source4/auth/gensec/gensec_gssapi.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Kerberos backend for GENSEC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
   7    Copyright (C) Stefan Metzmacher <metze@samba.org> 2004-2005
   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 2 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
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26 #include "system/kerberos.h"
  27 #include "system/network.h"
  28 #include "auth/kerberos/kerberos.h"
  29 #include "librpc/gen_ndr/ndr_krb5pac.h"
  30 #include "auth/auth.h"
  31
  32 struct gensec_gssapi_state {
  33         gss_ctx_id_t gssapi_context;
  34         struct gss_channel_bindings_struct *input_chan_bindings;
  35         gss_name_t server_name;
  36         gss_name_t client_name;
  37         OM_uint32 want_flags, got_flags;
  38         const gss_OID_desc *gss_oid;
  39
  40         DATA_BLOB session_key;
  41         DATA_BLOB pac;
  42
  43         struct smb_krb5_context *smb_krb5_context;
  44         krb5_ccache ccache;
  45         const char *ccache_name;
  46         struct keytab_container *keytab;
  47         struct gssapi_creds_container *client_cred;
  48
  49         gss_cred_id_t cred;
  50         gss_cred_id_t delegated_cred_handle;
  51 };
  52
  53 static char *gssapi_error_string(TALLOC_CTX *mem_ctx,
  54                                  OM_uint32 maj_stat, OM_uint32 min_stat)
  55 {
  56         OM_uint32 disp_min_stat, disp_maj_stat;
  57         gss_buffer_desc maj_error_message;
  58         gss_buffer_desc min_error_message;
  59         OM_uint32 msg_ctx = 0;
  60
  61         char *ret;
  62
  63         maj_error_message.value = NULL;
  64         min_error_message.value = NULL;
  65
  66         disp_maj_stat = gss_display_status(&disp_min_stat, maj_stat, GSS_C_GSS_CODE,
  67                            GSS_C_NULL_OID, &msg_ctx, &maj_error_message);
  68         disp_maj_stat = gss_display_status(&disp_min_stat, min_stat, GSS_C_MECH_CODE,
  69                            GSS_C_NULL_OID, &msg_ctx, &min_error_message);
  70         ret = talloc_asprintf(mem_ctx, "%s: %s", (char *)maj_error_message.value, (char *)min_error_message.value);
  71
  72         gss_release_buffer(&disp_min_stat, &maj_error_message);
  73         gss_release_buffer(&disp_min_stat, &min_error_message);
  74
  75         return ret;
  76 }
  77
  78
  79 static int gensec_gssapi_destory(void *ptr)
  80 {
  81         struct gensec_gssapi_state *gensec_gssapi_state = ptr;
  82         OM_uint32 maj_stat, min_stat;
  83
  84         if (gensec_gssapi_state->cred != GSS_C_NO_CREDENTIAL) {
  85                 maj_stat = gss_release_cred(&min_stat,
  86                                             &gensec_gssapi_state->cred);
  87         }
  88         if (gensec_gssapi_state->delegated_cred_handle != GSS_C_NO_CREDENTIAL) {
  89                 maj_stat = gss_release_cred(&min_stat,
  90                                             &gensec_gssapi_state->delegated_cred_handle);
  91         }
  92
  93         if (gensec_gssapi_state->gssapi_context != GSS_C_NO_CONTEXT) {
  94                 maj_stat = gss_delete_sec_context (&min_stat,
  95                                                    &gensec_gssapi_state->gssapi_context,
  96                                                    GSS_C_NO_BUFFER);
  97         }
  98
  99         if (gensec_gssapi_state->server_name != GSS_C_NO_NAME) {
 100                 maj_stat = gss_release_name(&min_stat, &gensec_gssapi_state->server_name);
 101         }
 102         if (gensec_gssapi_state->client_name != GSS_C_NO_NAME) {
 103                 maj_stat = gss_release_name(&min_stat, &gensec_gssapi_state->client_name);
 104         }
 105         return 0;
 106 }
 107
 108 static NTSTATUS gensec_gssapi_start(struct gensec_security *gensec_security)
 109 {
 110         struct gensec_gssapi_state *gensec_gssapi_state;
 111         krb5_error_code ret;
 112
 113         gensec_gssapi_state = talloc(gensec_security, struct gensec_gssapi_state);
 114         if (!gensec_gssapi_state) {
 115                 return NT_STATUS_NO_MEMORY;
 116         }
 117
 118         gensec_security->private_data = gensec_gssapi_state;
 119
 120         gensec_gssapi_state->gssapi_context = GSS_C_NO_CONTEXT;
 121         gensec_gssapi_state->server_name = GSS_C_NO_NAME;
 122         gensec_gssapi_state->client_name = GSS_C_NO_NAME;
 123
 124         /* TODO: Fill in channel bindings */
 125         gensec_gssapi_state->input_chan_bindings = GSS_C_NO_CHANNEL_BINDINGS;
 126
 127         gensec_gssapi_state->want_flags = 0;
 128         if (lp_parm_bool(-1, "gensec_gssapi", "mutual", True)) {
 129                 gensec_gssapi_state->want_flags |= GSS_C_MUTUAL_FLAG;
 130         }
 131         if (lp_parm_bool(-1, "gensec_gssapi", "delegation", True)) {
 132                 gensec_gssapi_state->want_flags |= GSS_C_DELEG_FLAG;
 133         }
 134
 135         gensec_gssapi_state->got_flags = 0;
 136
 137         gensec_gssapi_state->session_key = data_blob(NULL, 0);
 138         gensec_gssapi_state->pac = data_blob(NULL, 0);
 139
 140         gensec_gssapi_state->cred = GSS_C_NO_CREDENTIAL;
 141         gensec_gssapi_state->delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 142
 143         talloc_set_destructor(gensec_gssapi_state, gensec_gssapi_destory);
 144
 145         if (gensec_security->want_features & GENSEC_FEATURE_SIGN) {
 146                 gensec_gssapi_state->want_flags |= GSS_C_INTEG_FLAG;
 147         }
 148         if (gensec_security->want_features & GENSEC_FEATURE_SEAL) {
 149                 gensec_gssapi_state->want_flags |= GSS_C_CONF_FLAG;
 150         }
 151         if (gensec_security->want_features & GENSEC_FEATURE_DCE_STYLE) {
 152                 gensec_gssapi_state->want_flags |= GSS_C_DCE_STYLE;
 153         }
 154
 155         gensec_gssapi_state->gss_oid = gss_mech_krb5;
 156
 157         ret = smb_krb5_init_context(gensec_gssapi_state,
 158                                     &gensec_gssapi_state->smb_krb5_context);
 159         if (ret) {
 160                 DEBUG(1,("gensec_krb5_start: krb5_init_context failed (%s)\n",
 161                          error_message(ret)));
 162                 return NT_STATUS_INTERNAL_ERROR;
 163         }
 164         return NT_STATUS_OK;
 165 }
 166
 167 static NTSTATUS gensec_gssapi_server_start(struct gensec_security *gensec_security)
 168 {
 169         NTSTATUS nt_status;
 170         OM_uint32 maj_stat, min_stat;
 171         int ret;
 172         const char *principal;
 173         struct gensec_gssapi_state *gensec_gssapi_state;
 174         struct cli_credentials *machine_account;
 175
 176         nt_status = gensec_gssapi_start(gensec_security);
 177         if (!NT_STATUS_IS_OK(nt_status)) {
 178                 return nt_status;
 179         }
 180
 181         gensec_gssapi_state = gensec_security->private_data;
 182
 183         machine_account = gensec_get_credentials(gensec_security);
 184
 185         if (!machine_account) {
 186                 DEBUG(3, ("No machine account credentials specified\n"));
 187                 return NT_STATUS_INVALID_PARAMETER;
 188         } else {
 189                 ret = cli_credentials_get_keytab(machine_account, &gensec_gssapi_state->keytab);
 190                 if (ret) {
 191                         DEBUG(3, ("Could not create memory keytab!\n"));
 192                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 193                 }
 194         }
 195
 196         principal = cli_credentials_get_principal(machine_account,
 197                                                   machine_account);
 198
 199         /* This might have been explicity set to NULL, ie use what the client calls us */
 200         if (principal) {
 201                 gss_buffer_desc name_token;
 202
 203                 name_token.value  = discard_const_p(uint8_t, principal);
 204                 name_token.length = strlen(principal);
 205
 206                 maj_stat = gss_import_name (&min_stat,
 207                                             &name_token,
 208                                             GSS_C_NT_USER_NAME,
 209                                             &gensec_gssapi_state->server_name);
 210
 211                 if (maj_stat) {
 212                         DEBUG(2, ("GSS Import name of %s failed: %s\n",
 213                                   (char *)name_token.value,
 214                                   gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 215                         return NT_STATUS_UNSUCCESSFUL;
 216                 }
 217         } else {
 218                 gensec_gssapi_state->server_name = GSS_C_NO_NAME;
 219         }
 220
 221         maj_stat = gsskrb5_acquire_cred(&min_stat,
 222                                         gensec_gssapi_state->keytab->keytab,
 223                                         gensec_gssapi_state->server_name,
 224                                         GSS_C_INDEFINITE,
 225                                         GSS_C_NULL_OID_SET,
 226                                         GSS_C_ACCEPT,
 227                                         &gensec_gssapi_state->cred,
 228                                         NULL,
 229                                         NULL);
 230         if (maj_stat) {
 231                 DEBUG(1, ("Aquiring acceptor credentails failed: %s\n",
 232                           gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 233                 return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 234         }
 235
 236         return NT_STATUS_OK;
 237
 238 }
 239
 240 static NTSTATUS gensec_gssapi_client_start(struct gensec_security *gensec_security)
 241 {
 242         struct gensec_gssapi_state *gensec_gssapi_state;
 243         struct cli_credentials *creds = gensec_get_credentials(gensec_security);
 244         krb5_error_code ret;
 245         NTSTATUS nt_status;
 246         gss_buffer_desc name_token;
 247         gss_OID name_type;
 248         OM_uint32 maj_stat, min_stat;
 249         const char *hostname = gensec_get_target_hostname(gensec_security);
 250         const char *principal;
 251         struct gssapi_creds_container *gcc;
 252
 253         if (!hostname) {
 254                 DEBUG(1, ("Could not determine hostname for target computer, cannot use kerberos\n"));
 255                 return NT_STATUS_INVALID_PARAMETER;
 256         }
 257         if (is_ipaddress(hostname)) {
 258                 DEBUG(2, ("Cannot do GSSAPI to an IP address\n"));
 259                 return NT_STATUS_INVALID_PARAMETER;
 260         }
 261         if (strequal(hostname, "localhost")) {
 262                 DEBUG(2, ("GSSAPI to 'localhost' does not make sense\n"));
 263                 return NT_STATUS_INVALID_PARAMETER;
 264         }
 265
 266         nt_status = gensec_gssapi_start(gensec_security);
 267         if (!NT_STATUS_IS_OK(nt_status)) {
 268                 return nt_status;
 269         }
 270
 271         gensec_gssapi_state = gensec_security->private_data;
 272
 273         principal = gensec_get_target_principal(gensec_security);
 274         if (principal && lp_client_use_spnego_principal()) {
 275                 name_token.value  = discard_const_p(uint8_t, principal);
 276                 name_token.length = strlen(principal);
 277
 278                 name_type = GSS_C_NULL_OID;
 279         } else {
 280                 principal = talloc_asprintf(gensec_gssapi_state, "%s@%s",
 281                                             gensec_get_target_service(gensec_security),
 282                                             hostname);
 283
 284                 name_token.value  = discard_const_p(uint8_t, principal);
 285                 name_token.length = strlen(principal);
 286
 287                 name_type = GSS_C_NT_HOSTBASED_SERVICE;
 288         }
 289
 290         maj_stat = gss_import_name (&min_stat,
 291                                     &name_token,
 292                                     name_type,
 293                                     &gensec_gssapi_state->server_name);
 294         if (maj_stat) {
 295                 DEBUG(2, ("GSS Import name of %s failed: %s\n",
 296                           (char *)name_token.value,
 297                           gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 298                 return NT_STATUS_INVALID_PARAMETER;
 299         }
 300
 301         ret = cli_credentials_get_client_gss_creds(creds, &gcc);
 302         switch (ret) {
 303         case 0:
 304                 break;
 305         case KRB5_KDC_UNREACH:
 306                 DEBUG(3, ("Cannot reach a KDC we require\n"));
 307                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 308         default:
 309                 DEBUG(1, ("Aquiring initiator credentails failed\n"));
 310                 return NT_STATUS_UNSUCCESSFUL;
 311         }
 312
 313         gensec_gssapi_state->client_cred = gcc;
 314
 315         return NT_STATUS_OK;
 316 }
 317
 318
 319 /**
 320  * Check if the packet is one for this mechansim
 321  *
 322  * @param gensec_security GENSEC state
 323  * @param in The request, as a DATA_BLOB
 324  * @return Error, INVALID_PARAMETER if it's not a packet for us
 325  *                or NT_STATUS_OK if the packet is ok.
 326  */
 327
 328 static NTSTATUS gensec_gssapi_magic(struct gensec_security *gensec_security,
 329                                     const DATA_BLOB *in)
 330 {
 331         if (gensec_gssapi_check_oid(in, GENSEC_OID_KERBEROS5)) {
 332                 return NT_STATUS_OK;
 333         } else {
 334                 return NT_STATUS_INVALID_PARAMETER;
 335         }
 336 }
 337
 338
 339 /**
 340  * Next state function for the GSSAPI GENSEC mechanism
 341  *
 342  * @param gensec_gssapi_state GSSAPI State
 343  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 344  * @param in The request, as a DATA_BLOB
 345  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 346  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 347  *                or NT_STATUS_OK if the user is authenticated.
 348  */
 349
 350 static NTSTATUS gensec_gssapi_update(struct gensec_security *gensec_security,
 351                                    TALLOC_CTX *out_mem_ctx,
 352                                    const DATA_BLOB in, DATA_BLOB *out)
 353 {
 354         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 355         NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
 356         OM_uint32 maj_stat, min_stat;
 357         OM_uint32 min_stat2;
 358         gss_buffer_desc input_token, output_token;
 359         gss_OID gss_oid_p;
 360         input_token.length = in.length;
 361         input_token.value = in.data;
 362
 363         switch (gensec_security->gensec_role) {
 364         case GENSEC_CLIENT:
 365         {
 366                 maj_stat = gss_init_sec_context(&min_stat,
 367                                                 gensec_gssapi_state->client_cred->creds,
 368                                                 &gensec_gssapi_state->gssapi_context,
 369                                                 gensec_gssapi_state->server_name,
 370                                                 discard_const_p(gss_OID_desc, gensec_gssapi_state->gss_oid),
 371                                                 gensec_gssapi_state->want_flags,
 372                                                 0,
 373                                                 gensec_gssapi_state->input_chan_bindings,
 374                                                 &input_token,
 375                                                 NULL,
 376                                                 &output_token,
 377                                                 &gensec_gssapi_state->got_flags, /* ret flags */
 378                                                 NULL);
 379                 break;
 380         }
 381         case GENSEC_SERVER:
 382         {
 383                 maj_stat = gss_accept_sec_context(&min_stat,
 384                                                   &gensec_gssapi_state->gssapi_context,
 385                                                   gensec_gssapi_state->cred,
 386                                                   &input_token,
 387                                                   gensec_gssapi_state->input_chan_bindings,
 388                                                   &gensec_gssapi_state->client_name,
 389                                                   &gss_oid_p,
 390                                                   &output_token,
 391                                                   &gensec_gssapi_state->got_flags,
 392                                                   NULL,
 393                                                   &gensec_gssapi_state->delegated_cred_handle);
 394                 gensec_gssapi_state->gss_oid = gss_oid_p;
 395                 break;
 396         }
 397         default:
 398                 return NT_STATUS_INVALID_PARAMETER;
 399
 400         }
 401
 402         if (maj_stat == GSS_S_COMPLETE) {
 403                 *out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
 404                 gss_release_buffer(&min_stat2, &output_token);
 405
 406                 if (gensec_gssapi_state->got_flags & GSS_C_DELEG_FLAG) {
 407                         DEBUG(5, ("gensec_gssapi: credentials were delegated\n"));
 408                 } else {
 409                         DEBUG(5, ("gensec_gssapi: NO credentials were delegated\n"));
 410                 }
 411
 412                 return NT_STATUS_OK;
 413         } else if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 414                 *out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
 415                 gss_release_buffer(&min_stat2, &output_token);
 416
 417                 return NT_STATUS_MORE_PROCESSING_REQUIRED;
 418         } else if ((gensec_gssapi_state->gss_oid->length == gss_mech_krb5->length)
 419             && (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 420                        gensec_gssapi_state->gss_oid->length) == 0)) {
 421                 switch (min_stat) {
 422                 case KRB5_KDC_UNREACH:
 423                         DEBUG(3, ("Cannot reach a KDC we require: %s\n",
 424                                   gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 425                         return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 426                 case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 427                         DEBUG(3, ("Server is not registered with our KDC: %s\n",
 428                                   gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 429                         return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 430                 case KRB5KRB_AP_ERR_MSG_TYPE:
 431                         /* garbage input, possibly from the auto-mech detection */
 432                         return NT_STATUS_INVALID_PARAMETER;
 433                 default:
 434                         DEBUG(1, ("GSS(krb5) Update failed: %s\n",
 435                                   gssapi_error_string(out_mem_ctx, maj_stat, min_stat)));
 436                         return nt_status;
 437                 }
 438         } else {
 439                 DEBUG(1, ("GSS Update failed: %s\n",
 440                           gssapi_error_string(out_mem_ctx, maj_stat, min_stat)));
 441                 return nt_status;
 442         }
 443 }
 444
 445 static NTSTATUS gensec_gssapi_wrap(struct gensec_security *gensec_security,
 446                                    TALLOC_CTX *mem_ctx,
 447                                    const DATA_BLOB *in,
 448                                    DATA_BLOB *out)
 449 {
 450         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 451         OM_uint32 maj_stat, min_stat;
 452         gss_buffer_desc input_token, output_token;
 453         int conf_state;
 454         input_token.length = in->length;
 455         input_token.value = in->data;
 456
 457         maj_stat = gss_wrap(&min_stat,
 458                             gensec_gssapi_state->gssapi_context,
 459                             gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
 460                             GSS_C_QOP_DEFAULT,
 461                             &input_token,
 462                             &conf_state,
 463                             &output_token);
 464         if (GSS_ERROR(maj_stat)) {
 465                 DEBUG(1, ("gensec_gssapi_wrap: GSS Wrap failed: %s\n",
 466                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 467                 return NT_STATUS_ACCESS_DENIED;
 468         }
 469
 470         *out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 471         gss_release_buffer(&min_stat, &output_token);
 472
 473         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 474             && !conf_state) {
 475                 return NT_STATUS_ACCESS_DENIED;
 476         }
 477         return NT_STATUS_OK;
 478 }
 479
 480 static NTSTATUS gensec_gssapi_unwrap(struct gensec_security *gensec_security,
 481                                      TALLOC_CTX *mem_ctx,
 482                                      const DATA_BLOB *in,
 483                                      DATA_BLOB *out)
 484 {
 485         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 486         OM_uint32 maj_stat, min_stat;
 487         gss_buffer_desc input_token, output_token;
 488         int conf_state;
 489         gss_qop_t qop_state;
 490         input_token.length = in->length;
 491         input_token.value = in->data;
 492
 493         maj_stat = gss_unwrap(&min_stat,
 494                               gensec_gssapi_state->gssapi_context,
 495                               &input_token,
 496                               &output_token,
 497                               &conf_state,
 498                               &qop_state);
 499         if (GSS_ERROR(maj_stat)) {
 500                 DEBUG(1, ("gensec_gssapi_unwrap: GSS UnWrap failed: %s\n",
 501                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 502                 return NT_STATUS_ACCESS_DENIED;
 503         }
 504
 505         *out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 506         gss_release_buffer(&min_stat, &output_token);
 507
 508         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 509             && !conf_state) {
 510                 return NT_STATUS_ACCESS_DENIED;
 511         }
 512         return NT_STATUS_OK;
 513 }
 514
 515 static size_t gensec_gssapi_sig_size(struct gensec_security *gensec_security, size_t data_size)
 516 {
 517         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 518         OM_uint32 maj_stat, min_stat;
 519         OM_uint32 output_size;
 520         if ((gensec_gssapi_state->gss_oid->length != gss_mech_krb5->length)
 521             || (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 522                        gensec_gssapi_state->gss_oid->length) != 0)) {
 523                 DEBUG(1, ("NO sig size available for this mech\n"));
 524                 return 0;
 525         }
 526
 527         maj_stat = gsskrb5_wrap_size(&min_stat,
 528                                      gensec_gssapi_state->gssapi_context,
 529                                      gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
 530                                      GSS_C_QOP_DEFAULT,
 531                                      data_size,
 532                                      &output_size);
 533         if (GSS_ERROR(maj_stat)) {
 534                 TALLOC_CTX *mem_ctx = talloc_new(NULL);
 535                 DEBUG(1, ("gensec_gssapi_seal_packet: determinaing signature size with gss_wrap_size_limit failed: %s\n",
 536                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 537                 talloc_free(mem_ctx);
 538                 return 0;
 539         }
 540
 541         if (output_size < data_size) {
 542                 return 0;
 543         }
 544
 545         /* The difference between the max output and the max input must be the signature */
 546         return output_size - data_size;
 547 }
 548
 549 static NTSTATUS gensec_gssapi_seal_packet(struct gensec_security *gensec_security,
 550                                           TALLOC_CTX *mem_ctx,
 551                                           uint8_t *data, size_t length,
 552                                           const uint8_t *whole_pdu, size_t pdu_length,
 553                                           DATA_BLOB *sig)
 554 {
 555         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 556         OM_uint32 maj_stat, min_stat;
 557         gss_buffer_desc input_token, output_token;
 558         int conf_state;
 559         ssize_t sig_length;
 560
 561         input_token.length = length;
 562         input_token.value = data;
 563
 564         maj_stat = gss_wrap(&min_stat,
 565                             gensec_gssapi_state->gssapi_context,
 566                             gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
 567                             GSS_C_QOP_DEFAULT,
 568                             &input_token,
 569                             &conf_state,
 570                             &output_token);
 571         if (GSS_ERROR(maj_stat)) {
 572                 DEBUG(1, ("gensec_gssapi_seal_packet: GSS Wrap failed: %s\n",
 573                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 574                 return NT_STATUS_ACCESS_DENIED;
 575         }
 576
 577         sig_length = gensec_gssapi_sig_size(gensec_security, length);
 578
 579         /* Caller must pad to right boundary */
 580         if (output_token.length != (length + sig_length)) {
 581                 DEBUG(1, ("gensec_gssapi_seal_packet: GSS Wrap length [%d] does not match caller length [%d] plus sig size [%d] = [%d]\n",
 582                           output_token.length, length, sig_length, length + sig_length));
 583                 return NT_STATUS_INTERNAL_ERROR;
 584         }
 585
 586         memcpy(data, ((uint8_t *)output_token.value) + sig_length, length);
 587         *sig = data_blob_talloc(mem_ctx, (uint8_t *)output_token.value, sig_length);
 588
 589         dump_data_pw("gensec_gssapi_seal_packet: sig\n", sig->data, sig->length);
 590         dump_data_pw("gensec_gssapi_seal_packet: clear\n", data, length);
 591         dump_data_pw("gensec_gssapi_seal_packet: sealed\n", ((uint8_t *)output_token.value) + sig_length, output_token.length - sig_length);
 592
 593         gss_release_buffer(&min_stat, &output_token);
 594
 595         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 596             && !conf_state) {
 597                 return NT_STATUS_ACCESS_DENIED;
 598         }
 599         return NT_STATUS_OK;
 600 }
 601
 602 static NTSTATUS gensec_gssapi_unseal_packet(struct gensec_security *gensec_security,
 603                                             TALLOC_CTX *mem_ctx,
 604                                             uint8_t *data, size_t length,
 605                                             const uint8_t *whole_pdu, size_t pdu_length,
 606                                             const DATA_BLOB *sig)
 607 {
 608         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 609         OM_uint32 maj_stat, min_stat;
 610         gss_buffer_desc input_token, output_token;
 611         int conf_state;
 612         gss_qop_t qop_state;
 613         DATA_BLOB in;
 614
 615         dump_data_pw("gensec_gssapi_unseal_packet: sig\n", sig->data, sig->length);
 616
 617         in = data_blob_talloc(mem_ctx, NULL, sig->length + length);
 618
 619         memcpy(in.data, sig->data, sig->length);
 620         memcpy(in.data + sig->length, data, length);
 621
 622         input_token.length = in.length;
 623         input_token.value = in.data;
 624
 625         maj_stat = gss_unwrap(&min_stat,
 626                               gensec_gssapi_state->gssapi_context,
 627                               &input_token,
 628                               &output_token,
 629                               &conf_state,
 630                               &qop_state);
 631         if (GSS_ERROR(maj_stat)) {
 632                 DEBUG(1, ("gensec_gssapi_unseal_packet: GSS UnWrap failed: %s\n",
 633                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 634                 return NT_STATUS_ACCESS_DENIED;
 635         }
 636
 637         if (output_token.length != length) {
 638                 return NT_STATUS_INTERNAL_ERROR;
 639         }
 640
 641         memcpy(data, output_token.value, length);
 642
 643         gss_release_buffer(&min_stat, &output_token);
 644
 645         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 646             && !conf_state) {
 647                 return NT_STATUS_ACCESS_DENIED;
 648         }
 649         return NT_STATUS_OK;
 650 }
 651
 652 static NTSTATUS gensec_gssapi_sign_packet(struct gensec_security *gensec_security,
 653                                           TALLOC_CTX *mem_ctx,
 654                                           const uint8_t *data, size_t length,
 655                                           const uint8_t *whole_pdu, size_t pdu_length,
 656                                           DATA_BLOB *sig)
 657 {
 658         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 659         OM_uint32 maj_stat, min_stat;
 660         gss_buffer_desc input_token, output_token;
 661         int conf_state;
 662         ssize_t sig_length = 0;
 663
 664         input_token.length = length;
 665         input_token.value = discard_const_p(uint8_t *, data);
 666
 667         maj_stat = gss_wrap(&min_stat,
 668                             gensec_gssapi_state->gssapi_context,
 669                             0,
 670                             GSS_C_QOP_DEFAULT,
 671                             &input_token,
 672                             &conf_state,
 673                             &output_token);
 674         if (GSS_ERROR(maj_stat)) {
 675                 DEBUG(1, ("GSS Wrap failed: %s\n",
 676                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 677                 return NT_STATUS_ACCESS_DENIED;
 678         }
 679
 680         if (output_token.length < length) {
 681                 return NT_STATUS_INTERNAL_ERROR;
 682         }
 683
 684         sig_length = gensec_gssapi_sig_size(gensec_security, length);
 685
 686         /* Caller must pad to right boundary */
 687         if (output_token.length != (length + sig_length)) {
 688                 DEBUG(1, ("gensec_gssapi_sign_packet: GSS Wrap length [%d] does not match caller length [%d] plus sig size [%d] = [%d]\n",
 689                           output_token.length, length, sig_length, length + sig_length));
 690                 return NT_STATUS_INTERNAL_ERROR;
 691         }
 692
 693         *sig = data_blob_talloc(mem_ctx, (uint8_t *)output_token.value, sig_length);
 694
 695         dump_data_pw("gensec_gssapi_seal_packet: sig\n", sig->data, sig->length);
 696
 697         gss_release_buffer(&min_stat, &output_token);
 698
 699         return NT_STATUS_OK;
 700 }
 701
 702 static NTSTATUS gensec_gssapi_check_packet(struct gensec_security *gensec_security,
 703                                            TALLOC_CTX *mem_ctx,
 704                                            const uint8_t *data, size_t length,
 705                                            const uint8_t *whole_pdu, size_t pdu_length,
 706                                            const DATA_BLOB *sig)
 707 {
 708         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 709         OM_uint32 maj_stat, min_stat;
 710         gss_buffer_desc input_token, output_token;
 711         int conf_state;
 712         gss_qop_t qop_state;
 713         DATA_BLOB in;
 714
 715         dump_data_pw("gensec_gssapi_seal_packet: sig\n", sig->data, sig->length);
 716
 717         in = data_blob_talloc(mem_ctx, NULL, sig->length + length);
 718
 719         memcpy(in.data, sig->data, sig->length);
 720         memcpy(in.data + sig->length, data, length);
 721
 722         input_token.length = in.length;
 723         input_token.value = in.data;
 724
 725         maj_stat = gss_unwrap(&min_stat,
 726                               gensec_gssapi_state->gssapi_context,
 727                               &input_token,
 728                               &output_token,
 729                               &conf_state,
 730                               &qop_state);
 731         if (GSS_ERROR(maj_stat)) {
 732                 DEBUG(1, ("GSS UnWrap failed: %s\n",
 733                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 734                 return NT_STATUS_ACCESS_DENIED;
 735         }
 736
 737         if (output_token.length != length) {
 738                 return NT_STATUS_INTERNAL_ERROR;
 739         }
 740
 741         gss_release_buffer(&min_stat, &output_token);
 742
 743         return NT_STATUS_OK;
 744 }
 745
 746 static BOOL gensec_gssapi_have_feature(struct gensec_security *gensec_security,
 747                                        uint32_t feature)
 748 {
 749         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 750         if (feature & GENSEC_FEATURE_SIGN) {
 751                 return gensec_gssapi_state->got_flags & GSS_C_INTEG_FLAG;
 752         }
 753         if (feature & GENSEC_FEATURE_SEAL) {
 754                 return gensec_gssapi_state->got_flags & GSS_C_CONF_FLAG;
 755         }
 756         if (feature & GENSEC_FEATURE_SESSION_KEY) {
 757                 if ((gensec_gssapi_state->gss_oid->length == gss_mech_krb5->length)
 758                     && (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements, gensec_gssapi_state->gss_oid->length) == 0)) {
 759                         return True;
 760                 }
 761         }
 762         if (feature & GENSEC_FEATURE_DCE_STYLE) {
 763                 return gensec_gssapi_state->got_flags & GSS_C_DCE_STYLE;
 764         }
 765         if (feature & GENSEC_FEATURE_ASYNC_REPLIES) {
 766                 return True;
 767         }
 768         return False;
 769 }
 770
 771 static NTSTATUS gensec_gssapi_session_key(struct gensec_security *gensec_security,
 772                                           DATA_BLOB *session_key)
 773 {
 774         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 775
 776         if (gensec_gssapi_state->session_key.data) {
 777                 *session_key = gensec_gssapi_state->session_key;
 778                 return NT_STATUS_OK;
 779         }
 780
 781         /* Ensure we only call this for GSSAPI/krb5, otherwise things could get very ugly */
 782         if ((gensec_gssapi_state->gss_oid->length == gss_mech_krb5->length)
 783             && (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 784                        gensec_gssapi_state->gss_oid->length) == 0)) {
 785                 OM_uint32 maj_stat, min_stat;
 786                 gss_buffer_desc skey;
 787
 788                 maj_stat = gsskrb5_get_initiator_subkey(&min_stat,
 789                                                         gensec_gssapi_state->gssapi_context,
 790                                                         &skey);
 791
 792                 if (maj_stat == 0) {
 793                         DEBUG(10, ("Got KRB5 session key of length %d\n",
 794                                    (int)skey.length));
 795                         gensec_gssapi_state->session_key = data_blob_talloc(gensec_gssapi_state,
 796                                                                             skey.value, skey.length);
 797                         *session_key = gensec_gssapi_state->session_key;
 798                         dump_data_pw("KRB5 Session Key:\n", session_key->data, session_key->length);
 799
 800                         gss_release_buffer(&min_stat, &skey);
 801                         return NT_STATUS_OK;
 802                 }
 803                 return NT_STATUS_NO_USER_SESSION_KEY;
 804         }
 805
 806         DEBUG(1, ("NO session key for this mech\n"));
 807         return NT_STATUS_NO_USER_SESSION_KEY;
 808 }
 809
 810 static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_security,
 811                                          struct auth_session_info **_session_info)
 812 {
 813         NTSTATUS nt_status;
 814         TALLOC_CTX *mem_ctx;
 815         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 816         struct auth_serversupplied_info *server_info = NULL;
 817         struct auth_session_info *session_info = NULL;
 818         struct PAC_LOGON_INFO *logon_info;
 819         OM_uint32 maj_stat, min_stat;
 820         gss_buffer_desc name_token;
 821         gss_buffer_desc pac;
 822         krb5_keyblock *keyblock;
 823         time_t authtime;
 824         krb5_principal principal;
 825         char *principal_string;
 826         DATA_BLOB pac_blob;
 827
 828         if ((gensec_gssapi_state->gss_oid->length != gss_mech_krb5->length)
 829             || (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 830                        gensec_gssapi_state->gss_oid->length) != 0)) {
 831                 DEBUG(1, ("NO session info available for this mech\n"));
 832                 return NT_STATUS_INVALID_PARAMETER;
 833         }
 834
 835         mem_ctx = talloc_named(gensec_gssapi_state, 0, "gensec_gssapi_session_info context");
 836         NT_STATUS_HAVE_NO_MEMORY(mem_ctx);
 837
 838         maj_stat = gss_display_name (&min_stat,
 839                                      gensec_gssapi_state->client_name,
 840                                      &name_token,
 841                                      NULL);
 842         if (maj_stat) {
 843                 return NT_STATUS_FOOBAR;
 844         }
 845
 846         principal_string = talloc_strndup(mem_ctx, name_token.value, name_token.length);
 847
 848         gss_release_buffer(&min_stat, &name_token);
 849
 850         if (!principal_string) {
 851                 talloc_free(mem_ctx);
 852                 return NT_STATUS_NO_MEMORY;
 853         }
 854
 855         maj_stat = gss_krb5_copy_service_keyblock(&min_stat,
 856                                                   gensec_gssapi_state->gssapi_context,
 857                                                   &keyblock);
 858
 859         if (maj_stat == 0) {
 860                 maj_stat = gsskrb5_extract_authtime_from_sec_context(&min_stat,
 861                                                                      gensec_gssapi_state->gssapi_context,
 862                                                                      &authtime);
 863         }
 864
 865         if (maj_stat == 0) {
 866                 maj_stat = gsskrb5_extract_authz_data_from_sec_context(&min_stat,
 867                                                                        gensec_gssapi_state->gssapi_context,
 868                                                                        KRB5_AUTHDATA_WIN2K_PAC,
 869                                                                        &pac);
 870         }
 871
 872         if (maj_stat == 0) {
 873                 pac_blob = data_blob_talloc(mem_ctx, pac.value, pac.length);
 874                 gss_release_buffer(&min_stat, &pac);
 875         }
 876
 877         /* IF we have the PAC - otherwise we need to get this
 878          * data from elsewere - local ldb, or (TODO) lookup of some
 879          * kind...
 880          */
 881         if (maj_stat == 0) {
 882                 krb5_error_code ret;
 883
 884                 ret = krb5_parse_name(gensec_gssapi_state->smb_krb5_context->krb5_context,
 885                                       principal_string, &principal);
 886                 if (ret) {
 887                         talloc_free(mem_ctx);
 888                         return NT_STATUS_INVALID_PARAMETER;
 889                 }
 890
 891                 /* decode and verify the pac */
 892                 nt_status = kerberos_pac_logon_info(mem_ctx, &logon_info, pac_blob,
 893                                                     gensec_gssapi_state->smb_krb5_context->krb5_context,
 894                                                     NULL, keyblock, principal, authtime);
 895                 krb5_free_principal(gensec_gssapi_state->smb_krb5_context->krb5_context, principal);
 896
 897                 if (NT_STATUS_IS_OK(nt_status)) {
 898                         union netr_Validation validation;
 899                         validation.sam3 = &logon_info->info3;
 900                         nt_status = make_server_info_netlogon_validation(gensec_gssapi_state,
 901                                                                          NULL,
 902                                                                          3, &validation,
 903                                                                          &server_info);
 904                         if (!NT_STATUS_IS_OK(nt_status)) {
 905                                 talloc_free(mem_ctx);
 906                                 return nt_status;
 907                         }
 908                 } else {
 909                         maj_stat = 1;
 910                 }
 911         }
 912
 913         if (maj_stat) {
 914                 DEBUG(1, ("Unable to use PAC, resorting to local user lookup!\n"));
 915                 nt_status = sam_get_server_info_principal(mem_ctx, principal_string,
 916                                                           &server_info);
 917
 918                 if (!NT_STATUS_IS_OK(nt_status)) {
 919                         talloc_free(mem_ctx);
 920                         return nt_status;
 921                 }
 922         }
 923
 924         /* references the server_info into the session_info */
 925         nt_status = auth_generate_session_info(gensec_gssapi_state, server_info, &session_info);
 926         talloc_free(mem_ctx);
 927         talloc_free(server_info);
 928         NT_STATUS_NOT_OK_RETURN(nt_status);
 929
 930         nt_status = gensec_gssapi_session_key(gensec_security, &session_info->session_key);
 931         NT_STATUS_NOT_OK_RETURN(nt_status);
 932
 933         if (!(gensec_gssapi_state->got_flags & GSS_C_DELEG_FLAG)) {
 934                 DEBUG(10, ("gensec_gssapi: NO delegated credentials supplied by client\n"));
 935         } else {
 936                 krb5_error_code ret;
 937                 DEBUG(10, ("gensec_gssapi: delegated credentials supplied by client\n"));
 938                 session_info->credentials = cli_credentials_init(session_info);
 939                 if (!session_info->credentials) {
 940                         return NT_STATUS_NO_MEMORY;
 941                 }
 942
 943                 cli_credentials_set_conf(session_info->credentials);
 944
 945                 ret = cli_credentials_set_client_gss_creds(session_info->credentials,
 946                                                            gensec_gssapi_state->delegated_cred_handle,
 947                                                            CRED_SPECIFIED);
 948                 if (ret) {
 949                         return NT_STATUS_NO_MEMORY;
 950                 }
 951                 /* It has been taken from this place... */
 952                 gensec_gssapi_state->delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 953         }
 954         *_session_info = session_info;
 955
 956         return NT_STATUS_OK;
 957 }
 958
 959 static const char *gensec_gssapi_krb5_oids[] = {
 960         GENSEC_OID_KERBEROS5,
 961         GENSEC_OID_KERBEROS5_OLD,
 962         NULL
 963 };
 964
 965 /* As a server, this could in theory accept any GSSAPI mech */
 966 static const struct gensec_security_ops gensec_gssapi_krb5_security_ops = {
 967         .name           = "gssapi_krb5",
 968         .auth_type      = DCERPC_AUTH_TYPE_KRB5,
 969         .oid            = gensec_gssapi_krb5_oids,
 970         .client_start   = gensec_gssapi_client_start,
 971         .server_start   = gensec_gssapi_server_start,
 972         .magic          = gensec_gssapi_magic,
 973         .update         = gensec_gssapi_update,
 974         .session_key    = gensec_gssapi_session_key,
 975         .session_info   = gensec_gssapi_session_info,
 976         .sig_size       = gensec_gssapi_sig_size,
 977         .sign_packet    = gensec_gssapi_sign_packet,
 978         .check_packet   = gensec_gssapi_check_packet,
 979         .seal_packet    = gensec_gssapi_seal_packet,
 980         .unseal_packet  = gensec_gssapi_unseal_packet,
 981         .wrap           = gensec_gssapi_wrap,
 982         .unwrap         = gensec_gssapi_unwrap,
 983         .have_feature   = gensec_gssapi_have_feature,
 984         .enabled        = True
 985 };
 986
 987 NTSTATUS gensec_gssapi_init(void)
 988 {
 989         NTSTATUS ret;
 990
 991         ret = gensec_register(&gensec_gssapi_krb5_security_ops);
 992         if (!NT_STATUS_IS_OK(ret)) {
 993                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 994                         gensec_gssapi_krb5_security_ops.name));
 995                 return ret;
 996         }
 997
 998         return ret;
 999 }