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/auth.h"
  26 #include "asn_1.h"
  27
  28 #undef DBGC_CLASS
  29 #define DBGC_CLASS DBGC_AUTH
  30
  31 static BOOL read_negTokenInit(struct asn1_data *asn1, struct spnego_negTokenInit *token)
  32 {
  33         ZERO_STRUCTP(token);
  34
  35         asn1_start_tag(asn1, ASN1_CONTEXT(0));
  36         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
  37
  38         while (!asn1->has_error && 0 < asn1_tag_remaining(asn1)) {
  39                 int i;
  40                 uint8_t context;
  41                 if (!asn1_peek_uint8(asn1, &context)) {
  42                         asn1->has_error = True;
  43                         break;
  44                 }
  45
  46                 switch (context) {
  47                 /* Read mechTypes */
  48                 case ASN1_CONTEXT(0):
  49                         asn1_start_tag(asn1, ASN1_CONTEXT(0));
  50                         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
  51
  52                         token->mechTypes = talloc(NULL, const char *);
  53                         for (i = 0; !asn1->has_error &&
  54                                      0 < asn1_tag_remaining(asn1); i++) {
  55                                 token->mechTypes = talloc_realloc(NULL,
  56                                                                   token->mechTypes,
  57                                                                   const char *, i+2);
  58                                 asn1_read_OID(asn1, token->mechTypes + i);
  59                                 if (token->mechTypes[i]) {
  60                                         talloc_steal(token->mechTypes,
  61                                                      token->mechTypes[i]);
  62                                 }
  63                         }
  64                         token->mechTypes[i] = NULL;
  65
  66                         asn1_end_tag(asn1);
  67                         asn1_end_tag(asn1);
  68                         break;
  69                 /* Read reqFlags */
  70                 case ASN1_CONTEXT(1):
  71                         asn1_start_tag(asn1, ASN1_CONTEXT(1));
  72                         asn1_read_Integer(asn1, &token->reqFlags);
  73                         token->reqFlags |= SPNEGO_REQ_FLAG;
  74                         asn1_end_tag(asn1);
  75                         break;
  76                 /* Read mechToken */
  77                 case ASN1_CONTEXT(2):
  78                         asn1_start_tag(asn1, ASN1_CONTEXT(2));
  79                         asn1_read_OctetString(asn1, &token->mechToken);
  80                         asn1_end_tag(asn1);
  81                         break;
  82                 /* Read mecListMIC */
  83                 case ASN1_CONTEXT(3):
  84                 {
  85                         uint8_t type_peek;
  86                         asn1_start_tag(asn1, ASN1_CONTEXT(3));
  87                         if (!asn1_peek_uint8(asn1, &type_peek)) {
  88                                 asn1->has_error = True;
  89                                 break;
  90                         }
  91                         if (type_peek == ASN1_OCTET_STRING) {
  92                                 asn1_read_OctetString(asn1,
  93                                                       &token->mechListMIC);
  94                         } else {
  95                                 /* RFC 2478 says we have an Octet String here,
  96                                    but W2k sends something different... */
  97                                 char *mechListMIC;
  98                                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
  99                                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 100                                 asn1_read_GeneralString(asn1, &mechListMIC);
 101                                 asn1_pop_tag(asn1);
 102                                 asn1_pop_tag(asn1);
 103
 104                                 token->targetPrincipal = mechListMIC;
 105                         }
 106                         asn1_end_tag(asn1);
 107                         break;
 108                 }
 109                 default:
 110                         asn1->has_error = True;
 111                         break;
 112                 }
 113         }
 114
 115         asn1_end_tag(asn1);
 116         asn1_end_tag(asn1);
 117
 118         return !asn1->has_error;
 119 }
 120
 121 static BOOL write_negTokenInit(struct asn1_data *asn1, struct spnego_negTokenInit *token)
 122 {
 123         asn1_push_tag(asn1, ASN1_CONTEXT(0));
 124         asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 125
 126         /* Write mechTypes */
 127         if (token->mechTypes && *token->mechTypes) {
 128                 int i;
 129
 130                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 131                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 132                 for (i = 0; token->mechTypes[i]; i++) {
 133                         asn1_write_OID(asn1, token->mechTypes[i]);
 134                 }
 135                 asn1_pop_tag(asn1);
 136                 asn1_pop_tag(asn1);
 137         }
 138
 139         /* write reqFlags */
 140         if (token->reqFlags & SPNEGO_REQ_FLAG) {
 141                 int flags = token->reqFlags & ~SPNEGO_REQ_FLAG;
 142
 143                 asn1_push_tag(asn1, ASN1_CONTEXT(1));
 144                 asn1_write_Integer(asn1, flags);
 145                 asn1_pop_tag(asn1);
 146         }
 147
 148         /* write mechToken */
 149         if (token->mechToken.data) {
 150                 asn1_push_tag(asn1, ASN1_CONTEXT(2));
 151                 asn1_write_OctetString(asn1, token->mechToken.data,
 152                                        token->mechToken.length);
 153                 asn1_pop_tag(asn1);
 154         }
 155
 156         /* write mechListMIC */
 157         if (token->mechListMIC.data) {
 158                 asn1_push_tag(asn1, ASN1_CONTEXT(3));
 159 #if 0
 160                 /* This is what RFC 2478 says ... */
 161                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 162                                        token->mechListMIC.length);
 163 #else
 164                 /* ... but unfortunately this is what Windows
 165                    sends/expects */
 166                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 167                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 168                 asn1_push_tag(asn1, ASN1_GENERAL_STRING);
 169                 asn1_write(asn1, token->mechListMIC.data,
 170                            token->mechListMIC.length);
 171                 asn1_pop_tag(asn1);
 172                 asn1_pop_tag(asn1);
 173                 asn1_pop_tag(asn1);
 174 #endif
 175                 asn1_pop_tag(asn1);
 176         }
 177
 178         asn1_pop_tag(asn1);
 179         asn1_pop_tag(asn1);
 180
 181         return !asn1->has_error;
 182 }
 183
 184 static BOOL read_negTokenTarg(struct asn1_data *asn1, struct spnego_negTokenTarg *token)
 185 {
 186         ZERO_STRUCTP(token);
 187
 188         asn1_start_tag(asn1, ASN1_CONTEXT(1));
 189         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
 190
 191         while (!asn1->has_error && 0 < asn1_tag_remaining(asn1)) {
 192                 uint8_t context;
 193                 if (!asn1_peek_uint8(asn1, &context)) {
 194                         asn1->has_error = True;
 195                         break;
 196                 }
 197
 198                 switch (context) {
 199                 case ASN1_CONTEXT(0):
 200                         asn1_start_tag(asn1, ASN1_CONTEXT(0));
 201                         asn1_start_tag(asn1, ASN1_ENUMERATED);
 202                         asn1_read_uint8(asn1, &token->negResult);
 203                         asn1_end_tag(asn1);
 204                         asn1_end_tag(asn1);
 205                         break;
 206                 case ASN1_CONTEXT(1):
 207                         asn1_start_tag(asn1, ASN1_CONTEXT(1));
 208                         asn1_read_OID(asn1, &token->supportedMech);
 209                         asn1_end_tag(asn1);
 210                         break;
 211                 case ASN1_CONTEXT(2):
 212                         asn1_start_tag(asn1, ASN1_CONTEXT(2));
 213                         asn1_read_OctetString(asn1, &token->responseToken);
 214                         asn1_end_tag(asn1);
 215                         break;
 216                 case ASN1_CONTEXT(3):
 217                         asn1_start_tag(asn1, ASN1_CONTEXT(3));
 218                         asn1_read_OctetString(asn1, &token->mechListMIC);
 219                         asn1_end_tag(asn1);
 220                         break;
 221                 default:
 222                         asn1->has_error = True;
 223                         break;
 224                 }
 225         }
 226
 227         asn1_end_tag(asn1);
 228         asn1_end_tag(asn1);
 229
 230         return !asn1->has_error;
 231 }
 232
 233 static BOOL write_negTokenTarg(struct asn1_data *asn1, struct spnego_negTokenTarg *token)
 234 {
 235         asn1_push_tag(asn1, ASN1_CONTEXT(1));
 236         asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 237
 238         if (token->negResult != SPNEGO_NONE_RESULT) {
 239                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 240                 asn1_write_enumerated(asn1, token->negResult);
 241                 asn1_pop_tag(asn1);
 242         }
 243
 244         if (token->supportedMech) {
 245                 asn1_push_tag(asn1, ASN1_CONTEXT(1));
 246                 asn1_write_OID(asn1, token->supportedMech);
 247                 asn1_pop_tag(asn1);
 248         }
 249
 250         if (token->responseToken.data) {
 251                 asn1_push_tag(asn1, ASN1_CONTEXT(2));
 252                 asn1_write_OctetString(asn1, token->responseToken.data,
 253                                        token->responseToken.length);
 254                 asn1_pop_tag(asn1);
 255         }
 256
 257         if (token->mechListMIC.data) {
 258                 asn1_push_tag(asn1, ASN1_CONTEXT(3));
 259                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 260                                       token->mechListMIC.length);
 261                 asn1_pop_tag(asn1);
 262         }
 263
 264         asn1_pop_tag(asn1);
 265         asn1_pop_tag(asn1);
 266
 267         return !asn1->has_error;
 268 }
 269
 270 ssize_t spnego_read_data(DATA_BLOB data, struct spnego_data *token)
 271 {
 272         struct asn1_data asn1;
 273         ssize_t ret = -1;
 274         uint8_t context;
 275
 276         ZERO_STRUCTP(token);
 277         ZERO_STRUCT(asn1);
 278
 279         if (data.length == 0) {
 280                 return ret;
 281         }
 282
 283         asn1_load(&asn1, data);
 284
 285         if (!asn1_peek_uint8(&asn1, &context)) {
 286                 asn1.has_error = True;
 287         } else {
 288                 switch (context) {
 289                 case ASN1_APPLICATION(0):
 290                         asn1_start_tag(&asn1, ASN1_APPLICATION(0));
 291                         asn1_check_OID(&asn1, GENSEC_OID_SPNEGO);
 292                         if (read_negTokenInit(&asn1, &token->negTokenInit)) {
 293                                 token->type = SPNEGO_NEG_TOKEN_INIT;
 294                         }
 295                         asn1_end_tag(&asn1);
 296                         break;
 297                 case ASN1_CONTEXT(1):
 298                         if (read_negTokenTarg(&asn1, &token->negTokenTarg)) {
 299                                 token->type = SPNEGO_NEG_TOKEN_TARG;
 300                         }
 301                         break;
 302                 default:
 303                         asn1.has_error = True;
 304                         break;
 305                 }
 306         }
 307
 308         if (!asn1.has_error) ret = asn1.ofs;
 309         asn1_free(&asn1);
 310
 311         return ret;
 312 }
 313
 314 ssize_t spnego_write_data(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, struct spnego_data *spnego)
 315 {
 316         struct asn1_data asn1;
 317         ssize_t ret = -1;
 318
 319         ZERO_STRUCT(asn1);
 320
 321         switch (spnego->type) {
 322         case SPNEGO_NEG_TOKEN_INIT:
 323                 asn1_push_tag(&asn1, ASN1_APPLICATION(0));
 324                 asn1_write_OID(&asn1, GENSEC_OID_SPNEGO);
 325                 write_negTokenInit(&asn1, &spnego->negTokenInit);
 326                 asn1_pop_tag(&asn1);
 327                 break;
 328         case SPNEGO_NEG_TOKEN_TARG:
 329                 write_negTokenTarg(&asn1, &spnego->negTokenTarg);
 330                 break;
 331         default:
 332                 asn1.has_error = True;
 333                 break;
 334         }
 335
 336         if (!asn1.has_error) {
 337                 *blob = data_blob_talloc(mem_ctx, asn1.data, asn1.length);
 338                 ret = asn1.ofs;
 339         }
 340         asn1_free(&asn1);
 341
 342         return ret;
 343 }
 344
 345 BOOL spnego_free_data(struct spnego_data *spnego)
 346 {
 347         BOOL ret = True;
 348
 349         if (!spnego) goto out;
 350
 351         switch(spnego->type) {
 352         case SPNEGO_NEG_TOKEN_INIT:
 353                 if (spnego->negTokenInit.mechTypes) {
 354                         talloc_free(spnego->negTokenInit.mechTypes);
 355                 }
 356                 data_blob_free(&spnego->negTokenInit.mechToken);
 357                 data_blob_free(&spnego->negTokenInit.mechListMIC);
 358                 talloc_free(spnego->negTokenInit.targetPrincipal);
 359                 break;
 360         case SPNEGO_NEG_TOKEN_TARG:
 361                 if (spnego->negTokenTarg.supportedMech) {
 362                         talloc_free(discard_const(spnego->negTokenTarg.supportedMech));
 363                 }
 364                 data_blob_free(&spnego->negTokenTarg.responseToken);
 365                 data_blob_free(&spnego->negTokenTarg.mechListMIC);
 366                 break;
 367         default:
 368                 ret = False;
 369                 break;
 370         }
 371         ZERO_STRUCTP(spnego);
 372 out:
 373         return ret;
 374 }
 375