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 #include "krb5_init_context.h"
  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 #ifdef SAMBA4_USES_HEIMDAL
  56         if (ctx->pvt_log_data) {
  57                 /* Otherwise krb5_free_context will try and close what we
  58                  * have already free()ed */
  59                 krb5_set_warn_dest(ctx->krb5_context, NULL);
  60                 krb5_closelog(ctx->krb5_context,
  61                                 (krb5_log_facility *)ctx->pvt_log_data);
  62         }
  63 #else
  64         krb5_set_trace_callback(ctx->krb5_context, NULL, NULL);
  65 #endif
  66         krb5_free_context(ctx->krb5_context);
  67         return 0;
  68 }
  69
  70 /* We never close down the DEBUG system, and no need to unreference the use */
  71 static void smb_krb5_debug_close(void *private_data) {
  72         return;
  73 }
  74
  75 #ifdef SAMBA4_USES_HEIMDAL
  76 static void smb_krb5_debug_wrapper(const char *timestr, const char *msg, void *private_data)
  77 {
  78         DEBUG(3, ("Kerberos: %s\n", msg));
  79 }
  80 #else
  81 static void smb_krb5_debug_wrapper(krb5_context context,
  82                                    const struct krb5_trace_info *info,
  83                                    void *cb_data)
  84 {
  85         DEBUG(3, ("Kerberos: %s\n", info->message));
  86 }
  87 #endif
  88
  89 /*
  90   handle recv events on a smb_krb5 socket
  91 */
  92 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
  93 {
  94         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
  95         DATA_BLOB blob;
  96         size_t nread, dsize;
  97
  98         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
  99         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 100                 talloc_free(tmp_ctx);
 101                 return;
 102         }
 103
 104         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
 105         if (blob.data == NULL && dsize != 0) {
 106                 smb_krb5->status = NT_STATUS_NO_MEMORY;
 107                 talloc_free(tmp_ctx);
 108                 return;
 109         }
 110
 111         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
 112         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 113                 talloc_free(tmp_ctx);
 114                 return;
 115         }
 116         blob.length = nread;
 117
 118         if (nread == 0) {
 119                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 120                 talloc_free(tmp_ctx);
 121                 return;
 122         }
 123
 124         DEBUG(4,("Received smb_krb5 packet of length %d\n",
 125                  (int)blob.length));
 126
 127         talloc_steal(smb_krb5, blob.data);
 128         smb_krb5->reply = blob;
 129         talloc_free(tmp_ctx);
 130 }
 131
 132 static NTSTATUS smb_krb5_full_packet(void *private_data, DATA_BLOB data)
 133 {
 134         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 135         talloc_steal(smb_krb5, data.data);
 136         smb_krb5->reply = data;
 137         smb_krb5->reply.length -= 4;
 138         smb_krb5->reply.data += 4;
 139         return NT_STATUS_OK;
 140 }
 141
 142 /*
 143   handle request timeouts
 144 */
 145 static void smb_krb5_request_timeout(struct tevent_context *event_ctx,
 146                                   struct tevent_timer *te, struct timeval t,
 147                                   void *private_data)
 148 {
 149         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 150         DEBUG(5,("Timed out smb_krb5 packet\n"));
 151         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
 152 }
 153
 154 static void smb_krb5_error_handler(void *private_data, NTSTATUS status)
 155 {
 156         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 157         smb_krb5->status = status;
 158 }
 159
 160 /*
 161   handle send events on a smb_krb5 socket
 162 */
 163 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
 164 {
 165         NTSTATUS status;
 166
 167         size_t len;
 168
 169         len = smb_krb5->request.length;
 170         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
 171
 172         if (!NT_STATUS_IS_OK(status)) return;
 173
 174         TEVENT_FD_READABLE(smb_krb5->fde);
 175
 176         TEVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
 177         return;
 178 }
 179
 180
 181 /*
 182   handle fd events on a smb_krb5_socket
 183 */
 184 static void smb_krb5_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 185                                  uint16_t flags, void *private_data)
 186 {
 187         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 188         switch (smb_krb5->hi->proto) {
 189         case KRB5_KRBHST_UDP:
 190                 if (flags & TEVENT_FD_READ) {
 191                         smb_krb5_socket_recv(smb_krb5);
 192                         return;
 193                 }
 194                 if (flags & TEVENT_FD_WRITE) {
 195                         smb_krb5_socket_send(smb_krb5);
 196                         return;
 197                 }
 198                 /* not reached */
 199                 return;
 200         case KRB5_KRBHST_TCP:
 201                 if (flags & TEVENT_FD_READ) {
 202                         packet_recv(smb_krb5->packet);
 203                         return;
 204                 }
 205                 if (flags & TEVENT_FD_WRITE) {
 206                         packet_queue_run(smb_krb5->packet);
 207                         return;
 208                 }
 209                 /* not reached */
 210                 return;
 211         case KRB5_KRBHST_HTTP:
 212                 /* can't happen */
 213                 break;
 214         }
 215 }
 216
 217
 218 krb5_error_code smb_krb5_send_and_recv_func(krb5_context context,
 219                                             void *data,
 220                                             krb5_krbhst_info *hi,
 221                                             time_t timeout,
 222                                             const krb5_data *send_buf,
 223                                             krb5_data *recv_buf)
 224 {
 225         krb5_error_code ret;
 226         NTSTATUS status;
 227         const char *name;
 228         struct addrinfo *ai, *a;
 229         struct smb_krb5_socket *smb_krb5;
 230
 231         DATA_BLOB send_blob;
 232
 233         struct tevent_context *ev;
 234         TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 235         if (!tmp_ctx) {
 236                 return ENOMEM;
 237         }
 238
 239         if (!data) {
 240                 /* If no event context was available, then create one for this loop */
 241                 ev = tevent_context_init(tmp_ctx);
 242                 if (!ev) {
 243                         talloc_free(tmp_ctx);
 244                         return ENOMEM;
 245                 }
 246         } else {
 247                 ev = talloc_get_type_abort(data, struct tevent_context);
 248         }
 249
 250         send_blob = data_blob_const(send_buf->data, send_buf->length);
 251
 252         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 253         if (ret) {
 254                 talloc_free(tmp_ctx);
 255                 return ret;
 256         }
 257
 258         for (a = ai; a; a = a->ai_next) {
 259                 struct socket_address *remote_addr;
 260                 smb_krb5 = talloc(tmp_ctx, struct smb_krb5_socket);
 261                 if (!smb_krb5) {
 262                         talloc_free(tmp_ctx);
 263                         return ENOMEM;
 264                 }
 265                 smb_krb5->hi = hi;
 266
 267                 switch (a->ai_family) {
 268                 case PF_INET:
 269                         name = "ipv4";
 270                         break;
 271 #ifdef HAVE_IPV6
 272                 case PF_INET6:
 273                         name = "ipv6";
 274                         break;
 275 #endif
 276                 default:
 277                         talloc_free(tmp_ctx);
 278                         return EINVAL;
 279                 }
 280
 281                 status = NT_STATUS_INVALID_PARAMETER;
 282                 switch (hi->proto) {
 283                 case KRB5_KRBHST_UDP:
 284                         status = socket_create(name, SOCKET_TYPE_DGRAM, &smb_krb5->sock, 0);
 285                         break;
 286                 case KRB5_KRBHST_TCP:
 287                         status = socket_create(name, SOCKET_TYPE_STREAM, &smb_krb5->sock, 0);
 288                         break;
 289                 case KRB5_KRBHST_HTTP:
 290                         talloc_free(tmp_ctx);
 291                         return EINVAL;
 292                 }
 293                 if (!NT_STATUS_IS_OK(status)) {
 294                         talloc_free(smb_krb5);
 295                         continue;
 296                 }
 297
 298                 talloc_steal(smb_krb5, smb_krb5->sock);
 299
 300                 remote_addr = socket_address_from_sockaddr(smb_krb5, a->ai_addr, a->ai_addrlen);
 301                 if (!remote_addr) {
 302                         talloc_free(smb_krb5);
 303                         continue;
 304                 }
 305
 306                 status = socket_connect_ev(smb_krb5->sock, NULL, remote_addr, 0, ev);
 307                 if (!NT_STATUS_IS_OK(status)) {
 308                         talloc_free(smb_krb5);
 309                         continue;
 310                 }
 311
 312                 /* Setup the FDE, start listening for read events
 313                  * from the start (otherwise we may miss a socket
 314                  * drop) and mark as AUTOCLOSE along with the fde */
 315
 316                 /* Ths is equivilant to EVENT_FD_READABLE(smb_krb5->fde) */
 317                 smb_krb5->fde = tevent_add_fd(ev, smb_krb5->sock,
 318                                               socket_get_fd(smb_krb5->sock),
 319                                               TEVENT_FD_READ,
 320                                               smb_krb5_socket_handler, smb_krb5);
 321                 /* its now the job of the event layer to close the socket */
 322                 tevent_fd_set_close_fn(smb_krb5->fde, socket_tevent_fd_close_fn);
 323                 socket_set_flags(smb_krb5->sock, SOCKET_FLAG_NOCLOSE);
 324
 325                 tevent_add_timer(ev, smb_krb5,
 326                                  timeval_current_ofs(timeout, 0),
 327                                  smb_krb5_request_timeout, smb_krb5);
 328
 329                 smb_krb5->status = NT_STATUS_OK;
 330                 smb_krb5->reply = data_blob(NULL, 0);
 331
 332                 switch (hi->proto) {
 333                 case KRB5_KRBHST_UDP:
 334                         TEVENT_FD_WRITEABLE(smb_krb5->fde);
 335                         smb_krb5->request = send_blob;
 336                         break;
 337                 case KRB5_KRBHST_TCP:
 338
 339                         smb_krb5->packet = packet_init(smb_krb5);
 340                         if (smb_krb5->packet == NULL) {
 341                                 talloc_free(smb_krb5);
 342                                 return ENOMEM;
 343                         }
 344                         packet_set_private(smb_krb5->packet, smb_krb5);
 345                         packet_set_socket(smb_krb5->packet, smb_krb5->sock);
 346                         packet_set_callback(smb_krb5->packet, smb_krb5_full_packet);
 347                         packet_set_full_request(smb_krb5->packet, packet_full_request_u32);
 348                         packet_set_error_handler(smb_krb5->packet, smb_krb5_error_handler);
 349                         packet_set_event_context(smb_krb5->packet, ev);
 350                         packet_set_fde(smb_krb5->packet, smb_krb5->fde);
 351
 352                         smb_krb5->request = data_blob_talloc(smb_krb5, NULL, send_blob.length + 4);
 353                         RSIVAL(smb_krb5->request.data, 0, send_blob.length);
 354                         memcpy(smb_krb5->request.data+4, send_blob.data, send_blob.length);
 355                         packet_send(smb_krb5->packet, smb_krb5->request);
 356                         break;
 357                 case KRB5_KRBHST_HTTP:
 358                         talloc_free(tmp_ctx);
 359                         return EINVAL;
 360                 }
 361                 while ((NT_STATUS_IS_OK(smb_krb5->status)) && !smb_krb5->reply.length) {
 362                         if (tevent_loop_once(ev) != 0) {
 363                                 talloc_free(tmp_ctx);
 364                                 return EINVAL;
 365                         }
 366
 367                         /* After each and every event loop, reset the
 368                          * send_to_kdc pointers to what they were when
 369                          * we entered this loop.  That way, if a
 370                          * nested event has invalidated them, we put
 371                          * it back before we return to the heimdal
 372                          * code */
 373                         ret = krb5_set_send_to_kdc_func(context,
 374                                                         smb_krb5_send_and_recv_func,
 375                                                         data);
 376                         if (ret != 0) {
 377                                 talloc_free(tmp_ctx);
 378                                 return ret;
 379                         }
 380                 }
 381                 if (NT_STATUS_EQUAL(smb_krb5->status, NT_STATUS_IO_TIMEOUT)) {
 382                         talloc_free(smb_krb5);
 383                         continue;
 384                 }
 385
 386                 if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 387                         struct tsocket_address *addr = socket_address_to_tsocket_address(smb_krb5, remote_addr);
 388                         const char *addr_string = NULL;
 389                         if (addr) {
 390                                 addr_string = tsocket_address_inet_addr_string(addr, smb_krb5);
 391                         } else {
 392                                 addr_string = NULL;
 393                         }
 394                         DEBUG(2,("Error reading smb_krb5 reply packet: %s from %s\n", nt_errstr(smb_krb5->status),
 395                                  addr_string));
 396                         talloc_free(smb_krb5);
 397                         continue;
 398                 }
 399
 400                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
 401                 if (ret) {
 402                         talloc_free(tmp_ctx);
 403                         return ret;
 404                 }
 405                 talloc_free(smb_krb5);
 406
 407                 break;
 408         }
 409         talloc_free(tmp_ctx);
 410         if (a) {
 411                 return 0;
 412         }
 413         return KRB5_KDC_UNREACH;
 414 }
 415
 416 krb5_error_code
 417 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
 418                             struct loadparm_context *lp_ctx,
 419                             krb5_context *_krb5_context)
 420 {
 421         krb5_error_code ret;
 422         char **config_files;
 423         const char *config_file, *realm;
 424         krb5_context krb5_ctx;
 425
 426         initialize_krb5_error_table();
 427
 428         ret = krb5_init_context(&krb5_ctx);
 429         if (ret) {
 430                 DEBUG(1,("krb5_init_context failed (%s)\n",
 431                          error_message(ret)));
 432                 return ret;
 433         }
 434
 435         config_file = lpcfg_config_path(tmp_ctx, lp_ctx, "krb5.conf");
 436         if (!config_file) {
 437                 krb5_free_context(krb5_ctx);
 438                 return ENOMEM;
 439         }
 440
 441         /* Use our local krb5.conf file by default */
 442         ret = krb5_prepend_config_files_default(config_file == NULL?"":config_file, &config_files);
 443         if (ret) {
 444                 DEBUG(1,("krb5_prepend_config_files_default failed (%s)\n",
 445                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 446                 krb5_free_context(krb5_ctx);
 447                 return ret;
 448         }
 449
 450         ret = krb5_set_config_files(krb5_ctx, config_files);
 451         krb5_free_config_files(config_files);
 452         if (ret) {
 453                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 454                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 455                 krb5_free_context(krb5_ctx);
 456                 return ret;
 457         }
 458
 459         realm = lpcfg_realm(lp_ctx);
 460         if (realm != NULL) {
 461                 ret = krb5_set_default_realm(krb5_ctx, realm);
 462                 if (ret) {
 463                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 464                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 465                         krb5_free_context(krb5_ctx);
 466                         return ret;
 467                 }
 468         }
 469
 470         *_krb5_context = krb5_ctx;
 471         return 0;
 472 }
 473
 474 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 475                                       struct tevent_context *ev,
 476                                       struct loadparm_context *lp_ctx,
 477                                       struct smb_krb5_context **smb_krb5_context)
 478 {
 479         krb5_error_code ret;
 480         TALLOC_CTX *tmp_ctx;
 481         krb5_context kctx;
 482 #ifdef SAMBA4_USES_HEIMDAL
 483         krb5_log_facility *logf;
 484 #endif
 485
 486         initialize_krb5_error_table();
 487
 488         tmp_ctx = talloc_new(parent_ctx);
 489         *smb_krb5_context = talloc_zero(tmp_ctx, struct smb_krb5_context);
 490
 491         if (!*smb_krb5_context || !tmp_ctx) {
 492                 talloc_free(tmp_ctx);
 493                 return ENOMEM;
 494         }
 495
 496         ret = smb_krb5_init_context_basic(tmp_ctx, lp_ctx, &kctx);
 497         if (ret) {
 498                 DEBUG(1,("smb_krb5_context_init_basic failed (%s)\n",
 499                          error_message(ret)));
 500                 talloc_free(tmp_ctx);
 501                 return ret;
 502         }
 503         (*smb_krb5_context)->krb5_context = kctx;
 504
 505         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy);
 506
 507 #ifdef SAMBA4_USES_HEIMDAL
 508         /* TODO: Should we have a different name here? */
 509         ret = krb5_initlog(kctx, "Samba", &logf);
 510
 511         if (ret) {
 512                 DEBUG(1,("krb5_initlog failed (%s)\n",
 513                          smb_get_krb5_error_message(kctx, ret, tmp_ctx)));
 514                 talloc_free(tmp_ctx);
 515                 return ret;
 516         }
 517         (*smb_krb5_context)->pvt_log_data = logf;
 518
 519         ret = krb5_addlog_func(kctx, logf, 0 /* min */, -1 /* max */,
 520                                smb_krb5_debug_wrapper,
 521                                 smb_krb5_debug_close, NULL);
 522         if (ret) {
 523                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
 524                          smb_get_krb5_error_message(kctx, ret, tmp_ctx)));
 525                 talloc_free(tmp_ctx);
 526                 return ret;
 527         }
 528         krb5_set_warn_dest(kctx, logf);
 529
 530         /* Set use of our socket lib */
 531         if (ev) {
 532                 struct tevent_context *previous_ev;
 533                 ret = smb_krb5_context_set_event_ctx(*smb_krb5_context,
 534                                                      ev, &previous_ev);
 535                 if (ret) {
 536                         talloc_free(tmp_ctx);
 537                         return ret;
 538                 }
 539         }
 540
 541         /* Set options in kerberos */
 542
 543         krb5_set_dns_canonicalize_hostname(kctx,
 544                         lpcfg_parm_bool(lp_ctx, NULL, "krb5",
 545                                         "set_dns_canonicalize", false));
 546 #else
 547         ret = krb5_set_trace_callback(kctx, smb_krb5_debug_wrapper, NULL);
 548         if (ret && ret != KRB5_TRACE_NOSUPP) {
 549                 DEBUG(1, ("krb5_set_trace_callback failed (%s)\n"
 550                           smb_get_krb5_error_message(kctx, ret, tmp_ctx)));
 551                 talloc_free(tmp_ctx);
 552                 return ret;
 553         }
 554 #endif
 555         talloc_steal(parent_ctx, *smb_krb5_context);
 556         talloc_free(tmp_ctx);
 557
 558         return 0;
 559 }
 560
 561 krb5_error_code smb_krb5_context_set_event_ctx(struct smb_krb5_context *smb_krb5_context,
 562                                                struct tevent_context *ev,
 563                                                struct tevent_context **previous_ev)
 564 {
 565         int ret;
 566         if (!ev) {
 567                 return EINVAL;
 568         }
 569
 570         *previous_ev = smb_krb5_context->current_ev;
 571
 572         smb_krb5_context->current_ev = talloc_reference(smb_krb5_context, ev);
 573         if (!smb_krb5_context->current_ev) {
 574                 return ENOMEM;
 575         }
 576
 577         /* Set use of our socket lib */
 578         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 579                                         smb_krb5_send_and_recv_func,
 580                                         ev);
 581         if (ret) {
 582                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 583                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 584                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 585                 talloc_free(tmp_ctx);
 586                 talloc_unlink(smb_krb5_context, smb_krb5_context->current_ev);
 587                 smb_krb5_context->current_ev = NULL;
 588                 return ret;
 589         }
 590         return 0;
 591 }
 592
 593 krb5_error_code smb_krb5_context_remove_event_ctx(struct smb_krb5_context *smb_krb5_context,
 594                                                   struct tevent_context *previous_ev,
 595                                                   struct tevent_context *ev)
 596 {
 597         int ret;
 598         talloc_unlink(smb_krb5_context, ev);
 599         /* If there was a mismatch with things happening on a stack, then don't wipe things */
 600         smb_krb5_context->current_ev = previous_ev;
 601         /* Set use of our socket lib */
 602         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 603                                         smb_krb5_send_and_recv_func,
 604                                         previous_ev);
 605         if (ret) {
 606                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 607                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 608                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 609                 talloc_free(tmp_ctx);
 610                 return ret;
 611         }
 612         return 0;
 613 }