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                 if (data->has_error) {
 131                         break;
 132                 }
 133         }
 134         OIDs[i] = NULL;
 135         asn1_end_tag(data);
 136         asn1_end_tag(data);
 137
 138         if (principal) {
 139                 *principal = NULL;
 140         }
 141         if (secblob) {
 142                 *secblob = data_blob_null;
 143         }
 144
 145         /*
 146           Win7 + Live Sign-in Assistant attaches a mechToken
 147           ASN1_CONTEXT(2) to the negTokenInit packet
 148           which breaks our negotiation if we just assume
 149           the next tag is ASN1_CONTEXT(3).
 150         */
 151
 152         if (asn1_peek_tag(data, ASN1_CONTEXT(1))) {
 153                 uint8 flags;
 154
 155                 /* reqFlags [1] ContextFlags  OPTIONAL */
 156                 asn1_start_tag(data, ASN1_CONTEXT(1));
 157                 asn1_start_tag(data, ASN1_BIT_STRING);
 158                 while (asn1_tag_remaining(data) > 0) {
 159                         asn1_read_uint8(data, &flags);
 160                 }
 161                 asn1_end_tag(data);
 162                 asn1_end_tag(data);
 163         }
 164
 165         if (asn1_peek_tag(data, ASN1_CONTEXT(2))) {
 166                 DATA_BLOB sblob = data_blob_null;
 167                 /* mechToken [2] OCTET STRING  OPTIONAL */
 168                 asn1_start_tag(data, ASN1_CONTEXT(2));
 169                 asn1_read_OctetString(data, ctx, &sblob);
 170                 asn1_end_tag(data);
 171                 if (secblob) {
 172                         *secblob = sblob;
 173                 } else {
 174                         data_blob_free(&sblob);
 175                 }
 176         }
 177
 178         if (asn1_peek_tag(data, ASN1_CONTEXT(3))) {
 179                 char *princ = NULL;
 180                 /* mechListMIC [3] OCTET STRING  OPTIONAL */
 181                 asn1_start_tag(data, ASN1_CONTEXT(3));
 182                 asn1_start_tag(data, ASN1_SEQUENCE(0));
 183                 asn1_start_tag(data, ASN1_CONTEXT(0));
 184                 asn1_read_GeneralString(data, ctx, &princ);
 185                 asn1_end_tag(data);
 186                 asn1_end_tag(data);
 187                 asn1_end_tag(data);
 188                 if (principal) {
 189                         *principal = princ;
 190                 } else {
 191                         TALLOC_FREE(princ);
 192                 }
 193         }
 194
 195         asn1_end_tag(data);
 196         asn1_end_tag(data);
 197
 198         asn1_end_tag(data);
 199
 200         ret = !data->has_error;
 201         if (data->has_error) {
 202                 int j;
 203                 if (principal) {
 204                         TALLOC_FREE(*principal);
 205                 }
 206                 if (secblob) {
 207                         data_blob_free(secblob);
 208                 }
 209                 for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
 210                         TALLOC_FREE(OIDs[j]);
 211                 }
 212         }
 213
 214         asn1_free(data);
 215         return ret;
 216 }
 217
 218 /*
 219   generate a krb5 GSS-API wrapper packet given a ticket
 220 */
 221 DATA_BLOB spnego_gen_krb5_wrap(TALLOC_CTX *ctx, const DATA_BLOB ticket, const uint8 tok_id[2])
 222 {
 223         ASN1_DATA *data;
 224         DATA_BLOB ret;
 225
 226         data = asn1_init(talloc_tos());
 227         if (data == NULL) {
 228                 return data_blob_null;
 229         }
 230
 231         asn1_push_tag(data, ASN1_APPLICATION(0));
 232         asn1_write_OID(data, OID_KERBEROS5);
 233
 234         asn1_write(data, tok_id, 2);
 235         asn1_write(data, ticket.data, ticket.length);
 236         asn1_pop_tag(data);
 237
 238         if (data->has_error) {
 239                 DEBUG(1,("Failed to build krb5 wrapper at offset %d\n", (int)data->ofs));
 240         }
 241
 242         ret = data_blob_talloc(ctx, data->data, data->length);
 243         asn1_free(data);
 244
 245         return ret;
 246 }
 247
 248 /*
 249   parse a krb5 GSS-API wrapper packet giving a ticket
 250 */
 251 bool spnego_parse_krb5_wrap(TALLOC_CTX *ctx, DATA_BLOB blob, DATA_BLOB *ticket, uint8 tok_id[2])
 252 {
 253         bool ret;
 254         ASN1_DATA *data;
 255         int data_remaining;
 256
 257         data = asn1_init(talloc_tos());
 258         if (data == NULL) {
 259                 return false;
 260         }
 261
 262         asn1_load(data, blob);
 263         asn1_start_tag(data, ASN1_APPLICATION(0));
 264         asn1_check_OID(data, OID_KERBEROS5);
 265
 266         data_remaining = asn1_tag_remaining(data);
 267
 268         if (data_remaining < 3) {
 269                 data->has_error = True;
 270         } else {
 271                 asn1_read(data, tok_id, 2);
 272                 data_remaining -= 2;
 273                 *ticket = data_blob_talloc(ctx, NULL, data_remaining);
 274                 asn1_read(data, ticket->data, ticket->length);
 275         }
 276
 277         asn1_end_tag(data);
 278
 279         ret = !data->has_error;
 280
 281         if (data->has_error) {
 282                 data_blob_free(ticket);
 283         }
 284
 285         asn1_free(data);
 286
 287         return ret;
 288 }
 289
 290
 291 /*
 292    generate a SPNEGO krb5 negTokenInit packet, ready for a EXTENDED_SECURITY
 293    kerberos session setup
 294 */
 295 int spnego_gen_krb5_negTokenInit(TALLOC_CTX *ctx,
 296                             const char *principal, int time_offset,
 297                             DATA_BLOB *targ,
 298                             DATA_BLOB *session_key_krb5, uint32 extra_ap_opts,
 299                             time_t *expire_time)
 300 {
 301         int retval;
 302         DATA_BLOB tkt, tkt_wrapped;
 303         const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_KERBEROS5, OID_NTLMSSP, NULL};
 304
 305         /* get a kerberos ticket for the service and extract the session key */
 306         retval = cli_krb5_get_ticket(ctx, principal, time_offset,
 307                                           &tkt, session_key_krb5,
 308                                           extra_ap_opts, NULL,
 309                                           expire_time, NULL);
 310         if (retval) {
 311                 return retval;
 312         }
 313
 314         /* wrap that up in a nice GSS-API wrapping */
 315         tkt_wrapped = spnego_gen_krb5_wrap(ctx, tkt, TOK_ID_KRB_AP_REQ);
 316
 317         /* and wrap that in a shiny SPNEGO wrapper */
 318         *targ = spnego_gen_negTokenInit(ctx, krb_mechs, &tkt_wrapped, NULL);
 319
 320         data_blob_free(&tkt_wrapped);
 321         data_blob_free(&tkt);
 322
 323         return retval;
 324 }
 325
 326
 327 /*
 328   parse a spnego NTLMSSP challenge packet giving two security blobs
 329 */
 330 bool spnego_parse_challenge(TALLOC_CTX *ctx, const DATA_BLOB blob,
 331                             DATA_BLOB *chal1, DATA_BLOB *chal2)
 332 {
 333         bool ret;
 334         ASN1_DATA *data;
 335
 336         ZERO_STRUCTP(chal1);
 337         ZERO_STRUCTP(chal2);
 338
 339         data = asn1_init(talloc_tos());
 340         if (data == NULL) {
 341                 return false;
 342         }
 343
 344         asn1_load(data, blob);
 345         asn1_start_tag(data,ASN1_CONTEXT(1));
 346         asn1_start_tag(data,ASN1_SEQUENCE(0));
 347
 348         asn1_start_tag(data,ASN1_CONTEXT(0));
 349         asn1_check_enumerated(data,1);
 350         asn1_end_tag(data);
 351
 352         asn1_start_tag(data,ASN1_CONTEXT(1));
 353         asn1_check_OID(data, OID_NTLMSSP);
 354         asn1_end_tag(data);
 355
 356         asn1_start_tag(data,ASN1_CONTEXT(2));
 357         asn1_read_OctetString(data, ctx, chal1);
 358         asn1_end_tag(data);
 359
 360         /* the second challenge is optional (XP doesn't send it) */
 361         if (asn1_tag_remaining(data)) {
 362                 asn1_start_tag(data,ASN1_CONTEXT(3));
 363                 asn1_read_OctetString(data, ctx, chal2);
 364                 asn1_end_tag(data);
 365         }
 366
 367         asn1_end_tag(data);
 368         asn1_end_tag(data);
 369
 370         ret = !data->has_error;
 371
 372         if (data->has_error) {
 373                 data_blob_free(chal1);
 374                 data_blob_free(chal2);
 375         }
 376
 377         asn1_free(data);
 378         return ret;
 379 }
 380
 381
 382 /*
 383  generate a SPNEGO auth packet. This will contain the encrypted passwords
 384 */
 385 DATA_BLOB spnego_gen_auth(TALLOC_CTX *ctx, DATA_BLOB blob)
 386 {
 387         ASN1_DATA *data;
 388         DATA_BLOB ret;
 389
 390         data = asn1_init(talloc_tos());
 391         if (data == NULL) {
 392                 return data_blob_null;
 393         }
 394
 395         asn1_push_tag(data, ASN1_CONTEXT(1));
 396         asn1_push_tag(data, ASN1_SEQUENCE(0));
 397         asn1_push_tag(data, ASN1_CONTEXT(2));
 398         asn1_write_OctetString(data,blob.data,blob.length);
 399         asn1_pop_tag(data);
 400         asn1_pop_tag(data);
 401         asn1_pop_tag(data);
 402
 403         ret = data_blob_talloc(ctx, data->data, data->length);
 404
 405         asn1_free(data);
 406
 407         return ret;
 408 }
 409
 410 /*
 411  parse a SPNEGO auth packet. This contains the encrypted passwords
 412 */
 413 bool spnego_parse_auth_and_mic(TALLOC_CTX *ctx, DATA_BLOB blob,
 414                                 DATA_BLOB *auth, DATA_BLOB *signature)
 415 {
 416         ssize_t len;
 417         struct spnego_data token;
 418
 419         len = spnego_read_data(talloc_tos(), blob, &token);
 420         if (len == -1) {
 421                 DEBUG(3,("spnego_parse_auth: spnego_read_data failed\n"));
 422                 return false;
 423         }
 424
 425         if (token.type != SPNEGO_NEG_TOKEN_TARG) {
 426                 DEBUG(3,("spnego_parse_auth: wrong token type: %d\n",
 427                         token.type));
 428                 spnego_free_data(&token);
 429                 return false;
 430         }
 431
 432         *auth = data_blob_talloc(ctx,
 433                                  token.negTokenTarg.responseToken.data,
 434                                  token.negTokenTarg.responseToken.length);
 435
 436         if (!signature) {
 437                 goto done;
 438         }
 439
 440         *signature = data_blob_talloc(ctx,
 441                                  token.negTokenTarg.mechListMIC.data,
 442                                  token.negTokenTarg.mechListMIC.length);
 443
 444 done:
 445         spnego_free_data(&token);
 446
 447         return true;
 448 }
 449
 450 bool spnego_parse_auth(TALLOC_CTX *ctx, DATA_BLOB blob, DATA_BLOB *auth)
 451 {
 452         return spnego_parse_auth_and_mic(ctx, blob, auth, NULL);
 453 }
 454
 455 /*
 456   generate a minimal SPNEGO response packet.  Doesn't contain much.
 457 */
 458 DATA_BLOB spnego_gen_auth_response_and_mic(TALLOC_CTX *ctx,
 459                                            NTSTATUS nt_status,
 460                                            const char *mechOID,
 461                                            DATA_BLOB *reply,
 462                                            DATA_BLOB *mechlistMIC)
 463 {
 464         ASN1_DATA *data;
 465         DATA_BLOB ret;
 466         uint8 negResult;
 467
 468         if (NT_STATUS_IS_OK(nt_status)) {
 469                 negResult = SPNEGO_ACCEPT_COMPLETED;
 470         } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 471                 negResult = SPNEGO_ACCEPT_INCOMPLETE;
 472         } else {
 473                 negResult = SPNEGO_REJECT;
 474         }
 475
 476         data = asn1_init(talloc_tos());
 477         if (data == NULL) {
 478                 return data_blob_null;
 479         }
 480
 481         asn1_push_tag(data, ASN1_CONTEXT(1));
 482         asn1_push_tag(data, ASN1_SEQUENCE(0));
 483         asn1_push_tag(data, ASN1_CONTEXT(0));
 484         asn1_write_enumerated(data, negResult);
 485         asn1_pop_tag(data);
 486
 487         if (mechOID) {
 488                 asn1_push_tag(data,ASN1_CONTEXT(1));
 489                 asn1_write_OID(data, mechOID);
 490                 asn1_pop_tag(data);
 491         }
 492
 493         if (reply && reply->data != NULL) {
 494                 asn1_push_tag(data,ASN1_CONTEXT(2));
 495                 asn1_write_OctetString(data, reply->data, reply->length);
 496                 asn1_pop_tag(data);
 497         }
 498
 499         if (mechlistMIC && mechlistMIC->data != NULL) {
 500                 asn1_push_tag(data, ASN1_CONTEXT(3));
 501                 asn1_write_OctetString(data,
 502                                         mechlistMIC->data,
 503                                         mechlistMIC->length);
 504                 asn1_pop_tag(data);
 505         }
 506
 507         asn1_pop_tag(data);
 508         asn1_pop_tag(data);
 509
 510         ret = data_blob_talloc(ctx, data->data, data->length);
 511         asn1_free(data);
 512         return ret;
 513 }
 514
 515 DATA_BLOB spnego_gen_auth_response(TALLOC_CTX *ctx, DATA_BLOB *reply,
 516                                    NTSTATUS nt_status, const char *mechOID)
 517 {
 518         return spnego_gen_auth_response_and_mic(ctx, nt_status,
 519                                                 mechOID, reply, NULL);
 520 }
 521
 522 /*
 523  parse a SPNEGO auth packet. This contains the encrypted passwords
 524 */
 525 bool spnego_parse_auth_response(TALLOC_CTX *ctx,
 526                                 DATA_BLOB blob, NTSTATUS nt_status,
 527                                 const char *mechOID,
 528                                 DATA_BLOB *auth)
 529 {
 530         ASN1_DATA *data;
 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 false;
 544         }
 545
 546         asn1_load(data, blob);
 547         asn1_start_tag(data, ASN1_CONTEXT(1));
 548         asn1_start_tag(data, ASN1_SEQUENCE(0));
 549         asn1_start_tag(data, ASN1_CONTEXT(0));
 550         asn1_check_enumerated(data, negResult);
 551         asn1_end_tag(data);
 552
 553         *auth = data_blob_null;
 554
 555         if (asn1_tag_remaining(data)) {
 556                 asn1_start_tag(data,ASN1_CONTEXT(1));
 557                 asn1_check_OID(data, mechOID);
 558                 asn1_end_tag(data);
 559
 560                 if (asn1_tag_remaining(data)) {
 561                         asn1_start_tag(data,ASN1_CONTEXT(2));
 562                         asn1_read_OctetString(data, ctx, auth);
 563                         asn1_end_tag(data);
 564                 }
 565         } else if (negResult == SPNEGO_ACCEPT_INCOMPLETE) {
 566                 data->has_error = 1;
 567         }
 568
 569         /* Binding against Win2K DC returns a duplicate of the responseToken in
 570          * the optional mechListMIC field. This is a bug in Win2K. We ignore
 571          * this field if it exists. Win2K8 may return a proper mechListMIC at
 572          * which point we need to implement the integrity checking. */
 573         if (asn1_tag_remaining(data)) {
 574                 DATA_BLOB mechList = data_blob_null;
 575                 asn1_start_tag(data, ASN1_CONTEXT(3));
 576                 asn1_read_OctetString(data, ctx, &mechList);
 577                 asn1_end_tag(data);
 578                 data_blob_free(&mechList);
 579                 DEBUG(5,("spnego_parse_auth_response received mechListMIC, "
 580                     "ignoring.\n"));
 581         }
 582
 583         asn1_end_tag(data);
 584         asn1_end_tag(data);
 585
 586         if (data->has_error) {
 587                 DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data->ofs));
 588                 asn1_free(data);
 589                 data_blob_free(auth);
 590                 return False;
 591         }
 592
 593         asn1_free(data);
 594         return True;
 595 }
 596
 597 bool spnego_mech_list_blob(TALLOC_CTX *mem_ctx,
 598                            char **oid_list, DATA_BLOB *raw_data)
 599 {
 600         ASN1_DATA *data;
 601         unsigned int idx;
 602
 603         if (!oid_list || !oid_list[0] || !raw_data) {
 604                 return false;
 605         }
 606
 607         data = asn1_init(talloc_tos());
 608         if (data == NULL) {
 609                 return false;
 610         }
 611
 612         asn1_push_tag(data, ASN1_SEQUENCE(0));
 613         for (idx = 0; oid_list[idx]; idx++) {
 614                 asn1_write_OID(data, oid_list[idx]);
 615         }
 616         asn1_pop_tag(data);
 617
 618         if (data->has_error) {
 619                 DEBUG(3, (__location__ " failed at %d\n", (int)data->ofs));
 620                 asn1_free(data);
 621                 return false;
 622         }
 623
 624         *raw_data = data_blob_talloc(mem_ctx, data->data, data->length);
 625         if (!raw_data->data) {
 626                 DEBUG(3, (__location__": data_blob_talloc() failed!\n"));
 627                 asn1_free(data);
 628                 return false;
 629         }
 630
 631         asn1_free(data);
 632         return true;
 633 }