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 RCSID("$Id$");
  37
  38 /* Should we enable the HTTP hack? */
  39 int enable_http = -1;
  40
  41 /* Log over requests to the KDC */
  42 const char *request_log;
  43
  44 /* A string describing on what ports to listen */
  45 const char *port_str;
  46
  47 krb5_addresses explicit_addresses;
  48
  49 size_t max_request;             /* maximal size of a request */
  50
  51 /*
  52  * a tuple describing on what to listen
  53  */
  54
  55 struct port_desc{
  56     int family;
  57     int type;
  58     int port;
  59 };
  60
  61 /* the current ones */
  62
  63 static struct port_desc *ports;
  64 static int num_ports;
  65
  66 /*
  67  * add `family, port, protocol' to the list with duplicate suppresion.
  68  */
  69
  70 static void
  71 add_port(krb5_context context,
  72          int family, int port, const char *protocol)
  73 {
  74     int type;
  75     int i;
  76
  77     if(strcmp(protocol, "udp") == 0)
  78         type = SOCK_DGRAM;
  79     else if(strcmp(protocol, "tcp") == 0)
  80         type = SOCK_STREAM;
  81     else
  82         return;
  83     for(i = 0; i < num_ports; i++){
  84         if(ports[i].type == type
  85            && ports[i].port == port
  86            && ports[i].family == family)
  87             return;
  88     }
  89     ports = realloc(ports, (num_ports + 1) * sizeof(*ports));
  90     if (ports == NULL)
  91         krb5_err (context, 1, errno, "realloc");
  92     ports[num_ports].family = family;
  93     ports[num_ports].type   = type;
  94     ports[num_ports].port   = port;
  95     num_ports++;
  96 }
  97
  98 /*
  99  * add a triple but with service -> port lookup
 100  * (this prints warnings for stuff that does not exist)
 101  */
 102
 103 static void
 104 add_port_service(krb5_context context,
 105                  int family, const char *service, int port,
 106                  const char *protocol)
 107 {
 108     port = krb5_getportbyname (context, service, protocol, port);
 109     add_port (context, family, port, protocol);
 110 }
 111
 112 /*
 113  * add the port with service -> port lookup or string -> number
 114  * (no warning is printed)
 115  */
 116
 117 static void
 118 add_port_string (krb5_context context,
 119                  int family, const char *str, const char *protocol)
 120 {
 121     struct servent *sp;
 122     int port;
 123
 124     sp = roken_getservbyname (str, protocol);
 125     if (sp != NULL) {
 126         port = sp->s_port;
 127     } else {
 128         char *end;
 129
 130         port = htons(strtol(str, &end, 0));
 131         if (end == str)
 132             return;
 133     }
 134     add_port (context, family, port, protocol);
 135 }
 136
 137 /*
 138  * add the standard collection of ports for `family'
 139  */
 140
 141 static void
 142 add_standard_ports (krb5_context context,
 143                     krb5_kdc_configuration *config,
 144                     int family)
 145 {
 146     add_port_service(context, family, "kerberos", 88, "udp");
 147     add_port_service(context, family, "kerberos", 88, "tcp");
 148     add_port_service(context, family, "kerberos-sec", 88, "udp");
 149     add_port_service(context, family, "kerberos-sec", 88, "tcp");
 150     if(enable_http)
 151         add_port_service(context, family, "http", 80, "tcp");
 152     if(config->enable_524) {
 153         add_port_service(context, family, "krb524", 4444, "udp");
 154         add_port_service(context, family, "krb524", 4444, "tcp");
 155     }
 156     if(config->enable_v4) {
 157         add_port_service(context, family, "kerberos-iv", 750, "udp");
 158         add_port_service(context, family, "kerberos-iv", 750, "tcp");
 159     }
 160     if (config->enable_kaserver)
 161         add_port_service(context, family, "afs3-kaserver", 7004, "udp");
 162     if(config->enable_kx509) {
 163         add_port_service(context, family, "kca_service", 9878, "udp");
 164         add_port_service(context, family, "kca_service", 9878, "tcp");
 165     }
 166
 167 }
 168
 169 /*
 170  * parse the set of space-delimited ports in `str' and add them.
 171  * "+" => all the standard ones
 172  * otherwise it's port|service[/protocol]
 173  */
 174
 175 static void
 176 parse_ports(krb5_context context,
 177             krb5_kdc_configuration *config,
 178             const char *str)
 179 {
 180     char *pos = NULL;
 181     char *p;
 182     char *str_copy = strdup (str);
 183
 184     p = strtok_r(str_copy, " \t", &pos);
 185     while(p != NULL) {
 186         if(strcmp(p, "+") == 0) {
 187 #ifdef HAVE_IPV6
 188             add_standard_ports(context, config, AF_INET6);
 189 #endif
 190             add_standard_ports(context, config, AF_INET);
 191         } else {
 192             char *q = strchr(p, '/');
 193             if(q){
 194                 *q++ = 0;
 195 #ifdef HAVE_IPV6
 196                 add_port_string(context, AF_INET6, p, q);
 197 #endif
 198                 add_port_string(context, AF_INET, p, q);
 199             }else {
 200 #ifdef HAVE_IPV6
 201                 add_port_string(context, AF_INET6, p, "udp");
 202                 add_port_string(context, AF_INET6, p, "tcp");
 203 #endif
 204                 add_port_string(context, AF_INET, p, "udp");
 205                 add_port_string(context, AF_INET, p, "tcp");
 206             }
 207         }
 208
 209         p = strtok_r(NULL, " \t", &pos);
 210     }
 211     free (str_copy);
 212 }
 213
 214 /*
 215  * every socket we listen on
 216  */
 217
 218 struct descr {
 219     int s;
 220     int type;
 221     int port;
 222     unsigned char *buf;
 223     size_t size;
 224     size_t len;
 225     time_t timeout;
 226     struct sockaddr_storage __ss;
 227     struct sockaddr *sa;
 228     socklen_t sock_len;
 229     char addr_string[128];
 230 };
 231
 232 static void
 233 init_descr(struct descr *d)
 234 {
 235     memset(d, 0, sizeof(*d));
 236     d->sa = (struct sockaddr *)&d->__ss;
 237     d->s = -1;
 238 }
 239
 240 /*
 241  * re-initialize all `n' ->sa in `d'.
 242  */
 243
 244 static void
 245 reinit_descrs (struct descr *d, int n)
 246 {
 247     int i;
 248
 249     for (i = 0; i < n; ++i)
 250         d[i].sa = (struct sockaddr *)&d[i].__ss;
 251 }
 252
 253 /*
 254  * Create the socket (family, type, port) in `d'
 255  */
 256
 257 static void
 258 init_socket(krb5_context context,
 259             krb5_kdc_configuration *config,
 260             struct descr *d, krb5_address *a, int family, int type, int port)
 261 {
 262     krb5_error_code ret;
 263     struct sockaddr_storage __ss;
 264     struct sockaddr *sa = (struct sockaddr *)&__ss;
 265     krb5_socklen_t sa_size = sizeof(__ss);
 266
 267     init_descr (d);
 268
 269     ret = krb5_addr2sockaddr (context, a, sa, &sa_size, port);
 270     if (ret) {
 271         krb5_warn(context, ret, "krb5_addr2sockaddr");
 272         close(d->s);
 273         d->s = -1;
 274         return;
 275     }
 276
 277     if (sa->sa_family != family)
 278         return;
 279
 280     d->s = socket(family, type, 0);
 281     if(d->s < 0){
 282         krb5_warn(context, errno, "socket(%d, %d, 0)", family, type);
 283         d->s = -1;
 284         return;
 285     }
 286 #if defined(HAVE_SETSOCKOPT) && defined(SOL_SOCKET) && defined(SO_REUSEADDR)
 287     {
 288         int one = 1;
 289         setsockopt(d->s, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof(one));
 290     }
 291 #endif
 292     d->type = type;
 293     d->port = port;
 294
 295     if(bind(d->s, sa, sa_size) < 0){
 296         char a_str[256];
 297         size_t len;
 298
 299         krb5_print_address (a, a_str, sizeof(a_str), &len);
 300         krb5_warn(context, errno, "bind %s/%d", a_str, ntohs(port));
 301         close(d->s);
 302         d->s = -1;
 303         return;
 304     }
 305     if(type == SOCK_STREAM && listen(d->s, SOMAXCONN) < 0){
 306         char a_str[256];
 307         size_t len;
 308
 309         krb5_print_address (a, a_str, sizeof(a_str), &len);
 310         krb5_warn(context, errno, "listen %s/%d", a_str, ntohs(port));
 311         close(d->s);
 312         d->s = -1;
 313         return;
 314     }
 315 }
 316
 317 /*
 318  * Allocate descriptors for all the sockets that we should listen on
 319  * and return the number of them.
 320  */
 321
 322 static int
 323 init_sockets(krb5_context context,
 324              krb5_kdc_configuration *config,
 325              struct descr **desc)
 326 {
 327     krb5_error_code ret;
 328     int i, j;
 329     struct descr *d;
 330     int num = 0;
 331     krb5_addresses addresses;
 332
 333     if (explicit_addresses.len) {
 334         addresses = explicit_addresses;
 335     } else {
 336         ret = krb5_get_all_server_addrs (context, &addresses);
 337         if (ret)
 338             krb5_err (context, 1, ret, "krb5_get_all_server_addrs");
 339     }
 340     parse_ports(context, config, port_str);
 341     d = malloc(addresses.len * num_ports * sizeof(*d));
 342     if (d == NULL)
 343         krb5_errx(context, 1, "malloc(%lu) failed",
 344                   (unsigned long)num_ports * sizeof(*d));
 345
 346     for (i = 0; i < num_ports; i++){
 347         for (j = 0; j < addresses.len; ++j) {
 348             init_socket(context, config, &d[num], &addresses.val[j],
 349                         ports[i].family, ports[i].type, ports[i].port);
 350             if(d[num].s != -1){
 351                 char a_str[80];
 352                 size_t len;
 353
 354                 krb5_print_address (&addresses.val[j], a_str,
 355                                     sizeof(a_str), &len);
 356
 357                 kdc_log(context, config, 5, "listening on %s port %u/%s",
 358                         a_str,
 359                         ntohs(ports[i].port),
 360                         (ports[i].type == SOCK_STREAM) ? "tcp" : "udp");
 361                 /* XXX */
 362                 num++;
 363             }
 364         }
 365     }
 366     krb5_free_addresses (context, &addresses);
 367     d = realloc(d, num * sizeof(*d));
 368     if (d == NULL && num != 0)
 369         krb5_errx(context, 1, "realloc(%lu) failed",
 370                   (unsigned long)num * sizeof(*d));
 371     reinit_descrs (d, num);
 372     *desc = d;
 373     return num;
 374 }
 375
 376 /*
 377  *
 378  */
 379
 380 static const char *
 381 descr_type(struct descr *d)
 382 {
 383     if (d->type == SOCK_DGRAM)
 384         return "udp";
 385     else if (d->type == SOCK_STREAM)
 386         return "tcp";
 387     return "unknown";
 388 }
 389
 390 static void
 391 addr_to_string(krb5_context context,
 392                struct sockaddr *addr, size_t addr_len, char *str, size_t len)
 393 {
 394     krb5_address a;
 395     if(krb5_sockaddr2address(context, addr, &a) == 0) {
 396         if(krb5_print_address(&a, str, len, &len) == 0) {
 397             krb5_free_address(context, &a);
 398             return;
 399         }
 400         krb5_free_address(context, &a);
 401     }
 402     snprintf(str, len, "<family=%d>", addr->sa_family);
 403 }
 404
 405 /*
 406  *
 407  */
 408
 409 static void
 410 send_reply(krb5_context context,
 411            krb5_kdc_configuration *config,
 412            krb5_boolean prependlength,
 413            struct descr *d,
 414            krb5_data *reply)
 415 {
 416     kdc_log(context, config, 5,
 417             "sending %lu bytes to %s", (unsigned long)reply->length,
 418             d->addr_string);
 419     if(prependlength){
 420         unsigned char l[4];
 421         l[0] = (reply->length >> 24) & 0xff;
 422         l[1] = (reply->length >> 16) & 0xff;
 423         l[2] = (reply->length >> 8) & 0xff;
 424         l[3] = reply->length & 0xff;
 425         if(sendto(d->s, l, sizeof(l), 0, d->sa, d->sock_len) < 0) {
 426             kdc_log (context, config,
 427                      0, "sendto(%s): %s", d->addr_string, strerror(errno));
 428             return;
 429         }
 430     }
 431     if(sendto(d->s, reply->data, reply->length, 0, d->sa, d->sock_len) < 0) {
 432         kdc_log (context, config,
 433                  0, "sendto(%s): %s", d->addr_string, strerror(errno));
 434         return;
 435     }
 436 }
 437
 438 /*
 439  * Handle the request in `buf, len' to socket `d'
 440  */
 441
 442 static void
 443 do_request(krb5_context context,
 444            krb5_kdc_configuration *config,
 445            void *buf, size_t len, krb5_boolean prependlength,
 446            struct descr *d)
 447 {
 448     krb5_error_code ret;
 449     krb5_data reply;
 450     int datagram_reply = (d->type == SOCK_DGRAM);
 451
 452     krb5_kdc_update_time(NULL);
 453
 454     krb5_data_zero(&reply);
 455     ret = krb5_kdc_process_request(context, config,
 456                                    buf, len, &reply, &prependlength,
 457                                    d->addr_string, d->sa,
 458                                    datagram_reply);
 459     if(request_log)
 460         krb5_kdc_save_request(context, request_log, buf, len, &reply, d->sa);
 461     if(reply.length){
 462         send_reply(context, config, prependlength, d, &reply);
 463         krb5_data_free(&reply);
 464     }
 465     if(ret)
 466         kdc_log(context, config, 0,
 467                 "Failed processing %lu byte request from %s",
 468                 (unsigned long)len, d->addr_string);
 469 }
 470
 471 /*
 472  * Handle incoming data to the UDP socket in `d'
 473  */
 474
 475 static void
 476 handle_udp(krb5_context context,
 477            krb5_kdc_configuration *config,
 478            struct descr *d)
 479 {
 480     unsigned char *buf;
 481     int n;
 482
 483     buf = malloc(max_request);
 484     if(buf == NULL){
 485         kdc_log(context, config, 0, "Failed to allocate %lu bytes", (unsigned long)max_request);
 486         return;
 487     }
 488
 489     d->sock_len = sizeof(d->__ss);
 490     n = recvfrom(d->s, buf, max_request, 0, d->sa, &d->sock_len);
 491     if(n < 0)
 492         krb5_warn(context, errno, "recvfrom");
 493     else {
 494         addr_to_string (context, d->sa, d->sock_len,
 495                         d->addr_string, sizeof(d->addr_string));
 496         do_request(context, config, buf, n, FALSE, d);
 497     }
 498     free (buf);
 499 }
 500
 501 static void
 502 clear_descr(struct descr *d)
 503 {
 504     if(d->buf)
 505         memset(d->buf, 0, d->size);
 506     d->len = 0;
 507     if(d->s != -1)
 508         close(d->s);
 509     d->s = -1;
 510 }
 511
 512
 513 /* remove HTTP %-quoting from buf */
 514 static int
 515 de_http(char *buf)
 516 {
 517     unsigned char *p, *q;
 518     for(p = q = (unsigned char *)buf; *p; p++, q++) {
 519         if(*p == '%' && isxdigit(p[1]) && isxdigit(p[2])) {
 520             unsigned int x;
 521             if(sscanf((char *)p + 1, "%2x", &x) != 1)
 522                 return -1;
 523             *q = x;
 524             p += 2;
 525         } else
 526             *q = *p;
 527     }
 528     *q = '\0';
 529     return 0;
 530 }
 531
 532 #define TCP_TIMEOUT 4
 533
 534 /*
 535  * accept a new TCP connection on `d[parent]' and store it in `d[child]'
 536  */
 537
 538 static void
 539 add_new_tcp (krb5_context context,
 540              krb5_kdc_configuration *config,
 541              struct descr *d, int parent, int child)
 542 {
 543     int s;
 544
 545     if (child == -1)
 546         return;
 547
 548     d[child].sock_len = sizeof(d[child].__ss);
 549     s = accept(d[parent].s, d[child].sa, &d[child].sock_len);
 550     if(s < 0) {
 551         krb5_warn(context, errno, "accept");
 552         return;
 553     }
 554
 555     if (s >= FD_SETSIZE) {
 556         krb5_warnx(context, "socket FD too large");
 557         close (s);
 558         return;
 559     }
 560
 561     d[child].s = s;
 562     d[child].timeout = time(NULL) + TCP_TIMEOUT;
 563     d[child].type = SOCK_STREAM;
 564     addr_to_string (context,
 565                     d[child].sa, d[child].sock_len,
 566                     d[child].addr_string, sizeof(d[child].addr_string));
 567 }
 568
 569 /*
 570  * Grow `d' to handle at least `n'.
 571  * Return != 0 if fails
 572  */
 573
 574 static int
 575 grow_descr (krb5_context context,
 576             krb5_kdc_configuration *config,
 577             struct descr *d, size_t n)
 578 {
 579     if (d->size - d->len < n) {
 580         unsigned char *tmp;
 581         size_t grow;
 582
 583         grow = max(1024, d->len + n);
 584         if (d->size + grow > max_request) {
 585             kdc_log(context, config, 0, "Request exceeds max request size (%lu bytes).",
 586                     (unsigned long)d->size + grow);
 587             clear_descr(d);
 588             return -1;
 589         }
 590         tmp = realloc (d->buf, d->size + grow);
 591         if (tmp == NULL) {
 592             kdc_log(context, config, 0, "Failed to re-allocate %lu bytes.",
 593                     (unsigned long)d->size + grow);
 594             clear_descr(d);
 595             return -1;
 596         }
 597         d->size += grow;
 598         d->buf = tmp;
 599     }
 600     return 0;
 601 }
 602
 603 /*
 604  * Try to handle the TCP data at `d->buf, d->len'.
 605  * Return -1 if failed, 0 if succesful, and 1 if data is complete.
 606  */
 607
 608 static int
 609 handle_vanilla_tcp (krb5_context context,
 610                     krb5_kdc_configuration *config,
 611                     struct descr *d)
 612 {
 613     krb5_storage *sp;
 614     uint32_t len;
 615
 616     sp = krb5_storage_from_mem(d->buf, d->len);
 617     if (sp == NULL) {
 618         kdc_log (context, config, 0, "krb5_storage_from_mem failed");
 619         return -1;
 620     }
 621     krb5_ret_uint32(sp, &len);
 622     krb5_storage_free(sp);
 623     if(d->len - 4 >= len) {
 624         memmove(d->buf, d->buf + 4, d->len - 4);
 625         d->len -= 4;
 626         return 1;
 627     }
 628     return 0;
 629 }
 630
 631 /*
 632  * Try to handle the TCP/HTTP data at `d->buf, d->len'.
 633  * Return -1 if failed, 0 if succesful, and 1 if data is complete.
 634  */
 635
 636 static int
 637 handle_http_tcp (krb5_context context,
 638                  krb5_kdc_configuration *config,
 639                  struct descr *d)
 640 {
 641     char *s, *p, *t;
 642     void *data;
 643     char *proto;
 644     int len;
 645
 646     s = (char *)d->buf;
 647
 648     p = strstr(s, "\r\n");
 649     if (p == NULL) {
 650         kdc_log(context, config, 0, "Malformed HTTP request from %s", d->addr_string);
 651         return -1;
 652     }
 653     *p = 0;
 654
 655     p = NULL;
 656     t = strtok_r(s, " \t", &p);
 657     if (t == NULL) {
 658         kdc_log(context, config, 0, "Malformed HTTP request from %s", d->addr_string);
 659         return -1;
 660     }
 661     t = strtok_r(NULL, " \t", &p);
 662     if(t == NULL) {
 663         kdc_log(context, config, 0, "Malformed HTTP request from %s", d->addr_string);
 664         return -1;
 665     }
 666     data = malloc(strlen(t));
 667     if (data == NULL) {
 668         kdc_log(context, config, 0, "Failed to allocate %lu bytes",
 669                 (unsigned long)strlen(t));
 670         return -1;
 671     }
 672     if(*t == '/')
 673         t++;
 674     if(de_http(t) != 0) {
 675         kdc_log(context, config, 0, "Malformed HTTP request from %s", d->addr_string);
 676         kdc_log(context, config, 5, "HTTP request: %s", t);
 677         free(data);
 678         return -1;
 679     }
 680     proto = strtok_r(NULL, " \t", &p);
 681     if (proto == NULL) {
 682         kdc_log(context, config, 0, "Malformed HTTP request from %s", d->addr_string);
 683         free(data);
 684         return -1;
 685     }
 686     len = base64_decode(t, data);
 687     if(len <= 0){
 688         const char *msg =
 689             " 404 Not found\r\n"
 690             "Server: Heimdal/" VERSION "\r\n"
 691             "Cache-Control: no-cache\r\n"
 692             "Pragma: no-cache\r\n"
 693             "Content-type: text/html\r\n"
 694             "Content-transfer-encoding: 8bit\r\n\r\n"
 695             "<TITLE>404 Not found</TITLE>\r\n"
 696             "<H1>404 Not found</H1>\r\n"
 697             "That page doesn't exist, maybe you are looking for "
 698             "<A HREF=\"http://www.h5l.org/\">Heimdal</A>?\r\n";
 699         kdc_log(context, config, 0, "HTTP request from %s is non KDC request", d->addr_string);
 700         kdc_log(context, config, 5, "HTTP request: %s", t);
 701         free(data);
 702         if (write(d->s, proto, strlen(proto)) < 0) {
 703             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 704                     d->addr_string, strerror(errno));
 705             return -1;
 706         }
 707         if (write(d->s, msg, strlen(msg)) < 0) {
 708             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 709                     d->addr_string, strerror(errno));
 710             return -1;
 711         }
 712         return -1;
 713     }
 714     {
 715         const char *msg =
 716             " 200 OK\r\n"
 717             "Server: Heimdal/" VERSION "\r\n"
 718             "Cache-Control: no-cache\r\n"
 719             "Pragma: no-cache\r\n"
 720             "Content-type: application/octet-stream\r\n"
 721             "Content-transfer-encoding: binary\r\n\r\n";
 722         if (write(d->s, proto, strlen(proto)) < 0) {
 723             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 724                     d->addr_string, strerror(errno));
 725             return -1;
 726         }
 727         if (write(d->s, msg, strlen(msg)) < 0) {
 728             kdc_log(context, config, 0, "HTTP write failed: %s: %s",
 729                     d->addr_string, strerror(errno));
 730             return -1;
 731         }
 732     }
 733     memcpy(d->buf, data, len);
 734     d->len = len;
 735     free(data);
 736     return 1;
 737 }
 738
 739 /*
 740  * Handle incoming data to the TCP socket in `d[index]'
 741  */
 742
 743 static void
 744 handle_tcp(krb5_context context,
 745            krb5_kdc_configuration *config,
 746            struct descr *d, int idx, int min_free)
 747 {
 748     unsigned char buf[1024];
 749     int n;
 750     int ret = 0;
 751
 752     if (d[idx].timeout == 0) {
 753         add_new_tcp (context, config, d, idx, min_free);
 754         return;
 755     }
 756
 757     n = recvfrom(d[idx].s, buf, sizeof(buf), 0, NULL, NULL);
 758     if(n < 0){
 759         krb5_warn(context, errno, "recvfrom failed from %s to %s/%d",
 760                   d[idx].addr_string, descr_type(d + idx),
 761                   ntohs(d[idx].port));
 762         return;
 763     } else if (n == 0) {
 764         krb5_warnx(context, "connection closed before end of data after %lu "
 765                    "bytes from %s to %s/%d", (unsigned long)d[idx].len,
 766                    d[idx].addr_string, descr_type(d + idx),
 767                    ntohs(d[idx].port));
 768         clear_descr (d + idx);
 769         return;
 770     }
 771     if (grow_descr (context, config, &d[idx], n))
 772         return;
 773     memcpy(d[idx].buf + d[idx].len, buf, n);
 774     d[idx].len += n;
 775     if(d[idx].len > 4 && d[idx].buf[0] == 0) {
 776         ret = handle_vanilla_tcp (context, config, &d[idx]);
 777     } else if(enable_http &&
 778               d[idx].len >= 4 &&
 779               strncmp((char *)d[idx].buf, "GET ", 4) == 0 &&
 780               strncmp((char *)d[idx].buf + d[idx].len - 4,
 781                       "\r\n\r\n", 4) == 0) {
 782         ret = handle_http_tcp (context, config, &d[idx]);
 783         if (ret < 0)
 784             clear_descr (d + idx);
 785     } else if (d[idx].len > 4) {
 786         kdc_log (context, config,
 787                  0, "TCP data of strange type from %s to %s/%d",
 788                  d[idx].addr_string, descr_type(d + idx),
 789                  ntohs(d[idx].port));
 790         if (d[idx].buf[0] & 0x80) {
 791             krb5_data reply;
 792
 793             kdc_log (context, config, 0, "TCP extension not supported");
 794
 795             ret = krb5_mk_error(context,
 796                                 KRB5KRB_ERR_FIELD_TOOLONG,
 797                                 NULL,
 798                                 NULL,
 799                                 NULL,
 800                                 NULL,
 801                                 NULL,
 802                                 NULL,
 803                                 &reply);
 804             if (ret == 0) {
 805                 send_reply(context, config, TRUE, d + idx, &reply);
 806                 krb5_data_free(&reply);
 807             }
 808         }
 809         clear_descr(d + idx);
 810         return;
 811     }
 812     if (ret < 0)
 813         return;
 814     else if (ret == 1) {
 815         do_request(context, config,
 816                    d[idx].buf, d[idx].len, TRUE, &d[idx]);
 817         clear_descr(d + idx);
 818     }
 819 }
 820
 821 void
 822 loop(krb5_context context,
 823      krb5_kdc_configuration *config)
 824 {
 825     struct descr *d;
 826     int ndescr;
 827
 828     ndescr = init_sockets(context, config, &d);
 829     if(ndescr <= 0)
 830         krb5_errx(context, 1, "No sockets!");
 831     kdc_log(context, config, 0, "KDC started");
 832     while(exit_flag == 0){
 833         struct timeval tmout;
 834         fd_set fds;
 835         int min_free = -1;
 836         int max_fd = 0;
 837         int i;
 838
 839         FD_ZERO(&fds);
 840         for(i = 0; i < ndescr; i++) {
 841             if(d[i].s >= 0){
 842                 if(d[i].type == SOCK_STREAM &&
 843                    d[i].timeout && d[i].timeout < time(NULL)) {
 844                     kdc_log(context, config, 1,
 845                             "TCP-connection from %s expired after %lu bytes",
 846                             d[i].addr_string, (unsigned long)d[i].len);
 847                     clear_descr(&d[i]);
 848                     continue;
 849                 }
 850                 if(max_fd < d[i].s)
 851                     max_fd = d[i].s;
 852                 if (max_fd >= FD_SETSIZE)
 853                     krb5_errx(context, 1, "fd too large");
 854                 FD_SET(d[i].s, &fds);
 855             } else if(min_free < 0 || i < min_free)
 856                 min_free = i;
 857         }
 858         if(min_free == -1){
 859             struct descr *tmp;
 860             tmp = realloc(d, (ndescr + 4) * sizeof(*d));
 861             if(tmp == NULL)
 862                 krb5_warnx(context, "No memory");
 863             else {
 864                 d = tmp;
 865                 reinit_descrs (d, ndescr);
 866                 memset(d + ndescr, 0, 4 * sizeof(*d));
 867                 for(i = ndescr; i < ndescr + 4; i++)
 868                     init_descr (&d[i]);
 869                 min_free = ndescr;
 870                 ndescr += 4;
 871             }
 872         }
 873
 874         tmout.tv_sec = TCP_TIMEOUT;
 875         tmout.tv_usec = 0;
 876         switch(select(max_fd + 1, &fds, 0, 0, &tmout)){
 877         case 0:
 878             break;
 879         case -1:
 880             if (errno != EINTR)
 881                 krb5_warn(context, errno, "select");
 882             break;
 883         default:
 884             for(i = 0; i < ndescr; i++)
 885                 if(d[i].s >= 0 && FD_ISSET(d[i].s, &fds)) {
 886                     if(d[i].type == SOCK_DGRAM)
 887                         handle_udp(context, config, &d[i]);
 888                     else if(d[i].type == SOCK_STREAM)
 889                         handle_tcp(context, config, d, i, min_free);
 890                 }
 891         }
 892     }
 893     if(exit_flag == SIGXCPU)
 894         kdc_log(context, config, 0, "CPU time limit exceeded");
 895     else if(exit_flag == SIGINT || exit_flag == SIGTERM)
 896         kdc_log(context, config, 0, "Terminated");
 897     else
 898         kdc_log(context, config, 0, "Unexpected exit reason: %d", exit_flag);
 899     free (d);
 900 }