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