source4/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 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
  26 #undef DBGC_CLASS
  27 #define DBGC_CLASS DBGC_AUTH
  28
  29 static BOOL read_negTokenInit(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 = malloc(sizeof(*token->mechTypes));
  51                         for (i = 0; !asn1->has_error &&
  52                                      0 < asn1_tag_remaining(asn1); i++) {
  53                                 token->mechTypes =
  54                                         realloc(token->mechTypes, (i + 2) *
  55                                                 sizeof(*token->mechTypes));
  56                                 asn1_read_OID(asn1, token->mechTypes + i);
  57                         }
  58                         token->mechTypes[i] = NULL;
  59
  60                         asn1_end_tag(asn1);
  61                         asn1_end_tag(asn1);
  62                         break;
  63                 /* Read reqFlags */
  64                 case ASN1_CONTEXT(1):
  65                         asn1_start_tag(asn1, ASN1_CONTEXT(1));
  66                         asn1_read_Integer(asn1, &token->reqFlags);
  67                         token->reqFlags |= SPNEGO_REQ_FLAG;
  68                         asn1_end_tag(asn1);
  69                         break;
  70                 /* Read mechToken */
  71                 case ASN1_CONTEXT(2):
  72                         asn1_start_tag(asn1, ASN1_CONTEXT(2));
  73                         asn1_read_OctetString(asn1, &token->mechToken);
  74                         asn1_end_tag(asn1);
  75                         break;
  76                 /* Read mecListMIC */
  77                 case ASN1_CONTEXT(3):
  78                 {
  79                         uint8_t type_peek;
  80                         asn1_start_tag(asn1, ASN1_CONTEXT(3));
  81                         if (!asn1_peek_uint8(asn1, &type_peek)) {
  82                                 asn1->has_error = True;
  83                                 break;
  84                         }
  85                         if (type_peek == ASN1_OCTET_STRING) {
  86                                 asn1_read_OctetString(asn1,
  87                                                       &token->mechListMIC);
  88                         } else {
  89                                 /* RFC 2478 says we have an Octet String here,
  90                                    but W2k sends something different... */
  91                                 char *mechListMIC;
  92                                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
  93                                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
  94                                 asn1_read_GeneralString(asn1, &mechListMIC);
  95                                 asn1_pop_tag(asn1);
  96                                 asn1_pop_tag(asn1);
  97
  98                                 token->targetPrincipal = mechListMIC;
  99                         }
 100                         asn1_end_tag(asn1);
 101                         break;
 102                 }
 103                 default:
 104                         asn1->has_error = True;
 105                         break;
 106                 }
 107         }
 108
 109         asn1_end_tag(asn1);
 110         asn1_end_tag(asn1);
 111
 112         return !asn1->has_error;
 113 }
 114
 115 static BOOL write_negTokenInit(ASN1_DATA *asn1, struct spnego_negTokenInit *token)
 116 {
 117         asn1_push_tag(asn1, ASN1_CONTEXT(0));
 118         asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 119
 120         /* Write mechTypes */
 121         if (token->mechTypes && *token->mechTypes) {
 122                 int i;
 123
 124                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 125                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 126                 for (i = 0; token->mechTypes[i]; i++) {
 127                         asn1_write_OID(asn1, token->mechTypes[i]);
 128                 }
 129                 asn1_pop_tag(asn1);
 130                 asn1_pop_tag(asn1);
 131         }
 132
 133         /* write reqFlags */
 134         if (token->reqFlags & SPNEGO_REQ_FLAG) {
 135                 int flags = token->reqFlags & ~SPNEGO_REQ_FLAG;
 136
 137                 asn1_push_tag(asn1, ASN1_CONTEXT(1));
 138                 asn1_write_Integer(asn1, flags);
 139                 asn1_pop_tag(asn1);
 140         }
 141
 142         /* write mechToken */
 143         if (token->mechToken.data) {
 144                 asn1_push_tag(asn1, ASN1_CONTEXT(2));
 145                 asn1_write_OctetString(asn1, token->mechToken.data,
 146                                        token->mechToken.length);
 147                 asn1_pop_tag(asn1);
 148         }
 149
 150         /* write mechListMIC */
 151         if (token->mechListMIC.data) {
 152                 asn1_push_tag(asn1, ASN1_CONTEXT(3));
 153 #if 0
 154                 /* This is what RFC 2478 says ... */
 155                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 156                                        token->mechListMIC.length);
 157 #else
 158                 /* ... but unfortunately this is what Windows
 159                    sends/expects */
 160                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 161                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 162                 asn1_push_tag(asn1, ASN1_GENERAL_STRING);
 163                 asn1_write(asn1, token->mechListMIC.data,
 164                            token->mechListMIC.length);
 165                 asn1_pop_tag(asn1);
 166                 asn1_pop_tag(asn1);
 167                 asn1_pop_tag(asn1);
 168 #endif
 169                 asn1_pop_tag(asn1);
 170         }
 171
 172         asn1_pop_tag(asn1);
 173         asn1_pop_tag(asn1);
 174
 175         return !asn1->has_error;
 176 }
 177
 178 static BOOL read_negTokenTarg(ASN1_DATA *asn1, struct spnego_negTokenTarg *token)
 179 {
 180         ZERO_STRUCTP(token);
 181
 182         asn1_start_tag(asn1, ASN1_CONTEXT(1));
 183         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
 184
 185         while (!asn1->has_error && 0 < asn1_tag_remaining(asn1)) {
 186                 uint8_t context;
 187                 if (!asn1_peek_uint8(asn1, &context)) {
 188                         asn1->has_error = True;
 189                         break;
 190                 }
 191
 192                 switch (context) {
 193                 case ASN1_CONTEXT(0):
 194                         asn1_start_tag(asn1, ASN1_CONTEXT(0));
 195                         asn1_start_tag(asn1, ASN1_ENUMERATED);
 196                         asn1_read_uint8(asn1, &token->negResult);
 197                         asn1_end_tag(asn1);
 198                         asn1_end_tag(asn1);
 199                         break;
 200                 case ASN1_CONTEXT(1):
 201                         asn1_start_tag(asn1, ASN1_CONTEXT(1));
 202                         asn1_read_OID(asn1, &token->supportedMech);
 203                         asn1_end_tag(asn1);
 204                         break;
 205                 case ASN1_CONTEXT(2):
 206                         asn1_start_tag(asn1, ASN1_CONTEXT(2));
 207                         asn1_read_OctetString(asn1, &token->responseToken);
 208                         asn1_end_tag(asn1);
 209                         break;
 210                 case ASN1_CONTEXT(3):
 211                         asn1_start_tag(asn1, ASN1_CONTEXT(3));
 212                         asn1_read_OctetString(asn1, &token->mechListMIC);
 213                         asn1_end_tag(asn1);
 214                         break;
 215                 default:
 216                         asn1->has_error = True;
 217                         break;
 218                 }
 219         }
 220
 221         asn1_end_tag(asn1);
 222         asn1_end_tag(asn1);
 223
 224         return !asn1->has_error;
 225 }
 226
 227 static BOOL write_negTokenTarg(ASN1_DATA *asn1, struct spnego_negTokenTarg *token)
 228 {
 229         asn1_push_tag(asn1, ASN1_CONTEXT(1));
 230         asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 231
 232         if (token->negResult != SPNEGO_NONE_RESULT) {
 233                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 234                 asn1_write_enumerated(asn1, token->negResult);
 235                 asn1_pop_tag(asn1);
 236         }
 237
 238         if (token->supportedMech) {
 239                 asn1_push_tag(asn1, ASN1_CONTEXT(1));
 240                 asn1_write_OID(asn1, token->supportedMech);
 241                 asn1_pop_tag(asn1);
 242         }
 243
 244         if (token->responseToken.data) {
 245                 asn1_push_tag(asn1, ASN1_CONTEXT(2));
 246                 asn1_write_OctetString(asn1, token->responseToken.data,
 247                                        token->responseToken.length);
 248                 asn1_pop_tag(asn1);
 249         }
 250
 251         if (token->mechListMIC.data) {
 252                 asn1_push_tag(asn1, ASN1_CONTEXT(3));
 253                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 254                                       token->mechListMIC.length);
 255                 asn1_pop_tag(asn1);
 256         }
 257
 258         asn1_pop_tag(asn1);
 259         asn1_pop_tag(asn1);
 260
 261         return !asn1->has_error;
 262 }
 263
 264 ssize_t spnego_read_data(DATA_BLOB data, struct spnego_data *token)
 265 {
 266         ASN1_DATA asn1;
 267         ssize_t ret = -1;
 268         uint8_t context;
 269
 270         ZERO_STRUCTP(token);
 271         ZERO_STRUCT(asn1);
 272
 273         if (data.length == 0) {
 274                 return ret;
 275         }
 276
 277         asn1_load(&asn1, data);
 278
 279         if (!asn1_peek_uint8(&asn1, &context)) {
 280                 asn1.has_error = True;
 281         } else {
 282                 switch (context) {
 283                 case ASN1_APPLICATION(0):
 284                         asn1_start_tag(&asn1, ASN1_APPLICATION(0));
 285                         asn1_check_OID(&asn1, OID_SPNEGO);
 286                         if (read_negTokenInit(&asn1, &token->negTokenInit)) {
 287                                 token->type = SPNEGO_NEG_TOKEN_INIT;
 288                         }
 289                         asn1_end_tag(&asn1);
 290                         break;
 291                 case ASN1_CONTEXT(1):
 292                         if (read_negTokenTarg(&asn1, &token->negTokenTarg)) {
 293                                 token->type = SPNEGO_NEG_TOKEN_TARG;
 294                         }
 295                         break;
 296                 default:
 297                         asn1.has_error = True;
 298                         break;
 299                 }
 300         }
 301
 302         if (!asn1.has_error) ret = asn1.ofs;
 303         asn1_free(&asn1);
 304
 305         return ret;
 306 }
 307
 308 ssize_t spnego_write_data(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, struct spnego_data *spnego)
 309 {
 310         ASN1_DATA asn1;
 311         ssize_t ret = -1;
 312
 313         ZERO_STRUCT(asn1);
 314
 315         switch (spnego->type) {
 316         case SPNEGO_NEG_TOKEN_INIT:
 317                 asn1_push_tag(&asn1, ASN1_APPLICATION(0));
 318                 asn1_write_OID(&asn1, OID_SPNEGO);
 319                 write_negTokenInit(&asn1, &spnego->negTokenInit);
 320                 asn1_pop_tag(&asn1);
 321                 break;
 322         case SPNEGO_NEG_TOKEN_TARG:
 323                 write_negTokenTarg(&asn1, &spnego->negTokenTarg);
 324                 break;
 325         default:
 326                 asn1.has_error = True;
 327                 break;
 328         }
 329
 330         if (!asn1.has_error) {
 331                 *blob = data_blob_talloc(mem_ctx, asn1.data, asn1.length);
 332                 ret = asn1.ofs;
 333         }
 334         asn1_free(&asn1);
 335
 336         return ret;
 337 }
 338
 339 BOOL spnego_free_data(struct spnego_data *spnego)
 340 {
 341         BOOL ret = True;
 342
 343         if (!spnego) goto out;
 344
 345         switch(spnego->type) {
 346         case SPNEGO_NEG_TOKEN_INIT:
 347                 if (spnego->negTokenInit.mechTypes) {
 348                         int i;
 349                         for (i = 0; spnego->negTokenInit.mechTypes[i]; i++) {
 350                                 free(spnego->negTokenInit.mechTypes[i]);
 351                         }
 352                         free(spnego->negTokenInit.mechTypes);
 353                 }
 354                 data_blob_free(&spnego->negTokenInit.mechToken);
 355                 data_blob_free(&spnego->negTokenInit.mechListMIC);
 356                 SAFE_FREE(spnego->negTokenInit.targetPrincipal);
 357                 break;
 358         case SPNEGO_NEG_TOKEN_TARG:
 359                 if (spnego->negTokenTarg.supportedMech) {
 360                         free(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