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 "authdata.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 ****************************************************************/
  73
  74  NTSTATUS decode_pac_data(TALLOC_CTX *mem_ctx,
  75                          DATA_BLOB *pac_data_blob,
  76                          krb5_context context,
  77                          krb5_keyblock *service_keyblock,
  78                          krb5_const_principal client_principal,
  79                          time_t tgs_authtime,
  80                          struct PAC_DATA **pac_data_out)
  81 {
  82         NTSTATUS status;
  83         enum ndr_err_code ndr_err;
  84         krb5_error_code ret;
  85         DATA_BLOB modified_pac_blob;
  86
  87         NTTIME tgs_authtime_nttime;
  88         krb5_principal client_principal_pac = NULL;
  89         int i;
  90
  91         struct PAC_SIGNATURE_DATA *srv_sig_ptr = NULL;
  92         struct PAC_SIGNATURE_DATA *kdc_sig_ptr = NULL;
  93         struct PAC_SIGNATURE_DATA *srv_sig_wipe = NULL;
  94         struct PAC_SIGNATURE_DATA *kdc_sig_wipe = NULL;
  95         struct PAC_LOGON_NAME *logon_name = NULL;
  96         struct PAC_LOGON_INFO *logon_info = NULL;
  97         struct PAC_DATA *pac_data = NULL;
  98         struct PAC_DATA_RAW *pac_data_raw = NULL;
  99
 100         DATA_BLOB *srv_sig_blob = NULL;
 101         DATA_BLOB *kdc_sig_blob = NULL;
 102
 103         bool bool_ret;
 104
 105         *pac_data_out = NULL;
 106
 107         pac_data = TALLOC_ZERO_P(mem_ctx, struct PAC_DATA);
 108         pac_data_raw = TALLOC_ZERO_P(mem_ctx, struct PAC_DATA_RAW);
 109         kdc_sig_wipe = TALLOC_ZERO_P(mem_ctx, struct PAC_SIGNATURE_DATA);
 110         srv_sig_wipe = TALLOC_ZERO_P(mem_ctx, struct PAC_SIGNATURE_DATA);
 111         if (!pac_data_raw || !pac_data || !kdc_sig_wipe || !srv_sig_wipe) {
 112                 return NT_STATUS_NO_MEMORY;
 113         }
 114
 115         ndr_err = ndr_pull_struct_blob(pac_data_blob, pac_data,
 116                         NULL, pac_data,
 117                        (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
 118         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 119                 status = ndr_map_error2ntstatus(ndr_err);
 120                 DEBUG(0,("can't parse the PAC: %s\n",
 121                         nt_errstr(status)));
 122                 return status;
 123         }
 124
 125         if (pac_data->num_buffers < 4) {
 126                 /* we need logon_ingo, service_key and kdc_key */
 127                 DEBUG(0,("less than 4 PAC buffers\n"));
 128                 return NT_STATUS_INVALID_PARAMETER;
 129         }
 130
 131         ndr_err = ndr_pull_struct_blob(pac_data_blob, pac_data_raw,
 132                                        NULL, pac_data_raw,
 133                                        (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA_RAW);
 134         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 135                 status = ndr_map_error2ntstatus(ndr_err);
 136                 DEBUG(0,("can't parse the PAC: %s\n",
 137                         nt_errstr(status)));
 138                 return status;
 139         }
 140
 141         if (pac_data_raw->num_buffers < 4) {
 142                 /* we need logon_ingo, service_key and kdc_key */
 143                 DEBUG(0,("less than 4 PAC buffers\n"));
 144                 return NT_STATUS_INVALID_PARAMETER;
 145         }
 146
 147         if (pac_data->num_buffers != pac_data_raw->num_buffers) {
 148                 /* we need logon_ingo, service_key and kdc_key */
 149                 DEBUG(0,("misparse!  PAC_DATA has %d buffers while PAC_DATA_RAW has %d\n",
 150                          pac_data->num_buffers, pac_data_raw->num_buffers));
 151                 return NT_STATUS_INVALID_PARAMETER;
 152         }
 153
 154         for (i=0; i < pac_data->num_buffers; i++) {
 155                 if (pac_data->buffers[i].type != pac_data_raw->buffers[i].type) {
 156                         DEBUG(0,("misparse!  PAC_DATA buffer %d has type %d while PAC_DATA_RAW has %d\n",
 157                                  i, pac_data->buffers[i].type, pac_data->buffers[i].type));
 158                         return NT_STATUS_INVALID_PARAMETER;
 159                 }
 160                 switch (pac_data->buffers[i].type) {
 161                         case PAC_TYPE_LOGON_INFO:
 162                                 if (!pac_data->buffers[i].info) {
 163                                         break;
 164                                 }
 165                                 logon_info = pac_data->buffers[i].info->logon_info.info;
 166                                 break;
 167                         case PAC_TYPE_SRV_CHECKSUM:
 168                                 if (!pac_data->buffers[i].info) {
 169                                         break;
 170                                 }
 171                                 srv_sig_ptr = &pac_data->buffers[i].info->srv_cksum;
 172                                 srv_sig_blob = &pac_data_raw->buffers[i].info->remaining;
 173                                 break;
 174                         case PAC_TYPE_KDC_CHECKSUM:
 175                                 if (!pac_data->buffers[i].info) {
 176                                         break;
 177                                 }
 178                                 kdc_sig_ptr = &pac_data->buffers[i].info->kdc_cksum;
 179                                 kdc_sig_blob = &pac_data_raw->buffers[i].info->remaining;
 180                                 break;
 181                         case PAC_TYPE_LOGON_NAME:
 182                                 logon_name = &pac_data->buffers[i].info->logon_name;
 183                                 break;
 184                         default:
 185                                 break;
 186                 }
 187         }
 188
 189         if (!logon_info) {
 190                 DEBUG(0,("PAC no logon_info\n"));
 191                 return NT_STATUS_INVALID_PARAMETER;
 192         }
 193
 194         if (!logon_name) {
 195                 DEBUG(0,("PAC no logon_name\n"));
 196                 return NT_STATUS_INVALID_PARAMETER;
 197         }
 198
 199         if (!srv_sig_ptr || !srv_sig_blob) {
 200                 DEBUG(0,("PAC no srv_key\n"));
 201                 return NT_STATUS_INVALID_PARAMETER;
 202         }
 203
 204         if (!kdc_sig_ptr || !kdc_sig_blob) {
 205                 DEBUG(0,("PAC no kdc_key\n"));
 206                 return NT_STATUS_INVALID_PARAMETER;
 207         }
 208
 209         /* Find and zero out the signatures, as required by the signing algorithm */
 210
 211         /* We find the data blobs above, now we parse them to get at the exact portion we should zero */
 212         ndr_err = ndr_pull_struct_blob(kdc_sig_blob, kdc_sig_wipe,
 213                                        NULL, kdc_sig_wipe,
 214                                        (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
 215         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 216                 status = ndr_map_error2ntstatus(ndr_err);
 217                 DEBUG(0,("can't parse the KDC signature: %s\n",
 218                         nt_errstr(status)));
 219                 return status;
 220         }
 221
 222         ndr_err = ndr_pull_struct_blob(srv_sig_blob, srv_sig_wipe,
 223                                        NULL, srv_sig_wipe,
 224                                        (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
 225         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 226                 status = ndr_map_error2ntstatus(ndr_err);
 227                 DEBUG(0,("can't parse the SRV signature: %s\n",
 228                         nt_errstr(status)));
 229                 return status;
 230         }
 231
 232         /* Now zero the decoded structure */
 233         memset(kdc_sig_wipe->signature.data, '\0', kdc_sig_wipe->signature.length);
 234         memset(srv_sig_wipe->signature.data, '\0', srv_sig_wipe->signature.length);
 235
 236         /* and reencode, back into the same place it came from */
 237         ndr_err = ndr_push_struct_blob(kdc_sig_blob, pac_data_raw,
 238                                        NULL, kdc_sig_wipe,
 239                                        (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
 240         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 241                 status = ndr_map_error2ntstatus(ndr_err);
 242                 DEBUG(0,("can't repack the KDC signature: %s\n",
 243                         nt_errstr(status)));
 244                 return status;
 245         }
 246         ndr_err = ndr_push_struct_blob(srv_sig_blob, pac_data_raw,
 247                                        NULL, srv_sig_wipe,
 248                                        (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
 249         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 250                 status = ndr_map_error2ntstatus(ndr_err);
 251                 DEBUG(0,("can't repack the SRV signature: %s\n",
 252                         nt_errstr(status)));
 253                 return status;
 254         }
 255
 256         /* push out the whole structure, but now with zero'ed signatures */
 257         ndr_err = ndr_push_struct_blob(&modified_pac_blob, pac_data_raw,
 258                                        NULL, pac_data_raw,
 259                                        (ndr_push_flags_fn_t)ndr_push_PAC_DATA_RAW);
 260         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 261                 status = ndr_map_error2ntstatus(ndr_err);
 262                 DEBUG(0,("can't repack the RAW PAC: %s\n",
 263                         nt_errstr(status)));
 264                 return status;
 265         }
 266
 267         /* verify by service_key */
 268         ret = check_pac_checksum(mem_ctx,
 269                                  modified_pac_blob, srv_sig_ptr,
 270                                  context,
 271                                  service_keyblock);
 272         if (ret) {
 273                 DEBUG(1, ("PAC Decode: Failed to verify the service signature: %s\n",
 274                           error_message(ret)));
 275                 return NT_STATUS_ACCESS_DENIED;
 276         }
 277
 278         /* Convert to NT time, so as not to loose accuracy in comparison */
 279         unix_to_nt_time(&tgs_authtime_nttime, tgs_authtime);
 280
 281         if (tgs_authtime_nttime != logon_name->logon_time) {
 282                 DEBUG(2, ("PAC Decode: Logon time mismatch between ticket and PAC!\n"));
 283                 DEBUG(2, ("PAC Decode: PAC: %s\n", nt_time_string(mem_ctx, logon_name->logon_time)));
 284                 DEBUG(2, ("PAC Decode: Ticket: %s\n", nt_time_string(mem_ctx, tgs_authtime_nttime)));
 285                 return NT_STATUS_ACCESS_DENIED;
 286         }
 287
 288         ret = smb_krb5_parse_name_norealm(context, logon_name->account_name,
 289                                     &client_principal_pac);
 290         if (ret) {
 291                 DEBUG(2, ("Could not parse name from incoming PAC: [%s]: %s\n",
 292                           logon_name->account_name,
 293                           error_message(ret)));
 294                 return NT_STATUS_INVALID_PARAMETER;
 295         }
 296
 297         bool_ret = smb_krb5_principal_compare_any_realm(
 298                 context, client_principal, client_principal_pac);
 299
 300         krb5_free_principal(context, client_principal_pac);
 301
 302         if (!bool_ret) {
 303                 DEBUG(2, ("Name in PAC [%s] does not match principal name in ticket\n",
 304                           logon_name->account_name));
 305                 return NT_STATUS_ACCESS_DENIED;
 306         }
 307
 308         DEBUG(3,("Found account name from PAC: %s [%s]\n",
 309                  logon_info->info3.base.account_name.string,
 310                  logon_info->info3.base.full_name.string));
 311
 312         DEBUG(10,("Successfully validated Kerberos PAC\n"));
 313
 314         if (DEBUGLEVEL >= 10) {
 315                 const char *s;
 316                 s = NDR_PRINT_STRUCT_STRING(mem_ctx, PAC_DATA, pac_data);
 317                 if (s) {
 318                         DEBUGADD(10,("%s\n", s));
 319                 }
 320         }
 321
 322         *pac_data_out = pac_data;
 323
 324         return NT_STATUS_OK;
 325 }
 326
 327 /****************************************************************
 328 Given a username, password and other details, return the
 329 PAC_LOGON_INFO (the structure containing the important user
 330 information such as groups).
 331 ****************************************************************/
 332
 333 NTSTATUS kerberos_return_pac(TALLOC_CTX *mem_ctx,
 334                              const char *name,
 335                              const char *pass,
 336                              time_t time_offset,
 337                              time_t *expire_time,
 338                              time_t *renew_till_time,
 339                              const char *cache_name,
 340                              bool request_pac,
 341                              bool add_netbios_addr,
 342                              time_t renewable_time,
 343                              const char *impersonate_princ_s,
 344                              struct PAC_LOGON_INFO **logon_info)
 345 {
 346         krb5_error_code ret;
 347         NTSTATUS status = NT_STATUS_INVALID_PARAMETER;
 348         DATA_BLOB tkt, ap_rep, sesskey1, sesskey2;
 349         char *client_princ_out = NULL;
 350         const char *auth_princ = NULL;
 351         const char *local_service = NULL;
 352         const char *cc = "MEMORY:kerberos_return_pac";
 353
 354         ZERO_STRUCT(tkt);
 355         ZERO_STRUCT(ap_rep);
 356         ZERO_STRUCT(sesskey1);
 357         ZERO_STRUCT(sesskey2);
 358
 359         if (!name || !pass) {
 360                 return NT_STATUS_INVALID_PARAMETER;
 361         }
 362
 363         if (cache_name) {
 364                 cc = cache_name;
 365         }
 366
 367         if (!strchr_m(name, '@')) {
 368                 auth_princ = talloc_asprintf(mem_ctx, "%s@%s", name,
 369                         lp_realm());
 370         } else {
 371                 auth_princ = name;
 372         }
 373         NT_STATUS_HAVE_NO_MEMORY(auth_princ);
 374
 375         local_service = talloc_asprintf(mem_ctx, "%s$@%s",
 376                                         global_myname(), lp_realm());
 377         NT_STATUS_HAVE_NO_MEMORY(local_service);
 378
 379         ret = kerberos_kinit_password_ext(auth_princ,
 380                                           pass,
 381                                           time_offset,
 382                                           expire_time,
 383                                           renew_till_time,
 384                                           cc,
 385                                           request_pac,
 386                                           add_netbios_addr,
 387                                           renewable_time,
 388                                           &status);
 389         if (ret) {
 390                 DEBUG(1,("kinit failed for '%s' with: %s (%d)\n",
 391                         auth_princ, error_message(ret), ret));
 392                 /* status already set */
 393                 goto out;
 394         }
 395
 396         DEBUG(10,("got TGT for %s in %s\n", auth_princ, cc));
 397         if (expire_time) {
 398                 DEBUGADD(10,("\tvalid until: %s (%d)\n",
 399                         http_timestring(talloc_tos(), *expire_time),
 400                         (int)*expire_time));
 401         }
 402         if (renew_till_time) {
 403                 DEBUGADD(10,("\trenewable till: %s (%d)\n",
 404                         http_timestring(talloc_tos(), *renew_till_time),
 405                         (int)*renew_till_time));
 406         }
 407
 408         /* we cannot continue with krb5 when UF_DONT_REQUIRE_PREAUTH is set,
 409          * in that case fallback to NTLM - gd */
 410
 411         if (expire_time && renew_till_time &&
 412             (*expire_time == 0) && (*renew_till_time == 0)) {
 413                 return NT_STATUS_INVALID_LOGON_TYPE;
 414         }
 415
 416         ret = cli_krb5_get_ticket(local_service,
 417                                   time_offset,
 418                                   &tkt,
 419                                   &sesskey1,
 420                                   0,
 421                                   cc,
 422                                   NULL,
 423                                   impersonate_princ_s);
 424         if (ret) {
 425                 DEBUG(1,("failed to get ticket for %s: %s\n",
 426                         local_service, error_message(ret)));
 427                 if (impersonate_princ_s) {
 428                         DEBUGADD(1,("tried S4U2SELF impersonation as: %s\n",
 429                                 impersonate_princ_s));
 430                 }
 431                 status = krb5_to_nt_status(ret);
 432                 goto out;
 433         }
 434         status = ads_verify_ticket(mem_ctx,
 435                                    lp_realm(),
 436                                    time_offset,
 437                                    &tkt,
 438                                    &client_princ_out,
 439                                    logon_info,
 440                                    &ap_rep,
 441                                    &sesskey2,
 442                                    False);
 443         if (!NT_STATUS_IS_OK(status)) {
 444                 DEBUG(1,("ads_verify_ticket failed: %s\n",
 445                         nt_errstr(status)));
 446                 goto out;
 447         }
 448
 449         if (!*logon_info) {
 450                 DEBUG(1,("no PAC\n"));
 451                 status = NT_STATUS_INVALID_PARAMETER;
 452                 goto out;
 453         }
 454
 455 out:
 456         if (cc != cache_name) {
 457                 ads_kdestroy(cc);
 458         }
 459
 460         data_blob_free(&tkt);
 461         data_blob_free(&ap_rep);
 462         data_blob_free(&sesskey1);
 463         data_blob_free(&sesskey2);
 464
 465         TALLOC_FREE(client_princ_out);
 466
 467         return status;
 468 }
 469
 470 #endif