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                 if (!asn1_read_OID(data,ctx, &OIDs[i])) {
 130                         break;
 131                 }
 132                 if (data->has_error) {
 133                         break;
 134                 }
 135         }
 136         OIDs[i] = NULL;
 137         asn1_end_tag(data);
 138         asn1_end_tag(data);
 139
 140         if (principal) {
 141                 *principal = NULL;
 142         }
 143         if (secblob) {
 144                 *secblob = data_blob_null;
 145         }
 146
 147         /*
 148           Win7 + Live Sign-in Assistant attaches a mechToken
 149           ASN1_CONTEXT(2) to the negTokenInit packet
 150           which breaks our negotiation if we just assume
 151           the next tag is ASN1_CONTEXT(3).
 152         */
 153
 154         if (asn1_peek_tag(data, ASN1_CONTEXT(1))) {
 155                 uint8 flags;
 156
 157                 /* reqFlags [1] ContextFlags  OPTIONAL */
 158                 asn1_start_tag(data, ASN1_CONTEXT(1));
 159                 asn1_start_tag(data, ASN1_BIT_STRING);
 160                 while (asn1_tag_remaining(data) > 0) {
 161                         asn1_read_uint8(data, &flags);
 162                 }
 163                 asn1_end_tag(data);
 164                 asn1_end_tag(data);
 165         }
 166
 167         if (asn1_peek_tag(data, ASN1_CONTEXT(2))) {
 168                 DATA_BLOB sblob = data_blob_null;
 169                 /* mechToken [2] OCTET STRING  OPTIONAL */
 170                 asn1_start_tag(data, ASN1_CONTEXT(2));
 171                 asn1_read_OctetString(data, ctx, &sblob);
 172                 asn1_end_tag(data);
 173                 if (secblob) {
 174                         *secblob = sblob;
 175                 } else {
 176                         data_blob_free(&sblob);
 177                 }
 178         }
 179
 180         if (asn1_peek_tag(data, ASN1_CONTEXT(3))) {
 181                 char *princ = NULL;
 182                 /* mechListMIC [3] OCTET STRING  OPTIONAL */
 183                 asn1_start_tag(data, ASN1_CONTEXT(3));
 184                 asn1_start_tag(data, ASN1_SEQUENCE(0));
 185                 asn1_start_tag(data, ASN1_CONTEXT(0));
 186                 asn1_read_GeneralString(data, ctx, &princ);
 187                 asn1_end_tag(data);
 188                 asn1_end_tag(data);
 189                 asn1_end_tag(data);
 190                 if (principal) {
 191                         *principal = princ;
 192                 } else {
 193                         TALLOC_FREE(princ);
 194                 }
 195         }
 196
 197         asn1_end_tag(data);
 198         asn1_end_tag(data);
 199
 200         asn1_end_tag(data);
 201
 202         ret = !data->has_error;
 203         if (data->has_error) {
 204                 int j;
 205                 if (principal) {
 206                         TALLOC_FREE(*principal);
 207                 }
 208                 if (secblob) {
 209                         data_blob_free(secblob);
 210                 }
 211                 for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
 212                         TALLOC_FREE(OIDs[j]);
 213                 }
 214         }
 215
 216         asn1_free(data);
 217         return ret;
 218 }
 219
 220 /*
 221   generate a krb5 GSS-API wrapper packet given a ticket
 222 */
 223 DATA_BLOB spnego_gen_krb5_wrap(TALLOC_CTX *ctx, const DATA_BLOB ticket, const uint8 tok_id[2])
 224 {
 225         ASN1_DATA *data;
 226         DATA_BLOB ret;
 227
 228         data = asn1_init(talloc_tos());
 229         if (data == NULL) {
 230                 return data_blob_null;
 231         }
 232
 233         asn1_push_tag(data, ASN1_APPLICATION(0));
 234         asn1_write_OID(data, OID_KERBEROS5);
 235
 236         asn1_write(data, tok_id, 2);
 237         asn1_write(data, ticket.data, ticket.length);
 238         asn1_pop_tag(data);
 239
 240         if (data->has_error) {
 241                 DEBUG(1,("Failed to build krb5 wrapper at offset %d\n", (int)data->ofs));
 242         }
 243
 244         ret = data_blob_talloc(ctx, data->data, data->length);
 245         asn1_free(data);
 246
 247         return ret;
 248 }
 249
 250 /*
 251   parse a krb5 GSS-API wrapper packet giving a ticket
 252 */
 253 bool spnego_parse_krb5_wrap(TALLOC_CTX *ctx, DATA_BLOB blob, DATA_BLOB *ticket, uint8 tok_id[2])
 254 {
 255         bool ret;
 256         ASN1_DATA *data;
 257         int data_remaining;
 258
 259         data = asn1_init(talloc_tos());
 260         if (data == NULL) {
 261                 return false;
 262         }
 263
 264         asn1_load(data, blob);
 265         asn1_start_tag(data, ASN1_APPLICATION(0));
 266         asn1_check_OID(data, OID_KERBEROS5);
 267
 268         data_remaining = asn1_tag_remaining(data);
 269
 270         if (data_remaining < 3) {
 271                 data->has_error = True;
 272         } else {
 273                 asn1_read(data, tok_id, 2);
 274                 data_remaining -= 2;
 275                 *ticket = data_blob_talloc(ctx, NULL, data_remaining);
 276                 asn1_read(data, ticket->data, ticket->length);
 277         }
 278
 279         asn1_end_tag(data);
 280
 281         ret = !data->has_error;
 282
 283         if (data->has_error) {
 284                 data_blob_free(ticket);
 285         }
 286
 287         asn1_free(data);
 288
 289         return ret;
 290 }
 291
 292
 293 /*
 294    generate a SPNEGO krb5 negTokenInit packet, ready for a EXTENDED_SECURITY
 295    kerberos session setup
 296 */
 297 int spnego_gen_krb5_negTokenInit(TALLOC_CTX *ctx,
 298                             const char *principal, int time_offset,
 299                             DATA_BLOB *targ,
 300                             DATA_BLOB *session_key_krb5, uint32 extra_ap_opts,
 301                             time_t *expire_time)
 302 {
 303         int retval;
 304         DATA_BLOB tkt, tkt_wrapped;
 305         const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_KERBEROS5, OID_NTLMSSP, NULL};
 306
 307         /* get a kerberos ticket for the service and extract the session key */
 308         retval = cli_krb5_get_ticket(ctx, principal, time_offset,
 309                                           &tkt, session_key_krb5,
 310                                           extra_ap_opts, NULL,
 311                                           expire_time, NULL);
 312         if (retval) {
 313                 return retval;
 314         }
 315
 316         /* wrap that up in a nice GSS-API wrapping */
 317         tkt_wrapped = spnego_gen_krb5_wrap(ctx, tkt, TOK_ID_KRB_AP_REQ);
 318
 319         /* and wrap that in a shiny SPNEGO wrapper */
 320         *targ = spnego_gen_negTokenInit(ctx, krb_mechs, &tkt_wrapped, NULL);
 321
 322         data_blob_free(&tkt_wrapped);
 323         data_blob_free(&tkt);
 324
 325         return retval;
 326 }
 327
 328
 329 /*
 330   parse a spnego NTLMSSP challenge packet giving two security blobs
 331 */
 332 bool spnego_parse_challenge(TALLOC_CTX *ctx, const DATA_BLOB blob,
 333                             DATA_BLOB *chal1, DATA_BLOB *chal2)
 334 {
 335         bool ret;
 336         ASN1_DATA *data;
 337
 338         ZERO_STRUCTP(chal1);
 339         ZERO_STRUCTP(chal2);
 340
 341         data = asn1_init(talloc_tos());
 342         if (data == NULL) {
 343                 return false;
 344         }
 345
 346         asn1_load(data, blob);
 347         asn1_start_tag(data,ASN1_CONTEXT(1));
 348         asn1_start_tag(data,ASN1_SEQUENCE(0));
 349
 350         asn1_start_tag(data,ASN1_CONTEXT(0));
 351         asn1_check_enumerated(data,1);
 352         asn1_end_tag(data);
 353
 354         asn1_start_tag(data,ASN1_CONTEXT(1));
 355         asn1_check_OID(data, OID_NTLMSSP);
 356         asn1_end_tag(data);
 357
 358         asn1_start_tag(data,ASN1_CONTEXT(2));
 359         asn1_read_OctetString(data, ctx, chal1);
 360         asn1_end_tag(data);
 361
 362         /* the second challenge is optional (XP doesn't send it) */
 363         if (asn1_tag_remaining(data)) {
 364                 asn1_start_tag(data,ASN1_CONTEXT(3));
 365                 asn1_read_OctetString(data, ctx, chal2);
 366                 asn1_end_tag(data);
 367         }
 368
 369         asn1_end_tag(data);
 370         asn1_end_tag(data);
 371
 372         ret = !data->has_error;
 373
 374         if (data->has_error) {
 375                 data_blob_free(chal1);
 376                 data_blob_free(chal2);
 377         }
 378
 379         asn1_free(data);
 380         return ret;
 381 }
 382
 383
 384 /*
 385  generate a SPNEGO auth packet. This will contain the encrypted passwords
 386 */
 387 DATA_BLOB spnego_gen_auth(TALLOC_CTX *ctx, DATA_BLOB blob)
 388 {
 389         ASN1_DATA *data;
 390         DATA_BLOB ret;
 391
 392         data = asn1_init(talloc_tos());
 393         if (data == NULL) {
 394                 return data_blob_null;
 395         }
 396
 397         asn1_push_tag(data, ASN1_CONTEXT(1));
 398         asn1_push_tag(data, ASN1_SEQUENCE(0));
 399         asn1_push_tag(data, ASN1_CONTEXT(2));
 400         asn1_write_OctetString(data,blob.data,blob.length);
 401         asn1_pop_tag(data);
 402         asn1_pop_tag(data);
 403         asn1_pop_tag(data);
 404
 405         ret = data_blob_talloc(ctx, data->data, data->length);
 406
 407         asn1_free(data);
 408
 409         return ret;
 410 }
 411
 412 /*
 413  parse a SPNEGO auth packet. This contains the encrypted passwords
 414 */
 415 bool spnego_parse_auth_and_mic(TALLOC_CTX *ctx, DATA_BLOB blob,
 416                                 DATA_BLOB *auth, DATA_BLOB *signature)
 417 {
 418         ssize_t len;
 419         struct spnego_data token;
 420
 421         len = spnego_read_data(talloc_tos(), blob, &token);
 422         if (len == -1) {
 423                 DEBUG(3,("spnego_parse_auth: spnego_read_data failed\n"));
 424                 return false;
 425         }
 426
 427         if (token.type != SPNEGO_NEG_TOKEN_TARG) {
 428                 DEBUG(3,("spnego_parse_auth: wrong token type: %d\n",
 429                         token.type));
 430                 spnego_free_data(&token);
 431                 return false;
 432         }
 433
 434         *auth = data_blob_talloc(ctx,
 435                                  token.negTokenTarg.responseToken.data,
 436                                  token.negTokenTarg.responseToken.length);
 437
 438         if (!signature) {
 439                 goto done;
 440         }
 441
 442         *signature = data_blob_talloc(ctx,
 443                                  token.negTokenTarg.mechListMIC.data,
 444                                  token.negTokenTarg.mechListMIC.length);
 445
 446 done:
 447         spnego_free_data(&token);
 448
 449         return true;
 450 }
 451
 452 bool spnego_parse_auth(TALLOC_CTX *ctx, DATA_BLOB blob, DATA_BLOB *auth)
 453 {
 454         return spnego_parse_auth_and_mic(ctx, blob, auth, NULL);
 455 }
 456
 457 /*
 458   generate a minimal SPNEGO response packet.  Doesn't contain much.
 459 */
 460 DATA_BLOB spnego_gen_auth_response_and_mic(TALLOC_CTX *ctx,
 461                                            NTSTATUS nt_status,
 462                                            const char *mechOID,
 463                                            DATA_BLOB *reply,
 464                                            DATA_BLOB *mechlistMIC)
 465 {
 466         ASN1_DATA *data;
 467         DATA_BLOB ret;
 468         uint8 negResult;
 469
 470         if (NT_STATUS_IS_OK(nt_status)) {
 471                 negResult = SPNEGO_ACCEPT_COMPLETED;
 472         } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 473                 negResult = SPNEGO_ACCEPT_INCOMPLETE;
 474         } else {
 475                 negResult = SPNEGO_REJECT;
 476         }
 477
 478         data = asn1_init(talloc_tos());
 479         if (data == NULL) {
 480                 return data_blob_null;
 481         }
 482
 483         asn1_push_tag(data, ASN1_CONTEXT(1));
 484         asn1_push_tag(data, ASN1_SEQUENCE(0));
 485         asn1_push_tag(data, ASN1_CONTEXT(0));
 486         asn1_write_enumerated(data, negResult);
 487         asn1_pop_tag(data);
 488
 489         if (mechOID) {
 490                 asn1_push_tag(data,ASN1_CONTEXT(1));
 491                 asn1_write_OID(data, mechOID);
 492                 asn1_pop_tag(data);
 493         }
 494
 495         if (reply && reply->data != NULL) {
 496                 asn1_push_tag(data,ASN1_CONTEXT(2));
 497                 asn1_write_OctetString(data, reply->data, reply->length);
 498                 asn1_pop_tag(data);
 499         }
 500
 501         if (mechlistMIC && mechlistMIC->data != NULL) {
 502                 asn1_push_tag(data, ASN1_CONTEXT(3));
 503                 asn1_write_OctetString(data,
 504                                         mechlistMIC->data,
 505                                         mechlistMIC->length);
 506                 asn1_pop_tag(data);
 507         }
 508
 509         asn1_pop_tag(data);
 510         asn1_pop_tag(data);
 511
 512         ret = data_blob_talloc(ctx, data->data, data->length);
 513         asn1_free(data);
 514         return ret;
 515 }
 516
 517 DATA_BLOB spnego_gen_auth_response(TALLOC_CTX *ctx, DATA_BLOB *reply,
 518                                    NTSTATUS nt_status, const char *mechOID)
 519 {
 520         return spnego_gen_auth_response_and_mic(ctx, nt_status,
 521                                                 mechOID, reply, NULL);
 522 }
 523
 524 /*
 525  parse a SPNEGO auth packet. This contains the encrypted passwords
 526 */
 527 bool spnego_parse_auth_response(TALLOC_CTX *ctx,
 528                                 DATA_BLOB blob, NTSTATUS nt_status,
 529                                 const char *mechOID,
 530                                 DATA_BLOB *auth)
 531 {
 532         ASN1_DATA *data;
 533         uint8 negResult;
 534
 535         if (NT_STATUS_IS_OK(nt_status)) {
 536                 negResult = SPNEGO_ACCEPT_COMPLETED;
 537         } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 538                 negResult = SPNEGO_ACCEPT_INCOMPLETE;
 539         } else {
 540                 negResult = SPNEGO_REJECT;
 541         }
 542
 543         data = asn1_init(talloc_tos());
 544         if (data == NULL) {
 545                 return false;
 546         }
 547
 548         asn1_load(data, blob);
 549         asn1_start_tag(data, ASN1_CONTEXT(1));
 550         asn1_start_tag(data, ASN1_SEQUENCE(0));
 551         asn1_start_tag(data, ASN1_CONTEXT(0));
 552         asn1_check_enumerated(data, negResult);
 553         asn1_end_tag(data);
 554
 555         *auth = data_blob_null;
 556
 557         if (asn1_tag_remaining(data)) {
 558                 asn1_start_tag(data,ASN1_CONTEXT(1));
 559                 asn1_check_OID(data, mechOID);
 560                 asn1_end_tag(data);
 561
 562                 if (asn1_tag_remaining(data)) {
 563                         asn1_start_tag(data,ASN1_CONTEXT(2));
 564                         asn1_read_OctetString(data, ctx, auth);
 565                         asn1_end_tag(data);
 566                 }
 567         } else if (negResult == SPNEGO_ACCEPT_INCOMPLETE) {
 568                 data->has_error = 1;
 569         }
 570
 571         /* Binding against Win2K DC returns a duplicate of the responseToken in
 572          * the optional mechListMIC field. This is a bug in Win2K. We ignore
 573          * this field if it exists. Win2K8 may return a proper mechListMIC at
 574          * which point we need to implement the integrity checking. */
 575         if (asn1_tag_remaining(data)) {
 576                 DATA_BLOB mechList = data_blob_null;
 577                 asn1_start_tag(data, ASN1_CONTEXT(3));
 578                 asn1_read_OctetString(data, ctx, &mechList);
 579                 asn1_end_tag(data);
 580                 data_blob_free(&mechList);
 581                 DEBUG(5,("spnego_parse_auth_response received mechListMIC, "
 582                     "ignoring.\n"));
 583         }
 584
 585         asn1_end_tag(data);
 586         asn1_end_tag(data);
 587
 588         if (data->has_error) {
 589                 DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data->ofs));
 590                 asn1_free(data);
 591                 data_blob_free(auth);
 592                 return False;
 593         }
 594
 595         asn1_free(data);
 596         return True;
 597 }
 598
 599 bool spnego_mech_list_blob(TALLOC_CTX *mem_ctx,
 600                            char **oid_list, DATA_BLOB *raw_data)
 601 {
 602         ASN1_DATA *data;
 603         unsigned int idx;
 604
 605         if (!oid_list || !oid_list[0] || !raw_data) {
 606                 return false;
 607         }
 608
 609         data = asn1_init(talloc_tos());
 610         if (data == NULL) {
 611                 return false;
 612         }
 613
 614         asn1_push_tag(data, ASN1_SEQUENCE(0));
 615         for (idx = 0; oid_list[idx]; idx++) {
 616                 asn1_write_OID(data, oid_list[idx]);
 617         }
 618         asn1_pop_tag(data);
 619
 620         if (data->has_error) {
 621                 DEBUG(3, (__location__ " failed at %d\n", (int)data->ofs));
 622                 asn1_free(data);
 623                 return false;
 624         }
 625
 626         *raw_data = data_blob_talloc(mem_ctx, data->data, data->length);
 627         if (!raw_data->data) {
 628                 DEBUG(3, (__location__": data_blob_talloc() failed!\n"));
 629                 asn1_free(data);
 630                 return false;
 631         }
 632
 633         asn1_free(data);
 634         return true;
 635 }