libcli/auth/spnego_parse.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    RFC2478 Compliant SPNEGO implementation
   5
   6    Copyright (C) Jim McDonough <jmcd@us.ibm.com>   2003
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  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 "../lib/util/asn1.h"
  26
  27 static bool read_negTokenInit(struct asn1_data *asn1, TALLOC_CTX *mem_ctx,
  28                               struct spnego_negTokenInit *token)
  29 {
  30         ZERO_STRUCTP(token);
  31
  32         if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
  33         if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;
  34
  35         while (asn1_tag_remaining(asn1) > 0) {
  36                 int i;
  37                 uint8_t context;
  38
  39                 if (!asn1_peek_uint8(asn1, &context)) {
  40                         asn1_set_error(asn1);
  41                         break;
  42                 }
  43
  44                 switch (context) {
  45                 /* Read mechTypes */
  46                 case ASN1_CONTEXT(0): {
  47                         const char **mechTypes;
  48
  49                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
  50                         if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;
  51
  52                         mechTypes = talloc(mem_ctx, const char *);
  53                         if (mechTypes == NULL) {
  54                                 asn1_set_error(asn1);
  55                                 return false;
  56                         }
  57                         for (i = 0; asn1_tag_remaining(asn1) > 0; i++) {
  58                                 char *oid;
  59                                 const char **p;
  60                                 p = talloc_realloc(mem_ctx,
  61                                                    mechTypes,
  62                                                    const char *, i+2);
  63                                 if (p == NULL) {
  64                                         talloc_free(mechTypes);
  65                                         asn1_set_error(asn1);
  66                                         return false;
  67                                 }
  68                                 mechTypes = p;
  69
  70                                 if (!asn1_read_OID(asn1, mechTypes, &oid)) return false;
  71                                 mechTypes[i] = oid;
  72                         }
  73                         mechTypes[i] = NULL;
  74                         token->mechTypes = mechTypes;
  75
  76                         asn1_end_tag(asn1);
  77                         asn1_end_tag(asn1);
  78                         break;
  79                 }
  80                 /* Read reqFlags */
  81                 case ASN1_CONTEXT(1):
  82                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(1))) return false;
  83                         if (!asn1_read_BitString(asn1, mem_ctx, &token->reqFlags,
  84                                             &token->reqFlagsPadding)) return false;
  85                         if (!asn1_end_tag(asn1)) return false;
  86                         break;
  87                 /* Read mechToken */
  88                 case ASN1_CONTEXT(2):
  89                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(2))) return false;
  90                         if (!asn1_read_OctetString(asn1, mem_ctx, &token->mechToken)) return false;
  91                         if (!asn1_end_tag(asn1)) return false;
  92                         break;
  93                 /* Read mecListMIC */
  94                 case ASN1_CONTEXT(3):
  95                 {
  96                         uint8_t type_peek;
  97                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(3))) return false;
  98                         if (!asn1_peek_uint8(asn1, &type_peek)) {
  99                                 asn1_set_error(asn1);
 100                                 break;
 101                         }
 102                         if (type_peek == ASN1_OCTET_STRING) {
 103                                 if (!asn1_read_OctetString(asn1, mem_ctx,
 104                                                       &token->mechListMIC)) return false;
 105                         } else {
 106                                 /* RFC 2478 says we have an Octet String here,
 107                                    but W2k sends something different... */
 108                                 char *mechListMIC;
 109                                 if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;
 110                                 if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
 111                                 if (!asn1_read_GeneralString(asn1, mem_ctx, &mechListMIC)) return false;
 112                                 if (!asn1_end_tag(asn1)) return false;
 113                                 if (!asn1_end_tag(asn1)) return false;
 114
 115                                 token->targetPrincipal = mechListMIC;
 116                         }
 117                         if (!asn1_end_tag(asn1)) return false;
 118                         break;
 119                 }
 120                 default:
 121                         asn1_set_error(asn1);
 122                         break;
 123                 }
 124         }
 125
 126         if (!asn1_end_tag(asn1)) return false;
 127         if (!asn1_end_tag(asn1)) return false;
 128
 129         return !asn1_has_error(asn1);
 130 }
 131
 132 static bool write_negTokenInit(struct asn1_data *asn1, struct spnego_negTokenInit *token)
 133 {
 134         if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
 135         if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;
 136
 137         /* Write mechTypes */
 138         if (token->mechTypes && *token->mechTypes) {
 139                 int i;
 140
 141                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
 142                 if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;
 143                 for (i = 0; token->mechTypes[i]; i++) {
 144                         if (!asn1_write_OID(asn1, token->mechTypes[i])) return false;
 145                 }
 146                 if (!asn1_pop_tag(asn1)) return false;
 147                 if (!asn1_pop_tag(asn1)) return false;
 148         }
 149
 150         /* write reqFlags */
 151         if (token->reqFlags.length > 0) {
 152                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(1))) return false;
 153                 if (!asn1_write_BitString(asn1, token->reqFlags.data,
 154                                      token->reqFlags.length,
 155                                      token->reqFlagsPadding)) return false;
 156                 if (!asn1_pop_tag(asn1)) return false;
 157         }
 158
 159         /* write mechToken */
 160         if (token->mechToken.data) {
 161                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(2))) return false;
 162                 if (!asn1_write_OctetString(asn1, token->mechToken.data,
 163                                        token->mechToken.length)) return false;
 164                 if (!asn1_pop_tag(asn1)) return false;
 165         }
 166
 167         /* write mechListMIC */
 168         if (token->mechListMIC.data) {
 169                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(3))) return false;
 170 #if 0
 171                 /* This is what RFC 2478 says ... */
 172                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 173                                        token->mechListMIC.length);
 174 #else
 175                 /* ... but unfortunately this is what Windows
 176                    sends/expects */
 177                 if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;
 178                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
 179                 if (!asn1_push_tag(asn1, ASN1_GENERAL_STRING)) return false;
 180                 if (!asn1_write(asn1, token->mechListMIC.data,
 181                            token->mechListMIC.length)) return false;
 182                 if (!asn1_pop_tag(asn1)) return false;
 183                 if (!asn1_pop_tag(asn1)) return false;
 184                 if (!asn1_pop_tag(asn1)) return false;
 185 #endif
 186                 if (!asn1_pop_tag(asn1)) return false;
 187         }
 188
 189         if (!asn1_pop_tag(asn1)) return false;
 190         if (!asn1_pop_tag(asn1)) return false;
 191
 192         return !asn1_has_error(asn1);
 193 }
 194
 195 static bool read_negTokenTarg(struct asn1_data *asn1, TALLOC_CTX *mem_ctx,
 196                               struct spnego_negTokenTarg *token)
 197 {
 198         ZERO_STRUCTP(token);
 199
 200         if (!asn1_start_tag(asn1, ASN1_CONTEXT(1))) return false;
 201         if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;
 202
 203         while (asn1_tag_remaining(asn1) > 0) {
 204                 uint8_t context;
 205                 uint8_t neg_result;
 206                 char *oid;
 207
 208                 if (!asn1_peek_uint8(asn1, &context)) {
 209                         asn1_set_error(asn1);
 210                         break;
 211                 }
 212
 213                 switch (context) {
 214                 case ASN1_CONTEXT(0):
 215                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
 216                         if (!asn1_start_tag(asn1, ASN1_ENUMERATED)) return false;
 217                         if (!asn1_read_uint8(asn1, &neg_result)) return false;
 218                         token->negResult = neg_result;
 219                         if (!asn1_end_tag(asn1)) return false;
 220                         if (!asn1_end_tag(asn1)) return false;
 221                         break;
 222                 case ASN1_CONTEXT(1):
 223                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(1))) return false;
 224                         if (!asn1_read_OID(asn1, mem_ctx, &oid)) return false;
 225                         token->supportedMech = oid;
 226                         if (!asn1_end_tag(asn1)) return false;
 227                         break;
 228                 case ASN1_CONTEXT(2):
 229                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(2))) return false;
 230                         if (!asn1_read_OctetString(asn1, mem_ctx, &token->responseToken)) return false;
 231                         if (!asn1_end_tag(asn1)) return false;
 232                         break;
 233                 case ASN1_CONTEXT(3):
 234                         if (!asn1_start_tag(asn1, ASN1_CONTEXT(3))) return false;
 235                         if (!asn1_read_OctetString(asn1, mem_ctx, &token->mechListMIC)) return false;
 236                         if (!asn1_end_tag(asn1)) return false;
 237                         break;
 238                 default:
 239                         asn1_set_error(asn1);
 240                         break;
 241                 }
 242         }
 243
 244         if (!asn1_end_tag(asn1)) return false;
 245         if (!asn1_end_tag(asn1)) return false;
 246
 247         return !asn1_has_error(asn1);
 248 }
 249
 250 static bool write_negTokenTarg(struct asn1_data *asn1, struct spnego_negTokenTarg *token)
 251 {
 252         if (!asn1_push_tag(asn1, ASN1_CONTEXT(1))) return false;
 253         if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;
 254
 255         if (token->negResult != SPNEGO_NONE_RESULT) {
 256                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
 257                 if (!asn1_write_enumerated(asn1, token->negResult)) return false;
 258                 if (!asn1_pop_tag(asn1)) return false;
 259         }
 260
 261         if (token->supportedMech) {
 262                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(1))) return false;
 263                 if (!asn1_write_OID(asn1, token->supportedMech)) return false;
 264                 if (!asn1_pop_tag(asn1)) return false;
 265         }
 266
 267         if (token->responseToken.data) {
 268                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(2))) return false;
 269                 if (!asn1_write_OctetString(asn1, token->responseToken.data,
 270                                        token->responseToken.length)) return false;
 271                 if (!asn1_pop_tag(asn1)) return false;
 272         }
 273
 274         if (token->mechListMIC.data) {
 275                 if (!asn1_push_tag(asn1, ASN1_CONTEXT(3))) return false;
 276                 if (!asn1_write_OctetString(asn1, token->mechListMIC.data,
 277                                       token->mechListMIC.length)) return false;
 278                 if (!asn1_pop_tag(asn1)) return false;
 279         }
 280
 281         if (!asn1_pop_tag(asn1)) return false;
 282         if (!asn1_pop_tag(asn1)) return false;
 283
 284         return !asn1_has_error(asn1);
 285 }
 286
 287 ssize_t spnego_read_data(TALLOC_CTX *mem_ctx, DATA_BLOB data, struct spnego_data *token)
 288 {
 289         struct asn1_data *asn1;
 290         ssize_t ret = -1;
 291         uint8_t context;
 292
 293         ZERO_STRUCTP(token);
 294
 295         if (data.length == 0) {
 296                 return ret;
 297         }
 298
 299         asn1 = asn1_init(mem_ctx);
 300         if (asn1 == NULL) {
 301                 return -1;
 302         }
 303
 304         if (!asn1_load(asn1, data)) goto err;
 305
 306         if (!asn1_peek_uint8(asn1, &context)) {
 307                 asn1_set_error(asn1);
 308         } else {
 309                 switch (context) {
 310                 case ASN1_APPLICATION(0):
 311                         if (!asn1_start_tag(asn1, ASN1_APPLICATION(0))) goto err;
 312                         if (!asn1_check_OID(asn1, OID_SPNEGO)) goto err;
 313                         if (read_negTokenInit(asn1, mem_ctx, &token->negTokenInit)) {
 314                                 token->type = SPNEGO_NEG_TOKEN_INIT;
 315                         }
 316                         if (!asn1_end_tag(asn1)) goto err;
 317                         break;
 318                 case ASN1_CONTEXT(1):
 319                         if (read_negTokenTarg(asn1, mem_ctx, &token->negTokenTarg)) {
 320                                 token->type = SPNEGO_NEG_TOKEN_TARG;
 321                         }
 322                         break;
 323                 default:
 324                         asn1_set_error(asn1);
 325                         break;
 326                 }
 327         }
 328
 329         if (!asn1_has_error(asn1)) {
 330                 ret = asn1_current_ofs(asn1);
 331         }
 332
 333   err:
 334
 335         asn1_free(asn1);
 336
 337         return ret;
 338 }
 339
 340 ssize_t spnego_write_data(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, struct spnego_data *spnego)
 341 {
 342         struct asn1_data *asn1 = asn1_init(mem_ctx);
 343         ssize_t ret = -1;
 344
 345         if (asn1 == NULL) {
 346                 return -1;
 347         }
 348
 349         switch (spnego->type) {
 350         case SPNEGO_NEG_TOKEN_INIT:
 351                 if (!asn1_push_tag(asn1, ASN1_APPLICATION(0))) goto err;
 352                 if (!asn1_write_OID(asn1, OID_SPNEGO)) goto err;
 353                 if (!write_negTokenInit(asn1, &spnego->negTokenInit)) goto err;
 354                 if (!asn1_pop_tag(asn1)) goto err;
 355                 break;
 356         case SPNEGO_NEG_TOKEN_TARG:
 357                 write_negTokenTarg(asn1, &spnego->negTokenTarg);
 358                 break;
 359         default:
 360                 asn1_set_error(asn1);
 361                 break;
 362         }
 363
 364         if (!asn1_extract_blob(asn1, mem_ctx, blob)) {
 365                 goto err;
 366         }
 367
 368         ret = asn1_current_ofs(asn1);
 369
 370   err:
 371
 372         asn1_free(asn1);
 373
 374         return ret;
 375 }
 376
 377 bool spnego_free_data(struct spnego_data *spnego)
 378 {
 379         bool ret = true;
 380
 381         if (!spnego) goto out;
 382
 383         switch(spnego->type) {
 384         case SPNEGO_NEG_TOKEN_INIT:
 385                 if (spnego->negTokenInit.mechTypes) {
 386                         talloc_free(discard_const(spnego->negTokenInit.mechTypes));
 387                 }
 388                 data_blob_free(&spnego->negTokenInit.reqFlags);
 389                 data_blob_free(&spnego->negTokenInit.mechToken);
 390                 data_blob_free(&spnego->negTokenInit.mechListMIC);
 391                 talloc_free(spnego->negTokenInit.targetPrincipal);
 392                 break;
 393         case SPNEGO_NEG_TOKEN_TARG:
 394                 if (spnego->negTokenTarg.supportedMech) {
 395                         talloc_free(discard_const(spnego->negTokenTarg.supportedMech));
 396                 }
 397                 data_blob_free(&spnego->negTokenTarg.responseToken);
 398                 data_blob_free(&spnego->negTokenTarg.mechListMIC);
 399                 break;
 400         default:
 401                 ret = false;
 402                 break;
 403         }
 404         ZERO_STRUCTP(spnego);
 405 out:
 406         return ret;
 407 }
 408
 409 bool spnego_write_mech_types(TALLOC_CTX *mem_ctx,
 410                              const char * const *mech_types,
 411                              DATA_BLOB *blob)
 412 {
 413         bool ret = false;
 414         struct asn1_data *asn1 = asn1_init(mem_ctx);
 415
 416         if (asn1 == NULL) {
 417                 return false;
 418         }
 419
 420         /* Write mechTypes */
 421         if (mech_types && *mech_types) {
 422                 int i;
 423
 424                 if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) goto err;
 425                 for (i = 0; mech_types[i]; i++) {
 426                         if (!asn1_write_OID(asn1, mech_types[i])) goto err;
 427                 }
 428                 if (!asn1_pop_tag(asn1)) goto err;
 429         }
 430
 431         if (asn1_has_error(asn1)) {
 432                 goto err;
 433         }
 434
 435         if (!asn1_extract_blob(asn1, mem_ctx, blob)) {
 436                 goto err;
 437         }
 438
 439         ret = true;
 440
 441   err:
 442
 443         asn1_free(asn1);
 444
 445         return ret;
 446 }