lib/krb5/send_to_kdc.c

   1 /*
   2  * Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Portions Copyright (c) 2010 - 2013 Apple Inc. All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "krb5_locl.h"
  37 #include "send_to_kdc_plugin.h"
  38
  39 /**
  40  * @section send_to_kdc Locating and sending packets to the KDC
  41  *
  42  * The send to kdc code is responsible to request the list of KDC from
  43  * the locate-kdc subsystem and then send requests to each of them.
  44  *
  45  * - Each second a new hostname is tried.
  46  * - If the hostname have several addresses, the first will be tried
  47  *   directly then in turn the other will be tried every 3 seconds
  48  *   (host_timeout).
  49  * - UDP requests are tried 3 times, and it tried with a individual timeout of kdc_timeout / 3.
  50  * - TCP and HTTP requests are tried 1 time.
  51  *
  52  *  Total wait time shorter then (number of addresses * 3) + kdc_timeout seconds.
  53  *
  54  */
  55
  56 static int
  57 init_port(const char *s, int fallback)
  58 {
  59     int tmp;
  60
  61     if (s && sscanf(s, "%d", &tmp) == 1)
  62         return htons(tmp);
  63     return fallback;
  64 }
  65
  66 struct send_via_plugin_s {
  67     krb5_const_realm realm;
  68     krb5_krbhst_info *hi;
  69     time_t timeout;
  70     const krb5_data *send_data;
  71     krb5_data *receive;
  72 };
  73
  74
  75 static krb5_error_code KRB5_LIB_CALL
  76 kdccallback(krb5_context context, const void *plug, void *plugctx, void *userctx)
  77 {
  78     const krb5plugin_send_to_kdc_ftable *service = (const krb5plugin_send_to_kdc_ftable *)plug;
  79     struct send_via_plugin_s *ctx = userctx;
  80
  81     if (service->send_to_kdc == NULL)
  82         return KRB5_PLUGIN_NO_HANDLE;
  83     return service->send_to_kdc(context, plugctx, ctx->hi, ctx->timeout,
  84                                 ctx->send_data, ctx->receive);
  85 }
  86
  87 static krb5_error_code KRB5_LIB_CALL
  88 realmcallback(krb5_context context, const void *plug, void *plugctx, void *userctx)
  89 {
  90     const krb5plugin_send_to_kdc_ftable *service = (const krb5plugin_send_to_kdc_ftable *)plug;
  91     struct send_via_plugin_s *ctx = userctx;
  92
  93     if (service->send_to_realm == NULL)
  94         return KRB5_PLUGIN_NO_HANDLE;
  95     return service->send_to_realm(context, plugctx, ctx->realm, ctx->timeout,
  96                                   ctx->send_data, ctx->receive);
  97 }
  98
  99 static const char *const send_to_kdc_plugin_deps[] = { "krb5", NULL };
 100
 101 static const struct heim_plugin_data
 102 send_to_kdc_plugin_data = {
 103     "krb5",
 104     KRB5_PLUGIN_SEND_TO_KDC,
 105     KRB5_PLUGIN_SEND_TO_KDC_VERSION_0,
 106     send_to_kdc_plugin_deps,
 107     krb5_get_instance
 108 };
 109
 110 static krb5_error_code
 111 kdc_via_plugin(krb5_context context,
 112                krb5_krbhst_info *hi,
 113                time_t timeout,
 114                const krb5_data *send_data,
 115                krb5_data *receive)
 116 {
 117     struct send_via_plugin_s userctx;
 118
 119     userctx.realm = NULL;
 120     userctx.hi = hi;
 121     userctx.timeout = timeout;
 122     userctx.send_data = send_data;
 123     userctx.receive = receive;
 124
 125     return _krb5_plugin_run_f(context, &send_to_kdc_plugin_data, 0,
 126                               &userctx, kdccallback);
 127 }
 128
 129 static krb5_error_code
 130 realm_via_plugin(krb5_context context,
 131                  krb5_const_realm realm,
 132                  time_t timeout,
 133                  const krb5_data *send_data,
 134                  krb5_data *receive)
 135 {
 136     struct send_via_plugin_s userctx;
 137
 138     userctx.realm = realm;
 139     userctx.hi = NULL;
 140     userctx.timeout = timeout;
 141     userctx.send_data = send_data;
 142     userctx.receive = receive;
 143
 144     return _krb5_plugin_run_f(context, &send_to_kdc_plugin_data, 0,
 145                               &userctx, realmcallback);
 146 }
 147
 148 struct krb5_sendto_ctx_data {
 149     int flags;
 150     int type;
 151     krb5_sendto_ctx_func func;
 152     void *data;
 153     char *hostname;
 154     char *sitename;
 155     krb5_krbhst_handle krbhst;
 156
 157     /* context2 */
 158     const krb5_data *send_data;
 159     krb5_data response;
 160     heim_array_t hosts;
 161     int stateflags;
 162 #define KRBHST_COMPLETED        1
 163
 164     /* prexmit */
 165     krb5_sendto_prexmit prexmit_func;
 166     void *prexmit_ctx;
 167
 168     /* stats */
 169     struct {
 170         struct timeval start_time;
 171         struct timeval name_resolution;
 172         struct timeval krbhst;
 173         unsigned long sent_packets;
 174         unsigned long num_hosts;
 175     } stats;
 176     unsigned int stid;
 177 };
 178
 179 static void KRB5_CALLCONV
 180 dealloc_sendto_ctx(void *ptr)
 181 {
 182     krb5_sendto_ctx ctx = (krb5_sendto_ctx)ptr;
 183     if (ctx->hostname)
 184         free(ctx->hostname);
 185     if (ctx->sitename)
 186         free(ctx->sitename);
 187     heim_release(ctx->hosts);
 188     heim_release(ctx->krbhst);
 189 }
 190
 191 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 192 krb5_sendto_ctx_alloc(krb5_context context, krb5_sendto_ctx *ctx)
 193 {
 194     *ctx = heim_alloc(sizeof(**ctx), "sendto-context", dealloc_sendto_ctx);
 195     if (*ctx == NULL)
 196         return krb5_enomem(context);
 197     (*ctx)->hosts = heim_array_create();
 198
 199     return 0;
 200 }
 201
 202 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 203 krb5_sendto_ctx_add_flags(krb5_sendto_ctx ctx, int flags)
 204 {
 205     ctx->flags |= flags;
 206 }
 207
 208 KRB5_LIB_FUNCTION int KRB5_LIB_CALL
 209 krb5_sendto_ctx_get_flags(krb5_sendto_ctx ctx)
 210 {
 211     return ctx->flags;
 212 }
 213
 214 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 215 krb5_sendto_ctx_set_type(krb5_sendto_ctx ctx, int type)
 216 {
 217     ctx->type = type;
 218 }
 219
 220 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 221 krb5_sendto_ctx_set_func(krb5_sendto_ctx ctx,
 222                          krb5_sendto_ctx_func func,
 223                          void *data)
 224 {
 225     ctx->func = func;
 226     ctx->data = data;
 227 }
 228
 229 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 230 _krb5_sendto_ctx_set_prexmit(krb5_sendto_ctx ctx,
 231                              krb5_sendto_prexmit prexmit,
 232                              void *data)
 233 {
 234     ctx->prexmit_func = prexmit;
 235     ctx->prexmit_ctx = data;
 236 }
 237
 238 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 239 krb5_sendto_set_hostname(krb5_context context,
 240                          krb5_sendto_ctx ctx,
 241                          const char *hostname)
 242 {
 243     char *newname;
 244
 245     /*
 246      * Handle the case where hostname == ctx->hostname by copying it first, and
 247      * disposing of any previous value after.
 248      */
 249     newname = strdup(hostname);
 250     if (newname == NULL)
 251         return krb5_enomem(context);
 252     free(ctx->hostname);
 253     ctx->hostname = newname;
 254     return 0;
 255 }
 256
 257 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 258 krb5_sendto_set_sitename(krb5_context context,
 259                          krb5_sendto_ctx ctx,
 260                          const char *sitename)
 261 {
 262     char *newname;
 263
 264     newname = strdup(sitename);
 265     if (newname == NULL)
 266         return krb5_enomem(context);
 267     free(ctx->sitename);
 268     ctx->sitename = newname;
 269     return 0;
 270 }
 271
 272 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 273 _krb5_sendto_ctx_set_krb5hst(krb5_context context,
 274                              krb5_sendto_ctx ctx,
 275                              krb5_krbhst_handle handle)
 276 {
 277     heim_release(ctx->krbhst);
 278     ctx->krbhst = heim_retain(handle);
 279 }
 280
 281 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 282 krb5_sendto_ctx_free(krb5_context context, krb5_sendto_ctx ctx)
 283 {
 284     heim_release(ctx);
 285 }
 286
 287 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 288 _krb5_kdc_retry(krb5_context context, krb5_sendto_ctx ctx, void *data,
 289                 const krb5_data *reply, int *action)
 290 {
 291     krb5_error_code ret;
 292     KRB_ERROR error;
 293
 294     if(krb5_rd_error(context, reply, &error))
 295         return 0;
 296
 297     ret = krb5_error_from_rd_error(context, &error, NULL);
 298     krb5_free_error_contents(context, &error);
 299
 300     switch(ret) {
 301     case KRB5KRB_ERR_RESPONSE_TOO_BIG: {
 302         if (krb5_sendto_ctx_get_flags(ctx) & KRB5_KRBHST_FLAGS_LARGE_MSG)
 303             break;
 304         krb5_sendto_ctx_add_flags(ctx, KRB5_KRBHST_FLAGS_LARGE_MSG);
 305         *action = KRB5_SENDTO_RESET;
 306         break;
 307     }
 308     case KRB5KDC_ERR_SVC_UNAVAILABLE:
 309         *action = KRB5_SENDTO_RESET;
 310         break;
 311     }
 312     return 0;
 313 }
 314
 315 /*
 316  *
 317  */
 318
 319 struct host;
 320
 321 struct host_fun {
 322     krb5_error_code (*prepare)(krb5_context, struct host *, const krb5_data *);
 323     krb5_error_code (*send_fn)(krb5_context, struct host *);
 324     krb5_error_code (*recv_fn)(krb5_context, struct host *, krb5_data *);
 325     int ntries;
 326 };
 327
 328 struct host {
 329     enum host_state { CONNECT, CONNECTING, CONNECTED, WAITING_REPLY, DEAD } state;
 330     krb5_krbhst_info *hi;
 331     struct addrinfo *freeai;
 332     struct addrinfo *ai;
 333     rk_socket_t fd;
 334     const struct host_fun *fun;
 335     unsigned int tries;
 336     time_t timeout;
 337     krb5_data data;
 338     unsigned int tid;
 339 };
 340
 341 static void
 342 debug_host(krb5_context context, int level, struct host *host, const char *fmt, ...)
 343         __attribute__ ((__format__ (__printf__, 4, 5)));
 344
 345 static void
 346 debug_host(krb5_context context, int level, struct host *host, const char *fmt, ...)
 347 {
 348     const char *proto = "unknown";
 349     const char *state;
 350     char name[NI_MAXHOST], port[NI_MAXSERV];
 351     char *text = NULL;
 352     va_list ap;
 353     int ret;
 354
 355     if (!_krb5_have_debug(context, 5))
 356         return;
 357
 358     va_start(ap, fmt);
 359     ret = vasprintf(&text, fmt, ap);
 360     va_end(ap);
 361     if (ret == -1 || text == NULL)
 362         return;
 363
 364     if (host->hi->proto == KRB5_KRBHST_HTTP)
 365         proto = "http";
 366     else if (host->hi->proto == KRB5_KRBHST_TCP)
 367         proto = "tcp";
 368     else if (host->hi->proto == KRB5_KRBHST_UDP)
 369         proto = "udp";
 370
 371     if (getnameinfo(host->ai->ai_addr, host->ai->ai_addrlen,
 372                     name, sizeof(name), port, sizeof(port),
 373                     NI_NUMERICHOST|NI_NUMERICSERV|NI_NUMERICSCOPE) != 0)
 374         name[0] = '\0';
 375
 376     switch (host->state) {
 377     case CONNECT:       state = "CONNECT";              break;
 378     case CONNECTING:    state = "CONNECTING";           break;
 379     case CONNECTED:     state = "CONNECTED";            break;
 380     case WAITING_REPLY: state = "WAITING_REPLY";        break;
 381     case DEAD:          state = "DEAD";                 break;
 382     default:            state = "unknown";              break;
 383     }
 384
 385     _krb5_debug(context, level, "%s: %s %s:%s (%s) state=%s tid: %08x", text,
 386                 proto, name, port, host->hi->hostname, state, host->tid);
 387     free(text);
 388 }
 389
 390
 391 static void HEIM_CALLCONV
 392 deallocate_host(void *ptr)
 393 {
 394     struct host *host = ptr;
 395     if (!rk_IS_BAD_SOCKET(host->fd))
 396         rk_closesocket(host->fd);
 397     krb5_data_free(&host->data);
 398     if (host->freeai)
 399         freeaddrinfo(host->freeai);
 400     host->freeai = NULL;
 401     host->ai = NULL;
 402 }
 403
 404 static void
 405 host_dead(krb5_context context, struct host *host, const char *msg)
 406 {
 407     debug_host(context, 5, host, "%s", msg);
 408     rk_closesocket(host->fd);
 409     host->fd = rk_INVALID_SOCKET;
 410     host->state = DEAD;
 411 }
 412
 413 static krb5_error_code
 414 send_stream(krb5_context context, struct host *host)
 415 {
 416     ssize_t len;
 417
 418     len = krb5_net_write(context, &host->fd, host->data.data, host->data.length);
 419
 420     if (len < 0)
 421         return errno;
 422     else if (len < host->data.length) {
 423         host->data.length -= len;
 424         memmove(host->data.data, ((uint8_t *)host->data.data) + len, host->data.length - len);
 425         return -1;
 426     } else {
 427         krb5_data_free(&host->data);
 428         return 0;
 429     }
 430 }
 431
 432 static krb5_error_code
 433 recv_stream(krb5_context context, struct host *host)
 434 {
 435     krb5_error_code ret;
 436     size_t oldlen;
 437     ssize_t sret;
 438     int nbytes;
 439
 440     if (rk_SOCK_IOCTL(host->fd, FIONREAD, &nbytes) != 0 || nbytes <= 0)
 441         return HEIM_NET_CONN_REFUSED;
 442
 443     if (context->max_msg_size - host->data.length < nbytes) {
 444         krb5_set_error_message(context, KRB5KRB_ERR_FIELD_TOOLONG,
 445                                N_("TCP message from KDC too large %d", ""),
 446                                (int)(host->data.length + nbytes));
 447         return KRB5KRB_ERR_FIELD_TOOLONG;
 448     }
 449
 450     oldlen = host->data.length;
 451
 452     ret = krb5_data_realloc(&host->data, oldlen + nbytes + 1 /* NUL */);
 453     if (ret)
 454         return ret;
 455
 456     sret = krb5_net_read(context, &host->fd, ((uint8_t *)host->data.data) + oldlen, nbytes);
 457     if (sret <= 0) {
 458         ret = errno;
 459         return ret;
 460     }
 461     host->data.length = oldlen + sret;
 462     /* zero terminate for http transport */
 463     ((uint8_t *)host->data.data)[host->data.length] = '\0';
 464
 465     return 0;
 466 }
 467
 468 /*
 469  *
 470  */
 471
 472 static void
 473 host_next_timeout(krb5_context context, struct host *host)
 474 {
 475     host->timeout = context->kdc_timeout / host->fun->ntries;
 476     if (host->timeout == 0)
 477         host->timeout = 1;
 478
 479     host->timeout += time(NULL);
 480 }
 481
 482 /*
 483  * connected host
 484  */
 485
 486 static void
 487 host_connected(krb5_context context, krb5_sendto_ctx ctx, struct host *host)
 488 {
 489     krb5_error_code ret;
 490
 491     host->state = CONNECTED;
 492     /*
 493      * Now prepare data to send to host
 494      */
 495     if (ctx->prexmit_func) {
 496         krb5_data data;
 497
 498         krb5_data_zero(&data);
 499
 500         ret = ctx->prexmit_func(context, host->hi->proto,
 501                                 ctx->prexmit_ctx, host->fd, &data);
 502         if (ret == 0) {
 503             if (data.length == 0) {
 504                 host_dead(context, host, "prexmit function didn't send data");
 505                 return;
 506             }
 507             ret = host->fun->prepare(context, host, &data);
 508             krb5_data_free(&data);
 509         }
 510
 511     } else {
 512         ret = host->fun->prepare(context, host, ctx->send_data);
 513     }
 514     if (ret)
 515         debug_host(context, 5, host, "failed to prexmit/prepare");
 516 }
 517
 518 /*
 519  * connect host
 520  */
 521
 522 static void
 523 host_connect(krb5_context context, krb5_sendto_ctx ctx, struct host *host)
 524 {
 525     krb5_krbhst_info *hi = host->hi;
 526     struct addrinfo *ai = host->ai;
 527
 528     debug_host(context, 5, host, "connecting to host");
 529
 530     if (connect(host->fd, ai->ai_addr, ai->ai_addrlen) < 0) {
 531 #ifdef HAVE_WINSOCK
 532         if (WSAGetLastError() == WSAEWOULDBLOCK)
 533             errno = EINPROGRESS;
 534 #endif /* HAVE_WINSOCK */
 535         if (errno == EINPROGRESS && (hi->proto == KRB5_KRBHST_HTTP || hi->proto == KRB5_KRBHST_TCP)) {
 536             debug_host(context, 5, host, "connecting to %d", host->fd);
 537             host->state = CONNECTING;
 538         } else {
 539             host_dead(context, host, "failed to connect");
 540         }
 541     } else {
 542         host_connected(context, ctx, host);
 543     }
 544
 545     host_next_timeout(context, host);
 546 }
 547
 548 /*
 549  * HTTP transport
 550  */
 551
 552 static krb5_error_code
 553 prepare_http(krb5_context context, struct host *host, const krb5_data *data)
 554 {
 555     char *str = NULL, *request = NULL;
 556     krb5_error_code ret;
 557     int len;
 558
 559     heim_assert(host->data.length == 0, "prepare_http called twice");
 560
 561     len = rk_base64_encode(data->data, data->length, &str);
 562     if(len < 0)
 563         return ENOMEM;
 564
 565     if (context->http_proxy)
 566         ret = asprintf(&request, "GET http://%s/%s HTTP/1.0\r\n\r\n", host->hi->hostname, str);
 567     else
 568         ret = asprintf(&request, "GET /%s HTTP/1.0\r\n\r\n", str);
 569     free(str);
 570     if(ret < 0 || request == NULL)
 571         return ENOMEM;
 572
 573     host->data.data = request;
 574     host->data.length = strlen(request);
 575
 576     return 0;
 577 }
 578
 579 static krb5_error_code
 580 recv_http(krb5_context context, struct host *host, krb5_data *data)
 581 {
 582     krb5_error_code ret;
 583     unsigned long rep_len;
 584     size_t len;
 585     char *p;
 586
 587     /*
 588      * recv_stream returns a NUL terminated stream
 589      */
 590
 591     ret = recv_stream(context, host);
 592     if (ret)
 593         return ret;
 594
 595     p = strstr(host->data.data, "\r\n\r\n");
 596     if (p == NULL)
 597         return -1;
 598     p += 4;
 599
 600     len = host->data.length - (p - (char *)host->data.data);
 601     if (len < 4)
 602         return -1;
 603
 604     _krb5_get_int(p, &rep_len, 4);
 605     if (len < rep_len)
 606         return -1;
 607
 608     p += 4;
 609
 610     memmove(host->data.data, p, rep_len);
 611     host->data.length = rep_len;
 612
 613     *data = host->data;
 614     krb5_data_zero(&host->data);
 615
 616     return 0;
 617 }
 618
 619 /*
 620  * TCP transport
 621  */
 622
 623 static krb5_error_code
 624 prepare_tcp(krb5_context context, struct host *host, const krb5_data *data)
 625 {
 626     krb5_error_code ret;
 627     krb5_storage *sp;
 628
 629     heim_assert(host->data.length == 0, "prepare_tcp called twice");
 630
 631     sp = krb5_storage_emem();
 632     if (sp == NULL)
 633         return ENOMEM;
 634
 635     ret = krb5_store_data(sp, *data);
 636     if (ret) {
 637         krb5_storage_free(sp);
 638         return ret;
 639     }
 640     ret = krb5_storage_to_data(sp, &host->data);
 641     krb5_storage_free(sp);
 642
 643     return ret;
 644 }
 645
 646 static krb5_error_code
 647 recv_tcp(krb5_context context, struct host *host, krb5_data *data)
 648 {
 649     krb5_error_code ret;
 650     unsigned long pktlen;
 651
 652     ret = recv_stream(context, host);
 653     if (ret)
 654         return ret;
 655
 656     if (host->data.length < 4)
 657         return -1;
 658
 659     _krb5_get_int(host->data.data, &pktlen, 4);
 660
 661     if (pktlen > host->data.length - 4)
 662         return -1;
 663
 664     memmove(host->data.data, ((uint8_t *)host->data.data) + 4, host->data.length - 4);
 665     host->data.length -= 4;
 666
 667     *data = host->data;
 668     krb5_data_zero(&host->data);
 669
 670     return 0;
 671 }
 672
 673 /*
 674  * UDP transport
 675  */
 676
 677 static krb5_error_code
 678 prepare_udp(krb5_context context, struct host *host, const krb5_data *data)
 679 {
 680     return krb5_data_copy(&host->data, data->data, data->length);
 681 }
 682
 683 static krb5_error_code
 684 send_udp(krb5_context context, struct host *host)
 685 {
 686     if (send(host->fd, host->data.data, host->data.length, 0) < 0)
 687         return errno;
 688     return 0;
 689 }
 690
 691 static krb5_error_code
 692 recv_udp(krb5_context context, struct host *host, krb5_data *data)
 693 {
 694     krb5_error_code ret;
 695     int nbytes;
 696
 697
 698     if (rk_SOCK_IOCTL(host->fd, FIONREAD, &nbytes) != 0 || nbytes <= 0)
 699         return HEIM_NET_CONN_REFUSED;
 700
 701     if (context->max_msg_size < nbytes) {
 702         krb5_set_error_message(context, KRB5KRB_ERR_FIELD_TOOLONG,
 703                                N_("UDP message from KDC too large %d", ""),
 704                                (int)nbytes);
 705         return KRB5KRB_ERR_FIELD_TOOLONG;
 706     }
 707
 708     ret = krb5_data_alloc(data, nbytes);
 709     if (ret)
 710         return ret;
 711
 712     ret = recv(host->fd, data->data, data->length, 0);
 713     if (ret < 0) {
 714         ret = errno;
 715         krb5_data_free(data);
 716         return ret;
 717     }
 718     data->length = ret;
 719
 720     return 0;
 721 }
 722
 723 static const struct host_fun http_fun = {
 724     prepare_http,
 725     send_stream,
 726     recv_http,
 727     1
 728 };
 729 static const struct host_fun tcp_fun = {
 730     prepare_tcp,
 731     send_stream,
 732     recv_tcp,
 733     1
 734 };
 735 static const struct host_fun udp_fun = {
 736     prepare_udp,
 737     send_udp,
 738     recv_udp,
 739     3
 740 };
 741
 742
 743 /*
 744  * Host state machine
 745  */
 746
 747 static int
 748 eval_host_state(krb5_context context,
 749                 krb5_sendto_ctx ctx,
 750                 struct host *host,
 751                 int readable, int writeable)
 752 {
 753     krb5_error_code ret;
 754
 755     if (host->state == CONNECT) {
 756         /* check if its this host time to connect */
 757         if (host->timeout < time(NULL))
 758             host_connect(context, ctx, host);
 759         return 0;
 760     }
 761
 762     if (host->state == CONNECTING && writeable)
 763         host_connected(context, ctx, host);
 764
 765     if (readable) {
 766
 767         debug_host(context, 5, host, "reading packet");
 768
 769         ret = host->fun->recv_fn(context, host, &ctx->response);
 770         if (ret == -1) {
 771             /* not done yet */
 772         } else if (ret == 0) {
 773             /* if recv_foo function returns 0, we have a complete reply */
 774             debug_host(context, 5, host, "host completed");
 775             return 1;
 776         } else {
 777             host_dead(context, host, "host disconnected");
 778         }
 779     }
 780
 781     /* check if there is anything to send, state might DEAD after read */
 782     if (writeable && host->state == CONNECTED) {
 783
 784         ctx->stats.sent_packets++;
 785
 786         debug_host(context, 5, host, "writing packet");
 787
 788         ret = host->fun->send_fn(context, host);
 789         if (ret == -1) {
 790             /* not done yet */
 791         } else if (ret) {
 792             host_dead(context, host, "host dead, write failed");
 793         } else
 794             host->state = WAITING_REPLY;
 795     }
 796
 797     return 0;
 798 }
 799
 800 /*
 801  *
 802  */
 803
 804 static krb5_error_code
 805 submit_request(krb5_context context, krb5_sendto_ctx ctx, krb5_krbhst_info *hi)
 806 {
 807     unsigned long submitted_host = 0;
 808     struct addrinfo *freeai = NULL;
 809     struct timeval nrstart, nrstop;
 810     krb5_error_code ret;
 811     struct addrinfo *ai = NULL, *a;
 812     struct host *host;
 813
 814     ret = kdc_via_plugin(context, hi, context->kdc_timeout,
 815                          ctx->send_data, &ctx->response);
 816     if (ret == 0) {
 817         return 0;
 818     } else if (ret != KRB5_PLUGIN_NO_HANDLE) {
 819         _krb5_debug(context, 5, "send via plugin failed %s: %d",
 820                     hi->hostname, ret);
 821         return ret;
 822     }
 823
 824     /*
 825      * If we have a proxy, let use the address of the proxy instead of
 826      * the KDC and let the proxy deal with the resolving of the KDC.
 827      */
 828
 829     gettimeofday(&nrstart, NULL);
 830
 831     if (hi->proto == KRB5_KRBHST_HTTP && context->http_proxy) {
 832         char *proxy2 = strdup(context->http_proxy);
 833         char *el, *proxy  = proxy2;
 834         struct addrinfo hints;
 835         char portstr[NI_MAXSERV];
 836         unsigned short nport;
 837
 838         if (proxy == NULL)
 839             return ENOMEM;
 840         if (strncmp(proxy, "http://", 7) == 0)
 841             proxy += 7;
 842
 843         /* check for url terminating slash */
 844         el = strchr(proxy, '/');
 845         if (el != NULL)
 846             *el = '\0';
 847
 848         /* check for port in hostname, used below as port */
 849         el = strchr(proxy, ':');
 850         if(el != NULL)
 851             *el++ = '\0';
 852
 853         memset(&hints, 0, sizeof(hints));
 854         hints.ai_family   = PF_UNSPEC;
 855         hints.ai_socktype = SOCK_STREAM;
 856
 857         /* On some systems ntohs(foo(..., htons(...))) causes shadowing */
 858         nport = init_port(el, htons(80));
 859         snprintf(portstr, sizeof(portstr), "%d", ntohs(nport));
 860
 861         if (krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
 862                 NULL)) {
 863             hints.ai_flags &= ~AI_CANONNAME;
 864             hints.ai_flags |= AI_NUMERICHOST|AI_NUMERICSERV;
 865         }
 866         ret = getaddrinfo(proxy, portstr, &hints, &ai);
 867         free(proxy2);
 868         if (ret)
 869             return krb5_eai_to_heim_errno(ret, errno);
 870
 871         freeai = ai;
 872
 873     } else {
 874         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 875         if (ret)
 876             return ret;
 877     }
 878
 879     /* add up times */
 880     gettimeofday(&nrstop, NULL);
 881     timevalsub(&nrstop, &nrstart);
 882     timevaladd(&ctx->stats.name_resolution, &nrstop);
 883
 884     ctx->stats.num_hosts++;
 885
 886     for (a = ai; a != NULL; a = a->ai_next) {
 887         rk_socket_t fd;
 888
 889         fd = socket(a->ai_family, a->ai_socktype | SOCK_CLOEXEC, a->ai_protocol);
 890         if (rk_IS_BAD_SOCKET(fd))
 891             continue;
 892         rk_cloexec(fd);
 893
 894 #ifndef NO_LIMIT_FD_SETSIZE
 895         if (fd >= FD_SETSIZE) {
 896             _krb5_debug(context, 0, "fd too large for select");
 897             rk_closesocket(fd);
 898             continue;
 899         }
 900 #endif
 901         socket_set_nonblocking(fd, 1);
 902
 903         host = heim_alloc(sizeof(*host), "sendto-host", deallocate_host);
 904         if (host == NULL) {
 905             if (freeai)
 906                 freeaddrinfo(freeai);
 907             rk_closesocket(fd);
 908             return ENOMEM;
 909         }
 910         host->hi = hi;
 911         host->fd = fd;
 912         host->ai = a;
 913         host->freeai = freeai;
 914         freeai = NULL;
 915         /* next version of stid */
 916         host->tid = ctx->stid = (ctx->stid & 0xffff0000) | ((ctx->stid & 0xffff) + 1);
 917
 918         host->state = CONNECT;
 919
 920         switch (host->hi->proto) {
 921         case KRB5_KRBHST_HTTP :
 922             host->fun = &http_fun;
 923             break;
 924         case KRB5_KRBHST_TCP :
 925             host->fun = &tcp_fun;
 926             break;
 927         case KRB5_KRBHST_UDP :
 928             host->fun = &udp_fun;
 929             break;
 930         default:
 931             heim_abort("undefined http transport protocol: %d", (int)host->hi->proto);
 932         }
 933
 934         host->tries = host->fun->ntries;
 935
 936         /*
 937          * Connect directly next host, wait a host_timeout for each next address.
 938          * We try host_connect() here, checking the return code because as we do
 939          * non-blocking connects, any error here indicates that the address is just
 940          * offline.  That is, it's something like "No route to host" which is not
 941          * worth retrying.  And so, we fail directly and immediately to the next
 942          * address for this host without enqueueing the address for retries.
 943          */
 944         if (submitted_host == 0) {
 945             host_connect(context, ctx, host);
 946             if (host->state == DEAD)
 947                 continue;
 948         } else {
 949             debug_host(context, 5, host,
 950                        "Queuing host in future (in %ds), its the %lu address on the same name",
 951                        (int)(context->host_timeout * submitted_host), submitted_host + 1);
 952             host->timeout = time(NULL) + (submitted_host * context->host_timeout);
 953         }
 954
 955         heim_array_append_value(ctx->hosts, host);
 956         heim_release(host);
 957         submitted_host++;
 958     }
 959
 960     if (freeai)
 961         freeai = NULL;
 962
 963     if (submitted_host == 0)
 964         return KRB5_KDC_UNREACH;
 965
 966     return 0;
 967 }
 968
 969 struct wait_ctx {
 970     krb5_context context;
 971     krb5_sendto_ctx ctx;
 972     fd_set rfds;
 973     fd_set wfds;
 974     rk_socket_t max_fd;
 975     int got_reply;
 976     time_t timenow;
 977 };
 978
 979 static void
 980 wait_setup(heim_object_t obj, void *iter_ctx, int *stop)
 981 {
 982     struct wait_ctx *wait_ctx = iter_ctx;
 983     struct host *h = (struct host *)obj;
 984
 985     if (h->state == CONNECT) {
 986         if (h->timeout >= wait_ctx->timenow)
 987             return;
 988         host_connect(wait_ctx->context, wait_ctx->ctx, h);
 989     }
 990
 991     /* skip dead hosts */
 992     if (h->state == DEAD)
 993         return;
 994
 995     /* if host timed out, dec tries and (retry or kill host) */
 996     if (h->timeout < wait_ctx->timenow) {
 997         heim_assert(h->tries != 0, "tries should not reach 0");
 998         h->tries--;
 999         if (h->tries == 0) {
1000             host_dead(wait_ctx->context, h, "host timed out");
1001             return;
1002         } else {
1003             debug_host(wait_ctx->context, 5, h, "retrying sending to");
1004             host_next_timeout(wait_ctx->context, h);
1005             host_connected(wait_ctx->context, wait_ctx->ctx, h);
1006         }
1007     }
1008
1009 #ifndef NO_LIMIT_FD_SETSIZE
1010     heim_assert(h->fd < FD_SETSIZE, "fd too large");
1011 #endif
1012     switch (h->state) {
1013     case WAITING_REPLY:
1014         FD_SET(h->fd, &wait_ctx->rfds);
1015         break;
1016     case CONNECTING:
1017     case CONNECTED:
1018         FD_SET(h->fd, &wait_ctx->rfds);
1019         FD_SET(h->fd, &wait_ctx->wfds);
1020         break;
1021     default:
1022         debug_host(wait_ctx->context, 5, h, "invalid sendto host state");
1023         heim_abort("invalid sendto host state");
1024     }
1025     if (h->fd > wait_ctx->max_fd || wait_ctx->max_fd == rk_INVALID_SOCKET)
1026         wait_ctx->max_fd = h->fd;
1027 }
1028
1029 static int
1030 wait_filter_dead(heim_object_t obj, void *ctx)
1031 {
1032     struct host *h = (struct host *)obj;
1033     return (int)((h->state == DEAD) ? true : false);
1034 }
1035
1036 static void
1037 wait_accelerate(heim_object_t obj, void *ctx, int *stop)
1038 {
1039     struct host *h = (struct host *)obj;
1040
1041     if (h->state == CONNECT && h->timeout > 0)
1042         h->timeout--;
1043 }
1044
1045 static void
1046 wait_process(heim_object_t obj, void *ctx, int *stop)
1047 {
1048     struct wait_ctx *wait_ctx = ctx;
1049     struct host *h = (struct host *)obj;
1050     int readable, writeable;
1051     heim_assert(h->state != DEAD, "dead host resurected");
1052
1053 #ifndef NO_LIMIT_FD_SETSIZE
1054     heim_assert(h->fd < FD_SETSIZE, "fd too large");
1055 #endif
1056     readable = FD_ISSET(h->fd, &wait_ctx->rfds);
1057     writeable = FD_ISSET(h->fd, &wait_ctx->wfds);
1058
1059     if (readable || writeable || h->state == CONNECT)
1060         wait_ctx->got_reply |= eval_host_state(wait_ctx->context, wait_ctx->ctx, h, readable, writeable);
1061
1062     /* if there is already a reply, just fall though the array */
1063     if (wait_ctx->got_reply)
1064         *stop = 1;
1065 }
1066
1067 static krb5_error_code
1068 wait_response(krb5_context context, int *action, krb5_sendto_ctx ctx)
1069 {
1070     struct wait_ctx wait_ctx;
1071     struct timeval tv;
1072     int ret;
1073
1074     wait_ctx.context = context;
1075     wait_ctx.ctx = ctx;
1076     FD_ZERO(&wait_ctx.rfds);
1077     FD_ZERO(&wait_ctx.wfds);
1078     wait_ctx.max_fd = rk_INVALID_SOCKET;
1079
1080     /* oh, we have a reply, it must be a plugin that got it for us */
1081     if (ctx->response.length) {
1082         *action = KRB5_SENDTO_FILTER;
1083         return 0;
1084     }
1085
1086     wait_ctx.timenow = time(NULL);
1087
1088     heim_array_iterate_f(ctx->hosts, &wait_ctx, wait_setup);
1089     heim_array_filter_f(ctx->hosts, &wait_ctx, wait_filter_dead);
1090
1091     if (heim_array_get_length(ctx->hosts) == 0) {
1092         if (ctx->stateflags & KRBHST_COMPLETED) {
1093             _krb5_debug(context, 5, "no more hosts to send/recv packets to/from "
1094                          "trying to pulling more hosts");
1095             *action = KRB5_SENDTO_FAILED;
1096         } else {
1097             _krb5_debug(context, 5, "no more hosts to send/recv packets to/from "
1098                          "and no more hosts -> failure");
1099             *action = KRB5_SENDTO_TIMEOUT;
1100         }
1101         return 0;
1102     }
1103
1104     if (wait_ctx.max_fd == rk_INVALID_SOCKET) {
1105         /*
1106          * If we don't find a host which can make progress, then
1107          * we accelerate the process by moving all of the contestants
1108          * up by 1s.
1109          */
1110         _krb5_debug(context, 5, "wait_response: moving the contestants forward");
1111         heim_array_iterate_f(ctx->hosts, &wait_ctx, wait_accelerate);
1112         return 0;
1113     }
1114
1115     tv.tv_sec = 1;
1116     tv.tv_usec = 0;
1117
1118     ret = select(wait_ctx.max_fd + 1, &wait_ctx.rfds, &wait_ctx.wfds, NULL, &tv);
1119     if (ret < 0)
1120         return errno;
1121     if (ret == 0) {
1122         *action = KRB5_SENDTO_TIMEOUT;
1123         return 0;
1124     }
1125
1126     wait_ctx.got_reply = 0;
1127     heim_array_iterate_f(ctx->hosts, &wait_ctx, wait_process);
1128     if (wait_ctx.got_reply)
1129         *action = KRB5_SENDTO_FILTER;
1130     else
1131         *action = KRB5_SENDTO_CONTINUE;
1132
1133     return 0;
1134 }
1135
1136 static void
1137 reset_context(krb5_context context, krb5_sendto_ctx ctx)
1138 {
1139     krb5_data_free(&ctx->response);
1140     heim_release(ctx->hosts);
1141     ctx->hosts = heim_array_create();
1142     ctx->stateflags = 0;
1143 }
1144
1145
1146 /*
1147  *
1148  */
1149
1150 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
1151 krb5_sendto_context(krb5_context context,
1152                     krb5_sendto_ctx ctx,
1153                     const krb5_data *send_data,
1154                     krb5_const_realm realm,
1155                     krb5_data *receive)
1156 {
1157     krb5_error_code ret = 0;
1158     krb5_krbhst_handle handle = NULL;
1159     struct timeval nrstart, nrstop, stop_time;
1160     int type, freectx = 0;
1161     int action;
1162     int numreset = 0;
1163
1164     krb5_data_zero(receive);
1165
1166     if (ctx == NULL) {
1167         ret = krb5_sendto_ctx_alloc(context, &ctx);
1168         if (ret)
1169             goto out;
1170         freectx = 1;
1171     }
1172
1173     ctx->stid = (context->num_kdc_requests++) << 16;
1174
1175     memset(&ctx->stats, 0, sizeof(ctx->stats));
1176     gettimeofday(&ctx->stats.start_time, NULL);
1177
1178     type = ctx->type;
1179     if (type == 0) {
1180         if ((ctx->flags & KRB5_KRBHST_FLAGS_MASTER) || context->use_admin_kdc)
1181             type = KRB5_KRBHST_ADMIN;
1182         else
1183             type = KRB5_KRBHST_KDC;
1184     }
1185
1186     ctx->send_data = send_data;
1187
1188     if ((int)send_data->length > context->large_msg_size)
1189         ctx->flags |= KRB5_KRBHST_FLAGS_LARGE_MSG;
1190
1191     /* loop until we get back a appropriate response */
1192
1193     action = KRB5_SENDTO_INITIAL;
1194
1195     while (1) {
1196         krb5_krbhst_info *hi;
1197
1198         switch (action) {
1199         case KRB5_SENDTO_INITIAL:
1200             ret = realm_via_plugin(context, realm, context->kdc_timeout,
1201                                    send_data, &ctx->response);
1202             if (ret == 0 || ret != KRB5_PLUGIN_NO_HANDLE) {
1203                 action = KRB5_SENDTO_DONE;
1204                 break;
1205             }
1206             action = KRB5_SENDTO_KRBHST;
1207             HEIM_FALLTHROUGH;
1208         case KRB5_SENDTO_KRBHST:
1209             if (ctx->krbhst == NULL) {
1210                 ret = krb5_krbhst_init_flags(context, realm, type,
1211                                              ctx->flags, &handle);
1212                 if (ret)
1213                     goto out;
1214
1215                 if (ctx->hostname) {
1216                     ret = krb5_krbhst_set_hostname(context, handle, ctx->hostname);
1217                     if (ret)
1218                         goto out;
1219                 }
1220                 if (ctx->sitename) {
1221                     ret = krb5_krbhst_set_sitename(context, handle, ctx->sitename);
1222                     if (ret)
1223                         goto out;
1224                 }
1225             } else {
1226                 handle = heim_retain(ctx->krbhst);
1227             }
1228             action = KRB5_SENDTO_TIMEOUT;
1229             HEIM_FALLTHROUGH;
1230         case KRB5_SENDTO_TIMEOUT:
1231
1232             /*
1233              * If we completed, just got to next step
1234              */
1235
1236             if (ctx->stateflags & KRBHST_COMPLETED) {
1237                 action = KRB5_SENDTO_CONTINUE;
1238                 break;
1239             }
1240
1241             /*
1242              * Pull out next host, if there is no more, close the
1243              * handle and mark as completed.
1244              *
1245              * Collect time spent in krbhst (dns, plugin, etc)
1246              */
1247
1248
1249             gettimeofday(&nrstart, NULL);
1250
1251             ret = krb5_krbhst_next(context, handle, &hi);
1252
1253             gettimeofday(&nrstop, NULL);
1254             timevalsub(&nrstop, &nrstart);
1255             timevaladd(&ctx->stats.krbhst, &nrstop);
1256
1257             action = KRB5_SENDTO_CONTINUE;
1258             if (ret == 0) {
1259                 _krb5_debug(context, 5, "submitting new requests to new host");
1260                 if (submit_request(context, ctx, hi) != 0)
1261                     action = KRB5_SENDTO_TIMEOUT;
1262             } else {
1263                 _krb5_debug(context, 5, "out of hosts, waiting for replies");
1264                 ctx->stateflags |= KRBHST_COMPLETED;
1265             }
1266
1267             break;
1268         case KRB5_SENDTO_CONTINUE:
1269
1270             ret = wait_response(context, &action, ctx);
1271             if (ret)
1272                 goto out;
1273
1274             break;
1275         case KRB5_SENDTO_RESET:
1276             /* start over */
1277             _krb5_debug(context, 5,
1278                         "krb5_sendto trying over again (reset): %d",
1279                         numreset);
1280             reset_context(context, ctx);
1281             if (handle) {
1282                 krb5_krbhst_free(context, handle);
1283                 handle = NULL;
1284             }
1285             numreset++;
1286             if (numreset >= 3)
1287                 action = KRB5_SENDTO_FAILED;
1288             else
1289                 action = KRB5_SENDTO_KRBHST;
1290
1291             break;
1292         case KRB5_SENDTO_FILTER:
1293             /* default to next state, the filter function might modify this */
1294             action = KRB5_SENDTO_DONE;
1295
1296             if (ctx->func) {
1297                 ret = (*ctx->func)(context, ctx, ctx->data,
1298                                    &ctx->response, &action);
1299                 if (ret)
1300                     goto out;
1301
1302                 /*
1303                  * If we are not done, ask to continue/reset
1304                  */
1305                 switch (action) {
1306                 case KRB5_SENDTO_DONE:
1307                     break;
1308                 case KRB5_SENDTO_RESET:
1309                 case KRB5_SENDTO_CONTINUE:
1310                     /* free response to clear it out so we don't loop */
1311                     krb5_data_free(&ctx->response);
1312                     break;
1313                 default:
1314                     ret = KRB5_KDC_UNREACH;
1315                     krb5_set_error_message(context, ret,
1316                                            "sendto filter funcation return unsupported state: %d", (int)action);
1317                     goto out;
1318                 }
1319             }
1320             break;
1321         case KRB5_SENDTO_FAILED:
1322             ret = KRB5_KDC_UNREACH;
1323             goto out;
1324         case KRB5_SENDTO_DONE:
1325             ret = 0;
1326             goto out;
1327         default:
1328             heim_abort("invalid krb5_sendto_context state");
1329         }
1330     }
1331
1332 out:
1333     gettimeofday(&stop_time, NULL);
1334     timevalsub(&stop_time, &ctx->stats.start_time);
1335     if (ret == 0 && ctx->response.length) {
1336         *receive = ctx->response;
1337         krb5_data_zero(&ctx->response);
1338     } else {
1339         krb5_data_free(&ctx->response);
1340         krb5_clear_error_message (context);
1341         ret = KRB5_KDC_UNREACH;
1342         krb5_set_error_message(context, ret,
1343                                N_("unable to reach any KDC in realm %s", ""),
1344                                realm);
1345     }
1346
1347     _krb5_debug(context, 1,
1348                 "%s %s done: %d hosts: %lu packets: %lu"
1349                 " wc: %lld.%06lu nr: %lld.%06lu kh: %lld.%06lu tid: %08x",
1350                 __func__, realm, ret,
1351                 ctx->stats.num_hosts, ctx->stats.sent_packets,
1352                 (long long)stop_time.tv_sec,
1353                 (unsigned long)stop_time.tv_usec,
1354                 (long long)ctx->stats.name_resolution.tv_sec,
1355                 (unsigned long)ctx->stats.name_resolution.tv_usec,
1356                 (long long)ctx->stats.krbhst.tv_sec,
1357                 (unsigned long)ctx->stats.krbhst.tv_usec, ctx->stid);
1358
1359
1360     if (freectx)
1361         krb5_sendto_ctx_free(context, ctx);
1362     else
1363         reset_context(context, ctx);
1364
1365     if (handle)
1366         krb5_krbhst_free(context, handle);
1367
1368     return ret;
1369 }