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 "system/gssapi.h"
  26 #include <tevent.h>
  27 #include "auth/kerberos/kerberos.h"
  28 #include "lib/socket/socket.h"
  29 #include "lib/stream/packet.h"
  30 #include "system/network.h"
  31 #include "param/param.h"
  32 #include "libcli/resolve/resolve.h"
  33 #include "../lib/tsocket/tsocket.h"
  34 #include "krb5_init_context.h"
  35 /*
  36   context structure for operations on cldap packets
  37 */
  38 struct smb_krb5_socket {
  39         struct socket_context *sock;
  40
  41         /* the fd event */
  42         struct tevent_fd *fde;
  43
  44         NTSTATUS status;
  45         DATA_BLOB request, reply;
  46
  47         struct packet_context *packet;
  48
  49         size_t partial_read;
  50 #ifdef SAMBA4_USES_HEIMDAL
  51         krb5_krbhst_info *hi;
  52 #endif
  53 };
  54
  55 static krb5_error_code smb_krb5_context_destroy(struct smb_krb5_context *ctx)
  56 {
  57 #ifdef SAMBA4_USES_HEIMDAL
  58         if (ctx->pvt_log_data) {
  59                 /* Otherwise krb5_free_context will try and close what we
  60                  * have already free()ed */
  61                 krb5_set_warn_dest(ctx->krb5_context, NULL);
  62                 krb5_closelog(ctx->krb5_context,
  63                                 (krb5_log_facility *)ctx->pvt_log_data);
  64         }
  65 #endif
  66         krb5_free_context(ctx->krb5_context);
  67         return 0;
  68 }
  69
  70 #ifdef SAMBA4_USES_HEIMDAL
  71 /* We never close down the DEBUG system, and no need to unreference the use */
  72 static void smb_krb5_debug_close(void *private_data) {
  73         return;
  74 }
  75 #endif
  76
  77 #ifdef SAMBA4_USES_HEIMDAL
  78 static void smb_krb5_debug_wrapper(const char *timestr, const char *msg, void *private_data)
  79 {
  80         DEBUG(3, ("Kerberos: %s\n", msg));
  81 }
  82 #endif
  83
  84 #ifdef SAMBA4_USES_HEIMDAL
  85 /*
  86   handle recv events on a smb_krb5 socket
  87 */
  88 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
  89 {
  90         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
  91         DATA_BLOB blob;
  92         size_t nread, dsize;
  93
  94         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
  95         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  96                 talloc_free(tmp_ctx);
  97                 return;
  98         }
  99
 100         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
 101         if (blob.data == NULL && dsize != 0) {
 102                 smb_krb5->status = NT_STATUS_NO_MEMORY;
 103                 talloc_free(tmp_ctx);
 104                 return;
 105         }
 106
 107         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
 108         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 109                 talloc_free(tmp_ctx);
 110                 return;
 111         }
 112         blob.length = nread;
 113
 114         if (nread == 0) {
 115                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 116                 talloc_free(tmp_ctx);
 117                 return;
 118         }
 119
 120         DEBUG(4,("Received smb_krb5 packet of length %d\n",
 121                  (int)blob.length));
 122
 123         talloc_steal(smb_krb5, blob.data);
 124         smb_krb5->reply = blob;
 125         talloc_free(tmp_ctx);
 126 }
 127
 128 static NTSTATUS smb_krb5_full_packet(void *private_data, DATA_BLOB data)
 129 {
 130         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 131         talloc_steal(smb_krb5, data.data);
 132         smb_krb5->reply = data;
 133         smb_krb5->reply.length -= 4;
 134         smb_krb5->reply.data += 4;
 135         return NT_STATUS_OK;
 136 }
 137
 138 /*
 139   handle request timeouts
 140 */
 141 static void smb_krb5_request_timeout(struct tevent_context *event_ctx,
 142                                   struct tevent_timer *te, struct timeval t,
 143                                   void *private_data)
 144 {
 145         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 146         DEBUG(5,("Timed out smb_krb5 packet\n"));
 147         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
 148 }
 149
 150 static void smb_krb5_error_handler(void *private_data, NTSTATUS status)
 151 {
 152         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 153         smb_krb5->status = status;
 154 }
 155
 156 /*
 157   handle send events on a smb_krb5 socket
 158 */
 159 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
 160 {
 161         NTSTATUS status;
 162
 163         size_t len;
 164
 165         len = smb_krb5->request.length;
 166         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
 167
 168         if (!NT_STATUS_IS_OK(status)) return;
 169
 170         TEVENT_FD_READABLE(smb_krb5->fde);
 171
 172         TEVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
 173         return;
 174 }
 175
 176
 177 /*
 178   handle fd events on a smb_krb5_socket
 179 */
 180 static void smb_krb5_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 181                                  uint16_t flags, void *private_data)
 182 {
 183         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 184         switch (smb_krb5->hi->proto) {
 185         case KRB5_KRBHST_UDP:
 186                 if (flags & TEVENT_FD_READ) {
 187                         smb_krb5_socket_recv(smb_krb5);
 188                         return;
 189                 }
 190                 if (flags & TEVENT_FD_WRITE) {
 191                         smb_krb5_socket_send(smb_krb5);
 192                         return;
 193                 }
 194                 /* not reached */
 195                 return;
 196         case KRB5_KRBHST_TCP:
 197                 if (flags & TEVENT_FD_READ) {
 198                         packet_recv(smb_krb5->packet);
 199                         return;
 200                 }
 201                 if (flags & TEVENT_FD_WRITE) {
 202                         packet_queue_run(smb_krb5->packet);
 203                         return;
 204                 }
 205                 /* not reached */
 206                 return;
 207         case KRB5_KRBHST_HTTP:
 208                 /* can't happen */
 209                 break;
 210         }
 211 }
 212
 213 krb5_error_code smb_krb5_send_and_recv_func(krb5_context context,
 214                                             void *data,
 215                                             krb5_krbhst_info *hi,
 216                                             time_t timeout,
 217                                             const krb5_data *send_buf,
 218                                             krb5_data *recv_buf)
 219 {
 220         krb5_error_code ret;
 221         NTSTATUS status;
 222         const char *name;
 223         struct addrinfo *ai, *a;
 224         struct smb_krb5_socket *smb_krb5;
 225
 226         DATA_BLOB send_blob;
 227
 228         struct tevent_context *ev;
 229         TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 230         if (!tmp_ctx) {
 231                 return ENOMEM;
 232         }
 233
 234         if (!data) {
 235                 /* If no event context was available, then create one for this loop */
 236                 ev = samba_tevent_context_init(tmp_ctx);
 237                 if (!ev) {
 238                         talloc_free(tmp_ctx);
 239                         return ENOMEM;
 240                 }
 241         } else {
 242                 ev = talloc_get_type_abort(data, struct tevent_context);
 243         }
 244
 245         send_blob = data_blob_const(send_buf->data, send_buf->length);
 246
 247         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 248         if (ret) {
 249                 talloc_free(tmp_ctx);
 250                 return ret;
 251         }
 252
 253         for (a = ai; a; a = a->ai_next) {
 254                 struct socket_address *remote_addr;
 255                 smb_krb5 = talloc(tmp_ctx, struct smb_krb5_socket);
 256                 if (!smb_krb5) {
 257                         talloc_free(tmp_ctx);
 258                         return ENOMEM;
 259                 }
 260                 smb_krb5->hi = hi;
 261
 262                 switch (a->ai_family) {
 263                 case PF_INET:
 264                         name = "ipv4";
 265                         break;
 266 #ifdef HAVE_IPV6
 267                 case PF_INET6:
 268                         name = "ipv6";
 269                         break;
 270 #endif
 271                 default:
 272                         talloc_free(tmp_ctx);
 273                         return EINVAL;
 274                 }
 275
 276                 status = NT_STATUS_INVALID_PARAMETER;
 277                 switch (hi->proto) {
 278                 case KRB5_KRBHST_UDP:
 279                         status = socket_create(name, SOCKET_TYPE_DGRAM, &smb_krb5->sock, 0);
 280                         break;
 281                 case KRB5_KRBHST_TCP:
 282                         status = socket_create(name, SOCKET_TYPE_STREAM, &smb_krb5->sock, 0);
 283                         break;
 284                 case KRB5_KRBHST_HTTP:
 285                         talloc_free(tmp_ctx);
 286                         return EINVAL;
 287                 }
 288                 if (!NT_STATUS_IS_OK(status)) {
 289                         talloc_free(smb_krb5);
 290                         continue;
 291                 }
 292
 293                 talloc_steal(smb_krb5, smb_krb5->sock);
 294
 295                 remote_addr = socket_address_from_sockaddr(smb_krb5, a->ai_addr, a->ai_addrlen);
 296                 if (!remote_addr) {
 297                         talloc_free(smb_krb5);
 298                         continue;
 299                 }
 300
 301                 status = socket_connect_ev(smb_krb5->sock, NULL, remote_addr, 0, ev);
 302                 if (!NT_STATUS_IS_OK(status)) {
 303                         talloc_free(smb_krb5);
 304                         continue;
 305                 }
 306
 307                 /* Setup the FDE, start listening for read events
 308                  * from the start (otherwise we may miss a socket
 309                  * drop) and mark as AUTOCLOSE along with the fde */
 310
 311                 /* Ths is equivilant to EVENT_FD_READABLE(smb_krb5->fde) */
 312                 smb_krb5->fde = tevent_add_fd(ev, smb_krb5->sock,
 313                                               socket_get_fd(smb_krb5->sock),
 314                                               TEVENT_FD_READ,
 315                                               smb_krb5_socket_handler, smb_krb5);
 316                 /* its now the job of the event layer to close the socket */
 317                 tevent_fd_set_close_fn(smb_krb5->fde, socket_tevent_fd_close_fn);
 318                 socket_set_flags(smb_krb5->sock, SOCKET_FLAG_NOCLOSE);
 319
 320                 tevent_add_timer(ev, smb_krb5,
 321                                  timeval_current_ofs(timeout, 0),
 322                                  smb_krb5_request_timeout, smb_krb5);
 323
 324                 smb_krb5->status = NT_STATUS_OK;
 325                 smb_krb5->reply = data_blob(NULL, 0);
 326
 327                 switch (hi->proto) {
 328                 case KRB5_KRBHST_UDP:
 329                         TEVENT_FD_WRITEABLE(smb_krb5->fde);
 330                         smb_krb5->request = send_blob;
 331                         break;
 332                 case KRB5_KRBHST_TCP:
 333
 334                         smb_krb5->packet = packet_init(smb_krb5);
 335                         if (smb_krb5->packet == NULL) {
 336                                 talloc_free(smb_krb5);
 337                                 return ENOMEM;
 338                         }
 339                         packet_set_private(smb_krb5->packet, smb_krb5);
 340                         packet_set_socket(smb_krb5->packet, smb_krb5->sock);
 341                         packet_set_callback(smb_krb5->packet, smb_krb5_full_packet);
 342                         packet_set_full_request(smb_krb5->packet, packet_full_request_u32);
 343                         packet_set_error_handler(smb_krb5->packet, smb_krb5_error_handler);
 344                         packet_set_event_context(smb_krb5->packet, ev);
 345                         packet_set_fde(smb_krb5->packet, smb_krb5->fde);
 346
 347                         smb_krb5->request = data_blob_talloc(smb_krb5, NULL, send_blob.length + 4);
 348                         RSIVAL(smb_krb5->request.data, 0, send_blob.length);
 349                         memcpy(smb_krb5->request.data+4, send_blob.data, send_blob.length);
 350                         packet_send(smb_krb5->packet, smb_krb5->request);
 351                         break;
 352                 case KRB5_KRBHST_HTTP:
 353                         talloc_free(tmp_ctx);
 354                         return EINVAL;
 355                 }
 356                 while ((NT_STATUS_IS_OK(smb_krb5->status)) && !smb_krb5->reply.length) {
 357                         if (tevent_loop_once(ev) != 0) {
 358                                 talloc_free(tmp_ctx);
 359                                 return EINVAL;
 360                         }
 361
 362                         /* After each and every event loop, reset the
 363                          * send_to_kdc pointers to what they were when
 364                          * we entered this loop.  That way, if a
 365                          * nested event has invalidated them, we put
 366                          * it back before we return to the heimdal
 367                          * code */
 368                         ret = krb5_set_send_to_kdc_func(context,
 369                                                         smb_krb5_send_and_recv_func,
 370                                                         data);
 371                         if (ret != 0) {
 372                                 talloc_free(tmp_ctx);
 373                                 return ret;
 374                         }
 375                 }
 376                 if (NT_STATUS_EQUAL(smb_krb5->status, NT_STATUS_IO_TIMEOUT)) {
 377                         talloc_free(smb_krb5);
 378                         continue;
 379                 }
 380
 381                 if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 382                         struct tsocket_address *addr = socket_address_to_tsocket_address(smb_krb5, remote_addr);
 383                         const char *addr_string = NULL;
 384                         if (addr) {
 385                                 addr_string = tsocket_address_inet_addr_string(addr, smb_krb5);
 386                         } else {
 387                                 addr_string = NULL;
 388                         }
 389                         DEBUG(2,("Error reading smb_krb5 reply packet: %s from %s\n", nt_errstr(smb_krb5->status),
 390                                  addr_string));
 391                         talloc_free(smb_krb5);
 392                         continue;
 393                 }
 394
 395                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
 396                 if (ret) {
 397                         talloc_free(tmp_ctx);
 398                         return ret;
 399                 }
 400                 talloc_free(smb_krb5);
 401
 402                 break;
 403         }
 404         talloc_free(tmp_ctx);
 405         if (a) {
 406                 return 0;
 407         }
 408         return KRB5_KDC_UNREACH;
 409 }
 410 #endif
 411
 412 krb5_error_code
 413 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
 414                             struct loadparm_context *lp_ctx,
 415                             krb5_context *_krb5_context)
 416 {
 417         krb5_error_code ret;
 418 #ifdef SAMBA4_USES_HEIMDAL
 419         char **config_files;
 420         const char *config_file, *realm;
 421 #endif
 422         krb5_context krb5_ctx;
 423
 424         initialize_krb5_error_table();
 425
 426         ret = krb5_init_context(&krb5_ctx);
 427         if (ret) {
 428                 DEBUG(1,("krb5_init_context failed (%s)\n",
 429                          error_message(ret)));
 430                 return ret;
 431         }
 432
 433         /* The MIT Kerberos build relies on using the system krb5.conf file.
 434          * If you really want to use another file please set KRB5_CONFIG
 435          * accordingly. */
 436 #ifdef SAMBA4_USES_HEIMDAL
 437         config_file = lpcfg_config_path(tmp_ctx, lp_ctx, "krb5.conf");
 438         if (!config_file) {
 439                 krb5_free_context(krb5_ctx);
 440                 return ENOMEM;
 441         }
 442
 443         /* Use our local krb5.conf file by default */
 444         ret = krb5_prepend_config_files_default(config_file, &config_files);
 445         if (ret) {
 446                 DEBUG(1,("krb5_prepend_config_files_default 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         ret = krb5_set_config_files(krb5_ctx, config_files);
 453         krb5_free_config_files(config_files);
 454         if (ret) {
 455                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 456                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 457                 krb5_free_context(krb5_ctx);
 458                 return ret;
 459         }
 460
 461         realm = lpcfg_realm(lp_ctx);
 462         if (realm != NULL) {
 463                 ret = krb5_set_default_realm(krb5_ctx, realm);
 464                 if (ret) {
 465                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 466                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 467                         krb5_free_context(krb5_ctx);
 468                         return ret;
 469                 }
 470         }
 471 #endif
 472         *_krb5_context = krb5_ctx;
 473         return 0;
 474 }
 475
 476 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 477                                       struct loadparm_context *lp_ctx,
 478                                       struct smb_krb5_context **smb_krb5_context)
 479 {
 480         krb5_error_code ret;
 481         TALLOC_CTX *tmp_ctx;
 482         krb5_context kctx;
 483 #ifdef SAMBA4_USES_HEIMDAL
 484         krb5_log_facility *logf;
 485 #endif
 486
 487         initialize_krb5_error_table();
 488
 489         tmp_ctx = talloc_new(parent_ctx);
 490         *smb_krb5_context = talloc_zero(tmp_ctx, struct smb_krb5_context);
 491
 492         if (!*smb_krb5_context || !tmp_ctx) {
 493                 talloc_free(tmp_ctx);
 494                 return ENOMEM;
 495         }
 496
 497         ret = smb_krb5_init_context_basic(tmp_ctx, lp_ctx, &kctx);
 498         if (ret) {
 499                 DEBUG(1,("smb_krb5_context_init_basic failed (%s)\n",
 500                          error_message(ret)));
 501                 talloc_free(tmp_ctx);
 502                 return ret;
 503         }
 504         (*smb_krb5_context)->krb5_context = kctx;
 505
 506         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy);
 507
 508 #ifdef SAMBA4_USES_HEIMDAL
 509         /* TODO: Should we have a different name here? */
 510         ret = krb5_initlog(kctx, "Samba", &logf);
 511
 512         if (ret) {
 513                 DEBUG(1,("krb5_initlog failed (%s)\n",
 514                          smb_get_krb5_error_message(kctx, ret, tmp_ctx)));
 515                 talloc_free(tmp_ctx);
 516                 return ret;
 517         }
 518         (*smb_krb5_context)->pvt_log_data = logf;
 519
 520         ret = krb5_addlog_func(kctx, logf, 0 /* min */, -1 /* max */,
 521                                smb_krb5_debug_wrapper,
 522                                 smb_krb5_debug_close, NULL);
 523         if (ret) {
 524                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
 525                          smb_get_krb5_error_message(kctx, ret, tmp_ctx)));
 526                 talloc_free(tmp_ctx);
 527                 return ret;
 528         }
 529         krb5_set_warn_dest(kctx, logf);
 530
 531         /* Set options in kerberos */
 532
 533         krb5_set_dns_canonicalize_hostname(kctx,
 534                         lpcfg_parm_bool(lp_ctx, NULL, "krb5",
 535                                         "set_dns_canonicalize", false));
 536 #endif
 537         talloc_steal(parent_ctx, *smb_krb5_context);
 538         talloc_free(tmp_ctx);
 539
 540         return 0;
 541 }
 542
 543 #ifdef SAMBA4_USES_HEIMDAL
 544 krb5_error_code smb_krb5_context_set_event_ctx(struct smb_krb5_context *smb_krb5_context,
 545                                                struct tevent_context *ev,
 546                                                struct tevent_context **previous_ev)
 547 {
 548         int ret;
 549         if (!ev) {
 550                 return EINVAL;
 551         }
 552
 553         *previous_ev = smb_krb5_context->current_ev;
 554
 555         smb_krb5_context->current_ev = talloc_reference(smb_krb5_context, ev);
 556         if (!smb_krb5_context->current_ev) {
 557                 return ENOMEM;
 558         }
 559
 560         /* Set use of our socket lib */
 561         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 562                                         smb_krb5_send_and_recv_func,
 563                                         ev);
 564         if (ret) {
 565                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 566                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 567                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 568                 talloc_free(tmp_ctx);
 569                 talloc_unlink(smb_krb5_context, smb_krb5_context->current_ev);
 570                 smb_krb5_context->current_ev = NULL;
 571                 return ret;
 572         }
 573         return 0;
 574 }
 575
 576 krb5_error_code smb_krb5_context_remove_event_ctx(struct smb_krb5_context *smb_krb5_context,
 577                                                   struct tevent_context *previous_ev,
 578                                                   struct tevent_context *ev)
 579 {
 580         int ret;
 581         talloc_unlink(smb_krb5_context, ev);
 582         /* If there was a mismatch with things happening on a stack, then don't wipe things */
 583         smb_krb5_context->current_ev = previous_ev;
 584         /* Set use of our socket lib */
 585         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 586                                         smb_krb5_send_and_recv_func,
 587                                         previous_ev);
 588         if (ret) {
 589                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 590                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 591                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 592                 talloc_free(tmp_ctx);
 593                 return ret;
 594         }
 595         return 0;
 596 }
 597 #endif