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