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