kdc/connect.c

   1 /*
   2  * Copyright (c) 1997-2005 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 "kdc_locl.h"
  35
  36 /*
  37  * a tuple describing on what to listen
  38  */
  39
  40 struct port_desc{
  41     int family;
  42     int type;
  43     int port;
  44 };
  45
  46 /* the current ones */
  47
  48 static struct port_desc *ports;
  49 static size_t num_ports;
  50
  51 /*
  52  * add `family, port, protocol' to the list with duplicate suppresion.
  53  */
  54
  55 static void
  56 add_port(krb5_context context,
  57          int family, int port, const char *protocol)
  58 {
  59     int type;
  60     size_t i;
  61
  62     if(strcmp(protocol, "udp") == 0)
  63         type = SOCK_DGRAM;
  64     else if(strcmp(protocol, "tcp") == 0)
  65         type = SOCK_STREAM;
  66     else
  67         return;
  68     for(i = 0; i < num_ports; i++){
  69         if(ports[i].type == type
  70            && ports[i].port == port
  71            && ports[i].family == family)
  72             return;
  73     }
  74     ports = realloc(ports, (num_ports + 1) * sizeof(*ports));
  75     if (ports == NULL)
  76         krb5_err (context, 1, errno, "realloc");
  77     ports[num_ports].family = family;
  78     ports[num_ports].type   = type;
  79     ports[num_ports].port   = port;
  80     num_ports++;
  81 }
  82
  83 /*
  84  * add a triple but with service -> port lookup
  85  * (this prints warnings for stuff that does not exist)
  86  */
  87
  88 static void
  89 add_port_service(krb5_context context,
  90                  int family, const char *service, int port,
  91                  const char *protocol)
  92 {
  93     port = krb5_getportbyname (context, service, protocol, port);
  94     add_port (context, family, port, protocol);
  95 }
  96
  97 /*
  98  * add the port with service -> port lookup or string -> number
  99  * (no warning is printed)
 100  */
 101
 102 static void
 103 add_port_string (krb5_context context,
 104                  int family, const char *str, const char *protocol)
 105 {
 106     struct servent *sp;
 107     int port;
 108
 109     sp = roken_getservbyname (str, protocol);
 110     if (sp != NULL) {
 111         port = sp->s_port;
 112     } else {
 113         char *end;
 114
 115         port = htons(strtol(str, &end, 0));
 116         if (end == str)
 117             return;
 118     }
 119     add_port (context, family, port, protocol);
 120 }
 121
 122 /*
 123  * add the standard collection of ports for `family'
 124  */
 125
 126 static void
 127 add_standard_ports (krb5_context context,
 128                     krb5_kdc_configuration *config,
 129                     int family)
 130 {
 131     add_port_service(context, family, "kerberos", 88, "udp");
 132     add_port_service(context, family, "kerberos", 88, "tcp");
 133     add_port_service(context, family, "kerberos-sec", 88, "udp");
 134     add_port_service(context, family, "kerberos-sec", 88, "tcp");
 135     if(enable_http)
 136         add_port_service(context, family, "http", 80, "tcp");
 137     if(config->enable_kx509) {
 138         add_port_service(context, family, "kca_service", 9878, "udp");
 139         add_port_service(context, family, "kca_service", 9878, "tcp");
 140     }
 141
 142 }
 143
 144 /*
 145  * parse the set of space-delimited ports in `str' and add them.
 146  * "+" => all the standard ones
 147  * otherwise it's port|service[/protocol]
 148  */
 149
 150 static void
 151 parse_ports(krb5_context context,
 152             krb5_kdc_configuration *config,
 153             const char *str)
 154 {
 155     char *pos = NULL;
 156     char *p;
 157     char *str_copy = strdup (str);
 158
 159     p = strtok_r(str_copy, " \t", &pos);
 160     while(p != NULL) {
 161         if(strcmp(p, "+") == 0) {
 162 #ifdef HAVE_IPV6
 163             add_standard_ports(context, config, AF_INET6);
 164 #endif
 165             add_standard_ports(context, config, AF_INET);
 166         } else {
 167             char *q = strchr(p, '/');
 168             if(q){
 169                 *q++ = 0;
 170 #ifdef HAVE_IPV6
 171                 add_port_string(context, AF_INET6, p, q);
 172 #endif
 173                 add_port_string(context, AF_INET, p, q);
 174             }else {
 175 #ifdef HAVE_IPV6
 176                 add_port_string(context, AF_INET6, p, "udp");
 177                 add_port_string(context, AF_INET6, p, "tcp");
 178 #endif
 179                 add_port_string(context, AF_INET, p, "udp");
 180                 add_port_string(context, AF_INET, p, "tcp");
 181             }
 182         }
 183
 184         p = strtok_r(NULL, " \t", &pos);
 185     }
 186     free (str_copy);
 187 }
 188
 189 /*
 190  * every socket we listen on
 191  */
 192
 193 struct descr {
 194     krb5_socket_t s;
 195     int type;
 196     int port;
 197     unsigned char *buf;
 198     size_t size;
 199     size_t len;
 200     time_t timeout;
 201     struct sockaddr_storage __ss;
 202     struct sockaddr *sa;
 203     socklen_t sock_len;
 204     char addr_string[128];
 205 };
 206
 207 static void
 208 init_descr(struct descr *d)
 209 {
 210     memset(d, 0, sizeof(*d));
 211     d->sa = (struct sockaddr *)&d->__ss;
 212     d->s = rk_INVALID_SOCKET;
 213 }
 214
 215 /*
 216  * re-initialize all `n' ->sa in `d'.
 217  */
 218
 219 static void
 220 reinit_descrs (struct descr *d, int n)
 221 {
 222     int i;
 223
 224     for (i = 0; i < n; ++i)
 225         d[i].sa = (struct sockaddr *)&d[i].__ss;
 226 }
 227
 228 /*
 229  * Create the socket (family, type, port) in `d'
 230  */
 231
 232 static void
 233 init_socket(krb5_context context,
 234             krb5_kdc_configuration *config,
 235             struct descr *d, krb5_address *a, int family, int type, int port)
 236 {
 237     krb5_error_code ret;
 238     struct sockaddr_storage __ss;
 239     struct sockaddr *sa = (struct sockaddr *)&__ss;
 240     krb5_socklen_t sa_size = sizeof(__ss);
 241
 242     init_descr (d);
 243
 244     ret = krb5_addr2sockaddr (context, a, sa, &sa_size, port);
 245     if (ret) {
 246         krb5_warn(context, ret, "krb5_addr2sockaddr");
 247         rk_closesocket(d->s);
 248         d->s = rk_INVALID_SOCKET;
 249         return;
 250     }
 251
 252     if (sa->sa_family != family)
 253         return;
 254
 255     d->s = socket(family, type, 0);
 256     if(rk_IS_BAD_SOCKET(d->s)){
 257         krb5_warn(context, errno, "socket(%d, %d, 0)", family, type);
 258         d->s = rk_INVALID_SOCKET;
 259         return;
 260     }
 261 #if defined(HAVE_SETSOCKOPT) && defined(SOL_SOCKET) && defined(SO_REUSEADDR)
 262     {
 263         int one = 1;
 264         setsockopt(d->s, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof(one));
 265     }
 266 #endif
 267     d->type = type;
 268     d->port = port;
 269
 270     if(rk_IS_SOCKET_ERROR(bind(d->s, sa, sa_size))){
 271         char a_str[256];
 272         size_t len;
 273
 274         krb5_print_address (a, a_str, sizeof(a_str), &len);
 275         krb5_warn(context, errno, "bind %s/%d", a_str, ntohs(port));
 276         rk_closesocket(d->s);
 277         d->s = rk_INVALID_SOCKET;
 278         return;
 279     }
 280     if(type == SOCK_STREAM && rk_IS_SOCKET_ERROR(listen(d->s, SOMAXCONN))){
 281         char a_str[256];
 282         size_t len;
 283
 284         krb5_print_address (a, a_str, sizeof(a_str), &len);
 285         krb5_warn(context, errno, "listen %s/%d", a_str, ntohs(port));
 286         rk_closesocket(d->s);
 287         d->s = rk_INVALID_SOCKET;
 288         return;
 289     }
 290 }
 291
 292 /*
 293  * Allocate descriptors for all the sockets that we should listen on
 294  * and return the number of them.
 295  */
 296
 297 static int
 298 init_sockets(krb5_context context,
 299              krb5_kdc_configuration *config,
 300              struct descr **desc)
 301 {
 302     krb5_error_code ret;
 303     size_t i, j;
 304     struct descr *d;
 305     int num = 0;
 306     krb5_addresses addresses;
 307
 308     if (explicit_addresses.len) {
 309         addresses = explicit_addresses;
 310     } else {
 311         ret = krb5_get_all_server_addrs (context, &addresses);
 312         if (ret)
 313             krb5_err (context, 1, ret, "krb5_get_all_server_addrs");
 314     }
 315     parse_ports(context, config, port_str);
 316     d = malloc(addresses.len * num_ports * sizeof(*d));
 317     if (d == NULL)
 318         krb5_errx(context, 1, "malloc(%lu) failed",
 319                   (unsigned long)num_ports * sizeof(*d));
 320
 321     for (i = 0; i < num_ports; i++){
 322         for (j = 0; j < addresses.len; ++j) {
 323             init_socket(context, config, &d[num], &addresses.val[j],
 324                         ports[i].family, ports[i].type, ports[i].port);
 325             if(d[num].s != rk_INVALID_SOCKET){
 326                 char a_str[80];
 327                 size_t len;
 328
 329                 krb5_print_address (&addresses.val[j], a_str,
 330                                     sizeof(a_str), &len);
 331
 332                 kdc_log(context, config, 5, "listening on %s port %u/%s",
 333                         a_str,
 334                         ntohs(ports[i].port),
 335                         (ports[i].type == SOCK_STREAM) ? "tcp" : "udp");
 336                 /* XXX */
 337                 num++;
 338             }
 339         }
 340     }
 341     krb5_free_addresses (context, &addresses);
 342     d = realloc(d, num * sizeof(*d));
 343     if (d == NULL && num != 0)
 344         krb5_errx(context, 1, "realloc(%lu) failed",
 345                   (unsigned long)num * sizeof(*d));
 346     reinit_descrs (d, num);
 347     *desc = d;
 348     return num;
 349 }
 350
 351 /*
 352  *
 353  */
 354
 355 static const char *
 356 descr_type(struct descr *d)
 357 {
 358     if (d->type == SOCK_DGRAM)
 359         return "udp";
 360     else if (d->type == SOCK_STREAM)
 361         return "tcp";
 362     return "unknown";
 363 }
 364
 365 static void
 366 addr_to_string(krb5_context context,
 367                struct sockaddr *addr, size_t addr_len, char *str, size_t len)
 368 {
 369     krb5_address a;
 370     if(krb5_sockaddr2address(context, addr, &a) == 0) {
 371         if(krb5_print_address(&a, str, len, &len) == 0) {
 372             krb5_free_address(context, &a);
 373             return;
 374         }
 375         krb5_free_address(context, &a);
 376     }
 377     snprintf(str, len, "<family=%d>", addr->sa_family);
 378 }
 379
 380 /*
 381  *
 382  */
 383
 384 static void
 385 send_reply(krb5_context context,
 386            krb5_kdc_configuration *config,
 387            krb5_boolean prependlength,
 388            struct descr *d,
 389            krb5_data *reply)
 390 {
 391     kdc_log(context, config, 5,
 392             "sending %lu bytes to %s", (unsigned long)reply->length,
 393             d->addr_string);
 394     if(prependlength){
 395         unsigned char l[4];
 396         l[0] = (reply->length >> 24) & 0xff;
 397         l[1] = (reply->length >> 16) & 0xff;
 398         l[2] = (reply->length >> 8) & 0xff;
 399         l[3] = reply->length & 0xff;
 400         if(rk_IS_SOCKET_ERROR(sendto(d->s, l, sizeof(l), 0, d->sa, d->sock_len))) {
 401             kdc_log (context, config,
 402                      0, "sendto(%s): %s", d->addr_string,
 403                      strerror(rk_SOCK_ERRNO));
 404             return;
 405         }
 406     }
 407     if(rk_IS_SOCKET_ERROR(sendto(d->s, reply->data, reply->length, 0, d->sa, d->sock_len))) {
 408         kdc_log (context, config, 0, "sendto(%s): %s", d->addr_string,
 409                  strerror(rk_SOCK_ERRNO));
 410         return;
 411     }
 412 }
 413
 414 /*
 415  * Handle the request in `buf, len' to socket `d'
 416  */
 417
 418 static void
 419 do_request(krb5_context context,
 420            krb5_kdc_configuration *config,
 421            void *buf, size_t len, krb5_boolean prependlength,
 422            struct descr *d)
 423 {
 424     krb5_error_code ret;
 425     krb5_data reply;
 426     int datagram_reply = (d->type == SOCK_DGRAM);
 427
 428     krb5_kdc_update_time(NULL);
 429
 430     krb5_data_zero(&reply);
 431     ret = krb5_kdc_process_request(context, config,
 432                                    buf, len, &reply, &prependlength,
 433                                    d->addr_string, d->sa,
 434                                    datagram_reply);
 435     if(request_log)
 436         krb5_kdc_save_request(context, request_log, buf, len, &reply, d->sa);
 437     if(reply.length){
 438         send_reply(context, config, prependlength, d, &reply);
 439         krb5_data_free(&reply);
 440     }
 441     if(ret)
 442         kdc_log(context, config, 0,
 443                 "Failed processing %lu byte request from %s",
 444                 (unsigned long)len, d->addr_string);
 445 }
 446
 447 /*
 448  * Handle incoming data to the UDP socket in `d'
 449  */
 450
 451 static void
 452 handle_udp(krb5_context context,
 453            krb5_kdc_configuration *config,
 454            struct descr *d)
 455 {
 456     unsigned char *buf;
 457     ssize_t n;
 458
 459     buf = malloc(max_request_udp);
 460     if(buf == NULL){
 461         kdc_log(context, config, 0, "Failed to allocate %lu bytes", (unsigned long)max_request_udp);
 462         return;
 463     }
 464
 465     d->sock_len = sizeof(d->__ss);
 466     n = recvfrom(d->s, buf, max_request_udp, 0, d->sa, &d->sock_len);
 467     if(rk_IS_SOCKET_ERROR(n))
 468         krb5_warn(context, rk_SOCK_ERRNO, "recvfrom");
 469     else {
 470         addr_to_string (context, d->sa, d->sock_len,
 471                         d->addr_string, sizeof(d->addr_string));
 472         if ((size_t)n == max_request_udp) {
 473             krb5_data data;
 474             krb5_warn(context, errno,
 475                       "recvfrom: truncated packet from %s, asking for TCP",
 476                       d->addr_string);
 477             krb5_mk_error(context,
 478                           KRB5KRB_ERR_RESPONSE_TOO_BIG,
 479                           NULL,
 480                           NULL,
 481                           NULL,
 482                           NULL,
 483                           NULL,
 484                           NULL,
 485                           &data);
 486             send_reply(context, config, FALSE, d, &data);
 487             krb5_data_free(&data);
 488         } else {
 489             do_request(context, config, buf, n, FALSE, d);
 490         }
 491     }
 492     free (buf);
 493 }
 494
 495 static void
 496 clear_descr(struct descr *d)
 497 {
 498     if(d->buf)
 499         memset(d->buf, 0, d->size);
 500     d->len = 0;
 501     if(d->s != rk_INVALID_SOCKET)
 502         rk_closesocket(d->s);
 503     d->s = rk_INVALID_SOCKET;
 504 }
 505
 506
 507 /* remove HTTP %-quoting from buf */
 508 static int
 509 de_http(char *buf)
 510 {
 511     unsigned char *p, *q;
 512     for(p = q = (unsigned char *)buf; *p; p++, q++) {
 513         if(*p == '%' && isxdigit(p[1]) && isxdigit(p[2])) {
 514             unsigned int x;
 515             if(sscanf((char *)p + 1, "%2x", &x) != 1)
 516                 return -1;
 517             *q = x;
 518             p += 2;
 519         } else
 520             *q = *p;
 521     }
 522     *q = '\0';
 523     return 0;
 524 }
 525
 526 #define TCP_TIMEOUT 4
 527
 528 /*
 529  * accept a new TCP connection on `d[parent]' and store it in `d[child]'
 530  */
 531
 532 static void
 533 add_new_tcp (krb5_context context,
 534              krb5_kdc_configuration *config,
 535              struct descr *d, int parent, int child)
 536 {
 537     krb5_socket_t s;
 538
 539     if (child == -1)
 540         return;
 541
 542     d[child].sock_len = sizeof(d[child].__ss);
 543     s = accept(d[parent].s, d[child].sa, &d[child].sock_len);
 544     if(rk_IS_BAD_SOCKET(s)) {
 545         krb5_warn(context, rk_SOCK_ERRNO, "accept");
 546         return;
 547     }
 548
 549 #ifdef FD_SETSIZE
 550     if (s >= FD_SETSIZE) {
 551         krb5_warnx(context, "socket FD too large");
 552         rk_closesocket (s);
 553         return;
 554     }
 555 #endif
 556
 557     d[child].s = s;
 558     d[child].timeout = time(NULL) + TCP_TIMEOUT;
 559     d[child].type = SOCK_STREAM;
 560     addr_to_string (context,
 561                     d[child].sa, d[child].sock_len,
 562                     d[child].addr_string, sizeof(d[child].addr_string));
 563 }
 564
 565 /*
 566  * Grow `d' to handle at least `n'.
 567  * Return != 0 if fails
 568  */
 569
 570 static int
 571 grow_descr (krb5_context context,
 572             krb5_kdc_configuration *config,
 573             struct descr *d, size_t n)
 574 {
 575     if (d->size - d->len < n) {
 576         unsigned char *tmp;
 577         size_t grow;
 578
 579         grow = max(1024, d->len + n);
 580         if (d->size + grow > max_request_tcp) {
 581             kdc_log(context, config, 0, "Request exceeds max request size (%lu bytes).",
 582                     (unsigned long)d->size + grow);
 583             clear_descr(d);
 584             return -1;
 585         }
 586         tmp = realloc (d->buf, d->size + grow);
 587         if (tmp == NULL) {
 588             kdc_log(context, config, 0, "Failed to re-allocate %lu bytes.",
 589                     (unsigned long)d->size + grow);
 590             clear_descr(d);
 591             return -1;
 592         }
 593         d->size += grow;
 594         d->buf = tmp;
 595     }
 596     return 0;
 597 }
 598
 599 /*
 600  * Try to handle the TCP data at `d->buf, d->len'.
 601  * Return -1 if failed, 0 if succesful, and 1 if data is complete.
 602  */
 603
 604 static int
 605 handle_vanilla_tcp (krb5_context context,
 606                     krb5_kdc_configuration *config,
 607                     struct descr *d)
 608 {
 609     krb5_storage *sp;
 610     uint32_t len;
 611
 612     sp = krb5_storage_from_mem(d->buf, d->len);
 613     if (sp == NULL) {
 614         kdc_log (context, config, 0, "krb5_storage_from_mem failed");
 615         return -1;
 616     }
 617     krb5_ret_uint32(sp, &len);
 618     krb5_storage_free(sp);
 619     if(d->len - 4 >= len) {
 620         memmove(d->buf, d->buf + 4, d->len - 4);
 621         d->len -= 4;
 622         return 1;
 623     }
 624     return 0;
 625 }
 626
 627 /*
 628  * Try to handle the TCP/HTTP data at `d->buf, d->len'.
 629  * Return -1 if failed, 0 if succesful, and 1 if data is complete.
 630  */
 631
 632 static int
 633 handle_http_tcp (krb5_context context,
 634                  krb5_kdc_configuration *config,
 635                  struct descr *d)
 636 {
 637     char *s, *p, *t;
 638     void *data;
 639     char *proto;
 640     int len;
 641
 642     s = (char *)d->buf;
 643
 644     /* If its a multi line query, truncate off the first line */
 645     p = strstr(s, "\r\n");
 646     if (p)
 647         *p = 0;
 648
 649     p = NULL;
 650     t = strtok_r(s, " \t", &p);
 651     if (t == NULL) {
 652         kdc_log(context, config, 0,
 653                 "Missing HTTP operand (GET) request from %s", d->addr_string);
 654         return -1;
 655     }
 656
 657     t = strtok_r(NULL, " \t", &p);
 658     if(t == NULL) {
 659         kdc_log(context, config, 0,
 660                 "Missing HTTP GET data in request from %s", d->addr_string);
 661         return -1;
 662     }
 663
 664     data = malloc(strlen(t));
 665     if (data == NULL) {
 666         kdc_log(context, config, 0, "Failed to allocate %lu bytes",
 667                 (unsigned long)strlen(t));
 668         return -1;
 669     }
 670     if(*t == '/')
 671         t++;
 672     if(de_http(t) != 0) {
 673         kdc_log(context, config, 0, "Malformed HTTP request from %s", d->addr_string);
 674         kdc_log(context, config, 5, "HTTP request: %s", t);
 675         free(data);
 676         return -1;
 677     }
 678     proto = strtok_r(NULL, " \t", &p);
 679     if (proto == NULL) {
 680         kdc_log(context, config, 0, "Malformed HTTP request from %s", d->addr_string);
 681         free(data);
 682         return -1;
 683     }
 684     len = base64_decode(t, data);
 685     if(len <= 0){
 686         const char *msg =
 687             " 404 Not found\r\n"
 688             "Server: Heimdal/" VERSION "\r\n"
 689             "Cache-Control: no-cache\r\n"
 690             "Pragma: no-cache\r\n"
 691             "Content-type: text/html\r\n"
 692             "Content-transfer-encoding: 8bit\r\n\r\n"
 693             "<TITLE>404 Not found</TITLE>\r\n"
 694             "<H1>404 Not found</H1>\r\n"
 695             "That page doesn't exist, maybe you are looking for "
 696             "<A HREF=\"http://www.h5l.org/\">Heimdal</A>?\r\n";
 697         kdc_log(context, config, 0, "HTTP request from %s is non KDC request", d->addr_string);
 698         kdc_log(context, config, 5, "HTTP request: %s", t);
 699         free(data);
 700         if (rk_IS_SOCKET_ERROR(send(d->s, proto, strlen(proto), 0))) {
 701             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 702                     d->addr_string, strerror(rk_SOCK_ERRNO));
 703             return -1;
 704         }
 705         if (rk_IS_SOCKET_ERROR(send(d->s, msg, strlen(msg), 0))) {
 706             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 707                     d->addr_string, strerror(rk_SOCK_ERRNO));
 708             return -1;
 709         }
 710         return -1;
 711     }
 712     {
 713         const char *msg =
 714             " 200 OK\r\n"
 715             "Server: Heimdal/" VERSION "\r\n"
 716             "Cache-Control: no-cache\r\n"
 717             "Pragma: no-cache\r\n"
 718             "Content-type: application/octet-stream\r\n"
 719             "Content-transfer-encoding: binary\r\n\r\n";
 720         if (rk_IS_SOCKET_ERROR(send(d->s, proto, strlen(proto), 0))) {
 721             free(data);
 722             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 723                     d->addr_string, strerror(rk_SOCK_ERRNO));
 724             return -1;
 725         }
 726         if (rk_IS_SOCKET_ERROR(send(d->s, msg, strlen(msg), 0))) {
 727             free(data);
 728             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 729                     d->addr_string, strerror(rk_SOCK_ERRNO));
 730             return -1;
 731         }
 732     }
 733     if ((size_t)len > d->len)
 734         len = d->len;
 735     memcpy(d->buf, data, len);
 736     d->len = len;
 737     free(data);
 738     return 1;
 739 }
 740
 741 /*
 742  * Handle incoming data to the TCP socket in `d[index]'
 743  */
 744
 745 static void
 746 handle_tcp(krb5_context context,
 747            krb5_kdc_configuration *config,
 748            struct descr *d, int idx, int min_free)
 749 {
 750     unsigned char buf[1024];
 751     int n;
 752     int ret = 0;
 753
 754     if (d[idx].timeout == 0) {
 755         add_new_tcp (context, config, d, idx, min_free);
 756         return;
 757     }
 758
 759     n = recvfrom(d[idx].s, buf, sizeof(buf), 0, NULL, NULL);
 760     if(rk_IS_SOCKET_ERROR(n)){
 761         krb5_warn(context, rk_SOCK_ERRNO, "recvfrom failed from %s to %s/%d",
 762                   d[idx].addr_string, descr_type(d + idx),
 763                   ntohs(d[idx].port));
 764         return;
 765     } else if (n == 0) {
 766         krb5_warnx(context, "connection closed before end of data after %lu "
 767                    "bytes from %s to %s/%d", (unsigned long)d[idx].len,
 768                    d[idx].addr_string, descr_type(d + idx),
 769                    ntohs(d[idx].port));
 770         clear_descr (d + idx);
 771         return;
 772     }
 773     if (grow_descr (context, config, &d[idx], n))
 774         return;
 775     memcpy(d[idx].buf + d[idx].len, buf, n);
 776     d[idx].len += n;
 777     if(d[idx].len > 4 && d[idx].buf[0] == 0) {
 778         ret = handle_vanilla_tcp (context, config, &d[idx]);
 779     } else if(enable_http &&
 780               d[idx].len >= 4 &&
 781               strncmp((char *)d[idx].buf, "GET ", 4) == 0 &&
 782               strncmp((char *)d[idx].buf + d[idx].len - 4,
 783                       "\r\n\r\n", 4) == 0) {
 784
 785         /* remove the trailing \r\n\r\n so the string is NUL terminated */
 786         d[idx].buf[d[idx].len - 4] = '\0';
 787
 788         ret = handle_http_tcp (context, config, &d[idx]);
 789         if (ret < 0)
 790             clear_descr (d + idx);
 791     } else if (d[idx].len > 4) {
 792         kdc_log (context, config,
 793                  0, "TCP data of strange type from %s to %s/%d",
 794                  d[idx].addr_string, descr_type(d + idx),
 795                  ntohs(d[idx].port));
 796         if (d[idx].buf[0] & 0x80) {
 797             krb5_data reply;
 798
 799             kdc_log (context, config, 0, "TCP extension not supported");
 800
 801             ret = krb5_mk_error(context,
 802                                 KRB5KRB_ERR_FIELD_TOOLONG,
 803                                 NULL,
 804                                 NULL,
 805                                 NULL,
 806                                 NULL,
 807                                 NULL,
 808                                 NULL,
 809                                 &reply);
 810             if (ret == 0) {
 811                 send_reply(context, config, TRUE, d + idx, &reply);
 812                 krb5_data_free(&reply);
 813             }
 814         }
 815         clear_descr(d + idx);
 816         return;
 817     }
 818     if (ret < 0)
 819         return;
 820     else if (ret == 1) {
 821         do_request(context, config,
 822                    d[idx].buf, d[idx].len, TRUE, &d[idx]);
 823         clear_descr(d + idx);
 824     }
 825 }
 826
 827 krb5_boolean
 828 realloc_descrs(struct descr **d, unsigned int *ndescr)
 829 {
 830     struct descr *tmp;
 831     size_t i;
 832
 833     tmp = realloc(*d, (*ndescr + 4) * sizeof(**d));
 834     if(tmp == NULL)
 835         return FALSE;
 836
 837     *d = tmp;
 838     reinit_descrs (*d, *ndescr);
 839     memset(*d + *ndescr, 0, 4 * sizeof(**d));
 840     for(i = *ndescr; i < *ndescr + 4; i++)
 841         init_descr (*d + i);
 842
 843     *ndescr += 4;
 844
 845     return TRUE;
 846 }
 847
 848 int
 849 next_min_free(krb5_context context, struct descr **d, unsigned int *ndescr)
 850 {
 851     size_t i;
 852     int min_free;
 853
 854     for(i = 0; i < *ndescr; i++) {
 855         int s = (*d + i)->s;
 856         if(rk_IS_BAD_SOCKET(s))
 857             return i;
 858     }
 859
 860     min_free = *ndescr;
 861     if(!realloc_descrs(d, ndescr)) {
 862         min_free = -1;
 863         krb5_warnx(context, "No memory");
 864     }
 865
 866     return min_free;
 867 }
 868
 869 void
 870 loop(krb5_context context,
 871      krb5_kdc_configuration *config)
 872 {
 873     struct descr *d;
 874     unsigned int ndescr;
 875
 876     ndescr = init_sockets(context, config, &d);
 877     if(ndescr <= 0)
 878         krb5_errx(context, 1, "No sockets!");
 879     kdc_log(context, config, 0, "KDC started");
 880     while(exit_flag == 0){
 881         struct timeval tmout;
 882         fd_set fds;
 883         int min_free = -1;
 884         int max_fd = 0;
 885         size_t i;
 886
 887         FD_ZERO(&fds);
 888         for(i = 0; i < ndescr; i++) {
 889             if(!rk_IS_BAD_SOCKET(d[i].s)){
 890                 if(d[i].type == SOCK_STREAM &&
 891                    d[i].timeout && d[i].timeout < time(NULL)) {
 892                     kdc_log(context, config, 1,
 893                             "TCP-connection from %s expired after %lu bytes",
 894                             d[i].addr_string, (unsigned long)d[i].len);
 895                     clear_descr(&d[i]);
 896                     continue;
 897                 }
 898 #ifndef NO_LIMIT_FD_SETSIZE
 899                 if(max_fd < d[i].s)
 900                     max_fd = d[i].s;
 901 #ifdef FD_SETSIZE
 902                 if (max_fd >= FD_SETSIZE)
 903                     krb5_errx(context, 1, "fd too large");
 904 #endif
 905 #endif
 906                 FD_SET(d[i].s, &fds);
 907             }
 908         }
 909
 910         tmout.tv_sec = TCP_TIMEOUT;
 911         tmout.tv_usec = 0;
 912         switch(select(max_fd + 1, &fds, 0, 0, &tmout)){
 913         case 0:
 914             break;
 915         case -1:
 916             if (errno != EINTR)
 917                 krb5_warn(context, rk_SOCK_ERRNO, "select");
 918             break;
 919         default:
 920             for(i = 0; i < ndescr; i++)
 921                 if(!rk_IS_BAD_SOCKET(d[i].s) && FD_ISSET(d[i].s, &fds)) {
 922             min_free = next_min_free(context, &d, &ndescr);
 923
 924             if(d[i].type == SOCK_DGRAM)
 925                 handle_udp(context, config, &d[i]);
 926             else if(d[i].type == SOCK_STREAM)
 927                 handle_tcp(context, config, d, i, min_free);
 928                 }
 929         }
 930     }
 931     if (0);
 932 #ifdef SIGXCPU
 933     else if(exit_flag == SIGXCPU)
 934         kdc_log(context, config, 0, "CPU time limit exceeded");
 935 #endif
 936     else if(exit_flag == SIGINT || exit_flag == SIGTERM)
 937         kdc_log(context, config, 0, "Terminated");
 938     else
 939         kdc_log(context, config, 0, "Unexpected exit reason: %d", exit_flag);
 940     free (d);
 941 }