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 #include "../lib/tsocket/tsocket.h"
  33
  34 /*
  35   context structure for operations on cldap packets
  36 */
  37 struct smb_krb5_socket {
  38         struct socket_context *sock;
  39
  40         /* the fd event */
  41         struct tevent_fd *fde;
  42
  43         NTSTATUS status;
  44         DATA_BLOB request, reply;
  45
  46         struct packet_context *packet;
  47
  48         size_t partial_read;
  49
  50         krb5_krbhst_info *hi;
  51 };
  52
  53 static krb5_error_code smb_krb5_context_destroy(struct smb_krb5_context *ctx)
  54 {
  55         /* Otherwise krb5_free_context will try and close what we have already free()ed */
  56         krb5_set_warn_dest(ctx->krb5_context, NULL);
  57         krb5_closelog(ctx->krb5_context, ctx->logf);
  58         krb5_free_context(ctx->krb5_context);
  59         return 0;
  60 }
  61
  62 /* We never close down the DEBUG system, and no need to unreference the use */
  63 static void smb_krb5_debug_close(void *private_data) {
  64         return;
  65 }
  66
  67 static void smb_krb5_debug_wrapper(const char *timestr, const char *msg, void *private_data)
  68 {
  69         DEBUG(3, ("Kerberos: %s\n", msg));
  70 }
  71
  72 /*
  73   handle recv events on a smb_krb5 socket
  74 */
  75 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
  76 {
  77         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
  78         DATA_BLOB blob;
  79         size_t nread, dsize;
  80
  81         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
  82         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  83                 talloc_free(tmp_ctx);
  84                 return;
  85         }
  86
  87         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
  88         if (blob.data == NULL && dsize != 0) {
  89                 smb_krb5->status = NT_STATUS_NO_MEMORY;
  90                 talloc_free(tmp_ctx);
  91                 return;
  92         }
  93
  94         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
  95         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  96                 talloc_free(tmp_ctx);
  97                 return;
  98         }
  99         blob.length = nread;
 100
 101         if (nread == 0) {
 102                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 103                 talloc_free(tmp_ctx);
 104                 return;
 105         }
 106
 107         DEBUG(2,("Received smb_krb5 packet of length %d\n",
 108                  (int)blob.length));
 109
 110         talloc_steal(smb_krb5, blob.data);
 111         smb_krb5->reply = blob;
 112         talloc_free(tmp_ctx);
 113 }
 114
 115 static NTSTATUS smb_krb5_full_packet(void *private_data, DATA_BLOB data)
 116 {
 117         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 118         talloc_steal(smb_krb5, data.data);
 119         smb_krb5->reply = data;
 120         smb_krb5->reply.length -= 4;
 121         smb_krb5->reply.data += 4;
 122         return NT_STATUS_OK;
 123 }
 124
 125 /*
 126   handle request timeouts
 127 */
 128 static void smb_krb5_request_timeout(struct tevent_context *event_ctx,
 129                                   struct tevent_timer *te, struct timeval t,
 130                                   void *private_data)
 131 {
 132         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 133         DEBUG(5,("Timed out smb_krb5 packet\n"));
 134         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
 135 }
 136
 137 static void smb_krb5_error_handler(void *private_data, NTSTATUS status)
 138 {
 139         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 140         smb_krb5->status = status;
 141 }
 142
 143 /*
 144   handle send events on a smb_krb5 socket
 145 */
 146 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
 147 {
 148         NTSTATUS status;
 149
 150         size_t len;
 151
 152         len = smb_krb5->request.length;
 153         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
 154
 155         if (!NT_STATUS_IS_OK(status)) return;
 156
 157         TEVENT_FD_READABLE(smb_krb5->fde);
 158
 159         TEVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
 160         return;
 161 }
 162
 163
 164 /*
 165   handle fd events on a smb_krb5_socket
 166 */
 167 static void smb_krb5_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 168                                  uint16_t flags, void *private_data)
 169 {
 170         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 171         switch (smb_krb5->hi->proto) {
 172         case KRB5_KRBHST_UDP:
 173                 if (flags & TEVENT_FD_READ) {
 174                         smb_krb5_socket_recv(smb_krb5);
 175                         return;
 176                 }
 177                 if (flags & TEVENT_FD_WRITE) {
 178                         smb_krb5_socket_send(smb_krb5);
 179                         return;
 180                 }
 181                 /* not reached */
 182                 return;
 183         case KRB5_KRBHST_TCP:
 184                 if (flags & TEVENT_FD_READ) {
 185                         packet_recv(smb_krb5->packet);
 186                         return;
 187                 }
 188                 if (flags & TEVENT_FD_WRITE) {
 189                         packet_queue_run(smb_krb5->packet);
 190                         return;
 191                 }
 192                 /* not reached */
 193                 return;
 194         case KRB5_KRBHST_HTTP:
 195                 /* can't happen */
 196                 break;
 197         }
 198 }
 199
 200
 201 krb5_error_code smb_krb5_send_and_recv_func(krb5_context context,
 202                                             void *data,
 203                                             krb5_krbhst_info *hi,
 204                                             time_t timeout,
 205                                             const krb5_data *send_buf,
 206                                             krb5_data *recv_buf)
 207 {
 208         krb5_error_code ret;
 209         NTSTATUS status;
 210         struct socket_address *remote_addr;
 211         const char *name;
 212         struct addrinfo *ai, *a;
 213         struct smb_krb5_socket *smb_krb5;
 214
 215         DATA_BLOB send_blob;
 216
 217         struct tevent_context *ev;
 218         TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 219         if (!tmp_ctx) {
 220                 return ENOMEM;
 221         }
 222
 223         if (!data) {
 224                 /* If no event context was available, then create one for this loop */
 225                 ev = tevent_context_init(tmp_ctx);
 226                 if (!ev) {
 227                         talloc_free(tmp_ctx);
 228                         return ENOMEM;
 229                 }
 230         } else {
 231                 ev = talloc_get_type_abort(data, struct tevent_context);
 232         }
 233
 234         send_blob = data_blob_const(send_buf->data, send_buf->length);
 235
 236         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 237         if (ret) {
 238                 talloc_free(tmp_ctx);
 239                 return ret;
 240         }
 241
 242         for (a = ai; a; a = ai->ai_next) {
 243                 smb_krb5 = talloc(tmp_ctx, struct smb_krb5_socket);
 244                 if (!smb_krb5) {
 245                         talloc_free(tmp_ctx);
 246                         return ENOMEM;
 247                 }
 248                 smb_krb5->hi = hi;
 249
 250                 switch (a->ai_family) {
 251                 case PF_INET:
 252                         name = "ipv4";
 253                         break;
 254 #ifdef HAVE_IPV6
 255                 case PF_INET6:
 256                         name = "ipv6";
 257                         break;
 258 #endif
 259                 default:
 260                         talloc_free(tmp_ctx);
 261                         return EINVAL;
 262                 }
 263
 264                 status = NT_STATUS_INVALID_PARAMETER;
 265                 switch (hi->proto) {
 266                 case KRB5_KRBHST_UDP:
 267                         status = socket_create(name, SOCKET_TYPE_DGRAM, &smb_krb5->sock, 0);
 268                         break;
 269                 case KRB5_KRBHST_TCP:
 270                         status = socket_create(name, SOCKET_TYPE_STREAM, &smb_krb5->sock, 0);
 271                         break;
 272                 case KRB5_KRBHST_HTTP:
 273                         talloc_free(tmp_ctx);
 274                         return EINVAL;
 275                 }
 276                 if (!NT_STATUS_IS_OK(status)) {
 277                         talloc_free(smb_krb5);
 278                         continue;
 279                 }
 280
 281                 talloc_steal(smb_krb5, smb_krb5->sock);
 282
 283                 remote_addr = socket_address_from_sockaddr(smb_krb5, a->ai_addr, a->ai_addrlen);
 284                 if (!remote_addr) {
 285                         talloc_free(smb_krb5);
 286                         continue;
 287                 }
 288
 289                 status = socket_connect_ev(smb_krb5->sock, NULL, remote_addr, 0, ev);
 290                 if (!NT_STATUS_IS_OK(status)) {
 291                         talloc_free(smb_krb5);
 292                         continue;
 293                 }
 294                 talloc_free(remote_addr);
 295
 296                 /* Setup the FDE, start listening for read events
 297                  * from the start (otherwise we may miss a socket
 298                  * drop) and mark as AUTOCLOSE along with the fde */
 299
 300                 /* Ths is equivilant to EVENT_FD_READABLE(smb_krb5->fde) */
 301                 smb_krb5->fde = tevent_add_fd(ev, smb_krb5->sock,
 302                                               socket_get_fd(smb_krb5->sock),
 303                                               TEVENT_FD_READ,
 304                                               smb_krb5_socket_handler, smb_krb5);
 305                 /* its now the job of the event layer to close the socket */
 306                 tevent_fd_set_close_fn(smb_krb5->fde, socket_tevent_fd_close_fn);
 307                 socket_set_flags(smb_krb5->sock, SOCKET_FLAG_NOCLOSE);
 308
 309                 tevent_add_timer(ev, smb_krb5,
 310                                  timeval_current_ofs(timeout, 0),
 311                                  smb_krb5_request_timeout, smb_krb5);
 312
 313                 smb_krb5->status = NT_STATUS_OK;
 314                 smb_krb5->reply = data_blob(NULL, 0);
 315
 316                 switch (hi->proto) {
 317                 case KRB5_KRBHST_UDP:
 318                         TEVENT_FD_WRITEABLE(smb_krb5->fde);
 319                         smb_krb5->request = send_blob;
 320                         break;
 321                 case KRB5_KRBHST_TCP:
 322
 323                         smb_krb5->packet = packet_init(smb_krb5);
 324                         if (smb_krb5->packet == NULL) {
 325                                 talloc_free(smb_krb5);
 326                                 return ENOMEM;
 327                         }
 328                         packet_set_private(smb_krb5->packet, smb_krb5);
 329                         packet_set_socket(smb_krb5->packet, smb_krb5->sock);
 330                         packet_set_callback(smb_krb5->packet, smb_krb5_full_packet);
 331                         packet_set_full_request(smb_krb5->packet, packet_full_request_u32);
 332                         packet_set_error_handler(smb_krb5->packet, smb_krb5_error_handler);
 333                         packet_set_event_context(smb_krb5->packet, ev);
 334                         packet_set_fde(smb_krb5->packet, smb_krb5->fde);
 335
 336                         smb_krb5->request = data_blob_talloc(smb_krb5, NULL, send_blob.length + 4);
 337                         RSIVAL(smb_krb5->request.data, 0, send_blob.length);
 338                         memcpy(smb_krb5->request.data+4, send_blob.data, send_blob.length);
 339                         packet_send(smb_krb5->packet, smb_krb5->request);
 340                         break;
 341                 case KRB5_KRBHST_HTTP:
 342                         talloc_free(tmp_ctx);
 343                         return EINVAL;
 344                 }
 345                 while ((NT_STATUS_IS_OK(smb_krb5->status)) && !smb_krb5->reply.length) {
 346                         if (tevent_loop_once(ev) != 0) {
 347                                 talloc_free(tmp_ctx);
 348                                 return EINVAL;
 349                         }
 350
 351                         /* After each and every event loop, reset the
 352                          * send_to_kdc pointers to what they were when
 353                          * we entered this loop.  That way, if a
 354                          * nested event has invalidated them, we put
 355                          * it back before we return to the heimdal
 356                          * code */
 357                         ret = krb5_set_send_to_kdc_func(context,
 358                                                         smb_krb5_send_and_recv_func,
 359                                                         data);
 360                         if (ret != 0) {
 361                                 talloc_free(tmp_ctx);
 362                                 return ret;
 363                         }
 364                 }
 365                 if (NT_STATUS_EQUAL(smb_krb5->status, NT_STATUS_IO_TIMEOUT)) {
 366                         talloc_free(smb_krb5);
 367                         continue;
 368                 }
 369
 370                 if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 371                         struct tsocket_address *addr = socket_address_to_tsocket_address(smb_krb5, remote_addr);
 372                         const char *addr_string = NULL;
 373                         if (addr) {
 374                                 addr_string = tsocket_address_inet_addr_string(addr, smb_krb5);
 375                         } else {
 376                                 addr_string = NULL;
 377                         }
 378                         DEBUG(2,("Error reading smb_krb5 reply packet: %s from %s\n", nt_errstr(smb_krb5->status),
 379                                  addr_string));
 380                         talloc_free(smb_krb5);
 381                         continue;
 382                 }
 383
 384                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
 385                 if (ret) {
 386                         talloc_free(tmp_ctx);
 387                         return ret;
 388                 }
 389                 talloc_free(smb_krb5);
 390
 391                 break;
 392         }
 393         talloc_free(tmp_ctx);
 394         if (a) {
 395                 return 0;
 396         }
 397         return KRB5_KDC_UNREACH;
 398 }
 399
 400 krb5_error_code
 401 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
 402                             struct loadparm_context *lp_ctx,
 403                             krb5_context *_krb5_context)
 404 {
 405         krb5_error_code ret;
 406         char **config_files;
 407         const char *config_file, *realm;
 408         krb5_context krb5_ctx;
 409
 410         initialize_krb5_error_table();
 411
 412         ret = krb5_init_context(&krb5_ctx);
 413         if (ret) {
 414                 DEBUG(1,("krb5_init_context failed (%s)\n",
 415                          error_message(ret)));
 416                 return ret;
 417         }
 418
 419         config_file = config_path(tmp_ctx, lp_ctx, "krb5.conf");
 420         if (!config_file) {
 421                 krb5_free_context(krb5_ctx);
 422                 return ENOMEM;
 423         }
 424
 425         /* Use our local krb5.conf file by default */
 426         ret = krb5_prepend_config_files_default(config_file == NULL?"":config_file, &config_files);
 427         if (ret) {
 428                 DEBUG(1,("krb5_prepend_config_files_default 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         ret = krb5_set_config_files(krb5_ctx, config_files);
 435         krb5_free_config_files(config_files);
 436         if (ret) {
 437                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 438                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 439                 krb5_free_context(krb5_ctx);
 440                 return ret;
 441         }
 442
 443         realm = lpcfg_realm(lp_ctx);
 444         if (realm != NULL) {
 445                 ret = krb5_set_default_realm(krb5_ctx, realm);
 446                 if (ret) {
 447                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 448                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 449                         krb5_free_context(krb5_ctx);
 450                         return ret;
 451                 }
 452         }
 453
 454         *_krb5_context = krb5_ctx;
 455         return 0;
 456 }
 457
 458 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 459                                       struct tevent_context *ev,
 460                                       struct loadparm_context *lp_ctx,
 461                                       struct smb_krb5_context **smb_krb5_context)
 462 {
 463         krb5_error_code ret;
 464         TALLOC_CTX *tmp_ctx;
 465
 466         initialize_krb5_error_table();
 467
 468         tmp_ctx = talloc_new(parent_ctx);
 469         *smb_krb5_context = talloc_zero(tmp_ctx, struct smb_krb5_context);
 470
 471         if (!*smb_krb5_context || !tmp_ctx) {
 472                 talloc_free(tmp_ctx);
 473                 return ENOMEM;
 474         }
 475
 476         ret = smb_krb5_init_context_basic(tmp_ctx, lp_ctx,
 477                                           &(*smb_krb5_context)->krb5_context);
 478         if (ret) {
 479                 DEBUG(1,("smb_krb5_context_init_basic failed (%s)\n",
 480                          error_message(ret)));
 481                 talloc_free(tmp_ctx);
 482                 return ret;
 483         }
 484
 485         /* TODO: Should we have a different name here? */
 486         ret = krb5_initlog((*smb_krb5_context)->krb5_context, "Samba", &(*smb_krb5_context)->logf);
 487
 488         if (ret) {
 489                 DEBUG(1,("krb5_initlog failed (%s)\n",
 490                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 491                 krb5_free_context((*smb_krb5_context)->krb5_context);
 492                 talloc_free(tmp_ctx);
 493                 return ret;
 494         }
 495
 496         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy);
 497
 498         ret = krb5_addlog_func((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf, 0 /* min */, -1 /* max */,
 499                                smb_krb5_debug_wrapper, smb_krb5_debug_close, NULL);
 500         if (ret) {
 501                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
 502                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 503                 talloc_free(tmp_ctx);
 504                 return ret;
 505         }
 506         krb5_set_warn_dest((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf);
 507
 508         /* Set use of our socket lib */
 509         if (ev) {
 510                 struct tevent_context *previous_ev;
 511                 ret = smb_krb5_context_set_event_ctx(*smb_krb5_context,
 512                                                      ev, &previous_ev);
 513                 if (ret) {
 514                         talloc_free(tmp_ctx);
 515                         return ret;
 516                 }
 517         }
 518
 519         talloc_steal(parent_ctx, *smb_krb5_context);
 520         talloc_free(tmp_ctx);
 521
 522         /* Set options in kerberos */
 523
 524         krb5_set_dns_canonicalize_hostname((*smb_krb5_context)->krb5_context,
 525                                            lpcfg_parm_bool(lp_ctx, NULL, "krb5", "set_dns_canonicalize", false));
 526
 527         return 0;
 528 }
 529
 530 krb5_error_code smb_krb5_context_set_event_ctx(struct smb_krb5_context *smb_krb5_context,
 531                                                struct tevent_context *ev,
 532                                                struct tevent_context **previous_ev)
 533 {
 534         int ret;
 535         if (!ev) {
 536                 return EINVAL;
 537         }
 538
 539         *previous_ev = smb_krb5_context->current_ev;
 540
 541         smb_krb5_context->current_ev = talloc_reference(smb_krb5_context, ev);
 542         if (!smb_krb5_context->current_ev) {
 543                 return ENOMEM;
 544         }
 545
 546         /* Set use of our socket lib */
 547         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 548                                         smb_krb5_send_and_recv_func,
 549                                         ev);
 550         if (ret) {
 551                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 552                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 553                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 554                 talloc_free(tmp_ctx);
 555                 talloc_unlink(smb_krb5_context, smb_krb5_context->current_ev);
 556                 smb_krb5_context->current_ev = NULL;
 557                 return ret;
 558         }
 559         return 0;
 560 }
 561
 562 krb5_error_code smb_krb5_context_remove_event_ctx(struct smb_krb5_context *smb_krb5_context,
 563                                                   struct tevent_context *previous_ev,
 564                                                   struct tevent_context *ev)
 565 {
 566         int ret;
 567         talloc_unlink(smb_krb5_context, ev);
 568         /* If there was a mismatch with things happening on a stack, then don't wipe things */
 569         smb_krb5_context->current_ev = previous_ev;
 570         /* Set use of our socket lib */
 571         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 572                                         smb_krb5_send_and_recv_func,
 573                                         previous_ev);
 574         if (ret) {
 575                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 576                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 577                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 578                 talloc_free(tmp_ctx);
 579                 return ret;
 580         }
 581         return 0;
 582 }