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 #ifdef SAMBA4_USES_HEIMDAL
  90 /*
  91   handle recv events on a smb_krb5 socket
  92 */
  93 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
  94 {
  95         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
  96         DATA_BLOB blob;
  97         size_t nread, dsize;
  98
  99         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
 100         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 101                 talloc_free(tmp_ctx);
 102                 return;
 103         }
 104
 105         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
 106         if (blob.data == NULL && dsize != 0) {
 107                 smb_krb5->status = NT_STATUS_NO_MEMORY;
 108                 talloc_free(tmp_ctx);
 109                 return;
 110         }
 111
 112         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
 113         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 114                 talloc_free(tmp_ctx);
 115                 return;
 116         }
 117         blob.length = nread;
 118
 119         if (nread == 0) {
 120                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 121                 talloc_free(tmp_ctx);
 122                 return;
 123         }
 124
 125         DEBUG(4,("Received smb_krb5 packet of length %d\n",
 126                  (int)blob.length));
 127
 128         talloc_steal(smb_krb5, blob.data);
 129         smb_krb5->reply = blob;
 130         talloc_free(tmp_ctx);
 131 }
 132
 133 static NTSTATUS smb_krb5_full_packet(void *private_data, DATA_BLOB data)
 134 {
 135         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 136         talloc_steal(smb_krb5, data.data);
 137         smb_krb5->reply = data;
 138         smb_krb5->reply.length -= 4;
 139         smb_krb5->reply.data += 4;
 140         return NT_STATUS_OK;
 141 }
 142
 143 /*
 144   handle request timeouts
 145 */
 146 static void smb_krb5_request_timeout(struct tevent_context *event_ctx,
 147                                   struct tevent_timer *te, struct timeval t,
 148                                   void *private_data)
 149 {
 150         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 151         DEBUG(5,("Timed out smb_krb5 packet\n"));
 152         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
 153 }
 154
 155 static void smb_krb5_error_handler(void *private_data, NTSTATUS status)
 156 {
 157         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 158         smb_krb5->status = status;
 159 }
 160
 161 /*
 162   handle send events on a smb_krb5 socket
 163 */
 164 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
 165 {
 166         NTSTATUS status;
 167
 168         size_t len;
 169
 170         len = smb_krb5->request.length;
 171         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
 172
 173         if (!NT_STATUS_IS_OK(status)) return;
 174
 175         TEVENT_FD_READABLE(smb_krb5->fde);
 176
 177         TEVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
 178         return;
 179 }
 180
 181
 182 /*
 183   handle fd events on a smb_krb5_socket
 184 */
 185 static void smb_krb5_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 186                                  uint16_t flags, void *private_data)
 187 {
 188         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 189         switch (smb_krb5->hi->proto) {
 190         case KRB5_KRBHST_UDP:
 191                 if (flags & TEVENT_FD_READ) {
 192                         smb_krb5_socket_recv(smb_krb5);
 193                         return;
 194                 }
 195                 if (flags & TEVENT_FD_WRITE) {
 196                         smb_krb5_socket_send(smb_krb5);
 197                         return;
 198                 }
 199                 /* not reached */
 200                 return;
 201         case KRB5_KRBHST_TCP:
 202                 if (flags & TEVENT_FD_READ) {
 203                         packet_recv(smb_krb5->packet);
 204                         return;
 205                 }
 206                 if (flags & TEVENT_FD_WRITE) {
 207                         packet_queue_run(smb_krb5->packet);
 208                         return;
 209                 }
 210                 /* not reached */
 211                 return;
 212         case KRB5_KRBHST_HTTP:
 213                 /* can't happen */
 214                 break;
 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 #endif
 416
 417 krb5_error_code
 418 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
 419                             struct loadparm_context *lp_ctx,
 420                             krb5_context *_krb5_context)
 421 {
 422         krb5_error_code ret;
 423         char **config_files;
 424         const char *config_file, *realm;
 425         krb5_context krb5_ctx;
 426
 427         initialize_krb5_error_table();
 428
 429         ret = krb5_init_context(&krb5_ctx);
 430         if (ret) {
 431                 DEBUG(1,("krb5_init_context failed (%s)\n",
 432                          error_message(ret)));
 433                 return ret;
 434         }
 435
 436         config_file = lpcfg_config_path(tmp_ctx, lp_ctx, "krb5.conf");
 437         if (!config_file) {
 438                 krb5_free_context(krb5_ctx);
 439                 return ENOMEM;
 440         }
 441
 442         /* Use our local krb5.conf file by default */
 443         ret = krb5_prepend_config_files_default(config_file == NULL?"":config_file, &config_files);
 444         if (ret) {
 445                 DEBUG(1,("krb5_prepend_config_files_default failed (%s)\n",
 446                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 447                 krb5_free_context(krb5_ctx);
 448                 return ret;
 449         }
 450
 451         ret = krb5_set_config_files(krb5_ctx, config_files);
 452         krb5_free_config_files(config_files);
 453         if (ret) {
 454                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 455                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 456                 krb5_free_context(krb5_ctx);
 457                 return ret;
 458         }
 459
 460         realm = lpcfg_realm(lp_ctx);
 461         if (realm != NULL) {
 462                 ret = krb5_set_default_realm(krb5_ctx, realm);
 463                 if (ret) {
 464                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 465                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 466                         krb5_free_context(krb5_ctx);
 467                         return ret;
 468                 }
 469         }
 470
 471         *_krb5_context = krb5_ctx;
 472         return 0;
 473 }
 474
 475 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 476                                       struct tevent_context *ev,
 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 use of our socket lib */
 532         if (ev) {
 533                 struct tevent_context *previous_ev;
 534                 ret = smb_krb5_context_set_event_ctx(*smb_krb5_context,
 535                                                      ev, &previous_ev);
 536                 if (ret) {
 537                         talloc_free(tmp_ctx);
 538                         return ret;
 539                 }
 540         }
 541
 542         /* Set options in kerberos */
 543
 544         krb5_set_dns_canonicalize_hostname(kctx,
 545                         lpcfg_parm_bool(lp_ctx, NULL, "krb5",
 546                                         "set_dns_canonicalize", false));
 547 #else
 548         ret = krb5_set_trace_callback(kctx, smb_krb5_debug_wrapper, NULL);
 549         if (ret && ret != KRB5_TRACE_NOSUPP) {
 550                 DEBUG(1, ("krb5_set_trace_callback failed (%s)\n"
 551                           smb_get_krb5_error_message(kctx, ret, tmp_ctx)));
 552                 talloc_free(tmp_ctx);
 553                 return ret;
 554         }
 555 #endif
 556         talloc_steal(parent_ctx, *smb_krb5_context);
 557         talloc_free(tmp_ctx);
 558
 559         return 0;
 560 }
 561
 562 #ifdef SAMBA4_USES_HEIMDAL
 563 krb5_error_code smb_krb5_context_set_event_ctx(struct smb_krb5_context *smb_krb5_context,
 564                                                struct tevent_context *ev,
 565                                                struct tevent_context **previous_ev)
 566 {
 567         int ret;
 568         if (!ev) {
 569                 return EINVAL;
 570         }
 571
 572         *previous_ev = smb_krb5_context->current_ev;
 573
 574         smb_krb5_context->current_ev = talloc_reference(smb_krb5_context, ev);
 575         if (!smb_krb5_context->current_ev) {
 576                 return ENOMEM;
 577         }
 578
 579         /* Set use of our socket lib */
 580         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 581                                         smb_krb5_send_and_recv_func,
 582                                         ev);
 583         if (ret) {
 584                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 585                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 586                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 587                 talloc_free(tmp_ctx);
 588                 talloc_unlink(smb_krb5_context, smb_krb5_context->current_ev);
 589                 smb_krb5_context->current_ev = NULL;
 590                 return ret;
 591         }
 592         return 0;
 593 }
 594
 595 krb5_error_code smb_krb5_context_remove_event_ctx(struct smb_krb5_context *smb_krb5_context,
 596                                                   struct tevent_context *previous_ev,
 597                                                   struct tevent_context *ev)
 598 {
 599         int ret;
 600         talloc_unlink(smb_krb5_context, ev);
 601         /* If there was a mismatch with things happening on a stack, then don't wipe things */
 602         smb_krb5_context->current_ev = previous_ev;
 603         /* Set use of our socket lib */
 604         ret = krb5_set_send_to_kdc_func(smb_krb5_context->krb5_context,
 605                                         smb_krb5_send_and_recv_func,
 606                                         previous_ev);
 607         if (ret) {
 608                 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
 609                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 610                          smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, tmp_ctx)));
 611                 talloc_free(tmp_ctx);
 612                 return ret;
 613         }
 614         return 0;
 615 }
 616 #endif