source3/libads/authdata.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    kerberos authorization data (PAC) utility library
   4    Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
   6    Copyright (C) Andrew Tridgell 2001
   7    Copyright (C) Luke Howard 2002-2003
   8    Copyright (C) Stefan Metzmacher 2004-2005
   9    Copyright (C) Guenther Deschner 2005,2007,2008
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 3 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include "includes.h"
  26 #include "librpc/gen_ndr/ndr_krb5pac.h"
  27 #include "smb_krb5.h"
  28 #include "libads/kerberos_proto.h"
  29
  30 #ifdef HAVE_KRB5
  31
  32 /****************************************************************
  33 ****************************************************************/
  34
  35 static krb5_error_code check_pac_checksum(TALLOC_CTX *mem_ctx,
  36                                           DATA_BLOB pac_data,
  37                                           struct PAC_SIGNATURE_DATA *sig,
  38                                           krb5_context context,
  39                                           krb5_keyblock *keyblock)
  40 {
  41         krb5_error_code ret;
  42         krb5_checksum cksum;
  43         krb5_keyusage usage = 0;
  44
  45         smb_krb5_checksum_from_pac_sig(&cksum, sig);
  46
  47 #ifdef HAVE_KRB5_KU_OTHER_CKSUM /* Heimdal */
  48         usage = KRB5_KU_OTHER_CKSUM;
  49 #elif defined(HAVE_KRB5_KEYUSAGE_APP_DATA_CKSUM) /* MIT */
  50         usage = KRB5_KEYUSAGE_APP_DATA_CKSUM;
  51 #else
  52 #error UNKNOWN_KRB5_KEYUSAGE
  53 #endif
  54
  55         ret = smb_krb5_verify_checksum(context,
  56                                        keyblock,
  57                                        usage,
  58                                        &cksum,
  59                                        pac_data.data,
  60                                        pac_data.length);
  61
  62         if (ret) {
  63                 DEBUG(2,("check_pac_checksum: PAC Verification failed: %s (%d)\n",
  64                         error_message(ret), ret));
  65                 return ret;
  66         }
  67
  68         return ret;
  69 }
  70
  71 /**
  72 * @brief Decode a blob containing a NDR envoded PAC structure
  73 *
  74 * @param mem_ctx          - The memory context
  75 * @param pac_data_blob    - The data blob containing the NDR encoded data
  76 * @param context          - The Kerberos Context
  77 * @param service_keyblock - The Service Key used to verify the checksum
  78 * @param client_principal - The client principal
  79 * @param tgs_authtime     - The ticket timestamp
  80 * @param pac_data_out     - [out] The decoded PAC
  81 *
  82 * @return - A NTSTATUS error code
  83 */
  84 NTSTATUS decode_pac_data(TALLOC_CTX *mem_ctx,
  85                          DATA_BLOB *pac_data_blob,
  86                          krb5_context context,
  87                          krb5_keyblock *service_keyblock,
  88                          krb5_const_principal client_principal,
  89                          time_t tgs_authtime,
  90                          struct PAC_DATA **pac_data_out)
  91 {
  92         NTSTATUS status;
  93         enum ndr_err_code ndr_err;
  94         krb5_error_code ret;
  95         DATA_BLOB modified_pac_blob;
  96
  97         NTTIME tgs_authtime_nttime;
  98         krb5_principal client_principal_pac = NULL;
  99         int i;
 100
 101         struct PAC_SIGNATURE_DATA *srv_sig_ptr = NULL;
 102         struct PAC_SIGNATURE_DATA *kdc_sig_ptr = NULL;
 103         struct PAC_SIGNATURE_DATA *srv_sig_wipe = NULL;
 104         struct PAC_SIGNATURE_DATA *kdc_sig_wipe = NULL;
 105         struct PAC_LOGON_NAME *logon_name = NULL;
 106         struct PAC_LOGON_INFO *logon_info = NULL;
 107         struct PAC_DATA *pac_data = NULL;
 108         struct PAC_DATA_RAW *pac_data_raw = NULL;
 109
 110         DATA_BLOB *srv_sig_blob = NULL;
 111         DATA_BLOB *kdc_sig_blob = NULL;
 112
 113         bool bool_ret;
 114
 115         *pac_data_out = NULL;
 116
 117         pac_data = TALLOC_ZERO_P(mem_ctx, struct PAC_DATA);
 118         pac_data_raw = TALLOC_ZERO_P(mem_ctx, struct PAC_DATA_RAW);
 119         kdc_sig_wipe = TALLOC_ZERO_P(mem_ctx, struct PAC_SIGNATURE_DATA);
 120         srv_sig_wipe = TALLOC_ZERO_P(mem_ctx, struct PAC_SIGNATURE_DATA);
 121         if (!pac_data_raw || !pac_data || !kdc_sig_wipe || !srv_sig_wipe) {
 122                 return NT_STATUS_NO_MEMORY;
 123         }
 124
 125         ndr_err = ndr_pull_struct_blob(pac_data_blob, pac_data, pac_data,
 126                        (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
 127         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 128                 status = ndr_map_error2ntstatus(ndr_err);
 129                 DEBUG(0,("can't parse the PAC: %s\n",
 130                         nt_errstr(status)));
 131                 return status;
 132         }
 133
 134         if (pac_data->num_buffers < 4) {
 135                 /* we need logon_ingo, service_key and kdc_key */
 136                 DEBUG(0,("less than 4 PAC buffers\n"));
 137                 return NT_STATUS_INVALID_PARAMETER;
 138         }
 139
 140         ndr_err = ndr_pull_struct_blob(
 141                                 pac_data_blob, pac_data_raw, pac_data_raw,
 142                                 (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA_RAW);
 143         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 144                 status = ndr_map_error2ntstatus(ndr_err);
 145                 DEBUG(0,("can't parse the PAC: %s\n",
 146                         nt_errstr(status)));
 147                 return status;
 148         }
 149
 150         if (pac_data_raw->num_buffers < 4) {
 151                 /* we need logon_ingo, service_key and kdc_key */
 152                 DEBUG(0,("less than 4 PAC buffers\n"));
 153                 return NT_STATUS_INVALID_PARAMETER;
 154         }
 155
 156         if (pac_data->num_buffers != pac_data_raw->num_buffers) {
 157                 /* we need logon_ingo, service_key and kdc_key */
 158                 DEBUG(0, ("misparse! PAC_DATA has %d buffers while "
 159                           "PAC_DATA_RAW has %d\n", pac_data->num_buffers,
 160                           pac_data_raw->num_buffers));
 161                 return NT_STATUS_INVALID_PARAMETER;
 162         }
 163
 164         for (i=0; i < pac_data->num_buffers; i++) {
 165                 struct PAC_BUFFER *data_buf = &pac_data->buffers[i];
 166                 struct PAC_BUFFER_RAW *raw_buf = &pac_data_raw->buffers[i];
 167
 168                 if (data_buf->type != raw_buf->type) {
 169                         DEBUG(0, ("misparse! PAC_DATA buffer %d has type "
 170                                   "%d while PAC_DATA_RAW has %d\n", i,
 171                                   data_buf->type, raw_buf->type));
 172                         return NT_STATUS_INVALID_PARAMETER;
 173                 }
 174                 switch (data_buf->type) {
 175                 case PAC_TYPE_LOGON_INFO:
 176                         if (!data_buf->info) {
 177                                 break;
 178                         }
 179                         logon_info = data_buf->info->logon_info.info;
 180                         break;
 181                 case PAC_TYPE_SRV_CHECKSUM:
 182                         if (!data_buf->info) {
 183                                 break;
 184                         }
 185                         srv_sig_ptr = &data_buf->info->srv_cksum;
 186                         srv_sig_blob = &raw_buf->info->remaining;
 187                         break;
 188                 case PAC_TYPE_KDC_CHECKSUM:
 189                         if (!data_buf->info) {
 190                                 break;
 191                         }
 192                         kdc_sig_ptr = &data_buf->info->kdc_cksum;
 193                         kdc_sig_blob = &raw_buf->info->remaining;
 194                         break;
 195                 case PAC_TYPE_LOGON_NAME:
 196                         logon_name = &data_buf->info->logon_name;
 197                         break;
 198                 default:
 199                         break;
 200                 }
 201         }
 202
 203         if (!logon_info) {
 204                 DEBUG(0,("PAC no logon_info\n"));
 205                 return NT_STATUS_INVALID_PARAMETER;
 206         }
 207
 208         if (!logon_name) {
 209                 DEBUG(0,("PAC no logon_name\n"));
 210                 return NT_STATUS_INVALID_PARAMETER;
 211         }
 212
 213         if (!srv_sig_ptr || !srv_sig_blob) {
 214                 DEBUG(0,("PAC no srv_key\n"));
 215                 return NT_STATUS_INVALID_PARAMETER;
 216         }
 217
 218         if (!kdc_sig_ptr || !kdc_sig_blob) {
 219                 DEBUG(0,("PAC no kdc_key\n"));
 220                 return NT_STATUS_INVALID_PARAMETER;
 221         }
 222
 223         /* Find and zero out the signatures,
 224          * as required by the signing algorithm */
 225
 226         /* We find the data blobs above,
 227          * now we parse them to get at the exact portion we should zero */
 228         ndr_err = ndr_pull_struct_blob(
 229                         kdc_sig_blob, kdc_sig_wipe, kdc_sig_wipe,
 230                         (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
 231         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 232                 status = ndr_map_error2ntstatus(ndr_err);
 233                 DEBUG(0,("can't parse the KDC signature: %s\n",
 234                         nt_errstr(status)));
 235                 return status;
 236         }
 237
 238         ndr_err = ndr_pull_struct_blob(
 239                         srv_sig_blob, srv_sig_wipe, srv_sig_wipe,
 240                         (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
 241         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 242                 status = ndr_map_error2ntstatus(ndr_err);
 243                 DEBUG(0,("can't parse the SRV signature: %s\n",
 244                         nt_errstr(status)));
 245                 return status;
 246         }
 247
 248         /* Now zero the decoded structure */
 249         memset(kdc_sig_wipe->signature.data,
 250                 '\0', kdc_sig_wipe->signature.length);
 251         memset(srv_sig_wipe->signature.data,
 252                 '\0', srv_sig_wipe->signature.length);
 253
 254         /* and reencode, back into the same place it came from */
 255         ndr_err = ndr_push_struct_blob(
 256                         kdc_sig_blob, pac_data_raw, kdc_sig_wipe,
 257                         (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
 258         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 259                 status = ndr_map_error2ntstatus(ndr_err);
 260                 DEBUG(0,("can't repack the KDC signature: %s\n",
 261                         nt_errstr(status)));
 262                 return status;
 263         }
 264         ndr_err = ndr_push_struct_blob(
 265                         srv_sig_blob, pac_data_raw, srv_sig_wipe,
 266                         (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
 267         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 268                 status = ndr_map_error2ntstatus(ndr_err);
 269                 DEBUG(0,("can't repack the SRV signature: %s\n",
 270                         nt_errstr(status)));
 271                 return status;
 272         }
 273
 274         /* push out the whole structure, but now with zero'ed signatures */
 275         ndr_err = ndr_push_struct_blob(
 276                         &modified_pac_blob, pac_data_raw, pac_data_raw,
 277                         (ndr_push_flags_fn_t)ndr_push_PAC_DATA_RAW);
 278         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 279                 status = ndr_map_error2ntstatus(ndr_err);
 280                 DEBUG(0,("can't repack the RAW PAC: %s\n",
 281                         nt_errstr(status)));
 282                 return status;
 283         }
 284
 285         /* verify by service_key */
 286         ret = check_pac_checksum(mem_ctx,
 287                                  modified_pac_blob, srv_sig_ptr,
 288                                  context,
 289                                  service_keyblock);
 290         if (ret) {
 291                 DEBUG(1, ("PAC Decode: Failed to verify the service "
 292                           "signature: %s\n", error_message(ret)));
 293                 return NT_STATUS_ACCESS_DENIED;
 294         }
 295
 296         /* Convert to NT time, so as not to loose accuracy in comparison */
 297         unix_to_nt_time(&tgs_authtime_nttime, tgs_authtime);
 298
 299         if (tgs_authtime_nttime != logon_name->logon_time) {
 300                 DEBUG(2, ("PAC Decode: "
 301                           "Logon time mismatch between ticket and PAC!\n"));
 302                 DEBUG(2, ("PAC Decode: PAC: %s\n",
 303                           nt_time_string(mem_ctx, logon_name->logon_time)));
 304                 DEBUG(2, ("PAC Decode: Ticket: %s\n",
 305                           nt_time_string(mem_ctx, tgs_authtime_nttime)));
 306                 return NT_STATUS_ACCESS_DENIED;
 307         }
 308
 309         ret = smb_krb5_parse_name_norealm(context,
 310                                           logon_name->account_name,
 311                                           &client_principal_pac);
 312         if (ret) {
 313                 DEBUG(2, ("Could not parse name from PAC: [%s]:%s\n",
 314                           logon_name->account_name, error_message(ret)));
 315                 return NT_STATUS_INVALID_PARAMETER;
 316         }
 317
 318         bool_ret = smb_krb5_principal_compare_any_realm(context,
 319                                                         client_principal,
 320                                                         client_principal_pac);
 321
 322         krb5_free_principal(context, client_principal_pac);
 323
 324         if (!bool_ret) {
 325                 DEBUG(2, ("Name in PAC [%s] does not match principal name "
 326                           "in ticket\n", logon_name->account_name));
 327                 return NT_STATUS_ACCESS_DENIED;
 328         }
 329
 330         DEBUG(3,("Found account name from PAC: %s [%s]\n",
 331                  logon_info->info3.base.account_name.string,
 332                  logon_info->info3.base.full_name.string));
 333
 334         DEBUG(10,("Successfully validated Kerberos PAC\n"));
 335
 336         if (DEBUGLEVEL >= 10) {
 337                 const char *s;
 338                 s = NDR_PRINT_STRUCT_STRING(mem_ctx, PAC_DATA, pac_data);
 339                 if (s) {
 340                         DEBUGADD(10,("%s\n", s));
 341                 }
 342         }
 343
 344         *pac_data_out = pac_data;
 345
 346         return NT_STATUS_OK;
 347 }
 348
 349 /****************************************************************
 350 Given a username, password and other details, return the
 351 PAC_LOGON_INFO (the structure containing the important user
 352 information such as groups).
 353 ****************************************************************/
 354
 355 NTSTATUS kerberos_return_pac(TALLOC_CTX *mem_ctx,
 356                              const char *name,
 357                              const char *pass,
 358                              time_t time_offset,
 359                              time_t *expire_time,
 360                              time_t *renew_till_time,
 361                              const char *cache_name,
 362                              bool request_pac,
 363                              bool add_netbios_addr,
 364                              time_t renewable_time,
 365                              const char *impersonate_princ_s,
 366                              struct PAC_LOGON_INFO **logon_info)
 367 {
 368         krb5_error_code ret;
 369         NTSTATUS status = NT_STATUS_INVALID_PARAMETER;
 370         DATA_BLOB tkt, ap_rep, sesskey1, sesskey2;
 371         char *client_princ_out = NULL;
 372         const char *auth_princ = NULL;
 373         const char *local_service = NULL;
 374         const char *cc = "MEMORY:kerberos_return_pac";
 375
 376         ZERO_STRUCT(tkt);
 377         ZERO_STRUCT(ap_rep);
 378         ZERO_STRUCT(sesskey1);
 379         ZERO_STRUCT(sesskey2);
 380
 381         if (!name || !pass) {
 382                 return NT_STATUS_INVALID_PARAMETER;
 383         }
 384
 385         if (cache_name) {
 386                 cc = cache_name;
 387         }
 388
 389         if (!strchr_m(name, '@')) {
 390                 auth_princ = talloc_asprintf(mem_ctx, "%s@%s", name,
 391                         lp_realm());
 392         } else {
 393                 auth_princ = name;
 394         }
 395         NT_STATUS_HAVE_NO_MEMORY(auth_princ);
 396
 397         local_service = talloc_asprintf(mem_ctx, "%s$@%s",
 398                                         global_myname(), lp_realm());
 399         NT_STATUS_HAVE_NO_MEMORY(local_service);
 400
 401         ret = kerberos_kinit_password_ext(auth_princ,
 402                                           pass,
 403                                           time_offset,
 404                                           expire_time,
 405                                           renew_till_time,
 406                                           cc,
 407                                           request_pac,
 408                                           add_netbios_addr,
 409                                           renewable_time,
 410                                           &status);
 411         if (ret) {
 412                 DEBUG(1,("kinit failed for '%s' with: %s (%d)\n",
 413                         auth_princ, error_message(ret), ret));
 414                 /* status already set */
 415                 goto out;
 416         }
 417
 418         DEBUG(10,("got TGT for %s in %s\n", auth_princ, cc));
 419         if (expire_time) {
 420                 DEBUGADD(10,("\tvalid until: %s (%d)\n",
 421                         http_timestring(talloc_tos(), *expire_time),
 422                         (int)*expire_time));
 423         }
 424         if (renew_till_time) {
 425                 DEBUGADD(10,("\trenewable till: %s (%d)\n",
 426                         http_timestring(talloc_tos(), *renew_till_time),
 427                         (int)*renew_till_time));
 428         }
 429
 430         /* we cannot continue with krb5 when UF_DONT_REQUIRE_PREAUTH is set,
 431          * in that case fallback to NTLM - gd */
 432
 433         if (expire_time && renew_till_time &&
 434             (*expire_time == 0) && (*renew_till_time == 0)) {
 435                 return NT_STATUS_INVALID_LOGON_TYPE;
 436         }
 437
 438         ret = cli_krb5_get_ticket(mem_ctx,
 439                                   local_service,
 440                                   time_offset,
 441                                   &tkt,
 442                                   &sesskey1,
 443                                   0,
 444                                   cc,
 445                                   NULL,
 446                                   impersonate_princ_s);
 447         if (ret) {
 448                 DEBUG(1,("failed to get ticket for %s: %s\n",
 449                         local_service, error_message(ret)));
 450                 if (impersonate_princ_s) {
 451                         DEBUGADD(1,("tried S4U2SELF impersonation as: %s\n",
 452                                 impersonate_princ_s));
 453                 }
 454                 status = krb5_to_nt_status(ret);
 455                 goto out;
 456         }
 457         status = ads_verify_ticket(mem_ctx,
 458                                    lp_realm(),
 459                                    time_offset,
 460                                    &tkt,
 461                                    &client_princ_out,
 462                                    logon_info,
 463                                    &ap_rep,
 464                                    &sesskey2,
 465                                    False);
 466         if (!NT_STATUS_IS_OK(status)) {
 467                 DEBUG(1,("ads_verify_ticket failed: %s\n",
 468                         nt_errstr(status)));
 469                 goto out;
 470         }
 471
 472         if (!*logon_info) {
 473                 DEBUG(1,("no PAC\n"));
 474                 status = NT_STATUS_INVALID_PARAMETER;
 475                 goto out;
 476         }
 477
 478 out:
 479         if (cc != cache_name) {
 480                 ads_kdestroy(cc);
 481         }
 482
 483         data_blob_free(&tkt);
 484         data_blob_free(&ap_rep);
 485         data_blob_free(&sesskey1);
 486         data_blob_free(&sesskey2);
 487
 488         TALLOC_FREE(client_princ_out);
 489
 490         return status;
 491 }
 492
 493 #endif