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