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
  48         gss_cred_id_t cred;
  49 };
  50
  51 static char *gssapi_error_string(TALLOC_CTX *mem_ctx,
  52                                  OM_uint32 maj_stat, OM_uint32 min_stat)
  53 {
  54         OM_uint32 disp_min_stat, disp_maj_stat;
  55         gss_buffer_desc maj_error_message;
  56         gss_buffer_desc min_error_message;
  57         OM_uint32 msg_ctx = 0;
  58
  59         char *ret;
  60
  61         maj_error_message.value = NULL;
  62         min_error_message.value = NULL;
  63
  64         disp_maj_stat = gss_display_status(&disp_min_stat, maj_stat, GSS_C_GSS_CODE,
  65                            GSS_C_NULL_OID, &msg_ctx, &maj_error_message);
  66         disp_maj_stat = gss_display_status(&disp_min_stat, min_stat, GSS_C_MECH_CODE,
  67                            GSS_C_NULL_OID, &msg_ctx, &min_error_message);
  68         ret = talloc_asprintf(mem_ctx, "%s: %s", (char *)maj_error_message.value, (char *)min_error_message.value);
  69
  70         gss_release_buffer(&disp_min_stat, &maj_error_message);
  71         gss_release_buffer(&disp_min_stat, &min_error_message);
  72
  73         return ret;
  74 }
  75
  76
  77 static int gensec_gssapi_destory(void *ptr)
  78 {
  79         struct gensec_gssapi_state *gensec_gssapi_state = ptr;
  80         OM_uint32 maj_stat, min_stat;
  81
  82         if (gensec_gssapi_state->cred != GSS_C_NO_CREDENTIAL) {
  83                 maj_stat = gss_release_cred(&min_stat,
  84                                             &gensec_gssapi_state->cred);
  85         }
  86
  87         if (gensec_gssapi_state->gssapi_context != GSS_C_NO_CONTEXT) {
  88                 maj_stat = gss_delete_sec_context (&min_stat,
  89                                                    &gensec_gssapi_state->gssapi_context,
  90                                                    GSS_C_NO_BUFFER);
  91         }
  92
  93         if (gensec_gssapi_state->server_name != GSS_C_NO_NAME) {
  94                 maj_stat = gss_release_name(&min_stat, &gensec_gssapi_state->server_name);
  95         }
  96         if (gensec_gssapi_state->client_name != GSS_C_NO_NAME) {
  97                 maj_stat = gss_release_name(&min_stat, &gensec_gssapi_state->client_name);
  98         }
  99         return 0;
 100 }
 101
 102 static NTSTATUS gensec_gssapi_start(struct gensec_security *gensec_security)
 103 {
 104         struct gensec_gssapi_state *gensec_gssapi_state;
 105         krb5_error_code ret;
 106
 107         gensec_gssapi_state = talloc(gensec_security, struct gensec_gssapi_state);
 108         if (!gensec_gssapi_state) {
 109                 return NT_STATUS_NO_MEMORY;
 110         }
 111
 112         gensec_security->private_data = gensec_gssapi_state;
 113
 114         gensec_gssapi_state->gssapi_context = GSS_C_NO_CONTEXT;
 115         gensec_gssapi_state->server_name = GSS_C_NO_NAME;
 116         gensec_gssapi_state->client_name = GSS_C_NO_NAME;
 117
 118         /* TODO: Fill in channel bindings */
 119         gensec_gssapi_state->input_chan_bindings = GSS_C_NO_CHANNEL_BINDINGS;
 120
 121         gensec_gssapi_state->want_flags = GSS_C_MUTUAL_FLAG;
 122         gensec_gssapi_state->got_flags = 0;
 123
 124         gensec_gssapi_state->session_key = data_blob(NULL, 0);
 125         gensec_gssapi_state->pac = data_blob(NULL, 0);
 126
 127         gensec_gssapi_state->cred = GSS_C_NO_CREDENTIAL;
 128
 129         talloc_set_destructor(gensec_gssapi_state, gensec_gssapi_destory);
 130
 131         if (gensec_security->want_features & GENSEC_FEATURE_SIGN) {
 132                 gensec_gssapi_state->want_flags |= GSS_C_INTEG_FLAG;
 133         }
 134         if (gensec_security->want_features & GENSEC_FEATURE_SEAL) {
 135                 gensec_gssapi_state->want_flags |= GSS_C_CONF_FLAG;
 136         }
 137         if (gensec_security->want_features & GENSEC_FEATURE_DCE_STYLE) {
 138                 gensec_gssapi_state->want_flags |= GSS_C_DCE_STYLE;
 139         }
 140
 141         gensec_gssapi_state->gss_oid = gss_mech_krb5;
 142
 143         ret = smb_krb5_init_context(gensec_gssapi_state,
 144                                     &gensec_gssapi_state->smb_krb5_context);
 145         if (ret) {
 146                 DEBUG(1,("gensec_krb5_start: krb5_init_context failed (%s)\n",
 147                          error_message(ret)));
 148                 return NT_STATUS_INTERNAL_ERROR;
 149         }
 150         return NT_STATUS_OK;
 151 }
 152
 153 static NTSTATUS gensec_gssapi_server_start(struct gensec_security *gensec_security)
 154 {
 155         NTSTATUS nt_status;
 156         OM_uint32 maj_stat, min_stat;
 157         int ret;
 158         const char *principal;
 159         struct gensec_gssapi_state *gensec_gssapi_state;
 160         struct cli_credentials *machine_account;
 161
 162         nt_status = gensec_gssapi_start(gensec_security);
 163         if (!NT_STATUS_IS_OK(nt_status)) {
 164                 return nt_status;
 165         }
 166
 167         gensec_gssapi_state = gensec_security->private_data;
 168
 169         machine_account = gensec_get_credentials(gensec_security);
 170
 171         if (!machine_account) {
 172                 DEBUG(3, ("No machine account credentials specified\n"));
 173                 return NT_STATUS_INVALID_PARAMETER;
 174         } else {
 175                 ret = cli_credentials_get_keytab(machine_account, &gensec_gssapi_state->keytab);
 176                 if (ret) {
 177                         DEBUG(3, ("Could not create memory keytab!\n"));
 178                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 179                 }
 180         }
 181
 182         principal = cli_credentials_get_principal(machine_account,
 183                                                   machine_account);
 184
 185         /* This might have been explicity set to NULL, ie use what the client calls us */
 186         if (principal) {
 187                 gss_buffer_desc name_token;
 188
 189                 name_token.value  = discard_const_p(uint8_t, principal);
 190                 name_token.length = strlen(principal);
 191
 192                 maj_stat = gss_import_name (&min_stat,
 193                                             &name_token,
 194                                             GSS_C_NT_USER_NAME,
 195                                             &gensec_gssapi_state->server_name);
 196
 197                 if (maj_stat) {
 198                         DEBUG(2, ("GSS Import name of %s failed: %s\n",
 199                                   (char *)name_token.value,
 200                                   gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 201                         return NT_STATUS_UNSUCCESSFUL;
 202                 }
 203         } else {
 204                 gensec_gssapi_state->server_name = GSS_C_NO_NAME;
 205         }
 206
 207         maj_stat = gsskrb5_acquire_cred(&min_stat,
 208                                         gensec_gssapi_state->keytab->keytab, NULL,
 209                                         gensec_gssapi_state->server_name,
 210                                         GSS_C_INDEFINITE,
 211                                         GSS_C_NULL_OID_SET,
 212                                         GSS_C_ACCEPT,
 213                                         &gensec_gssapi_state->cred,
 214                                         NULL,
 215                                         NULL);
 216         if (maj_stat) {
 217                 DEBUG(1, ("Aquiring acceptor credentails failed: %s\n",
 218                           gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 219                 return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 220         }
 221
 222         return NT_STATUS_OK;
 223
 224 }
 225
 226 static NTSTATUS gensec_gssapi_client_start(struct gensec_security *gensec_security)
 227 {
 228         struct gensec_gssapi_state *gensec_gssapi_state;
 229         struct cli_credentials *creds = gensec_get_credentials(gensec_security);
 230         struct ccache_container *ccache;
 231         krb5_error_code ret;
 232         NTSTATUS nt_status;
 233         gss_buffer_desc name_token;
 234         gss_OID name_type;
 235         OM_uint32 maj_stat, min_stat;
 236         const char *hostname = gensec_get_target_hostname(gensec_security);
 237         const char *principal;
 238
 239         if (!hostname) {
 240                 DEBUG(1, ("Could not determine hostname for target computer, cannot use kerberos\n"));
 241                 return NT_STATUS_INVALID_PARAMETER;
 242         }
 243         if (is_ipaddress(hostname)) {
 244                 DEBUG(2, ("Cannot do GSSAPI to an IP address\n"));
 245                 return NT_STATUS_INVALID_PARAMETER;
 246         }
 247         if (strequal(hostname, "localhost")) {
 248                 DEBUG(2, ("GSSAPI to 'localhost' does not make sense\n"));
 249                 return NT_STATUS_INVALID_PARAMETER;
 250         }
 251
 252         nt_status = gensec_gssapi_start(gensec_security);
 253         if (!NT_STATUS_IS_OK(nt_status)) {
 254                 return nt_status;
 255         }
 256
 257         gensec_gssapi_state = gensec_security->private_data;
 258
 259         ret = cli_credentials_get_ccache(creds,
 260                                          &ccache);
 261         if (ret) {
 262                 DEBUG(1, ("Failed to get CCACHE for gensec_gssapi: %s\n", error_message(ret)));
 263                 return NT_STATUS_UNSUCCESSFUL;
 264         }
 265
 266         principal = cli_credentials_get_principal(creds,
 267                                                   gensec_gssapi_state);
 268         name_token.value  = discard_const_p(uint8_t, principal);
 269         name_token.length = strlen(principal);
 270
 271         maj_stat = gss_import_name (&min_stat,
 272                                     &name_token,
 273                                     GSS_C_NT_USER_NAME,
 274                                     &gensec_gssapi_state->client_name);
 275         if (maj_stat) {
 276                 DEBUG(2, ("GSS Import name of %s failed: %s\n",
 277                           (char *)name_token.value,
 278                           gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 279                 return NT_STATUS_INVALID_PARAMETER;
 280         }
 281
 282         principal = gensec_get_target_principal(gensec_security);
 283         if (principal && lp_client_use_spnego_principal()) {
 284                 name_token.value  = discard_const_p(uint8_t, principal);
 285                 name_token.length = strlen(principal);
 286
 287                 name_type = GSS_C_NULL_OID;
 288         } else {
 289                 principal = talloc_asprintf(gensec_gssapi_state, "%s@%s",
 290                                             gensec_get_target_service(gensec_security),
 291                                             hostname);
 292
 293                 name_token.value  = discard_const_p(uint8_t, principal);
 294                 name_token.length = strlen(principal);
 295
 296                 name_type = GSS_C_NT_HOSTBASED_SERVICE;
 297         }
 298
 299         maj_stat = gss_import_name (&min_stat,
 300                                     &name_token,
 301                                     name_type,
 302                                     &gensec_gssapi_state->server_name);
 303         if (maj_stat) {
 304                 DEBUG(2, ("GSS Import name of %s failed: %s\n",
 305                           (char *)name_token.value,
 306                           gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 307                 return NT_STATUS_INVALID_PARAMETER;
 308         }
 309
 310         maj_stat = gsskrb5_acquire_cred(&min_stat,
 311                                         NULL, ccache->ccache,
 312                                         gensec_gssapi_state->client_name,
 313                                         GSS_C_INDEFINITE,
 314                                         GSS_C_NULL_OID_SET,
 315                                         GSS_C_INITIATE,
 316                                         &gensec_gssapi_state->cred,
 317                                         NULL,
 318                                         NULL);
 319         if (maj_stat) {
 320                 switch (min_stat) {
 321                 case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 322                         DEBUG(3, ("Server [%s] is not registered with our KDC: %s\n",
 323                                   hostname, gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 324                         return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 325                 default:
 326                         DEBUG(1, ("Aquiring initiator credentails failed: %s\n",
 327                                   gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 328                         return NT_STATUS_UNSUCCESSFUL;
 329                 }
 330         }
 331
 332         return NT_STATUS_OK;
 333 }
 334
 335
 336 /**
 337  * Check if the packet is one for this mechansim
 338  *
 339  * @param gensec_security GENSEC state
 340  * @param in The request, as a DATA_BLOB
 341  * @return Error, INVALID_PARAMETER if it's not a packet for us
 342  *                or NT_STATUS_OK if the packet is ok.
 343  */
 344
 345 static NTSTATUS gensec_gssapi_magic(struct gensec_security *gensec_security,
 346                                     const DATA_BLOB *in)
 347 {
 348         if (gensec_gssapi_check_oid(in, GENSEC_OID_KERBEROS5)) {
 349                 return NT_STATUS_OK;
 350         } else {
 351                 return NT_STATUS_INVALID_PARAMETER;
 352         }
 353 }
 354
 355
 356 /**
 357  * Next state function for the GSSAPI GENSEC mechanism
 358  *
 359  * @param gensec_gssapi_state GSSAPI State
 360  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 361  * @param in The request, as a DATA_BLOB
 362  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 363  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 364  *                or NT_STATUS_OK if the user is authenticated.
 365  */
 366
 367 static NTSTATUS gensec_gssapi_update(struct gensec_security *gensec_security,
 368                                    TALLOC_CTX *out_mem_ctx,
 369                                    const DATA_BLOB in, DATA_BLOB *out)
 370 {
 371         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 372         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 373         OM_uint32 maj_stat, min_stat;
 374         OM_uint32 min_stat2;
 375         gss_buffer_desc input_token, output_token;
 376         gss_OID gss_oid_p;
 377         input_token.length = in.length;
 378         input_token.value = in.data;
 379
 380         switch (gensec_security->gensec_role) {
 381         case GENSEC_CLIENT:
 382         {
 383                 maj_stat = gss_init_sec_context(&min_stat,
 384                                                 gensec_gssapi_state->cred,
 385                                                 &gensec_gssapi_state->gssapi_context,
 386                                                 gensec_gssapi_state->server_name,
 387                                                 discard_const_p(gss_OID_desc, gensec_gssapi_state->gss_oid),
 388                                                 gensec_gssapi_state->want_flags,
 389                                                 0,
 390                                                 gensec_gssapi_state->input_chan_bindings,
 391                                                 &input_token,
 392                                                 NULL,
 393                                                 &output_token,
 394                                                 &gensec_gssapi_state->got_flags, /* ret flags */
 395                                                 NULL);
 396                 break;
 397         }
 398         case GENSEC_SERVER:
 399         {
 400                 maj_stat = gss_accept_sec_context(&min_stat,
 401                                                   &gensec_gssapi_state->gssapi_context,
 402                                                   gensec_gssapi_state->cred,
 403                                                   &input_token,
 404                                                   gensec_gssapi_state->input_chan_bindings,
 405                                                   &gensec_gssapi_state->client_name,
 406                                                   &gss_oid_p,
 407                                                   &output_token,
 408                                                   &gensec_gssapi_state->got_flags,
 409                                                   NULL,
 410                                                   NULL);
 411                 gensec_gssapi_state->gss_oid = gss_oid_p;
 412                 break;
 413         }
 414         default:
 415                 return NT_STATUS_INVALID_PARAMETER;
 416
 417         }
 418
 419         if (maj_stat == GSS_S_COMPLETE) {
 420                 *out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
 421                 gss_release_buffer(&min_stat2, &output_token);
 422
 423                 return NT_STATUS_OK;
 424         } else if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 425                 *out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
 426                 gss_release_buffer(&min_stat2, &output_token);
 427
 428                 return NT_STATUS_MORE_PROCESSING_REQUIRED;
 429         } else if ((gensec_gssapi_state->gss_oid->length == gss_mech_krb5->length)
 430             && (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 431                        gensec_gssapi_state->gss_oid->length) == 0)) {
 432                 switch (min_stat) {
 433                 case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 434                         DEBUG(3, ("Server is not registered with our KDC: %s\n",
 435                                   gssapi_error_string(gensec_gssapi_state, maj_stat, min_stat)));
 436                         return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 437                 case KRB5KRB_AP_ERR_MSG_TYPE:
 438                         /* garbage input, possibly from the auto-mech detection */
 439                         return NT_STATUS_INVALID_PARAMETER;
 440                 default:
 441                         DEBUG(1, ("GSS(krb5) Update failed: %s\n",
 442                                   gssapi_error_string(out_mem_ctx, maj_stat, min_stat)));
 443                         return nt_status;
 444                 }
 445         } else {
 446                 DEBUG(1, ("GSS Update failed: %s\n",
 447                           gssapi_error_string(out_mem_ctx, maj_stat, min_stat)));
 448                 return nt_status;
 449         }
 450 }
 451
 452 static NTSTATUS gensec_gssapi_wrap(struct gensec_security *gensec_security,
 453                                    TALLOC_CTX *mem_ctx,
 454                                    const DATA_BLOB *in,
 455                                    DATA_BLOB *out)
 456 {
 457         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 458         OM_uint32 maj_stat, min_stat;
 459         gss_buffer_desc input_token, output_token;
 460         int conf_state;
 461         input_token.length = in->length;
 462         input_token.value = in->data;
 463
 464         maj_stat = gss_wrap(&min_stat,
 465                             gensec_gssapi_state->gssapi_context,
 466                             gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
 467                             GSS_C_QOP_DEFAULT,
 468                             &input_token,
 469                             &conf_state,
 470                             &output_token);
 471         if (GSS_ERROR(maj_stat)) {
 472                 DEBUG(1, ("gensec_gssapi_wrap: GSS Wrap failed: %s\n",
 473                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 474                 return NT_STATUS_ACCESS_DENIED;
 475         }
 476
 477         *out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 478         gss_release_buffer(&min_stat, &output_token);
 479
 480         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 481             && !conf_state) {
 482                 return NT_STATUS_ACCESS_DENIED;
 483         }
 484         return NT_STATUS_OK;
 485 }
 486
 487 static NTSTATUS gensec_gssapi_unwrap(struct gensec_security *gensec_security,
 488                                      TALLOC_CTX *mem_ctx,
 489                                      const DATA_BLOB *in,
 490                                      DATA_BLOB *out)
 491 {
 492         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 493         OM_uint32 maj_stat, min_stat;
 494         gss_buffer_desc input_token, output_token;
 495         int conf_state;
 496         gss_qop_t qop_state;
 497         input_token.length = in->length;
 498         input_token.value = in->data;
 499
 500         maj_stat = gss_unwrap(&min_stat,
 501                               gensec_gssapi_state->gssapi_context,
 502                               &input_token,
 503                               &output_token,
 504                               &conf_state,
 505                               &qop_state);
 506         if (GSS_ERROR(maj_stat)) {
 507                 DEBUG(1, ("gensec_gssapi_unwrap: GSS UnWrap failed: %s\n",
 508                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 509                 return NT_STATUS_ACCESS_DENIED;
 510         }
 511
 512         *out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 513         gss_release_buffer(&min_stat, &output_token);
 514
 515         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 516             && !conf_state) {
 517                 return NT_STATUS_ACCESS_DENIED;
 518         }
 519         return NT_STATUS_OK;
 520 }
 521
 522 static size_t gensec_gssapi_sig_size(struct gensec_security *gensec_security, size_t data_size)
 523 {
 524         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 525         OM_uint32 maj_stat, min_stat;
 526         OM_uint32 output_size;
 527         if ((gensec_gssapi_state->gss_oid->length != gss_mech_krb5->length)
 528             || (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 529                        gensec_gssapi_state->gss_oid->length) != 0)) {
 530                 DEBUG(1, ("NO sig size available for this mech\n"));
 531                 return 0;
 532         }
 533
 534         maj_stat = gsskrb5_wrap_size(&min_stat,
 535                                      gensec_gssapi_state->gssapi_context,
 536                                      gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
 537                                      GSS_C_QOP_DEFAULT,
 538                                      data_size,
 539                                      &output_size);
 540         if (GSS_ERROR(maj_stat)) {
 541                 TALLOC_CTX *mem_ctx = talloc_new(NULL);
 542                 DEBUG(1, ("gensec_gssapi_seal_packet: determinaing signature size with gss_wrap_size_limit failed: %s\n",
 543                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 544                 talloc_free(mem_ctx);
 545                 return 0;
 546         }
 547
 548         if (output_size < data_size) {
 549                 return 0;
 550         }
 551
 552         /* The difference between the max output and the max input must be the signature */
 553         return output_size - data_size;
 554 }
 555
 556 static NTSTATUS gensec_gssapi_seal_packet(struct gensec_security *gensec_security,
 557                                           TALLOC_CTX *mem_ctx,
 558                                           uint8_t *data, size_t length,
 559                                           const uint8_t *whole_pdu, size_t pdu_length,
 560                                           DATA_BLOB *sig)
 561 {
 562         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 563         OM_uint32 maj_stat, min_stat;
 564         gss_buffer_desc input_token, output_token;
 565         int conf_state;
 566         ssize_t sig_length;
 567
 568         input_token.length = length;
 569         input_token.value = data;
 570
 571         maj_stat = gss_wrap(&min_stat,
 572                             gensec_gssapi_state->gssapi_context,
 573                             gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
 574                             GSS_C_QOP_DEFAULT,
 575                             &input_token,
 576                             &conf_state,
 577                             &output_token);
 578         if (GSS_ERROR(maj_stat)) {
 579                 DEBUG(1, ("gensec_gssapi_seal_packet: GSS Wrap failed: %s\n",
 580                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 581                 return NT_STATUS_ACCESS_DENIED;
 582         }
 583
 584         sig_length = gensec_gssapi_sig_size(gensec_security, length);
 585
 586         /* Caller must pad to right boundary */
 587         if (output_token.length != (length + sig_length)) {
 588                 DEBUG(1, ("gensec_gssapi_seal_packet: GSS Wrap length [%d] does not match caller length [%d] plus sig size [%d] = [%d]\n",
 589                           output_token.length, length, sig_length, length + sig_length));
 590                 return NT_STATUS_INTERNAL_ERROR;
 591         }
 592
 593         memcpy(data, ((uint8_t *)output_token.value) + sig_length, length);
 594         *sig = data_blob_talloc(mem_ctx, (uint8_t *)output_token.value, sig_length);
 595
 596         dump_data_pw("gensec_gssapi_seal_packet: sig\n", sig->data, sig->length);
 597         dump_data_pw("gensec_gssapi_seal_packet: clear\n", data, length);
 598         dump_data_pw("gensec_gssapi_seal_packet: sealed\n", ((uint8_t *)output_token.value) + sig_length, output_token.length - sig_length);
 599
 600         gss_release_buffer(&min_stat, &output_token);
 601
 602         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 603             && !conf_state) {
 604                 return NT_STATUS_ACCESS_DENIED;
 605         }
 606         return NT_STATUS_OK;
 607 }
 608
 609 static NTSTATUS gensec_gssapi_unseal_packet(struct gensec_security *gensec_security,
 610                                             TALLOC_CTX *mem_ctx,
 611                                             uint8_t *data, size_t length,
 612                                             const uint8_t *whole_pdu, size_t pdu_length,
 613                                             const DATA_BLOB *sig)
 614 {
 615         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 616         OM_uint32 maj_stat, min_stat;
 617         gss_buffer_desc input_token, output_token;
 618         int conf_state;
 619         gss_qop_t qop_state;
 620         DATA_BLOB in;
 621
 622         dump_data_pw("gensec_gssapi_unseal_packet: sig\n", sig->data, sig->length);
 623
 624         in = data_blob_talloc(mem_ctx, NULL, sig->length + length);
 625
 626         memcpy(in.data, sig->data, sig->length);
 627         memcpy(in.data + sig->length, data, length);
 628
 629         input_token.length = in.length;
 630         input_token.value = in.data;
 631
 632         maj_stat = gss_unwrap(&min_stat,
 633                               gensec_gssapi_state->gssapi_context,
 634                               &input_token,
 635                               &output_token,
 636                               &conf_state,
 637                               &qop_state);
 638         if (GSS_ERROR(maj_stat)) {
 639                 DEBUG(1, ("gensec_gssapi_unseal_packet: GSS UnWrap failed: %s\n",
 640                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 641                 return NT_STATUS_ACCESS_DENIED;
 642         }
 643
 644         if (output_token.length != length) {
 645                 return NT_STATUS_INTERNAL_ERROR;
 646         }
 647
 648         memcpy(data, output_token.value, length);
 649
 650         gss_release_buffer(&min_stat, &output_token);
 651
 652         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 653             && !conf_state) {
 654                 return NT_STATUS_ACCESS_DENIED;
 655         }
 656         return NT_STATUS_OK;
 657 }
 658
 659 static NTSTATUS gensec_gssapi_sign_packet(struct gensec_security *gensec_security,
 660                                           TALLOC_CTX *mem_ctx,
 661                                           const uint8_t *data, size_t length,
 662                                           const uint8_t *whole_pdu, size_t pdu_length,
 663                                           DATA_BLOB *sig)
 664 {
 665         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 666         OM_uint32 maj_stat, min_stat;
 667         gss_buffer_desc input_token, output_token;
 668         int conf_state;
 669         ssize_t sig_length = 0;
 670
 671         input_token.length = length;
 672         input_token.value = discard_const_p(uint8_t *, data);
 673
 674         maj_stat = gss_wrap(&min_stat,
 675                             gensec_gssapi_state->gssapi_context,
 676                             0,
 677                             GSS_C_QOP_DEFAULT,
 678                             &input_token,
 679                             &conf_state,
 680                             &output_token);
 681         if (GSS_ERROR(maj_stat)) {
 682                 DEBUG(1, ("GSS Wrap failed: %s\n",
 683                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 684                 return NT_STATUS_ACCESS_DENIED;
 685         }
 686
 687         if (output_token.length < length) {
 688                 return NT_STATUS_INTERNAL_ERROR;
 689         }
 690
 691         sig_length = gensec_gssapi_sig_size(gensec_security, length);
 692
 693         /* Caller must pad to right boundary */
 694         if (output_token.length != (length + sig_length)) {
 695                 DEBUG(1, ("gensec_gssapi_sign_packet: GSS Wrap length [%d] does not match caller length [%d] plus sig size [%d] = [%d]\n",
 696                           output_token.length, length, sig_length, length + sig_length));
 697                 return NT_STATUS_INTERNAL_ERROR;
 698         }
 699
 700         *sig = data_blob_talloc(mem_ctx, (uint8_t *)output_token.value, sig_length);
 701
 702         dump_data_pw("gensec_gssapi_seal_packet: sig\n", sig->data, sig->length);
 703
 704         gss_release_buffer(&min_stat, &output_token);
 705
 706         return NT_STATUS_OK;
 707 }
 708
 709 static NTSTATUS gensec_gssapi_check_packet(struct gensec_security *gensec_security,
 710                                            TALLOC_CTX *mem_ctx,
 711                                            const uint8_t *data, size_t length,
 712                                            const uint8_t *whole_pdu, size_t pdu_length,
 713                                            const DATA_BLOB *sig)
 714 {
 715         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 716         OM_uint32 maj_stat, min_stat;
 717         gss_buffer_desc input_token, output_token;
 718         int conf_state;
 719         gss_qop_t qop_state;
 720         DATA_BLOB in;
 721
 722         dump_data_pw("gensec_gssapi_seal_packet: sig\n", sig->data, sig->length);
 723
 724         in = data_blob_talloc(mem_ctx, NULL, sig->length + length);
 725
 726         memcpy(in.data, sig->data, sig->length);
 727         memcpy(in.data + sig->length, data, length);
 728
 729         input_token.length = in.length;
 730         input_token.value = in.data;
 731
 732         maj_stat = gss_unwrap(&min_stat,
 733                               gensec_gssapi_state->gssapi_context,
 734                               &input_token,
 735                               &output_token,
 736                               &conf_state,
 737                               &qop_state);
 738         if (GSS_ERROR(maj_stat)) {
 739                 DEBUG(1, ("GSS UnWrap failed: %s\n",
 740                           gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 741                 return NT_STATUS_ACCESS_DENIED;
 742         }
 743
 744         if (output_token.length != length) {
 745                 return NT_STATUS_INTERNAL_ERROR;
 746         }
 747
 748         gss_release_buffer(&min_stat, &output_token);
 749
 750         return NT_STATUS_OK;
 751 }
 752
 753 static BOOL gensec_gssapi_have_feature(struct gensec_security *gensec_security,
 754                                        uint32_t feature)
 755 {
 756         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 757         if (feature & GENSEC_FEATURE_SIGN) {
 758                 return gensec_gssapi_state->got_flags & GSS_C_INTEG_FLAG;
 759         }
 760         if (feature & GENSEC_FEATURE_SEAL) {
 761                 return gensec_gssapi_state->got_flags & GSS_C_CONF_FLAG;
 762         }
 763         if (feature & GENSEC_FEATURE_SESSION_KEY) {
 764                 if ((gensec_gssapi_state->gss_oid->length == gss_mech_krb5->length)
 765                     && (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements, gensec_gssapi_state->gss_oid->length) == 0)) {
 766                         return True;
 767                 }
 768         }
 769         if (feature & GENSEC_FEATURE_DCE_STYLE) {
 770                 return gensec_gssapi_state->got_flags & GSS_C_DCE_STYLE;
 771         }
 772         if (feature & GENSEC_FEATURE_ASYNC_REPLIES) {
 773                 return True;
 774         }
 775         return False;
 776 }
 777
 778 static NTSTATUS gensec_gssapi_session_key(struct gensec_security *gensec_security,
 779                                           DATA_BLOB *session_key)
 780 {
 781         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 782
 783         if (gensec_gssapi_state->session_key.data) {
 784                 *session_key = gensec_gssapi_state->session_key;
 785                 return NT_STATUS_OK;
 786         }
 787
 788         /* Ensure we only call this for GSSAPI/krb5, otherwise things could get very ugly */
 789         if ((gensec_gssapi_state->gss_oid->length == gss_mech_krb5->length)
 790             && (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 791                        gensec_gssapi_state->gss_oid->length) == 0)) {
 792                 OM_uint32 maj_stat, min_stat;
 793                 gss_buffer_desc skey;
 794
 795                 maj_stat = gsskrb5_get_initiator_subkey(&min_stat,
 796                                                         gensec_gssapi_state->gssapi_context,
 797                                                         &skey);
 798
 799                 if (maj_stat == 0) {
 800                         DEBUG(10, ("Got KRB5 session key of length %d\n",
 801                                    (int)skey.length));
 802                         gensec_gssapi_state->session_key = data_blob_talloc(gensec_gssapi_state,
 803                                                                             skey.value, skey.length);
 804                         *session_key = gensec_gssapi_state->session_key;
 805                         dump_data_pw("KRB5 Session Key:\n", session_key->data, session_key->length);
 806
 807                         gss_release_buffer(&min_stat, &skey);
 808                         return NT_STATUS_OK;
 809                 }
 810                 return NT_STATUS_NO_USER_SESSION_KEY;
 811         }
 812
 813         DEBUG(1, ("NO session key for this mech\n"));
 814         return NT_STATUS_NO_USER_SESSION_KEY;
 815 }
 816
 817 static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_security,
 818                                          struct auth_session_info **_session_info)
 819 {
 820         NTSTATUS nt_status;
 821         TALLOC_CTX *mem_ctx;
 822         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 823         struct auth_serversupplied_info *server_info = NULL;
 824         struct auth_session_info *session_info = NULL;
 825         struct PAC_LOGON_INFO *logon_info;
 826         OM_uint32 maj_stat, min_stat;
 827         gss_buffer_desc name_token;
 828         gss_buffer_desc pac;
 829         krb5_keyblock *keyblock;
 830         time_t authtime;
 831         krb5_principal principal;
 832         char *principal_string;
 833         DATA_BLOB pac_blob;
 834         DATA_BLOB unwrapped_pac;
 835
 836         if ((gensec_gssapi_state->gss_oid->length != gss_mech_krb5->length)
 837             || (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements,
 838                        gensec_gssapi_state->gss_oid->length) != 0)) {
 839                 DEBUG(1, ("NO session info available for this mech\n"));
 840                 return NT_STATUS_INVALID_PARAMETER;
 841         }
 842
 843         mem_ctx = talloc_named(gensec_gssapi_state, 0, "gensec_gssapi_session_info context");
 844         NT_STATUS_HAVE_NO_MEMORY(mem_ctx);
 845
 846         maj_stat = gss_display_name (&min_stat,
 847                                      gensec_gssapi_state->client_name,
 848                                      &name_token,
 849                                      NULL);
 850         if (maj_stat) {
 851                 return NT_STATUS_FOOBAR;
 852         }
 853
 854         principal_string = talloc_strndup(mem_ctx, name_token.value, name_token.length);
 855
 856         gss_release_buffer(&min_stat, &name_token);
 857
 858         if (!principal_string) {
 859                 talloc_free(mem_ctx);
 860                 return NT_STATUS_NO_MEMORY;
 861         }
 862
 863         maj_stat = gss_krb5_copy_service_keyblock(&min_stat,
 864                                                   gensec_gssapi_state->gssapi_context,
 865                                                   &keyblock);
 866
 867         if (maj_stat == 0) {
 868                 maj_stat = gsskrb5_extract_authtime_from_sec_context(&min_stat,
 869                                                                      gensec_gssapi_state->gssapi_context,
 870                                                                      &authtime);
 871         }
 872
 873         if (maj_stat == 0) {
 874                 maj_stat = gsskrb5_extract_authz_data_from_sec_context(&min_stat,
 875                                                                        gensec_gssapi_state->gssapi_context,
 876                                                                        KRB5_AUTHDATA_IF_RELEVANT,
 877                                                                        &pac);
 878         }
 879
 880         if (maj_stat == 0) {
 881                 pac_blob = data_blob_talloc(mem_ctx, pac.value, pac.length);
 882                 gss_release_buffer(&min_stat, &pac);
 883
 884                 if (!unwrap_pac(mem_ctx, &pac_blob, &unwrapped_pac)) {
 885                         /* No pac actually present */
 886                         maj_stat = 1;
 887                 }
 888         }
 889
 890         /* IF we have the PAC - otherwise we need to get this
 891          * data from elsewere - local ldb, or (TODO) lookup of some
 892          * kind...
 893          */
 894         if (maj_stat == 0) {
 895                 krb5_error_code ret;
 896
 897                 ret = krb5_parse_name(gensec_gssapi_state->smb_krb5_context->krb5_context,
 898                                       principal_string, &principal);
 899                 if (ret) {
 900                         talloc_free(mem_ctx);
 901                         return NT_STATUS_INVALID_PARAMETER;
 902                 }
 903
 904                 /* decode and verify the pac */
 905                 nt_status = kerberos_pac_logon_info(mem_ctx, &logon_info, unwrapped_pac,
 906                                                     gensec_gssapi_state->smb_krb5_context->krb5_context,
 907                                                     NULL, keyblock, principal, authtime);
 908                 krb5_free_principal(gensec_gssapi_state->smb_krb5_context->krb5_context, principal);
 909
 910                 if (NT_STATUS_IS_OK(nt_status)) {
 911                         union netr_Validation validation;
 912                         validation.sam3 = &logon_info->info3;
 913                         nt_status = make_server_info_netlogon_validation(gensec_gssapi_state,
 914                                                                          NULL,
 915                                                                          3, &validation,
 916                                                                          &server_info);
 917                         if (!NT_STATUS_IS_OK(nt_status)) {
 918                                 talloc_free(mem_ctx);
 919                                 return nt_status;
 920                         }
 921                 } else {
 922                         maj_stat = 1;
 923                 }
 924         }
 925
 926         if (maj_stat) {
 927                 DEBUG(1, ("Unable to use PAC, resorting to local user lookup!\n"));
 928                 nt_status = sam_get_server_info_principal(mem_ctx, principal_string,
 929                                                           &server_info);
 930
 931                 if (!NT_STATUS_IS_OK(nt_status)) {
 932                         talloc_free(mem_ctx);
 933                         return nt_status;
 934                 }
 935         }
 936
 937         /* references the server_info into the session_info */
 938         nt_status = auth_generate_session_info(gensec_gssapi_state, server_info, &session_info);
 939         talloc_free(mem_ctx);
 940         talloc_free(server_info);
 941         NT_STATUS_NOT_OK_RETURN(nt_status);
 942
 943         nt_status = gensec_gssapi_session_key(gensec_security, &session_info->session_key);
 944         NT_STATUS_NOT_OK_RETURN(nt_status);
 945
 946         *_session_info = session_info;
 947
 948         return NT_STATUS_OK;
 949 }
 950
 951 static const char *gensec_gssapi_krb5_oids[] = {
 952         GENSEC_OID_KERBEROS5,
 953         GENSEC_OID_KERBEROS5_OLD,
 954         NULL
 955 };
 956
 957 /* As a server, this could in theory accept any GSSAPI mech */
 958 static const struct gensec_security_ops gensec_gssapi_krb5_security_ops = {
 959         .name           = "gssapi_krb5",
 960         .auth_type      = DCERPC_AUTH_TYPE_KRB5,
 961         .oid            = gensec_gssapi_krb5_oids,
 962         .client_start   = gensec_gssapi_client_start,
 963         .server_start   = gensec_gssapi_server_start,
 964         .magic          = gensec_gssapi_magic,
 965         .update         = gensec_gssapi_update,
 966         .session_key    = gensec_gssapi_session_key,
 967         .session_info   = gensec_gssapi_session_info,
 968         .sig_size       = gensec_gssapi_sig_size,
 969         .sign_packet    = gensec_gssapi_sign_packet,
 970         .check_packet   = gensec_gssapi_check_packet,
 971         .seal_packet    = gensec_gssapi_seal_packet,
 972         .unseal_packet  = gensec_gssapi_unseal_packet,
 973         .wrap           = gensec_gssapi_wrap,
 974         .unwrap         = gensec_gssapi_unwrap,
 975         .have_feature   = gensec_gssapi_have_feature,
 976         .enabled        = True
 977 };
 978
 979 NTSTATUS gensec_gssapi_init(void)
 980 {
 981         NTSTATUS ret;
 982
 983         ret = gensec_register(&gensec_gssapi_krb5_security_ops);
 984         if (!NT_STATUS_IS_OK(ret)) {
 985                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 986                         gensec_gssapi_krb5_security_ops.name));
 987                 return ret;
 988         }
 989
 990         return ret;
 991 }