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(4,("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         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 = a->ai_next) {
 242                 struct socket_address *remote_addr;
 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
 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                         struct tsocket_address *addr = socket_address_to_tsocket_address(smb_krb5, remote_addr);
 371                         const char *addr_string = NULL;
 372                         if (addr) {
 373                                 addr_string = tsocket_address_inet_addr_string(addr, smb_krb5);
 374                         } else {
 375                                 addr_string = NULL;
 376                         }
 377                         DEBUG(2,("Error reading smb_krb5 reply packet: %s from %s\n", nt_errstr(smb_krb5->status),
 378                                  addr_string));
 379                         talloc_free(smb_krb5);
 380                         continue;
 381                 }
 382
 383                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
 384                 if (ret) {
 385                         talloc_free(tmp_ctx);
 386                         return ret;
 387                 }
 388                 talloc_free(smb_krb5);
 389
 390                 break;
 391         }
 392         talloc_free(tmp_ctx);
 393         if (a) {
 394                 return 0;
 395         }
 396         return KRB5_KDC_UNREACH;
 397 }
 398
 399 krb5_error_code
 400 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
 401                             struct loadparm_context *lp_ctx,
 402                             krb5_context *_krb5_context)
 403 {
 404         krb5_error_code ret;
 405         char **config_files;
 406         const char *config_file, *realm;
 407         krb5_context krb5_ctx;
 408
 409         initialize_krb5_error_table();
 410
 411         ret = krb5_init_context(&krb5_ctx);
 412         if (ret) {
 413                 DEBUG(1,("krb5_init_context failed (%s)\n",
 414                          error_message(ret)));
 415                 return ret;
 416         }
 417
 418         config_file = lpcfg_config_path(tmp_ctx, lp_ctx, "krb5.conf");
 419         if (!config_file) {
 420                 krb5_free_context(krb5_ctx);
 421                 return ENOMEM;
 422         }
 423
 424         /* Use our local krb5.conf file by default */
 425         ret = krb5_prepend_config_files_default(config_file == NULL?"":config_file, &config_files);
 426         if (ret) {
 427                 DEBUG(1,("krb5_prepend_config_files_default failed (%s)\n",
 428                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 429                 krb5_free_context(krb5_ctx);
 430                 return ret;
 431         }
 432
 433         ret = krb5_set_config_files(krb5_ctx, config_files);
 434         krb5_free_config_files(config_files);
 435         if (ret) {
 436                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 437                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 438                 krb5_free_context(krb5_ctx);
 439                 return ret;
 440         }
 441
 442         realm = lpcfg_realm(lp_ctx);
 443         if (realm != NULL) {
 444                 ret = krb5_set_default_realm(krb5_ctx, realm);
 445                 if (ret) {
 446                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 447                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 448                         krb5_free_context(krb5_ctx);
 449                         return ret;
 450                 }
 451         }
 452
 453         *_krb5_context = krb5_ctx;
 454         return 0;
 455 }
 456
 457 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 458                                       struct tevent_context *ev,
 459                                       struct loadparm_context *lp_ctx,
 460                                       struct smb_krb5_context **smb_krb5_context)
 461 {
 462         krb5_error_code ret;
 463         TALLOC_CTX *tmp_ctx;
 464
 465         initialize_krb5_error_table();
 466
 467         tmp_ctx = talloc_new(parent_ctx);
 468         *smb_krb5_context = talloc_zero(tmp_ctx, struct smb_krb5_context);
 469
 470         if (!*smb_krb5_context || !tmp_ctx) {
 471                 talloc_free(tmp_ctx);
 472                 return ENOMEM;
 473         }
 474
 475         ret = smb_krb5_init_context_basic(tmp_ctx, lp_ctx,
 476                                           &(*smb_krb5_context)->krb5_context);
 477         if (ret) {
 478                 DEBUG(1,("smb_krb5_context_init_basic failed (%s)\n",
 479                          error_message(ret)));
 480                 talloc_free(tmp_ctx);
 481                 return ret;
 482         }
 483
 484         /* TODO: Should we have a different name here? */
 485         ret = krb5_initlog((*smb_krb5_context)->krb5_context, "Samba", &(*smb_krb5_context)->logf);
 486
 487         if (ret) {
 488                 DEBUG(1,("krb5_initlog failed (%s)\n",
 489                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 490                 krb5_free_context((*smb_krb5_context)->krb5_context);
 491                 talloc_free(tmp_ctx);
 492                 return ret;
 493         }
 494
 495         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy);
 496
 497         ret = krb5_addlog_func((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf, 0 /* min */, -1 /* max */,
 498                                smb_krb5_debug_wrapper, smb_krb5_debug_close, NULL);
 499         if (ret) {
 500                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
 501                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 502                 talloc_free(tmp_ctx);
 503                 return ret;
 504         }
 505         krb5_set_warn_dest((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf);
 506
 507         /* Set use of our socket lib */
 508         if (ev) {
 509                 struct tevent_context *previous_ev;
 510                 ret = smb_krb5_context_set_event_ctx(*smb_krb5_context,
 511                                                      ev, &previous_ev);
 512                 if (ret) {
 513                         talloc_free(tmp_ctx);
 514                         return ret;
 515                 }
 516         }
 517
 518         talloc_steal(parent_ctx, *smb_krb5_context);
 519         talloc_free(tmp_ctx);
 520
 521         /* Set options in kerberos */
 522
 523         krb5_set_dns_canonicalize_hostname((*smb_krb5_context)->krb5_context,
 524                                            lpcfg_parm_bool(lp_ctx, NULL, "krb5", "set_dns_canonicalize", false));
 525
 526         return 0;
 527 }
 528
 529 krb5_error_code smb_krb5_context_set_event_ctx(struct smb_krb5_context *smb_krb5_context,
 530                                                struct tevent_context *ev,
 531                                                struct tevent_context **previous_ev)
 532 {
 533         int ret;
 534         if (!ev) {
 535                 return EINVAL;
 536         }
 537
 538         *previous_ev = smb_krb5_context->current_ev;
 539
 540         smb_krb5_context->current_ev = talloc_reference(smb_krb5_context, ev);
 541         if (!smb_krb5_context->current_ev) {
 542                 return ENOMEM;
 543         }
 544
 545         /* Set use of our socket lib */
 546         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 547                                         smb_krb5_send_and_recv_func,
 548                                         ev);
 549         if (ret) {
 550                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 551                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 552                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 553                 talloc_free(tmp_ctx);
 554                 talloc_unlink(smb_krb5_context, smb_krb5_context->current_ev);
 555                 smb_krb5_context->current_ev = NULL;
 556                 return ret;
 557         }
 558         return 0;
 559 }
 560
 561 krb5_error_code smb_krb5_context_remove_event_ctx(struct smb_krb5_context *smb_krb5_context,
 562                                                   struct tevent_context *previous_ev,
 563                                                   struct tevent_context *ev)
 564 {
 565         int ret;
 566         talloc_unlink(smb_krb5_context, ev);
 567         /* If there was a mismatch with things happening on a stack, then don't wipe things */
 568         smb_krb5_context->current_ev = previous_ev;
 569         /* Set use of our socket lib */
 570         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 571                                         smb_krb5_send_and_recv_func,
 572                                         previous_ev);
 573         if (ret) {
 574                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 575                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 576                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 577                 talloc_free(tmp_ctx);
 578                 return ret;
 579         }
 580         return 0;
 581 }