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