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    Copyright (C) Jeremy Allison 2010
   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 3 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    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "../libcli/auth/spnego.h"
  25 #include "smb_krb5.h"
  26 #include "../lib/util/asn1.h"
  27
  28 /*
  29   generate a negTokenInit packet given a list of supported
  30   OIDs (the mechanisms) a blob, and a principal name string
  31 */
  32
  33 DATA_BLOB spnego_gen_negTokenInit(TALLOC_CTX *ctx,
  34                                   const char *OIDs[],
  35                                   DATA_BLOB *psecblob,
  36                                   const char *principal)
  37 {
  38         int i;
  39         ASN1_DATA *data;
  40         DATA_BLOB ret;
  41
  42         data = asn1_init(talloc_tos());
  43         if (data == NULL) {
  44                 return data_blob_null;
  45         }
  46
  47         asn1_push_tag(data,ASN1_APPLICATION(0));
  48         asn1_write_OID(data,OID_SPNEGO);
  49         asn1_push_tag(data,ASN1_CONTEXT(0));
  50         asn1_push_tag(data,ASN1_SEQUENCE(0));
  51
  52         asn1_push_tag(data,ASN1_CONTEXT(0));
  53         asn1_push_tag(data,ASN1_SEQUENCE(0));
  54         for (i=0; OIDs[i]; i++) {
  55                 asn1_write_OID(data,OIDs[i]);
  56         }
  57         asn1_pop_tag(data);
  58         asn1_pop_tag(data);
  59
  60         if (psecblob && psecblob->length && psecblob->data) {
  61                 asn1_push_tag(data, ASN1_CONTEXT(2));
  62                 asn1_write_OctetString(data,psecblob->data,
  63                         psecblob->length);
  64                 asn1_pop_tag(data);
  65         }
  66
  67         if (principal) {
  68                 asn1_push_tag(data, ASN1_CONTEXT(3));
  69                 asn1_push_tag(data, ASN1_SEQUENCE(0));
  70                 asn1_push_tag(data, ASN1_CONTEXT(0));
  71                 asn1_write_GeneralString(data,principal);
  72                 asn1_pop_tag(data);
  73                 asn1_pop_tag(data);
  74                 asn1_pop_tag(data);
  75         }
  76
  77         asn1_pop_tag(data);
  78         asn1_pop_tag(data);
  79
  80         asn1_pop_tag(data);
  81
  82         if (data->has_error) {
  83                 DEBUG(1,("Failed to build negTokenInit at offset %d\n", (int)data->ofs));
  84         }
  85
  86         ret = data_blob_talloc(ctx, data->data, data->length);
  87         asn1_free(data);
  88
  89         return ret;
  90 }
  91
  92 /*
  93   parse a negTokenInit packet giving a GUID, a list of supported
  94   OIDs (the mechanisms) and a principal name string
  95 */
  96 bool spnego_parse_negTokenInit(TALLOC_CTX *ctx,
  97                                DATA_BLOB blob,
  98                                char *OIDs[ASN1_MAX_OIDS],
  99                                char **principal,
 100                                DATA_BLOB *secblob)
 101 {
 102         int i;
 103         bool ret;
 104         ASN1_DATA *data;
 105
 106         data = asn1_init(talloc_tos());
 107         if (data == NULL) {
 108                 return false;
 109         }
 110
 111         asn1_load(data, blob);
 112
 113         asn1_start_tag(data,ASN1_APPLICATION(0));
 114
 115         asn1_check_OID(data,OID_SPNEGO);
 116
 117         /* negTokenInit  [0]  NegTokenInit */
 118         asn1_start_tag(data,ASN1_CONTEXT(0));
 119         asn1_start_tag(data,ASN1_SEQUENCE(0));
 120
 121         /* mechTypes [0] MechTypeList  OPTIONAL */
 122
 123         /* Not really optional, we depend on this to decide
 124          * what mechanisms we have to work with. */
 125
 126         asn1_start_tag(data,ASN1_CONTEXT(0));
 127         asn1_start_tag(data,ASN1_SEQUENCE(0));
 128         for (i=0; asn1_tag_remaining(data) > 0 && i < ASN1_MAX_OIDS-1; i++) {
 129                 asn1_read_OID(data,ctx, &OIDs[i]);
 130         }
 131         OIDs[i] = NULL;
 132         asn1_end_tag(data);
 133         asn1_end_tag(data);
 134
 135         if (principal) {
 136                 *principal = NULL;
 137         }
 138         if (secblob) {
 139                 *secblob = data_blob_null;
 140         }
 141
 142         /*
 143           Win7 + Live Sign-in Assistant attaches a mechToken
 144           ASN1_CONTEXT(2) to the negTokenInit packet
 145           which breaks our negotiation if we just assume
 146           the next tag is ASN1_CONTEXT(3).
 147         */
 148
 149         if (asn1_peek_tag(data, ASN1_CONTEXT(1))) {
 150                 uint8 flags;
 151
 152                 /* reqFlags [1] ContextFlags  OPTIONAL */
 153                 asn1_start_tag(data, ASN1_CONTEXT(1));
 154                 asn1_start_tag(data, ASN1_BIT_STRING);
 155                 while (asn1_tag_remaining(data) > 0) {
 156                         asn1_read_uint8(data, &flags);
 157                 }
 158                 asn1_end_tag(data);
 159                 asn1_end_tag(data);
 160         }
 161
 162         if (asn1_peek_tag(data, ASN1_CONTEXT(2))) {
 163                 DATA_BLOB sblob = data_blob_null;
 164                 /* mechToken [2] OCTET STRING  OPTIONAL */
 165                 asn1_start_tag(data, ASN1_CONTEXT(2));
 166                 asn1_read_OctetString(data, ctx, &sblob);
 167                 asn1_end_tag(data);
 168                 if (secblob) {
 169                         *secblob = sblob;
 170                 } else {
 171                         data_blob_free(&sblob);
 172                 }
 173         }
 174
 175         if (asn1_peek_tag(data, ASN1_CONTEXT(3))) {
 176                 char *princ = NULL;
 177                 /* mechListMIC [3] OCTET STRING  OPTIONAL */
 178                 asn1_start_tag(data, ASN1_CONTEXT(3));
 179                 asn1_start_tag(data, ASN1_SEQUENCE(0));
 180                 asn1_start_tag(data, ASN1_CONTEXT(0));
 181                 asn1_read_GeneralString(data, ctx, &princ);
 182                 asn1_end_tag(data);
 183                 asn1_end_tag(data);
 184                 asn1_end_tag(data);
 185                 if (principal) {
 186                         *principal = princ;
 187                 } else {
 188                         TALLOC_FREE(princ);
 189                 }
 190         }
 191
 192         asn1_end_tag(data);
 193         asn1_end_tag(data);
 194
 195         asn1_end_tag(data);
 196
 197         ret = !data->has_error;
 198         if (data->has_error) {
 199                 int j;
 200                 if (principal) {
 201                         TALLOC_FREE(*principal);
 202                 }
 203                 if (secblob) {
 204                         data_blob_free(secblob);
 205                 }
 206                 for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
 207                         TALLOC_FREE(OIDs[j]);
 208                 }
 209         }
 210
 211         asn1_free(data);
 212         return ret;
 213 }
 214
 215 /*
 216   generate a krb5 GSS-API wrapper packet given a ticket
 217 */
 218 DATA_BLOB spnego_gen_krb5_wrap(TALLOC_CTX *ctx, const DATA_BLOB ticket, const uint8 tok_id[2])
 219 {
 220         ASN1_DATA *data;
 221         DATA_BLOB ret;
 222
 223         data = asn1_init(talloc_tos());
 224         if (data == NULL) {
 225                 return data_blob_null;
 226         }
 227
 228         asn1_push_tag(data, ASN1_APPLICATION(0));
 229         asn1_write_OID(data, OID_KERBEROS5);
 230
 231         asn1_write(data, tok_id, 2);
 232         asn1_write(data, ticket.data, ticket.length);
 233         asn1_pop_tag(data);
 234
 235         if (data->has_error) {
 236                 DEBUG(1,("Failed to build krb5 wrapper at offset %d\n", (int)data->ofs));
 237         }
 238
 239         ret = data_blob_talloc(ctx, data->data, data->length);
 240         asn1_free(data);
 241
 242         return ret;
 243 }
 244
 245 /*
 246   parse a krb5 GSS-API wrapper packet giving a ticket
 247 */
 248 bool spnego_parse_krb5_wrap(TALLOC_CTX *ctx, DATA_BLOB blob, DATA_BLOB *ticket, uint8 tok_id[2])
 249 {
 250         bool ret;
 251         ASN1_DATA *data;
 252         int data_remaining;
 253
 254         data = asn1_init(talloc_tos());
 255         if (data == NULL) {
 256                 return false;
 257         }
 258
 259         asn1_load(data, blob);
 260         asn1_start_tag(data, ASN1_APPLICATION(0));
 261         asn1_check_OID(data, OID_KERBEROS5);
 262
 263         data_remaining = asn1_tag_remaining(data);
 264
 265         if (data_remaining < 3) {
 266                 data->has_error = True;
 267         } else {
 268                 asn1_read(data, tok_id, 2);
 269                 data_remaining -= 2;
 270                 *ticket = data_blob_talloc(ctx, NULL, data_remaining);
 271                 asn1_read(data, ticket->data, ticket->length);
 272         }
 273
 274         asn1_end_tag(data);
 275
 276         ret = !data->has_error;
 277
 278         if (data->has_error) {
 279                 data_blob_free(ticket);
 280         }
 281
 282         asn1_free(data);
 283
 284         return ret;
 285 }
 286
 287
 288 /*
 289    generate a SPNEGO krb5 negTokenInit packet, ready for a EXTENDED_SECURITY
 290    kerberos session setup
 291 */
 292 int spnego_gen_krb5_negTokenInit(TALLOC_CTX *ctx,
 293                             const char *principal, int time_offset,
 294                             DATA_BLOB *targ,
 295                             DATA_BLOB *session_key_krb5, uint32 extra_ap_opts,
 296                             time_t *expire_time)
 297 {
 298         int retval;
 299         DATA_BLOB tkt, tkt_wrapped;
 300         const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_KERBEROS5, OID_NTLMSSP, NULL};
 301
 302         /* get a kerberos ticket for the service and extract the session key */
 303         retval = cli_krb5_get_ticket(ctx, principal, time_offset,
 304                                           &tkt, session_key_krb5,
 305                                           extra_ap_opts, NULL,
 306                                           expire_time, NULL);
 307         if (retval) {
 308                 return retval;
 309         }
 310
 311         /* wrap that up in a nice GSS-API wrapping */
 312         tkt_wrapped = spnego_gen_krb5_wrap(ctx, tkt, TOK_ID_KRB_AP_REQ);
 313
 314         /* and wrap that in a shiny SPNEGO wrapper */
 315         *targ = spnego_gen_negTokenInit(ctx, krb_mechs, &tkt_wrapped, NULL);
 316
 317         data_blob_free(&tkt_wrapped);
 318         data_blob_free(&tkt);
 319
 320         return retval;
 321 }
 322
 323
 324 /*
 325   parse a spnego NTLMSSP challenge packet giving two security blobs
 326 */
 327 bool spnego_parse_challenge(TALLOC_CTX *ctx, const DATA_BLOB blob,
 328                             DATA_BLOB *chal1, DATA_BLOB *chal2)
 329 {
 330         bool ret;
 331         ASN1_DATA *data;
 332
 333         ZERO_STRUCTP(chal1);
 334         ZERO_STRUCTP(chal2);
 335
 336         data = asn1_init(talloc_tos());
 337         if (data == NULL) {
 338                 return false;
 339         }
 340
 341         asn1_load(data, blob);
 342         asn1_start_tag(data,ASN1_CONTEXT(1));
 343         asn1_start_tag(data,ASN1_SEQUENCE(0));
 344
 345         asn1_start_tag(data,ASN1_CONTEXT(0));
 346         asn1_check_enumerated(data,1);
 347         asn1_end_tag(data);
 348
 349         asn1_start_tag(data,ASN1_CONTEXT(1));
 350         asn1_check_OID(data, OID_NTLMSSP);
 351         asn1_end_tag(data);
 352
 353         asn1_start_tag(data,ASN1_CONTEXT(2));
 354         asn1_read_OctetString(data, ctx, chal1);
 355         asn1_end_tag(data);
 356
 357         /* the second challenge is optional (XP doesn't send it) */
 358         if (asn1_tag_remaining(data)) {
 359                 asn1_start_tag(data,ASN1_CONTEXT(3));
 360                 asn1_read_OctetString(data, ctx, chal2);
 361                 asn1_end_tag(data);
 362         }
 363
 364         asn1_end_tag(data);
 365         asn1_end_tag(data);
 366
 367         ret = !data->has_error;
 368
 369         if (data->has_error) {
 370                 data_blob_free(chal1);
 371                 data_blob_free(chal2);
 372         }
 373
 374         asn1_free(data);
 375         return ret;
 376 }
 377
 378
 379 /*
 380  generate a SPNEGO auth packet. This will contain the encrypted passwords
 381 */
 382 DATA_BLOB spnego_gen_auth(TALLOC_CTX *ctx, DATA_BLOB blob)
 383 {
 384         ASN1_DATA *data;
 385         DATA_BLOB ret;
 386
 387         data = asn1_init(talloc_tos());
 388         if (data == NULL) {
 389                 return data_blob_null;
 390         }
 391
 392         asn1_push_tag(data, ASN1_CONTEXT(1));
 393         asn1_push_tag(data, ASN1_SEQUENCE(0));
 394         asn1_push_tag(data, ASN1_CONTEXT(2));
 395         asn1_write_OctetString(data,blob.data,blob.length);
 396         asn1_pop_tag(data);
 397         asn1_pop_tag(data);
 398         asn1_pop_tag(data);
 399
 400         ret = data_blob_talloc(ctx, data->data, data->length);
 401
 402         asn1_free(data);
 403
 404         return ret;
 405 }
 406
 407 /*
 408  parse a SPNEGO auth packet. This contains the encrypted passwords
 409 */
 410 bool spnego_parse_auth_and_mic(TALLOC_CTX *ctx, DATA_BLOB blob,
 411                                 DATA_BLOB *auth, DATA_BLOB *signature)
 412 {
 413         ssize_t len;
 414         struct spnego_data token;
 415
 416         len = spnego_read_data(talloc_tos(), blob, &token);
 417         if (len == -1) {
 418                 DEBUG(3,("spnego_parse_auth: spnego_read_data failed\n"));
 419                 return false;
 420         }
 421
 422         if (token.type != SPNEGO_NEG_TOKEN_TARG) {
 423                 DEBUG(3,("spnego_parse_auth: wrong token type: %d\n",
 424                         token.type));
 425                 spnego_free_data(&token);
 426                 return false;
 427         }
 428
 429         *auth = data_blob_talloc(ctx,
 430                                  token.negTokenTarg.responseToken.data,
 431                                  token.negTokenTarg.responseToken.length);
 432
 433         if (!signature) {
 434                 goto done;
 435         }
 436
 437         *signature = data_blob_talloc(ctx,
 438                                  token.negTokenTarg.mechListMIC.data,
 439                                  token.negTokenTarg.mechListMIC.length);
 440
 441 done:
 442         spnego_free_data(&token);
 443
 444         return true;
 445 }
 446
 447 bool spnego_parse_auth(TALLOC_CTX *ctx, DATA_BLOB blob, DATA_BLOB *auth)
 448 {
 449         return spnego_parse_auth_and_mic(ctx, blob, auth, NULL);
 450 }
 451
 452 /*
 453   generate a minimal SPNEGO response packet.  Doesn't contain much.
 454 */
 455 DATA_BLOB spnego_gen_auth_response_and_mic(TALLOC_CTX *ctx,
 456                                            NTSTATUS nt_status,
 457                                            const char *mechOID,
 458                                            DATA_BLOB *reply,
 459                                            DATA_BLOB *mechlistMIC)
 460 {
 461         ASN1_DATA *data;
 462         DATA_BLOB ret;
 463         uint8 negResult;
 464
 465         if (NT_STATUS_IS_OK(nt_status)) {
 466                 negResult = SPNEGO_ACCEPT_COMPLETED;
 467         } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 468                 negResult = SPNEGO_ACCEPT_INCOMPLETE;
 469         } else {
 470                 negResult = SPNEGO_REJECT;
 471         }
 472
 473         data = asn1_init(talloc_tos());
 474         if (data == NULL) {
 475                 return data_blob_null;
 476         }
 477
 478         asn1_push_tag(data, ASN1_CONTEXT(1));
 479         asn1_push_tag(data, ASN1_SEQUENCE(0));
 480         asn1_push_tag(data, ASN1_CONTEXT(0));
 481         asn1_write_enumerated(data, negResult);
 482         asn1_pop_tag(data);
 483
 484         if (mechOID) {
 485                 asn1_push_tag(data,ASN1_CONTEXT(1));
 486                 asn1_write_OID(data, mechOID);
 487                 asn1_pop_tag(data);
 488         }
 489
 490         if (reply && reply->data != NULL) {
 491                 asn1_push_tag(data,ASN1_CONTEXT(2));
 492                 asn1_write_OctetString(data, reply->data, reply->length);
 493                 asn1_pop_tag(data);
 494         }
 495
 496         if (mechlistMIC && mechlistMIC->data != NULL) {
 497                 asn1_push_tag(data, ASN1_CONTEXT(3));
 498                 asn1_write_OctetString(data,
 499                                         mechlistMIC->data,
 500                                         mechlistMIC->length);
 501                 asn1_pop_tag(data);
 502         }
 503
 504         asn1_pop_tag(data);
 505         asn1_pop_tag(data);
 506
 507         ret = data_blob_talloc(ctx, data->data, data->length);
 508         asn1_free(data);
 509         return ret;
 510 }
 511
 512 DATA_BLOB spnego_gen_auth_response(TALLOC_CTX *ctx, DATA_BLOB *reply,
 513                                    NTSTATUS nt_status, const char *mechOID)
 514 {
 515         return spnego_gen_auth_response_and_mic(ctx, nt_status,
 516                                                 mechOID, reply, NULL);
 517 }
 518
 519 /*
 520  parse a SPNEGO auth packet. This contains the encrypted passwords
 521 */
 522 bool spnego_parse_auth_response(TALLOC_CTX *ctx,
 523                                 DATA_BLOB blob, NTSTATUS nt_status,
 524                                 const char *mechOID,
 525                                 DATA_BLOB *auth)
 526 {
 527         ASN1_DATA *data;
 528         uint8 negResult;
 529
 530         if (NT_STATUS_IS_OK(nt_status)) {
 531                 negResult = SPNEGO_ACCEPT_COMPLETED;
 532         } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 533                 negResult = SPNEGO_ACCEPT_INCOMPLETE;
 534         } else {
 535                 negResult = SPNEGO_REJECT;
 536         }
 537
 538         data = asn1_init(talloc_tos());
 539         if (data == NULL) {
 540                 return false;
 541         }
 542
 543         asn1_load(data, blob);
 544         asn1_start_tag(data, ASN1_CONTEXT(1));
 545         asn1_start_tag(data, ASN1_SEQUENCE(0));
 546         asn1_start_tag(data, ASN1_CONTEXT(0));
 547         asn1_check_enumerated(data, negResult);
 548         asn1_end_tag(data);
 549
 550         *auth = data_blob_null;
 551
 552         if (asn1_tag_remaining(data)) {
 553                 asn1_start_tag(data,ASN1_CONTEXT(1));
 554                 asn1_check_OID(data, mechOID);
 555                 asn1_end_tag(data);
 556
 557                 if (asn1_tag_remaining(data)) {
 558                         asn1_start_tag(data,ASN1_CONTEXT(2));
 559                         asn1_read_OctetString(data, ctx, auth);
 560                         asn1_end_tag(data);
 561                 }
 562         } else if (negResult == SPNEGO_ACCEPT_INCOMPLETE) {
 563                 data->has_error = 1;
 564         }
 565
 566         /* Binding against Win2K DC returns a duplicate of the responseToken in
 567          * the optional mechListMIC field. This is a bug in Win2K. We ignore
 568          * this field if it exists. Win2K8 may return a proper mechListMIC at
 569          * which point we need to implement the integrity checking. */
 570         if (asn1_tag_remaining(data)) {
 571                 DATA_BLOB mechList = data_blob_null;
 572                 asn1_start_tag(data, ASN1_CONTEXT(3));
 573                 asn1_read_OctetString(data, ctx, &mechList);
 574                 asn1_end_tag(data);
 575                 data_blob_free(&mechList);
 576                 DEBUG(5,("spnego_parse_auth_response received mechListMIC, "
 577                     "ignoring.\n"));
 578         }
 579
 580         asn1_end_tag(data);
 581         asn1_end_tag(data);
 582
 583         if (data->has_error) {
 584                 DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data->ofs));
 585                 asn1_free(data);
 586                 data_blob_free(auth);
 587                 return False;
 588         }
 589
 590         asn1_free(data);
 591         return True;
 592 }
 593
 594 bool spnego_mech_list_blob(TALLOC_CTX *mem_ctx,
 595                            char **oid_list, DATA_BLOB *raw_data)
 596 {
 597         ASN1_DATA *data;
 598         unsigned int idx;
 599
 600         if (!oid_list || !oid_list[0] || !raw_data) {
 601                 return false;
 602         }
 603
 604         data = asn1_init(talloc_tos());
 605         if (data == NULL) {
 606                 return false;
 607         }
 608
 609         asn1_push_tag(data, ASN1_SEQUENCE(0));
 610         for (idx = 0; oid_list[idx]; idx++) {
 611                 asn1_write_OID(data, oid_list[idx]);
 612         }
 613         asn1_pop_tag(data);
 614
 615         if (data->has_error) {
 616                 DEBUG(3, (__location__ " failed at %d\n", (int)data->ofs));
 617                 asn1_free(data);
 618                 return false;
 619         }
 620
 621         *raw_data = data_blob_talloc(mem_ctx, data->data, data->length);
 622         if (!raw_data->data) {
 623                 DEBUG(3, (__location__": data_blob_talloc() failed!\n"));
 624                 asn1_free(data);
 625                 return false;
 626         }
 627
 628         asn1_free(data);
 629         return true;
 630 }