source/auth/gensec/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 2 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, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25 #include "auth/gensec/spnego.h"
  26 #include "auth/gensec/gensec.h"
  27 #include "libcli/util/asn_1.h"
  28
  29 static BOOL read_negTokenInit(struct asn1_data *asn1, struct spnego_negTokenInit *token)
  30 {
  31         ZERO_STRUCTP(token);
  32
  33         asn1_start_tag(asn1, ASN1_CONTEXT(0));
  34         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
  35
  36         while (!asn1->has_error && 0 < asn1_tag_remaining(asn1)) {
  37                 int i;
  38                 uint8_t context;
  39                 if (!asn1_peek_uint8(asn1, &context)) {
  40                         asn1->has_error = True;
  41                         break;
  42                 }
  43
  44                 switch (context) {
  45                 /* Read mechTypes */
  46                 case ASN1_CONTEXT(0):
  47                         asn1_start_tag(asn1, ASN1_CONTEXT(0));
  48                         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
  49
  50                         token->mechTypes = talloc(NULL, const char *);
  51                         for (i = 0; !asn1->has_error &&
  52                                      0 < asn1_tag_remaining(asn1); i++) {
  53                                 token->mechTypes = talloc_realloc(NULL,
  54                                                                   token->mechTypes,
  55                                                                   const char *, i+2);
  56                                 asn1_read_OID(asn1, token->mechTypes + i);
  57                                 if (token->mechTypes[i]) {
  58                                         talloc_steal(token->mechTypes,
  59                                                      token->mechTypes[i]);
  60                                 }
  61                         }
  62                         token->mechTypes[i] = NULL;
  63
  64                         asn1_end_tag(asn1);
  65                         asn1_end_tag(asn1);
  66                         break;
  67                 /* Read reqFlags */
  68                 case ASN1_CONTEXT(1):
  69                         asn1_start_tag(asn1, ASN1_CONTEXT(1));
  70                         asn1_read_Integer(asn1, &token->reqFlags);
  71                         token->reqFlags |= SPNEGO_REQ_FLAG;
  72                         asn1_end_tag(asn1);
  73                         break;
  74                 /* Read mechToken */
  75                 case ASN1_CONTEXT(2):
  76                         asn1_start_tag(asn1, ASN1_CONTEXT(2));
  77                         asn1_read_OctetString(asn1, &token->mechToken);
  78                         asn1_end_tag(asn1);
  79                         break;
  80                 /* Read mecListMIC */
  81                 case ASN1_CONTEXT(3):
  82                 {
  83                         uint8_t type_peek;
  84                         asn1_start_tag(asn1, ASN1_CONTEXT(3));
  85                         if (!asn1_peek_uint8(asn1, &type_peek)) {
  86                                 asn1->has_error = True;
  87                                 break;
  88                         }
  89                         if (type_peek == ASN1_OCTET_STRING) {
  90                                 asn1_read_OctetString(asn1,
  91                                                       &token->mechListMIC);
  92                         } else {
  93                                 /* RFC 2478 says we have an Octet String here,
  94                                    but W2k sends something different... */
  95                                 char *mechListMIC;
  96                                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
  97                                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
  98                                 asn1_read_GeneralString(asn1, &mechListMIC);
  99                                 asn1_pop_tag(asn1);
 100                                 asn1_pop_tag(asn1);
 101
 102                                 token->targetPrincipal = mechListMIC;
 103                         }
 104                         asn1_end_tag(asn1);
 105                         break;
 106                 }
 107                 default:
 108                         asn1->has_error = True;
 109                         break;
 110                 }
 111         }
 112
 113         asn1_end_tag(asn1);
 114         asn1_end_tag(asn1);
 115
 116         return !asn1->has_error;
 117 }
 118
 119 static BOOL write_negTokenInit(struct asn1_data *asn1, struct spnego_negTokenInit *token)
 120 {
 121         asn1_push_tag(asn1, ASN1_CONTEXT(0));
 122         asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 123
 124         /* Write mechTypes */
 125         if (token->mechTypes && *token->mechTypes) {
 126                 int i;
 127
 128                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 129                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 130                 for (i = 0; token->mechTypes[i]; i++) {
 131                         asn1_write_OID(asn1, token->mechTypes[i]);
 132                 }
 133                 asn1_pop_tag(asn1);
 134                 asn1_pop_tag(asn1);
 135         }
 136
 137         /* write reqFlags */
 138         if (token->reqFlags & SPNEGO_REQ_FLAG) {
 139                 int flags = token->reqFlags & ~SPNEGO_REQ_FLAG;
 140
 141                 asn1_push_tag(asn1, ASN1_CONTEXT(1));
 142                 asn1_write_Integer(asn1, flags);
 143                 asn1_pop_tag(asn1);
 144         }
 145
 146         /* write mechToken */
 147         if (token->mechToken.data) {
 148                 asn1_push_tag(asn1, ASN1_CONTEXT(2));
 149                 asn1_write_OctetString(asn1, token->mechToken.data,
 150                                        token->mechToken.length);
 151                 asn1_pop_tag(asn1);
 152         }
 153
 154         /* write mechListMIC */
 155         if (token->mechListMIC.data) {
 156                 asn1_push_tag(asn1, ASN1_CONTEXT(3));
 157 #if 0
 158                 /* This is what RFC 2478 says ... */
 159                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 160                                        token->mechListMIC.length);
 161 #else
 162                 /* ... but unfortunately this is what Windows
 163                    sends/expects */
 164                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 165                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 166                 asn1_push_tag(asn1, ASN1_GENERAL_STRING);
 167                 asn1_write(asn1, token->mechListMIC.data,
 168                            token->mechListMIC.length);
 169                 asn1_pop_tag(asn1);
 170                 asn1_pop_tag(asn1);
 171                 asn1_pop_tag(asn1);
 172 #endif
 173                 asn1_pop_tag(asn1);
 174         }
 175
 176         asn1_pop_tag(asn1);
 177         asn1_pop_tag(asn1);
 178
 179         return !asn1->has_error;
 180 }
 181
 182 static BOOL read_negTokenTarg(struct asn1_data *asn1, struct spnego_negTokenTarg *token)
 183 {
 184         ZERO_STRUCTP(token);
 185
 186         asn1_start_tag(asn1, ASN1_CONTEXT(1));
 187         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
 188
 189         while (!asn1->has_error && 0 < asn1_tag_remaining(asn1)) {
 190                 uint8_t context;
 191                 if (!asn1_peek_uint8(asn1, &context)) {
 192                         asn1->has_error = True;
 193                         break;
 194                 }
 195
 196                 switch (context) {
 197                 case ASN1_CONTEXT(0):
 198                         asn1_start_tag(asn1, ASN1_CONTEXT(0));
 199                         asn1_start_tag(asn1, ASN1_ENUMERATED);
 200                         asn1_read_uint8(asn1, &token->negResult);
 201                         asn1_end_tag(asn1);
 202                         asn1_end_tag(asn1);
 203                         break;
 204                 case ASN1_CONTEXT(1):
 205                         asn1_start_tag(asn1, ASN1_CONTEXT(1));
 206                         asn1_read_OID(asn1, &token->supportedMech);
 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, &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, &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(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         ZERO_STRUCT(asn1);
 276
 277         if (data.length == 0) {
 278                 return ret;
 279         }
 280
 281         asn1_load(&asn1, data);
 282
 283         if (!asn1_peek_uint8(&asn1, &context)) {
 284                 asn1.has_error = True;
 285         } else {
 286                 switch (context) {
 287                 case ASN1_APPLICATION(0):
 288                         asn1_start_tag(&asn1, ASN1_APPLICATION(0));
 289                         asn1_check_OID(&asn1, GENSEC_OID_SPNEGO);
 290                         if (read_negTokenInit(&asn1, &token->negTokenInit)) {
 291                                 token->type = SPNEGO_NEG_TOKEN_INIT;
 292                         }
 293                         asn1_end_tag(&asn1);
 294                         break;
 295                 case ASN1_CONTEXT(1):
 296                         if (read_negTokenTarg(&asn1, &token->negTokenTarg)) {
 297                                 token->type = SPNEGO_NEG_TOKEN_TARG;
 298                         }
 299                         break;
 300                 default:
 301                         asn1.has_error = True;
 302                         break;
 303                 }
 304         }
 305
 306         if (!asn1.has_error) ret = asn1.ofs;
 307         asn1_free(&asn1);
 308
 309         return ret;
 310 }
 311
 312 ssize_t spnego_write_data(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, struct spnego_data *spnego)
 313 {
 314         struct asn1_data asn1;
 315         ssize_t ret = -1;
 316
 317         ZERO_STRUCT(asn1);
 318
 319         switch (spnego->type) {
 320         case SPNEGO_NEG_TOKEN_INIT:
 321                 asn1_push_tag(&asn1, ASN1_APPLICATION(0));
 322                 asn1_write_OID(&asn1, GENSEC_OID_SPNEGO);
 323                 write_negTokenInit(&asn1, &spnego->negTokenInit);
 324                 asn1_pop_tag(&asn1);
 325                 break;
 326         case SPNEGO_NEG_TOKEN_TARG:
 327                 write_negTokenTarg(&asn1, &spnego->negTokenTarg);
 328                 break;
 329         default:
 330                 asn1.has_error = True;
 331                 break;
 332         }
 333
 334         if (!asn1.has_error) {
 335                 *blob = data_blob_talloc(mem_ctx, asn1.data, asn1.length);
 336                 ret = asn1.ofs;
 337         }
 338         asn1_free(&asn1);
 339
 340         return ret;
 341 }
 342
 343 BOOL spnego_free_data(struct spnego_data *spnego)
 344 {
 345         BOOL ret = True;
 346
 347         if (!spnego) goto out;
 348
 349         switch(spnego->type) {
 350         case SPNEGO_NEG_TOKEN_INIT:
 351                 if (spnego->negTokenInit.mechTypes) {
 352                         talloc_free(spnego->negTokenInit.mechTypes);
 353                 }
 354                 data_blob_free(&spnego->negTokenInit.mechToken);
 355                 data_blob_free(&spnego->negTokenInit.mechListMIC);
 356                 talloc_free(spnego->negTokenInit.targetPrincipal);
 357                 break;
 358         case SPNEGO_NEG_TOKEN_TARG:
 359                 if (spnego->negTokenTarg.supportedMech) {
 360                         talloc_free(discard_const(spnego->negTokenTarg.supportedMech));
 361                 }
 362                 data_blob_free(&spnego->negTokenTarg.responseToken);
 363                 data_blob_free(&spnego->negTokenTarg.mechListMIC);
 364                 break;
 365         default:
 366                 ret = False;
 367                 break;
 368         }
 369         ZERO_STRUCTP(spnego);
 370 out:
 371         return ret;
 372 }
 373