source3/libsmb/clispnego.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    simple kerberos5/SPNEGO routines
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2002
   6    Copyright (C) Luke Howard     2003
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "../libcli/auth/spnego.h"
  24 #include "smb_krb5.h"
  25
  26 /*
  27   generate a negTokenInit packet given a GUID, a list of supported
  28   OIDs (the mechanisms) and a principal name string
  29 */
  30 DATA_BLOB spnego_gen_negTokenInit(char guid[16],
  31                                   const char *OIDs[],
  32                                   const char *principal)
  33 {
  34         int i;
  35         ASN1_DATA *data;
  36         DATA_BLOB ret;
  37
  38         data = asn1_init(talloc_tos());
  39         if (data == NULL) {
  40                 return data_blob_null;
  41         }
  42
  43         asn1_write(data, guid, 16);
  44         asn1_push_tag(data,ASN1_APPLICATION(0));
  45         asn1_write_OID(data,OID_SPNEGO);
  46         asn1_push_tag(data,ASN1_CONTEXT(0));
  47         asn1_push_tag(data,ASN1_SEQUENCE(0));
  48
  49         asn1_push_tag(data,ASN1_CONTEXT(0));
  50         asn1_push_tag(data,ASN1_SEQUENCE(0));
  51         for (i=0; OIDs[i]; i++) {
  52                 asn1_write_OID(data,OIDs[i]);
  53         }
  54         asn1_pop_tag(data);
  55         asn1_pop_tag(data);
  56
  57         asn1_push_tag(data, ASN1_CONTEXT(3));
  58         asn1_push_tag(data, ASN1_SEQUENCE(0));
  59         asn1_push_tag(data, ASN1_CONTEXT(0));
  60         asn1_write_GeneralString(data,principal);
  61         asn1_pop_tag(data);
  62         asn1_pop_tag(data);
  63         asn1_pop_tag(data);
  64
  65         asn1_pop_tag(data);
  66         asn1_pop_tag(data);
  67
  68         asn1_pop_tag(data);
  69
  70         if (data->has_error) {
  71                 DEBUG(1,("Failed to build negTokenInit at offset %d\n", (int)data->ofs));
  72         }
  73
  74         ret = data_blob(data->data, data->length);
  75         asn1_free(data);
  76
  77         return ret;
  78 }
  79
  80 /*
  81   Generate a negTokenInit as used by the client side ... It has a mechType
  82   (OID), and a mechToken (a security blob) ...
  83
  84   Really, we need to break out the NTLMSSP stuff as well, because it could be
  85   raw in the packets!
  86 */
  87 DATA_BLOB gen_negTokenInit(const char *OID, DATA_BLOB blob)
  88 {
  89         ASN1_DATA *data;
  90         DATA_BLOB ret;
  91
  92         data = asn1_init(talloc_tos());
  93         if (data == NULL) {
  94                 return data_blob_null;
  95         }
  96
  97         asn1_push_tag(data, ASN1_APPLICATION(0));
  98         asn1_write_OID(data,OID_SPNEGO);
  99         asn1_push_tag(data, ASN1_CONTEXT(0));
 100         asn1_push_tag(data, ASN1_SEQUENCE(0));
 101
 102         asn1_push_tag(data, ASN1_CONTEXT(0));
 103         asn1_push_tag(data, ASN1_SEQUENCE(0));
 104         asn1_write_OID(data, OID);
 105         asn1_pop_tag(data);
 106         asn1_pop_tag(data);
 107
 108         asn1_push_tag(data, ASN1_CONTEXT(2));
 109         asn1_write_OctetString(data,blob.data,blob.length);
 110         asn1_pop_tag(data);
 111
 112         asn1_pop_tag(data);
 113         asn1_pop_tag(data);
 114
 115         asn1_pop_tag(data);
 116
 117         if (data->has_error) {
 118                 DEBUG(1,("Failed to build negTokenInit at offset %d\n", (int)data->ofs));
 119         }
 120
 121         ret = data_blob(data->data, data->length);
 122         asn1_free(data);
 123
 124         return ret;
 125 }
 126
 127 /*
 128   parse a negTokenInit packet giving a GUID, a list of supported
 129   OIDs (the mechanisms) and a principal name string
 130 */
 131 bool spnego_parse_negTokenInit(DATA_BLOB blob,
 132                                char *OIDs[ASN1_MAX_OIDS],
 133                                char **principal)
 134 {
 135         int i;
 136         bool ret;
 137         ASN1_DATA *data;
 138
 139         data = asn1_init(talloc_tos());
 140         if (data == NULL) {
 141                 return false;
 142         }
 143
 144         asn1_load(data, blob);
 145
 146         asn1_start_tag(data,ASN1_APPLICATION(0));
 147
 148         asn1_check_OID(data,OID_SPNEGO);
 149         asn1_start_tag(data,ASN1_CONTEXT(0));
 150         asn1_start_tag(data,ASN1_SEQUENCE(0));
 151
 152         asn1_start_tag(data,ASN1_CONTEXT(0));
 153         asn1_start_tag(data,ASN1_SEQUENCE(0));
 154         for (i=0; asn1_tag_remaining(data) > 0 && i < ASN1_MAX_OIDS-1; i++) {
 155                 const char *oid_str = NULL;
 156                 asn1_read_OID(data,talloc_autofree_context(),&oid_str);
 157                 OIDs[i] = CONST_DISCARD(char *, oid_str);
 158         }
 159         OIDs[i] = NULL;
 160         asn1_end_tag(data);
 161         asn1_end_tag(data);
 162
 163         *principal = NULL;
 164         if (asn1_tag_remaining(data) > 0) {
 165                 asn1_start_tag(data, ASN1_CONTEXT(3));
 166                 asn1_start_tag(data, ASN1_SEQUENCE(0));
 167                 asn1_start_tag(data, ASN1_CONTEXT(0));
 168                 asn1_read_GeneralString(data,talloc_autofree_context(),principal);
 169                 asn1_end_tag(data);
 170                 asn1_end_tag(data);
 171                 asn1_end_tag(data);
 172         }
 173
 174         asn1_end_tag(data);
 175         asn1_end_tag(data);
 176
 177         asn1_end_tag(data);
 178
 179         ret = !data->has_error;
 180         if (data->has_error) {
 181                 int j;
 182                 TALLOC_FREE(*principal);
 183                 for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
 184                         TALLOC_FREE(OIDs[j]);
 185                 }
 186         }
 187
 188         asn1_free(data);
 189         return ret;
 190 }
 191
 192 /*
 193   generate a negTokenTarg packet given a list of OIDs and a security blob
 194 */
 195 DATA_BLOB gen_negTokenTarg(const char *OIDs[], DATA_BLOB blob)
 196 {
 197         int i;
 198         ASN1_DATA *data;
 199         DATA_BLOB ret;
 200
 201         data = asn1_init(talloc_tos());
 202         if (data == NULL) {
 203                 return data_blob_null;
 204         }
 205
 206         asn1_push_tag(data, ASN1_APPLICATION(0));
 207         asn1_write_OID(data,OID_SPNEGO);
 208         asn1_push_tag(data, ASN1_CONTEXT(0));
 209         asn1_push_tag(data, ASN1_SEQUENCE(0));
 210
 211         asn1_push_tag(data, ASN1_CONTEXT(0));
 212         asn1_push_tag(data, ASN1_SEQUENCE(0));
 213         for (i=0; OIDs[i]; i++) {
 214                 asn1_write_OID(data,OIDs[i]);
 215         }
 216         asn1_pop_tag(data);
 217         asn1_pop_tag(data);
 218
 219         asn1_push_tag(data, ASN1_CONTEXT(2));
 220         asn1_write_OctetString(data,blob.data,blob.length);
 221         asn1_pop_tag(data);
 222
 223         asn1_pop_tag(data);
 224         asn1_pop_tag(data);
 225
 226         asn1_pop_tag(data);
 227
 228         if (data->has_error) {
 229                 DEBUG(1,("Failed to build negTokenTarg at offset %d\n", (int)data->ofs));
 230         }
 231
 232         ret = data_blob(data->data, data->length);
 233         asn1_free(data);
 234
 235         return ret;
 236 }
 237
 238 /*
 239   parse a negTokenTarg packet giving a list of OIDs and a security blob
 240 */
 241 bool parse_negTokenTarg(DATA_BLOB blob, char *OIDs[ASN1_MAX_OIDS], DATA_BLOB *secblob)
 242 {
 243         int i;
 244         ASN1_DATA *data;
 245
 246         data = asn1_init(talloc_tos());
 247         if (data == NULL) {
 248                 return false;
 249         }
 250
 251         asn1_load(data, blob);
 252         asn1_start_tag(data, ASN1_APPLICATION(0));
 253         asn1_check_OID(data,OID_SPNEGO);
 254         asn1_start_tag(data, ASN1_CONTEXT(0));
 255         asn1_start_tag(data, ASN1_SEQUENCE(0));
 256
 257         asn1_start_tag(data, ASN1_CONTEXT(0));
 258         asn1_start_tag(data, ASN1_SEQUENCE(0));
 259         for (i=0; asn1_tag_remaining(data) > 0 && i < ASN1_MAX_OIDS-1; i++) {
 260                 const char *oid_str = NULL;
 261                 asn1_read_OID(data,talloc_autofree_context(),&oid_str);
 262                 OIDs[i] = CONST_DISCARD(char *, oid_str);
 263         }
 264         OIDs[i] = NULL;
 265         asn1_end_tag(data);
 266         asn1_end_tag(data);
 267
 268         /* Skip any optional req_flags that are sent per RFC 4178 */
 269         if (asn1_peek_tag(data, ASN1_CONTEXT(1))) {
 270                 uint8 flags;
 271
 272                 asn1_start_tag(data, ASN1_CONTEXT(1));
 273                 asn1_start_tag(data, ASN1_BIT_STRING);
 274                 while (asn1_tag_remaining(data) > 0)
 275                         asn1_read_uint8(data, &flags);
 276                 asn1_end_tag(data);
 277                 asn1_end_tag(data);
 278         }
 279
 280         asn1_start_tag(data, ASN1_CONTEXT(2));
 281         asn1_read_OctetString(data,talloc_autofree_context(),secblob);
 282         asn1_end_tag(data);
 283
 284         asn1_end_tag(data);
 285         asn1_end_tag(data);
 286
 287         asn1_end_tag(data);
 288
 289         if (data->has_error) {
 290                 int j;
 291                 data_blob_free(secblob);
 292                 for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
 293                         TALLOC_FREE(OIDs[j]);
 294                 }
 295                 DEBUG(1,("Failed to parse negTokenTarg at offset %d\n", (int)data->ofs));
 296                 asn1_free(data);
 297                 return False;
 298         }
 299
 300         asn1_free(data);
 301         return True;
 302 }
 303
 304 /*
 305   generate a krb5 GSS-API wrapper packet given a ticket
 306 */
 307 DATA_BLOB spnego_gen_krb5_wrap(const DATA_BLOB ticket, const uint8 tok_id[2])
 308 {
 309         ASN1_DATA *data;
 310         DATA_BLOB ret;
 311
 312         data = asn1_init(talloc_tos());
 313         if (data == NULL) {
 314                 return data_blob_null;
 315         }
 316
 317         asn1_push_tag(data, ASN1_APPLICATION(0));
 318         asn1_write_OID(data, OID_KERBEROS5);
 319
 320         asn1_write(data, tok_id, 2);
 321         asn1_write(data, ticket.data, ticket.length);
 322         asn1_pop_tag(data);
 323
 324         if (data->has_error) {
 325                 DEBUG(1,("Failed to build krb5 wrapper at offset %d\n", (int)data->ofs));
 326         }
 327
 328         ret = data_blob(data->data, data->length);
 329         asn1_free(data);
 330
 331         return ret;
 332 }
 333
 334 /*
 335   parse a krb5 GSS-API wrapper packet giving a ticket
 336 */
 337 bool spnego_parse_krb5_wrap(DATA_BLOB blob, DATA_BLOB *ticket, uint8 tok_id[2])
 338 {
 339         bool ret;
 340         ASN1_DATA *data;
 341         int data_remaining;
 342
 343         data = asn1_init(talloc_tos());
 344         if (data == NULL) {
 345                 return false;
 346         }
 347
 348         asn1_load(data, blob);
 349         asn1_start_tag(data, ASN1_APPLICATION(0));
 350         asn1_check_OID(data, OID_KERBEROS5);
 351
 352         data_remaining = asn1_tag_remaining(data);
 353
 354         if (data_remaining < 3) {
 355                 data->has_error = True;
 356         } else {
 357                 asn1_read(data, tok_id, 2);
 358                 data_remaining -= 2;
 359                 *ticket = data_blob(NULL, data_remaining);
 360                 asn1_read(data, ticket->data, ticket->length);
 361         }
 362
 363         asn1_end_tag(data);
 364
 365         ret = !data->has_error;
 366
 367         if (data->has_error) {
 368                 data_blob_free(ticket);
 369         }
 370
 371         asn1_free(data);
 372
 373         return ret;
 374 }
 375
 376
 377 /*
 378    generate a SPNEGO negTokenTarg packet, ready for a EXTENDED_SECURITY
 379    kerberos session setup
 380 */
 381 int spnego_gen_negTokenTarg(const char *principal, int time_offset,
 382                             DATA_BLOB *targ,
 383                             DATA_BLOB *session_key_krb5, uint32 extra_ap_opts,
 384                             time_t *expire_time)
 385 {
 386         int retval;
 387         DATA_BLOB tkt, tkt_wrapped;
 388         const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_KERBEROS5, OID_NTLMSSP, NULL};
 389
 390         /* get a kerberos ticket for the service and extract the session key */
 391         retval = cli_krb5_get_ticket(principal, time_offset,
 392                                         &tkt, session_key_krb5, extra_ap_opts, NULL,
 393                                         expire_time, NULL);
 394
 395         if (retval)
 396                 return retval;
 397
 398         /* wrap that up in a nice GSS-API wrapping */
 399         tkt_wrapped = spnego_gen_krb5_wrap(tkt, TOK_ID_KRB_AP_REQ);
 400
 401         /* and wrap that in a shiny SPNEGO wrapper */
 402         *targ = gen_negTokenTarg(krb_mechs, tkt_wrapped);
 403
 404         data_blob_free(&tkt_wrapped);
 405         data_blob_free(&tkt);
 406
 407         return retval;
 408 }
 409
 410
 411 /*
 412   parse a spnego NTLMSSP challenge packet giving two security blobs
 413 */
 414 bool spnego_parse_challenge(const DATA_BLOB blob,
 415                             DATA_BLOB *chal1, DATA_BLOB *chal2)
 416 {
 417         bool ret;
 418         ASN1_DATA *data;
 419
 420         ZERO_STRUCTP(chal1);
 421         ZERO_STRUCTP(chal2);
 422
 423         data = asn1_init(talloc_tos());
 424         if (data == NULL) {
 425                 return false;
 426         }
 427
 428         asn1_load(data, blob);
 429         asn1_start_tag(data,ASN1_CONTEXT(1));
 430         asn1_start_tag(data,ASN1_SEQUENCE(0));
 431
 432         asn1_start_tag(data,ASN1_CONTEXT(0));
 433         asn1_check_enumerated(data,1);
 434         asn1_end_tag(data);
 435
 436         asn1_start_tag(data,ASN1_CONTEXT(1));
 437         asn1_check_OID(data, OID_NTLMSSP);
 438         asn1_end_tag(data);
 439
 440         asn1_start_tag(data,ASN1_CONTEXT(2));
 441         asn1_read_OctetString(data, talloc_autofree_context(), chal1);
 442         asn1_end_tag(data);
 443
 444         /* the second challenge is optional (XP doesn't send it) */
 445         if (asn1_tag_remaining(data)) {
 446                 asn1_start_tag(data,ASN1_CONTEXT(3));
 447                 asn1_read_OctetString(data, talloc_autofree_context(), chal2);
 448                 asn1_end_tag(data);
 449         }
 450
 451         asn1_end_tag(data);
 452         asn1_end_tag(data);
 453
 454         ret = !data->has_error;
 455
 456         if (data->has_error) {
 457                 data_blob_free(chal1);
 458                 data_blob_free(chal2);
 459         }
 460
 461         asn1_free(data);
 462         return ret;
 463 }
 464
 465
 466 /*
 467  generate a SPNEGO auth packet. This will contain the encrypted passwords
 468 */
 469 DATA_BLOB spnego_gen_auth(DATA_BLOB blob)
 470 {
 471         ASN1_DATA *data;
 472         DATA_BLOB ret;
 473
 474         data = asn1_init(talloc_tos());
 475         if (data == NULL) {
 476                 return data_blob_null;
 477         }
 478
 479         asn1_push_tag(data, ASN1_CONTEXT(1));
 480         asn1_push_tag(data, ASN1_SEQUENCE(0));
 481         asn1_push_tag(data, ASN1_CONTEXT(2));
 482         asn1_write_OctetString(data,blob.data,blob.length);
 483         asn1_pop_tag(data);
 484         asn1_pop_tag(data);
 485         asn1_pop_tag(data);
 486
 487         ret = data_blob(data->data, data->length);
 488
 489         asn1_free(data);
 490
 491         return ret;
 492 }
 493
 494 /*
 495  parse a SPNEGO auth packet. This contains the encrypted passwords
 496 */
 497 bool spnego_parse_auth(DATA_BLOB blob, DATA_BLOB *auth)
 498 {
 499         ssize_t len;
 500         struct spnego_data token;
 501
 502         len = spnego_read_data(talloc_tos(), blob, &token);
 503         if (len == -1) {
 504                 DEBUG(3,("spnego_parse_auth: spnego_read_data failed\n"));
 505                 return false;
 506         }
 507
 508         if (token.type != SPNEGO_NEG_TOKEN_TARG) {
 509                 DEBUG(3,("spnego_parse_auth: wrong token type: %d\n",
 510                         token.type));
 511                 spnego_free_data(&token);
 512                 return false;
 513         }
 514
 515         *auth = data_blob_talloc(talloc_tos(),
 516                                  token.negTokenTarg.responseToken.data,
 517                                  token.negTokenTarg.responseToken.length);
 518         spnego_free_data(&token);
 519
 520         return true;
 521 }
 522
 523 /*
 524   generate a minimal SPNEGO response packet.  Doesn't contain much.
 525 */
 526 DATA_BLOB spnego_gen_auth_response(DATA_BLOB *reply, NTSTATUS nt_status,
 527                                    const char *mechOID)
 528 {
 529         ASN1_DATA *data;
 530         DATA_BLOB ret;
 531         uint8 negResult;
 532
 533         if (NT_STATUS_IS_OK(nt_status)) {
 534                 negResult = SPNEGO_ACCEPT_COMPLETED;
 535         } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 536                 negResult = SPNEGO_ACCEPT_INCOMPLETE;
 537         } else {
 538                 negResult = SPNEGO_REJECT;
 539         }
 540
 541         data = asn1_init(talloc_tos());
 542         if (data == NULL) {
 543                 return data_blob_null;
 544         }
 545
 546         asn1_push_tag(data, ASN1_CONTEXT(1));
 547         asn1_push_tag(data, ASN1_SEQUENCE(0));
 548         asn1_push_tag(data, ASN1_CONTEXT(0));
 549         asn1_write_enumerated(data, negResult);
 550         asn1_pop_tag(data);
 551
 552         if (mechOID) {
 553                 asn1_push_tag(data,ASN1_CONTEXT(1));
 554                 asn1_write_OID(data, mechOID);
 555                 asn1_pop_tag(data);
 556         }
 557
 558         if (reply && reply->data != NULL) {
 559                 asn1_push_tag(data,ASN1_CONTEXT(2));
 560                 asn1_write_OctetString(data, reply->data, reply->length);
 561                 asn1_pop_tag(data);
 562         }
 563
 564         asn1_pop_tag(data);
 565         asn1_pop_tag(data);
 566
 567         ret = data_blob(data->data, data->length);
 568         asn1_free(data);
 569         return ret;
 570 }
 571
 572 /*
 573  parse a SPNEGO auth packet. This contains the encrypted passwords
 574 */
 575 bool spnego_parse_auth_response(DATA_BLOB blob, NTSTATUS nt_status,
 576                                 const char *mechOID,
 577                                 DATA_BLOB *auth)
 578 {
 579         ASN1_DATA *data;
 580         uint8 negResult;
 581
 582         if (NT_STATUS_IS_OK(nt_status)) {
 583                 negResult = SPNEGO_ACCEPT_COMPLETED;
 584         } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 585                 negResult = SPNEGO_ACCEPT_INCOMPLETE;
 586         } else {
 587                 negResult = SPNEGO_REJECT;
 588         }
 589
 590         data = asn1_init(talloc_tos());
 591         if (data == NULL) {
 592                 return false;
 593         }
 594
 595         asn1_load(data, blob);
 596         asn1_start_tag(data, ASN1_CONTEXT(1));
 597         asn1_start_tag(data, ASN1_SEQUENCE(0));
 598         asn1_start_tag(data, ASN1_CONTEXT(0));
 599         asn1_check_enumerated(data, negResult);
 600         asn1_end_tag(data);
 601
 602         *auth = data_blob_null;
 603
 604         if (asn1_tag_remaining(data)) {
 605                 asn1_start_tag(data,ASN1_CONTEXT(1));
 606                 asn1_check_OID(data, mechOID);
 607                 asn1_end_tag(data);
 608
 609                 if (asn1_tag_remaining(data)) {
 610                         asn1_start_tag(data,ASN1_CONTEXT(2));
 611                         asn1_read_OctetString(data, talloc_autofree_context(), auth);
 612                         asn1_end_tag(data);
 613                 }
 614         } else if (negResult == SPNEGO_ACCEPT_INCOMPLETE) {
 615                 data->has_error = 1;
 616         }
 617
 618         /* Binding against Win2K DC returns a duplicate of the responseToken in
 619          * the optional mechListMIC field. This is a bug in Win2K. We ignore
 620          * this field if it exists. Win2K8 may return a proper mechListMIC at
 621          * which point we need to implement the integrity checking. */
 622         if (asn1_tag_remaining(data)) {
 623                 DATA_BLOB mechList = data_blob_null;
 624                 asn1_start_tag(data, ASN1_CONTEXT(3));
 625                 asn1_read_OctetString(data, talloc_autofree_context(), &mechList);
 626                 asn1_end_tag(data);
 627                 data_blob_free(&mechList);
 628                 DEBUG(5,("spnego_parse_auth_response received mechListMIC, "
 629                     "ignoring.\n"));
 630         }
 631
 632         asn1_end_tag(data);
 633         asn1_end_tag(data);
 634
 635         if (data->has_error) {
 636                 DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data->ofs));
 637                 asn1_free(data);
 638                 data_blob_free(auth);
 639                 return False;
 640         }
 641
 642         asn1_free(data);
 643         return True;
 644 }