realm,
 374                 krb5_data *receive)
 375 {
 376     return krb5_sendto_kdc_flags(context, send_data, realm, receive, 0);
 377 }
 378
 379 krb5_error_code
 380 krb5_sendto_kdc2(krb5_context context,
 381                 const krb5_data *send_data,
 382                 const krb5_realm *realm,
 383                 krb5_data *receive,
 384                 krb5_boolean master)
 385 {
 386     return krb5_sendto_kdc_flags(context, send_data, realm, receive, master ? KRB5_KRBHST_FLAGS_MASTER : 0);
 387 }
 388
 389 krb5_error_code
 390 krb5_sendto_kdc_flags(krb5_context context,
 391                       const krb5_data *send_data,
 392                       const krb5_realm *realm,
 393                       krb5_data *receive,
 394                       int flags)
 395 {
 396     krb5_error_code ret;
 397     krb5_krbhst_handle handle;
 398     int type;
 399
 400     if ((flags & KRB5_KRBHST_FLAGS_MASTER) || context->use_admin_kdc)
 401         type = KRB5_KRBHST_ADMIN;
 402     else
 403         type = KRB5_KRBHST_KDC;
 404
 405     ret = krb5_krbhst_init_flags(context, *realm, type, flags, &handle);
 406     if (ret)
 407         return ret;
 408
 409     ret = krb5_sendto(context, send_data, handle, receive);
 410     krb5_krbhst_free(context, handle);
 411     if (ret == KRB5_KDC_UNREACH)
 412         krb5_set_error_string(context,
 413                               "unable to reach any KDC in realm %s", *realm);
 414     return ret;
 415 }