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