source4/auth/kerberos/krb5_init_context.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Wrapper for krb5_init_context
   4
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
   6    Copyright (C) Andrew Tridgell 2005
   7    Copyright (C) Stefan Metzmacher 2004
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "system/kerberos.h"
  25 #include <tevent.h>
  26 #include "auth/kerberos/kerberos.h"
  27 #include "lib/socket/socket.h"
  28 #include "lib/stream/packet.h"
  29 #include "system/network.h"
  30 #include "param/param.h"
  31 #include "libcli/resolve/resolve.h"
  32
  33 /*
  34   context structure for operations on cldap packets
  35 */
  36 struct smb_krb5_socket {
  37         struct socket_context *sock;
  38
  39         /* the fd event */
  40         struct tevent_fd *fde;
  41
  42         NTSTATUS status;
  43         DATA_BLOB request, reply;
  44
  45         struct packet_context *packet;
  46
  47         size_t partial_read;
  48
  49         krb5_krbhst_info *hi;
  50 };
  51
  52 static krb5_error_code smb_krb5_context_destroy(struct smb_krb5_context *ctx)
  53 {
  54         /* Otherwise krb5_free_context will try and close what we have already free()ed */
  55         krb5_set_warn_dest(ctx->krb5_context, NULL);
  56         krb5_closelog(ctx->krb5_context, ctx->logf);
  57         krb5_free_context(ctx->krb5_context);
  58         return 0;
  59 }
  60
  61 /* We never close down the DEBUG system, and no need to unreference the use */
  62 static void smb_krb5_debug_close(void *private_data) {
  63         return;
  64 }
  65
  66 static void smb_krb5_debug_wrapper(const char *timestr, const char *msg, void *private_data)
  67 {
  68         DEBUG(3, ("Kerberos: %s\n", msg));
  69 }
  70
  71 /*
  72   handle recv events on a smb_krb5 socket
  73 */
  74 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
  75 {
  76         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
  77         DATA_BLOB blob;
  78         size_t nread, dsize;
  79
  80         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
  81         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  82                 talloc_free(tmp_ctx);
  83                 return;
  84         }
  85
  86         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
  87         if (blob.data == NULL && dsize != 0) {
  88                 smb_krb5->status = NT_STATUS_NO_MEMORY;
  89                 talloc_free(tmp_ctx);
  90                 return;
  91         }
  92
  93         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
  94         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  95                 talloc_free(tmp_ctx);
  96                 return;
  97         }
  98         blob.length = nread;
  99
 100         if (nread == 0) {
 101                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 102                 talloc_free(tmp_ctx);
 103                 return;
 104         }
 105
 106         DEBUG(2,("Received smb_krb5 packet of length %d\n",
 107                  (int)blob.length));
 108
 109         talloc_steal(smb_krb5, blob.data);
 110         smb_krb5->reply = blob;
 111         talloc_free(tmp_ctx);
 112 }
 113
 114 static NTSTATUS smb_krb5_full_packet(void *private_data, DATA_BLOB data)
 115 {
 116         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 117         talloc_steal(smb_krb5, data.data);
 118         smb_krb5->reply = data;
 119         smb_krb5->reply.length -= 4;
 120         smb_krb5->reply.data += 4;
 121         return NT_STATUS_OK;
 122 }
 123
 124 /*
 125   handle request timeouts
 126 */
 127 static void smb_krb5_request_timeout(struct tevent_context *event_ctx,
 128                                   struct tevent_timer *te, struct timeval t,
 129                                   void *private_data)
 130 {
 131         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 132         DEBUG(5,("Timed out smb_krb5 packet\n"));
 133         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
 134 }
 135
 136 static void smb_krb5_error_handler(void *private_data, NTSTATUS status)
 137 {
 138         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 139         smb_krb5->status = status;
 140 }
 141
 142 /*
 143   handle send events on a smb_krb5 socket
 144 */
 145 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
 146 {
 147         NTSTATUS status;
 148
 149         size_t len;
 150
 151         len = smb_krb5->request.length;
 152         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
 153
 154         if (!NT_STATUS_IS_OK(status)) return;
 155
 156         TEVENT_FD_READABLE(smb_krb5->fde);
 157
 158         TEVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
 159         return;
 160 }
 161
 162
 163 /*
 164   handle fd events on a smb_krb5_socket
 165 */
 166 static void smb_krb5_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 167                                  uint16_t flags, void *private_data)
 168 {
 169         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 170         switch (smb_krb5->hi->proto) {
 171         case KRB5_KRBHST_UDP:
 172                 if (flags & TEVENT_FD_READ) {
 173                         smb_krb5_socket_recv(smb_krb5);
 174                         return;
 175                 }
 176                 if (flags & TEVENT_FD_WRITE) {
 177                         smb_krb5_socket_send(smb_krb5);
 178                         return;
 179                 }
 180                 /* not reached */
 181                 return;
 182         case KRB5_KRBHST_TCP:
 183                 if (flags & TEVENT_FD_READ) {
 184                         packet_recv(smb_krb5->packet);
 185                         return;
 186                 }
 187                 if (flags & TEVENT_FD_WRITE) {
 188                         packet_queue_run(smb_krb5->packet);
 189                         return;
 190                 }
 191                 /* not reached */
 192                 return;
 193         case KRB5_KRBHST_HTTP:
 194                 /* can't happen */
 195                 break;
 196         }
 197 }
 198
 199
 200 krb5_error_code smb_krb5_send_and_recv_func(krb5_context context,
 201                                             void *data,
 202                                             krb5_krbhst_info *hi,
 203                                             time_t timeout,
 204                                             const krb5_data *send_buf,
 205                                             krb5_data *recv_buf)
 206 {
 207         krb5_error_code ret;
 208         NTSTATUS status;
 209         struct socket_address *remote_addr;
 210         const char *name;
 211         struct addrinfo *ai, *a;
 212         struct smb_krb5_socket *smb_krb5;
 213
 214         DATA_BLOB send_blob;
 215
 216         struct tevent_context *ev;
 217         TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 218         if (!tmp_ctx) {
 219                 return ENOMEM;
 220         }
 221
 222         if (!data) {
 223                 /* If no event context was available, then create one for this loop */
 224                 ev = tevent_context_init(tmp_ctx);
 225                 if (!ev) {
 226                         talloc_free(tmp_ctx);
 227                         return ENOMEM;
 228                 }
 229         } else {
 230                 ev = talloc_get_type_abort(data, struct tevent_context);
 231         }
 232
 233         send_blob = data_blob_const(send_buf->data, send_buf->length);
 234
 235         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 236         if (ret) {
 237                 talloc_free(tmp_ctx);
 238                 return ret;
 239         }
 240
 241         for (a = ai; a; a = ai->ai_next) {
 242                 smb_krb5 = talloc(tmp_ctx, struct smb_krb5_socket);
 243                 if (!smb_krb5) {
 244                         talloc_free(tmp_ctx);
 245                         return ENOMEM;
 246                 }
 247                 smb_krb5->hi = hi;
 248
 249                 switch (a->ai_family) {
 250                 case PF_INET:
 251                         name = "ipv4";
 252                         break;
 253 #ifdef HAVE_IPV6
 254                 case PF_INET6:
 255                         name = "ipv6";
 256                         break;
 257 #endif
 258                 default:
 259                         talloc_free(tmp_ctx);
 260                         return EINVAL;
 261                 }
 262
 263                 status = NT_STATUS_INVALID_PARAMETER;
 264                 switch (hi->proto) {
 265                 case KRB5_KRBHST_UDP:
 266                         status = socket_create(name, SOCKET_TYPE_DGRAM, &smb_krb5->sock, 0);
 267                         break;
 268                 case KRB5_KRBHST_TCP:
 269                         status = socket_create(name, SOCKET_TYPE_STREAM, &smb_krb5->sock, 0);
 270                         break;
 271                 case KRB5_KRBHST_HTTP:
 272                         talloc_free(tmp_ctx);
 273                         return EINVAL;
 274                 }
 275                 if (!NT_STATUS_IS_OK(status)) {
 276                         talloc_free(smb_krb5);
 277                         continue;
 278                 }
 279
 280                 talloc_steal(smb_krb5, smb_krb5->sock);
 281
 282                 remote_addr = socket_address_from_sockaddr(smb_krb5, a->ai_addr, a->ai_addrlen);
 283                 if (!remote_addr) {
 284                         talloc_free(smb_krb5);
 285                         continue;
 286                 }
 287
 288                 status = socket_connect_ev(smb_krb5->sock, NULL, remote_addr, 0, ev);
 289                 if (!NT_STATUS_IS_OK(status)) {
 290                         talloc_free(smb_krb5);
 291                         continue;
 292                 }
 293                 talloc_free(remote_addr);
 294
 295                 /* Setup the FDE, start listening for read events
 296                  * from the start (otherwise we may miss a socket
 297                  * drop) and mark as AUTOCLOSE along with the fde */
 298
 299                 /* Ths is equivilant to EVENT_FD_READABLE(smb_krb5->fde) */
 300                 smb_krb5->fde = tevent_add_fd(ev, smb_krb5->sock,
 301                                               socket_get_fd(smb_krb5->sock),
 302                                               TEVENT_FD_READ,
 303                                               smb_krb5_socket_handler, smb_krb5);
 304                 /* its now the job of the event layer to close the socket */
 305                 tevent_fd_set_close_fn(smb_krb5->fde, socket_tevent_fd_close_fn);
 306                 socket_set_flags(smb_krb5->sock, SOCKET_FLAG_NOCLOSE);
 307
 308                 tevent_add_timer(ev, smb_krb5,
 309                                  timeval_current_ofs(timeout, 0),
 310                                  smb_krb5_request_timeout, smb_krb5);
 311
 312                 smb_krb5->status = NT_STATUS_OK;
 313                 smb_krb5->reply = data_blob(NULL, 0);
 314
 315                 switch (hi->proto) {
 316                 case KRB5_KRBHST_UDP:
 317                         TEVENT_FD_WRITEABLE(smb_krb5->fde);
 318                         smb_krb5->request = send_blob;
 319                         break;
 320                 case KRB5_KRBHST_TCP:
 321
 322                         smb_krb5->packet = packet_init(smb_krb5);
 323                         if (smb_krb5->packet == NULL) {
 324                                 talloc_free(smb_krb5);
 325                                 return ENOMEM;
 326                         }
 327                         packet_set_private(smb_krb5->packet, smb_krb5);
 328                         packet_set_socket(smb_krb5->packet, smb_krb5->sock);
 329                         packet_set_callback(smb_krb5->packet, smb_krb5_full_packet);
 330                         packet_set_full_request(smb_krb5->packet, packet_full_request_u32);
 331                         packet_set_error_handler(smb_krb5->packet, smb_krb5_error_handler);
 332                         packet_set_event_context(smb_krb5->packet, ev);
 333                         packet_set_fde(smb_krb5->packet, smb_krb5->fde);
 334
 335                         smb_krb5->request = data_blob_talloc(smb_krb5, NULL, send_blob.length + 4);
 336                         RSIVAL(smb_krb5->request.data, 0, send_blob.length);
 337                         memcpy(smb_krb5->request.data+4, send_blob.data, send_blob.length);
 338                         packet_send(smb_krb5->packet, smb_krb5->request);
 339                         break;
 340                 case KRB5_KRBHST_HTTP:
 341                         talloc_free(tmp_ctx);
 342                         return EINVAL;
 343                 }
 344                 while ((NT_STATUS_IS_OK(smb_krb5->status)) && !smb_krb5->reply.length) {
 345                         if (tevent_loop_once(ev) != 0) {
 346                                 talloc_free(tmp_ctx);
 347                                 return EINVAL;
 348                         }
 349
 350                         /* After each and every event loop, reset the
 351                          * send_to_kdc pointers to what they were when
 352                          * we entered this loop.  That way, if a
 353                          * nested event has invalidated them, we put
 354                          * it back before we return to the heimdal
 355                          * code */
 356                         ret = krb5_set_send_to_kdc_func(context,
 357                                                         smb_krb5_send_and_recv_func,
 358                                                         data);
 359                         if (ret != 0) {
 360                                 talloc_free(tmp_ctx);
 361                                 return ret;
 362                         }
 363                 }
 364                 if (NT_STATUS_EQUAL(smb_krb5->status, NT_STATUS_IO_TIMEOUT)) {
 365                         talloc_free(smb_krb5);
 366                         continue;
 367                 }
 368
 369                 if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 370                         DEBUG(2,("Error reading smb_krb5 reply packet: %s\n", nt_errstr(smb_krb5->status)));
 371                         talloc_free(smb_krb5);
 372                         continue;
 373                 }
 374
 375                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
 376                 if (ret) {
 377                         talloc_free(tmp_ctx);
 378                         return ret;
 379                 }
 380                 talloc_free(smb_krb5);
 381
 382                 break;
 383         }
 384         talloc_free(tmp_ctx);
 385         if (a) {
 386                 return 0;
 387         }
 388         return KRB5_KDC_UNREACH;
 389 }
 390
 391 krb5_error_code
 392 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
 393                             struct loadparm_context *lp_ctx,
 394                             krb5_context *_krb5_context)
 395 {
 396         krb5_error_code ret;
 397         char **config_files;
 398         const char *config_file, *realm;
 399         krb5_context krb5_ctx;
 400
 401         initialize_krb5_error_table();
 402
 403         ret = krb5_init_context(&krb5_ctx);
 404         if (ret) {
 405                 DEBUG(1,("krb5_init_context failed (%s)\n",
 406                          error_message(ret)));
 407                 return ret;
 408         }
 409
 410         config_file = config_path(tmp_ctx, lp_ctx, "krb5.conf");
 411         if (!config_file) {
 412                 krb5_free_context(krb5_ctx);
 413                 return ENOMEM;
 414         }
 415
 416         /* Use our local krb5.conf file by default */
 417         ret = krb5_prepend_config_files_default(config_file == NULL?"":config_file, &config_files);
 418         if (ret) {
 419                 DEBUG(1,("krb5_prepend_config_files_default failed (%s)\n",
 420                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 421                 krb5_free_context(krb5_ctx);
 422                 return ret;
 423         }
 424
 425         ret = krb5_set_config_files(krb5_ctx, config_files);
 426         krb5_free_config_files(config_files);
 427         if (ret) {
 428                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 429                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 430                 krb5_free_context(krb5_ctx);
 431                 return ret;
 432         }
 433
 434         realm = lpcfg_realm(lp_ctx);
 435         if (realm != NULL) {
 436                 ret = krb5_set_default_realm(krb5_ctx, realm);
 437                 if (ret) {
 438                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 439                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 440                         krb5_free_context(krb5_ctx);
 441                         return ret;
 442                 }
 443         }
 444
 445         *_krb5_context = krb5_ctx;
 446         return 0;
 447 }
 448
 449 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 450                                       struct tevent_context *ev,
 451                                       struct loadparm_context *lp_ctx,
 452                                       struct smb_krb5_context **smb_krb5_context)
 453 {
 454         krb5_error_code ret;
 455         TALLOC_CTX *tmp_ctx;
 456
 457         initialize_krb5_error_table();
 458
 459         tmp_ctx = talloc_new(parent_ctx);
 460         *smb_krb5_context = talloc_zero(tmp_ctx, struct smb_krb5_context);
 461
 462         if (!*smb_krb5_context || !tmp_ctx) {
 463                 talloc_free(tmp_ctx);
 464                 return ENOMEM;
 465         }
 466
 467         ret = smb_krb5_init_context_basic(tmp_ctx, lp_ctx,
 468                                           &(*smb_krb5_context)->krb5_context);
 469         if (ret) {
 470                 DEBUG(1,("smb_krb5_context_init_basic failed (%s)\n",
 471                          error_message(ret)));
 472                 talloc_free(tmp_ctx);
 473                 return ret;
 474         }
 475
 476         /* TODO: Should we have a different name here? */
 477         ret = krb5_initlog((*smb_krb5_context)->krb5_context, "Samba", &(*smb_krb5_context)->logf);
 478
 479         if (ret) {
 480                 DEBUG(1,("krb5_initlog failed (%s)\n",
 481                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 482                 krb5_free_context((*smb_krb5_context)->krb5_context);
 483                 talloc_free(tmp_ctx);
 484                 return ret;
 485         }
 486
 487         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy);
 488
 489         ret = krb5_addlog_func((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf, 0 /* min */, -1 /* max */,
 490                                smb_krb5_debug_wrapper, smb_krb5_debug_close, NULL);
 491         if (ret) {
 492                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
 493                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 494                 talloc_free(tmp_ctx);
 495                 return ret;
 496         }
 497         krb5_set_warn_dest((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf);
 498
 499         /* Set use of our socket lib */
 500         if (ev) {
 501                 struct tevent_context *previous_ev;
 502                 ret = smb_krb5_context_set_event_ctx(*smb_krb5_context,
 503                                                      ev, &previous_ev);
 504                 if (ret) {
 505                         talloc_free(tmp_ctx);
 506                         return ret;
 507                 }
 508         }
 509
 510         talloc_steal(parent_ctx, *smb_krb5_context);
 511         talloc_free(tmp_ctx);
 512
 513         /* Set options in kerberos */
 514
 515         krb5_set_dns_canonicalize_hostname((*smb_krb5_context)->krb5_context,
 516                                            lpcfg_parm_bool(lp_ctx, NULL, "krb5", "set_dns_canonicalize", false));
 517
 518         return 0;
 519 }
 520
 521 krb5_error_code smb_krb5_context_set_event_ctx(struct smb_krb5_context *smb_krb5_context,
 522                                                struct tevent_context *ev,
 523                                                struct tevent_context **previous_ev)
 524 {
 525         int ret;
 526         if (!ev) {
 527                 return EINVAL;
 528         }
 529
 530         *previous_ev = smb_krb5_context->current_ev;
 531
 532         smb_krb5_context->current_ev = talloc_reference(smb_krb5_context, ev);
 533         if (!smb_krb5_context->current_ev) {
 534                 return ENOMEM;
 535         }
 536
 537         /* Set use of our socket lib */
 538         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 539                                         smb_krb5_send_and_recv_func,
 540                                         ev);
 541         if (ret) {
 542                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 543                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 544                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 545                 talloc_free(tmp_ctx);
 546                 talloc_unlink(smb_krb5_context, smb_krb5_context->current_ev);
 547                 smb_krb5_context->current_ev = NULL;
 548                 return ret;
 549         }
 550         return 0;
 551 }
 552
 553 krb5_error_code smb_krb5_context_remove_event_ctx(struct smb_krb5_context *smb_krb5_context,
 554                                                   struct tevent_context *previous_ev,
 555                                                   struct tevent_context *ev)
 556 {
 557         int ret;
 558         talloc_unlink(smb_krb5_context, ev);
 559         /* If there was a mismatch with things happening on a stack, then don't wipe things */
 560         smb_krb5_context->current_ev = previous_ev;
 561         /* Set use of our socket lib */
 562         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 563                                         smb_krb5_send_and_recv_func,
 564                                         previous_ev);
 565         if (ret) {
 566                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 567                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 568                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 569                 talloc_free(tmp_ctx);
 570                 return ret;
 571         }
 572         return 0;
 573 }