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 "heimdal/lib/krb5/krb5_locl.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 "lib/events/events.h"
  31 #include "roken.h"
  32
  33 /*
  34   context structure for operations on cldap packets
  35 */
  36 struct smb_krb5_socket {
  37         struct socket_context *sock;
  38
  39         /* the fd event */
  40         struct fd_event *fde;
  41
  42         NTSTATUS status;
  43         DATA_BLOB request, reply;
  44
  45         struct packet_context *packet;
  46
  47         size_t partial_read;
  48
  49         krb5_krbhst_info *hi;
  50 };
  51
  52 static int smb_krb5_context_destroy_1(struct smb_krb5_context *ctx)
  53 {
  54         krb5_free_context(ctx->krb5_context);
  55         return 0;
  56 }
  57
  58 static int smb_krb5_context_destroy_2(struct smb_krb5_context *ctx)
  59 {
  60         /* Otherwise krb5_free_context will try and close what we have already free()ed */
  61         krb5_set_warn_dest(ctx->krb5_context, NULL);
  62         krb5_closelog(ctx->krb5_context, ctx->logf);
  63         smb_krb5_context_destroy_1(ctx);
  64         return 0;
  65 }
  66
  67 /* We never close down the DEBUG system, and no need to unreference the use */
  68 static void smb_krb5_debug_close(void *private) {
  69         return;
  70 }
  71
  72 static void smb_krb5_debug_wrapper(const char *timestr, const char *msg, void *private)
  73 {
  74         DEBUG(2, ("Kerberos: %s\n", msg));
  75 }
  76
  77 /*
  78   handle recv events on a smb_krb5 socket
  79 */
  80 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
  81 {
  82         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
  83         DATA_BLOB blob;
  84         size_t nread, dsize;
  85
  86         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
  87         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  88                 talloc_free(tmp_ctx);
  89                 return;
  90         }
  91
  92         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
  93         if (blob.data == NULL && dsize != 0) {
  94                 smb_krb5->status = NT_STATUS_NO_MEMORY;
  95                 talloc_free(tmp_ctx);
  96                 return;
  97         }
  98
  99         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
 100         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 101                 talloc_free(tmp_ctx);
 102                 return;
 103         }
 104         blob.length = nread;
 105
 106         if (nread == 0) {
 107                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 108                 talloc_free(tmp_ctx);
 109                 return;
 110         }
 111
 112         DEBUG(2,("Received smb_krb5 packet of length %d\n",
 113                  (int)blob.length));
 114
 115         talloc_steal(smb_krb5, blob.data);
 116         smb_krb5->reply = blob;
 117         talloc_free(tmp_ctx);
 118 }
 119
 120 static NTSTATUS smb_krb5_full_packet(void *private, DATA_BLOB data)
 121 {
 122         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private, struct smb_krb5_socket);
 123         talloc_steal(smb_krb5, data.data);
 124         smb_krb5->reply = data;
 125         smb_krb5->reply.length -= 4;
 126         smb_krb5->reply.data += 4;
 127         return NT_STATUS_OK;
 128 }
 129
 130 /*
 131   handle request timeouts
 132 */
 133 static void smb_krb5_request_timeout(struct event_context *event_ctx,
 134                                   struct timed_event *te, struct timeval t,
 135                                   void *private)
 136 {
 137         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private, struct smb_krb5_socket);
 138         DEBUG(5,("Timed out smb_krb5 packet\n"));
 139         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
 140 }
 141
 142 static void smb_krb5_error_handler(void *private, NTSTATUS status)
 143 {
 144         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private, struct smb_krb5_socket);
 145         smb_krb5->status = status;
 146 }
 147
 148 /*
 149   handle send events on a smb_krb5 socket
 150 */
 151 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
 152 {
 153         NTSTATUS status;
 154
 155         size_t len;
 156
 157         len = smb_krb5->request.length;
 158         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
 159
 160         if (!NT_STATUS_IS_OK(status)) return;
 161
 162         EVENT_FD_READABLE(smb_krb5->fde);
 163
 164         EVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
 165         return;
 166 }
 167
 168
 169 /*
 170   handle fd events on a smb_krb5_socket
 171 */
 172 static void smb_krb5_socket_handler(struct event_context *ev, struct fd_event *fde,
 173                                  uint16_t flags, void *private)
 174 {
 175         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private, struct smb_krb5_socket);
 176         switch (smb_krb5->hi->proto) {
 177         case KRB5_KRBHST_UDP:
 178                 if (flags & EVENT_FD_READ) {
 179                         smb_krb5_socket_recv(smb_krb5);
 180                         return;
 181                 }
 182                 if (flags & EVENT_FD_WRITE) {
 183                         smb_krb5_socket_send(smb_krb5);
 184                         return;
 185                 }
 186                 /* not reached */
 187                 return;
 188         case KRB5_KRBHST_TCP:
 189                 if (flags & EVENT_FD_READ) {
 190                         packet_recv(smb_krb5->packet);
 191                         return;
 192                 }
 193                 if (flags & EVENT_FD_WRITE) {
 194                         packet_queue_run(smb_krb5->packet);
 195                         return;
 196                 }
 197                 /* not reached */
 198                 return;
 199         case KRB5_KRBHST_HTTP:
 200                 /* can't happen */
 201                 break;
 202         }
 203 }
 204
 205
 206 krb5_error_code smb_krb5_send_and_recv_func(krb5_context context,
 207                                             void *data,
 208                                             krb5_krbhst_info *hi,
 209                                             const krb5_data *send_buf,
 210                                             krb5_data *recv_buf)
 211 {
 212         krb5_error_code ret;
 213         NTSTATUS status;
 214         struct socket_address *remote_addr;
 215         const char *name;
 216         struct addrinfo *ai, *a;
 217         struct smb_krb5_socket *smb_krb5;
 218
 219         struct event_context *ev = talloc_get_type(data, struct event_context);
 220
 221         DATA_BLOB send_blob = data_blob_const(send_buf->data, send_buf->length);
 222
 223         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 224         if (ret) {
 225                 return ret;
 226         }
 227
 228         for (a = ai; a; a = ai->ai_next) {
 229                 smb_krb5 = talloc(NULL, struct smb_krb5_socket);
 230                 if (!smb_krb5) {
 231                         return ENOMEM;
 232                 }
 233                 smb_krb5->hi = hi;
 234
 235                 switch (a->ai_family) {
 236                 case PF_INET:
 237                         name = "ipv4";
 238                         break;
 239 #ifdef HAVE_IPV6
 240                 case PF_INET6:
 241                         name = "ipv6";
 242                         break;
 243 #endif
 244                 default:
 245                         talloc_free(smb_krb5);
 246                         return EINVAL;
 247                 }
 248
 249                 status = NT_STATUS_INVALID_PARAMETER;
 250                 switch (hi->proto) {
 251                 case KRB5_KRBHST_UDP:
 252                         if (lp_parm_bool(-1, "krb5", "udp", True)) {
 253                                 status = socket_create(name, SOCKET_TYPE_DGRAM, &smb_krb5->sock, 0);
 254                         }
 255                         break;
 256                 case KRB5_KRBHST_TCP:
 257                         if (lp_parm_bool(-1, "krb5", "tcp", True)) {
 258                                 status = socket_create(name, SOCKET_TYPE_STREAM, &smb_krb5->sock, 0);
 259                         }
 260                         break;
 261                 case KRB5_KRBHST_HTTP:
 262                         talloc_free(smb_krb5);
 263                         return EINVAL;
 264                 }
 265                 if (!NT_STATUS_IS_OK(status)) {
 266                         talloc_free(smb_krb5);
 267                         continue;
 268                 }
 269
 270                 talloc_steal(smb_krb5, smb_krb5->sock);
 271
 272                 remote_addr = socket_address_from_sockaddr(smb_krb5, a->ai_addr, a->ai_addrlen);
 273                 if (!remote_addr) {
 274                         talloc_free(smb_krb5);
 275                         continue;
 276                 }
 277
 278                 status = socket_connect_ev(smb_krb5->sock, NULL, remote_addr, 0, ev);
 279                 if (!NT_STATUS_IS_OK(status)) {
 280                         talloc_free(smb_krb5);
 281                         continue;
 282                 }
 283                 talloc_free(remote_addr);
 284
 285                 /* Setup the FDE, start listening for read events
 286                  * from the start (otherwise we may miss a socket
 287                  * drop) and mark as AUTOCLOSE along with the fde */
 288
 289                 /* Ths is equivilant to EVENT_FD_READABLE(smb_krb5->fde) */
 290                 smb_krb5->fde = event_add_fd(ev, smb_krb5->sock,
 291                                              socket_get_fd(smb_krb5->sock),
 292                                              EVENT_FD_READ|EVENT_FD_AUTOCLOSE,
 293                                              smb_krb5_socket_handler, smb_krb5);
 294                 /* its now the job of the event layer to close the socket */
 295                 socket_set_flags(smb_krb5->sock, SOCKET_FLAG_NOCLOSE);
 296
 297                 event_add_timed(ev, smb_krb5,
 298                                 timeval_current_ofs(context->kdc_timeout, 0),
 299                                 smb_krb5_request_timeout, smb_krb5);
 300
 301
 302                 smb_krb5->status = NT_STATUS_OK;
 303                 smb_krb5->reply = data_blob(NULL, 0);
 304
 305                 switch (hi->proto) {
 306                 case KRB5_KRBHST_UDP:
 307                         EVENT_FD_WRITEABLE(smb_krb5->fde);
 308                         smb_krb5->request = send_blob;
 309                         break;
 310                 case KRB5_KRBHST_TCP:
 311
 312                         smb_krb5->packet = packet_init(smb_krb5);
 313                         if (smb_krb5->packet == NULL) {
 314                                 talloc_free(smb_krb5);
 315                                 return ENOMEM;
 316                         }
 317                         packet_set_private(smb_krb5->packet, smb_krb5);
 318                         packet_set_socket(smb_krb5->packet, smb_krb5->sock);
 319                         packet_set_callback(smb_krb5->packet, smb_krb5_full_packet);
 320                         packet_set_full_request(smb_krb5->packet, packet_full_request_u32);
 321                         packet_set_error_handler(smb_krb5->packet, smb_krb5_error_handler);
 322                         packet_set_event_context(smb_krb5->packet, ev);
 323                         packet_set_fde(smb_krb5->packet, smb_krb5->fde);
 324
 325                         smb_krb5->request = data_blob_talloc(smb_krb5, NULL, send_blob.length + 4);
 326                         RSIVAL(smb_krb5->request.data, 0, send_blob.length);
 327                         memcpy(smb_krb5->request.data+4, send_blob.data, send_blob.length);
 328                         packet_send(smb_krb5->packet, smb_krb5->request);
 329                         break;
 330                 case KRB5_KRBHST_HTTP:
 331                         talloc_free(smb_krb5);
 332                         return EINVAL;
 333                 }
 334                 while ((NT_STATUS_IS_OK(smb_krb5->status)) && !smb_krb5->reply.length) {
 335                         if (event_loop_once(ev) != 0) {
 336                                 talloc_free(smb_krb5);
 337                                 return EINVAL;
 338                         }
 339                 }
 340                 if (NT_STATUS_EQUAL(smb_krb5->status, NT_STATUS_IO_TIMEOUT)) {
 341                         talloc_free(smb_krb5);
 342                         continue;
 343                 }
 344
 345                 if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 346                         DEBUG(2,("Error reading smb_krb5 reply packet: %s\n", nt_errstr(smb_krb5->status)));
 347                         talloc_free(smb_krb5);
 348                         continue;
 349                 }
 350
 351                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
 352                 if (ret) {
 353                         talloc_free(smb_krb5);
 354                         return ret;
 355                 }
 356                 talloc_free(smb_krb5);
 357
 358                 break;
 359         }
 360         if (a) {
 361                 return 0;
 362         }
 363         return KRB5_KDC_UNREACH;
 364 }
 365
 366 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 367                                       struct event_context *ev,
 368                                        struct smb_krb5_context **smb_krb5_context)
 369 {
 370         krb5_error_code ret;
 371         TALLOC_CTX *tmp_ctx;
 372         char **config_files;
 373         const char *config_file;
 374
 375         initialize_krb5_error_table();
 376
 377         tmp_ctx = talloc_new(parent_ctx);
 378         *smb_krb5_context = talloc(tmp_ctx, struct smb_krb5_context);
 379
 380         if (!*smb_krb5_context || !tmp_ctx) {
 381                 talloc_free(tmp_ctx);
 382                 return ENOMEM;
 383         }
 384
 385         ret = krb5_init_context(&(*smb_krb5_context)->krb5_context);
 386         if (ret) {
 387                 DEBUG(1,("krb5_init_context failed (%s)\n",
 388                          error_message(ret)));
 389                 talloc_free(tmp_ctx);
 390                 return ret;
 391         }
 392
 393         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy_1);
 394
 395         config_file = config_path(tmp_ctx, "krb5.conf");
 396         if (!config_file) {
 397                 talloc_free(tmp_ctx);
 398                 return ENOMEM;
 399         }
 400
 401         /* Use our local krb5.conf file by default */
 402         ret = krb5_prepend_config_files_default(config_file, &config_files);
 403         if (ret) {
 404                 DEBUG(1,("krb5_prepend_config_files_default failed (%s)\n",
 405                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 406                 talloc_free(tmp_ctx);
 407                 return ret;
 408         }
 409
 410         ret = krb5_set_config_files((*smb_krb5_context)->krb5_context,
 411                                     config_files);
 412         krb5_free_config_files(config_files);
 413         if (ret) {
 414                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 415                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 416                 talloc_free(tmp_ctx);
 417                 return ret;
 418         }
 419
 420         if (lp_realm() && *lp_realm()) {
 421                 char *upper_realm = strupper_talloc(tmp_ctx, lp_realm());
 422                 if (!upper_realm) {
 423                         DEBUG(1,("gensec_krb5_start: could not uppercase realm: %s\n", lp_realm()));
 424                         talloc_free(tmp_ctx);
 425                         return ENOMEM;
 426                 }
 427                 ret = krb5_set_default_realm((*smb_krb5_context)->krb5_context, upper_realm);
 428                 if (ret) {
 429                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 430                                  smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 431                         talloc_free(tmp_ctx);
 432                         return ret;
 433                 }
 434         }
 435
 436         /* TODO: Should we have a different name here? */
 437         ret = krb5_initlog((*smb_krb5_context)->krb5_context, "Samba", &(*smb_krb5_context)->logf);
 438
 439         if (ret) {
 440                 DEBUG(1,("krb5_initlog failed (%s)\n",
 441                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 442                 talloc_free(tmp_ctx);
 443                 return ret;
 444         }
 445
 446         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy_2);
 447
 448         ret = krb5_addlog_func((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf, 0 /* min */, -1 /* max */,
 449                                smb_krb5_debug_wrapper, smb_krb5_debug_close, NULL);
 450         if (ret) {
 451                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
 452                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 453                 talloc_free(tmp_ctx);
 454                 return ret;
 455         }
 456         krb5_set_warn_dest((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf);
 457
 458         /* Set use of our socket lib */
 459         ret = krb5_set_send_to_kdc_func((*smb_krb5_context)->krb5_context,
 460                                         smb_krb5_send_and_recv_func,
 461                                         ev);
 462         if (ret) {
 463                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 464                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 465                 talloc_free(tmp_ctx);
 466                 return ret;
 467         }
 468
 469         talloc_steal(parent_ctx, *smb_krb5_context);
 470         talloc_free(tmp_ctx);
 471
 472         /* Set options in kerberos */
 473
 474         krb5_set_dns_canonicalize_hostname((*smb_krb5_context)->krb5_context,
 475                                            lp_parm_bool(-1, "krb5", "set_dns_canonicalize", false));
 476
 477         return 0;
 478 }
 479