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
  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 tevent_fd *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 krb5_error_code smb_krb5_context_destroy(struct smb_krb5_context *ctx)
  53 {
  54         /* Otherwise krb5_free_context will try and close what we have already free()ed */
  55         krb5_set_warn_dest(ctx->krb5_context, NULL);
  56         krb5_closelog(ctx->krb5_context, ctx->logf);
  57         krb5_free_context(ctx->krb5_context);
  58         return 0;
  59 }
  60
  61 /* We never close down the DEBUG system, and no need to unreference the use */
  62 static void smb_krb5_debug_close(void *private_data) {
  63         return;
  64 }
  65
  66 static void smb_krb5_debug_wrapper(const char *timestr, const char *msg, void *private_data)
  67 {
  68         DEBUG(3, ("Kerberos: %s\n", msg));
  69 }
  70
  71 /*
  72   handle recv events on a smb_krb5 socket
  73 */
  74 static void smb_krb5_socket_recv(struct smb_krb5_socket *smb_krb5)
  75 {
  76         TALLOC_CTX *tmp_ctx = talloc_new(smb_krb5);
  77         DATA_BLOB blob;
  78         size_t nread, dsize;
  79
  80         smb_krb5->status = socket_pending(smb_krb5->sock, &dsize);
  81         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  82                 talloc_free(tmp_ctx);
  83                 return;
  84         }
  85
  86         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
  87         if (blob.data == NULL && dsize != 0) {
  88                 smb_krb5->status = NT_STATUS_NO_MEMORY;
  89                 talloc_free(tmp_ctx);
  90                 return;
  91         }
  92
  93         smb_krb5->status = socket_recv(smb_krb5->sock, blob.data, blob.length, &nread);
  94         if (!NT_STATUS_IS_OK(smb_krb5->status)) {
  95                 talloc_free(tmp_ctx);
  96                 return;
  97         }
  98         blob.length = nread;
  99
 100         if (nread == 0) {
 101                 smb_krb5->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 102                 talloc_free(tmp_ctx);
 103                 return;
 104         }
 105
 106         DEBUG(2,("Received smb_krb5 packet of length %d\n",
 107                  (int)blob.length));
 108
 109         talloc_steal(smb_krb5, blob.data);
 110         smb_krb5->reply = blob;
 111         talloc_free(tmp_ctx);
 112 }
 113
 114 static NTSTATUS smb_krb5_full_packet(void *private_data, DATA_BLOB data)
 115 {
 116         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 117         talloc_steal(smb_krb5, data.data);
 118         smb_krb5->reply = data;
 119         smb_krb5->reply.length -= 4;
 120         smb_krb5->reply.data += 4;
 121         return NT_STATUS_OK;
 122 }
 123
 124 /*
 125   handle request timeouts
 126 */
 127 static void smb_krb5_request_timeout(struct tevent_context *event_ctx,
 128                                   struct tevent_timer *te, struct timeval t,
 129                                   void *private_data)
 130 {
 131         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 132         DEBUG(5,("Timed out smb_krb5 packet\n"));
 133         smb_krb5->status = NT_STATUS_IO_TIMEOUT;
 134 }
 135
 136 static void smb_krb5_error_handler(void *private_data, NTSTATUS status)
 137 {
 138         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 139         smb_krb5->status = status;
 140 }
 141
 142 /*
 143   handle send events on a smb_krb5 socket
 144 */
 145 static void smb_krb5_socket_send(struct smb_krb5_socket *smb_krb5)
 146 {
 147         NTSTATUS status;
 148
 149         size_t len;
 150
 151         len = smb_krb5->request.length;
 152         status = socket_send(smb_krb5->sock, &smb_krb5->request, &len);
 153
 154         if (!NT_STATUS_IS_OK(status)) return;
 155
 156         TEVENT_FD_READABLE(smb_krb5->fde);
 157
 158         TEVENT_FD_NOT_WRITEABLE(smb_krb5->fde);
 159         return;
 160 }
 161
 162
 163 /*
 164   handle fd events on a smb_krb5_socket
 165 */
 166 static void smb_krb5_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 167                                  uint16_t flags, void *private_data)
 168 {
 169         struct smb_krb5_socket *smb_krb5 = talloc_get_type(private_data, struct smb_krb5_socket);
 170         switch (smb_krb5->hi->proto) {
 171         case KRB5_KRBHST_UDP:
 172                 if (flags & TEVENT_FD_READ) {
 173                         smb_krb5_socket_recv(smb_krb5);
 174                         return;
 175                 }
 176                 if (flags & TEVENT_FD_WRITE) {
 177                         smb_krb5_socket_send(smb_krb5);
 178                         return;
 179                 }
 180                 /* not reached */
 181                 return;
 182         case KRB5_KRBHST_TCP:
 183                 if (flags & TEVENT_FD_READ) {
 184                         packet_recv(smb_krb5->packet);
 185                         return;
 186                 }
 187                 if (flags & TEVENT_FD_WRITE) {
 188                         packet_queue_run(smb_krb5->packet);
 189                         return;
 190                 }
 191                 /* not reached */
 192                 return;
 193         case KRB5_KRBHST_HTTP:
 194                 /* can't happen */
 195                 break;
 196         }
 197 }
 198
 199
 200 krb5_error_code smb_krb5_send_and_recv_func(krb5_context context,
 201                                             void *data,
 202                                             krb5_krbhst_info *hi,
 203                                             time_t timeout,
 204                                             const krb5_data *send_buf,
 205                                             krb5_data *recv_buf)
 206 {
 207         krb5_error_code ret;
 208         NTSTATUS status;
 209         struct socket_address *remote_addr;
 210         const char *name;
 211         struct addrinfo *ai, *a;
 212         struct smb_krb5_socket *smb_krb5;
 213
 214         struct tevent_context *ev = talloc_get_type(data, struct tevent_context);
 215
 216         DATA_BLOB send_blob = data_blob_const(send_buf->data, send_buf->length);
 217
 218         ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
 219         if (ret) {
 220                 return ret;
 221         }
 222
 223         for (a = ai; a; a = ai->ai_next) {
 224                 smb_krb5 = talloc(NULL, struct smb_krb5_socket);
 225                 if (!smb_krb5) {
 226                         return ENOMEM;
 227                 }
 228                 smb_krb5->hi = hi;
 229
 230                 switch (a->ai_family) {
 231                 case PF_INET:
 232                         name = "ipv4";
 233                         break;
 234 #ifdef HAVE_IPV6
 235                 case PF_INET6:
 236                         name = "ipv6";
 237                         break;
 238 #endif
 239                 default:
 240                         talloc_free(smb_krb5);
 241                         return EINVAL;
 242                 }
 243
 244                 status = NT_STATUS_INVALID_PARAMETER;
 245                 switch (hi->proto) {
 246                 case KRB5_KRBHST_UDP:
 247                         status = socket_create(name, SOCKET_TYPE_DGRAM, &smb_krb5->sock, 0);
 248                         break;
 249                 case KRB5_KRBHST_TCP:
 250                         status = socket_create(name, SOCKET_TYPE_STREAM, &smb_krb5->sock, 0);
 251                         break;
 252                 case KRB5_KRBHST_HTTP:
 253                         talloc_free(smb_krb5);
 254                         return EINVAL;
 255                 }
 256                 if (!NT_STATUS_IS_OK(status)) {
 257                         talloc_free(smb_krb5);
 258                         continue;
 259                 }
 260
 261                 talloc_steal(smb_krb5, smb_krb5->sock);
 262
 263                 remote_addr = socket_address_from_sockaddr(smb_krb5, a->ai_addr, a->ai_addrlen);
 264                 if (!remote_addr) {
 265                         talloc_free(smb_krb5);
 266                         continue;
 267                 }
 268
 269                 status = socket_connect_ev(smb_krb5->sock, NULL, remote_addr, 0, ev);
 270                 if (!NT_STATUS_IS_OK(status)) {
 271                         talloc_free(smb_krb5);
 272                         continue;
 273                 }
 274                 talloc_free(remote_addr);
 275
 276                 /* Setup the FDE, start listening for read events
 277                  * from the start (otherwise we may miss a socket
 278                  * drop) and mark as AUTOCLOSE along with the fde */
 279
 280                 /* Ths is equivilant to EVENT_FD_READABLE(smb_krb5->fde) */
 281                 smb_krb5->fde = tevent_add_fd(ev, smb_krb5->sock,
 282                                               socket_get_fd(smb_krb5->sock),
 283                                               TEVENT_FD_READ,
 284                                               smb_krb5_socket_handler, smb_krb5);
 285                 /* its now the job of the event layer to close the socket */
 286                 tevent_fd_set_close_fn(smb_krb5->fde, socket_tevent_fd_close_fn);
 287                 socket_set_flags(smb_krb5->sock, SOCKET_FLAG_NOCLOSE);
 288
 289                 tevent_add_timer(ev, smb_krb5,
 290                                  timeval_current_ofs(timeout, 0),
 291                                  smb_krb5_request_timeout, smb_krb5);
 292
 293                 smb_krb5->status = NT_STATUS_OK;
 294                 smb_krb5->reply = data_blob(NULL, 0);
 295
 296                 switch (hi->proto) {
 297                 case KRB5_KRBHST_UDP:
 298                         TEVENT_FD_WRITEABLE(smb_krb5->fde);
 299                         smb_krb5->request = send_blob;
 300                         break;
 301                 case KRB5_KRBHST_TCP:
 302
 303                         smb_krb5->packet = packet_init(smb_krb5);
 304                         if (smb_krb5->packet == NULL) {
 305                                 talloc_free(smb_krb5);
 306                                 return ENOMEM;
 307                         }
 308                         packet_set_private(smb_krb5->packet, smb_krb5);
 309                         packet_set_socket(smb_krb5->packet, smb_krb5->sock);
 310                         packet_set_callback(smb_krb5->packet, smb_krb5_full_packet);
 311                         packet_set_full_request(smb_krb5->packet, packet_full_request_u32);
 312                         packet_set_error_handler(smb_krb5->packet, smb_krb5_error_handler);
 313                         packet_set_event_context(smb_krb5->packet, ev);
 314                         packet_set_fde(smb_krb5->packet, smb_krb5->fde);
 315
 316                         smb_krb5->request = data_blob_talloc(smb_krb5, NULL, send_blob.length + 4);
 317                         RSIVAL(smb_krb5->request.data, 0, send_blob.length);
 318                         memcpy(smb_krb5->request.data+4, send_blob.data, send_blob.length);
 319                         packet_send(smb_krb5->packet, smb_krb5->request);
 320                         break;
 321                 case KRB5_KRBHST_HTTP:
 322                         talloc_free(smb_krb5);
 323                         return EINVAL;
 324                 }
 325                 while ((NT_STATUS_IS_OK(smb_krb5->status)) && !smb_krb5->reply.length) {
 326                         if (tevent_loop_once(ev) != 0) {
 327                                 talloc_free(smb_krb5);
 328                                 return EINVAL;
 329                         }
 330                 }
 331                 if (NT_STATUS_EQUAL(smb_krb5->status, NT_STATUS_IO_TIMEOUT)) {
 332                         talloc_free(smb_krb5);
 333                         continue;
 334                 }
 335
 336                 if (!NT_STATUS_IS_OK(smb_krb5->status)) {
 337                         DEBUG(2,("Error reading smb_krb5 reply packet: %s\n", nt_errstr(smb_krb5->status)));
 338                         talloc_free(smb_krb5);
 339                         continue;
 340                 }
 341
 342                 ret = krb5_data_copy(recv_buf, smb_krb5->reply.data, smb_krb5->reply.length);
 343                 if (ret) {
 344                         talloc_free(smb_krb5);
 345                         return ret;
 346                 }
 347                 talloc_free(smb_krb5);
 348
 349                 break;
 350         }
 351         if (a) {
 352                 return 0;
 353         }
 354         return KRB5_KDC_UNREACH;
 355 }
 356
 357 krb5_error_code
 358 smb_krb5_init_context_basic(TALLOC_CTX *tmp_ctx,
 359                             struct tevent_context *ev,
 360                             struct loadparm_context *lp_ctx,
 361                             krb5_context *_krb5_context)
 362 {
 363         krb5_error_code ret;
 364         char **config_files;
 365         const char *config_file, *realm;
 366         krb5_context krb5_ctx;
 367
 368         initialize_krb5_error_table();
 369
 370         ret = krb5_init_context(&krb5_ctx);
 371         if (ret) {
 372                 DEBUG(1,("krb5_init_context failed (%s)\n",
 373                          error_message(ret)));
 374                 return ret;
 375         }
 376
 377         config_file = config_path(tmp_ctx, lp_ctx, "krb5.conf");
 378         if (!config_file) {
 379                 krb5_free_context(krb5_ctx);
 380                 return ENOMEM;
 381         }
 382
 383         /* Use our local krb5.conf file by default */
 384         ret = krb5_prepend_config_files_default(config_file == NULL?"":config_file, &config_files);
 385         if (ret) {
 386                 DEBUG(1,("krb5_prepend_config_files_default failed (%s)\n",
 387                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 388                 krb5_free_context(krb5_ctx);
 389                 return ret;
 390         }
 391
 392         ret = krb5_set_config_files(krb5_ctx, config_files);
 393         krb5_free_config_files(config_files);
 394         if (ret) {
 395                 DEBUG(1,("krb5_set_config_files failed (%s)\n",
 396                          smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 397                 krb5_free_context(krb5_ctx);
 398                 return ret;
 399         }
 400
 401         realm = lp_realm(lp_ctx);
 402         if (realm != NULL) {
 403                 ret = krb5_set_default_realm(krb5_ctx, realm);
 404                 if (ret) {
 405                         DEBUG(1,("krb5_set_default_realm failed (%s)\n",
 406                                  smb_get_krb5_error_message(krb5_ctx, ret, tmp_ctx)));
 407                         krb5_free_context(krb5_ctx);
 408                         return ret;
 409                 }
 410         }
 411
 412         *_krb5_context = krb5_ctx;
 413         return 0;
 414 }
 415
 416 krb5_error_code smb_krb5_init_context(void *parent_ctx,
 417                                       struct tevent_context *ev,
 418                                       struct loadparm_context *lp_ctx,
 419                                        struct smb_krb5_context **smb_krb5_context)
 420 {
 421         krb5_error_code ret;
 422         TALLOC_CTX *tmp_ctx;
 423
 424         initialize_krb5_error_table();
 425
 426         tmp_ctx = talloc_new(parent_ctx);
 427         *smb_krb5_context = talloc(tmp_ctx, struct smb_krb5_context);
 428
 429         if (!*smb_krb5_context || !tmp_ctx) {
 430                 talloc_free(tmp_ctx);
 431                 return ENOMEM;
 432         }
 433
 434         ret = smb_krb5_init_context_basic(tmp_ctx, ev, lp_ctx,
 435                                           &(*smb_krb5_context)->krb5_context);
 436         if (ret) {
 437                 DEBUG(1,("smb_krb5_context_init_basic failed (%s)\n",
 438                          error_message(ret)));
 439                 talloc_free(tmp_ctx);
 440                 return ret;
 441         }
 442
 443         /* TODO: Should we have a different name here? */
 444         ret = krb5_initlog((*smb_krb5_context)->krb5_context, "Samba", &(*smb_krb5_context)->logf);
 445
 446         if (ret) {
 447                 DEBUG(1,("krb5_initlog failed (%s)\n",
 448                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 449                 krb5_free_context((*smb_krb5_context)->krb5_context);
 450                 talloc_free(tmp_ctx);
 451                 return ret;
 452         }
 453
 454         talloc_set_destructor(*smb_krb5_context, smb_krb5_context_destroy);
 455
 456         ret = krb5_addlog_func((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf, 0 /* min */, -1 /* max */,
 457                                smb_krb5_debug_wrapper, smb_krb5_debug_close, NULL);
 458         if (ret) {
 459                 DEBUG(1,("krb5_addlog_func failed (%s)\n",
 460                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 461                 talloc_free(tmp_ctx);
 462                 return ret;
 463         }
 464         krb5_set_warn_dest((*smb_krb5_context)->krb5_context, (*smb_krb5_context)->logf);
 465
 466         /* Set use of our socket lib */
 467         ret = krb5_set_send_to_kdc_func((*smb_krb5_context)->krb5_context,
 468                                         smb_krb5_send_and_recv_func,
 469                                         ev);
 470         if (ret) {
 471                 DEBUG(1,("krb5_set_send_recv_func failed (%s)\n",
 472                          smb_get_krb5_error_message((*smb_krb5_context)->krb5_context, ret, tmp_ctx)));
 473                 talloc_free(tmp_ctx);
 474                 return ret;
 475         }
 476
 477         talloc_steal(parent_ctx, *smb_krb5_context);
 478         talloc_free(tmp_ctx);
 479
 480         /* Set options in kerberos */
 481
 482         krb5_set_dns_canonicalize_hostname((*smb_krb5_context)->krb5_context,
 483                                            lp_parm_bool(lp_ctx, NULL, "krb5", "set_dns_canonicalize", false));
 484
 485         return 0;
 486 }
 487