source4/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 static BOOL read_negTokenInit(struct asn1_data *asn1, 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                                 token->mechTypes = talloc_realloc(NULL,
  53                                                                   token->mechTypes,
  54                                                                   const char *, i+2);
  55                                 asn1_read_OID(asn1, token->mechTypes + i);
  56                                 if (token->mechTypes[i]) {
  57                                         talloc_steal(token->mechTypes,
  58                                                      token->mechTypes[i]);
  59                                 }
  60                         }
  61                         token->mechTypes[i] = NULL;
  62
  63                         asn1_end_tag(asn1);
  64                         asn1_end_tag(asn1);
  65                         break;
  66                 /* Read reqFlags */
  67                 case ASN1_CONTEXT(1):
  68                         asn1_start_tag(asn1, ASN1_CONTEXT(1));
  69                         asn1_read_Integer(asn1, &token->reqFlags);
  70                         token->reqFlags |= SPNEGO_REQ_FLAG;
  71                         asn1_end_tag(asn1);
  72                         break;
  73                 /* Read mechToken */
  74                 case ASN1_CONTEXT(2):
  75                         asn1_start_tag(asn1, ASN1_CONTEXT(2));
  76                         asn1_read_OctetString(asn1, &token->mechToken);
  77                         asn1_end_tag(asn1);
  78                         break;
  79                 /* Read mecListMIC */
  80                 case ASN1_CONTEXT(3):
  81                 {
  82                         uint8_t type_peek;
  83                         asn1_start_tag(asn1, ASN1_CONTEXT(3));
  84                         if (!asn1_peek_uint8(asn1, &type_peek)) {
  85                                 asn1->has_error = True;
  86                                 break;
  87                         }
  88                         if (type_peek == ASN1_OCTET_STRING) {
  89                                 asn1_read_OctetString(asn1,
  90                                                       &token->mechListMIC);
  91                         } else {
  92                                 /* RFC 2478 says we have an Octet String here,
  93                                    but W2k sends something different... */
  94                                 char *mechListMIC;
  95                                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
  96                                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
  97                                 asn1_read_GeneralString(asn1, &mechListMIC);
  98                                 asn1_pop_tag(asn1);
  99                                 asn1_pop_tag(asn1);
 100
 101                                 token->targetPrincipal = mechListMIC;
 102                         }
 103                         asn1_end_tag(asn1);
 104                         break;
 105                 }
 106                 default:
 107                         asn1->has_error = True;
 108                         break;
 109                 }
 110         }
 111
 112         asn1_end_tag(asn1);
 113         asn1_end_tag(asn1);
 114
 115         return !asn1->has_error;
 116 }
 117
 118 static BOOL write_negTokenInit(struct asn1_data *asn1, struct spnego_negTokenInit *token)
 119 {
 120         asn1_push_tag(asn1, ASN1_CONTEXT(0));
 121         asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 122
 123         /* Write mechTypes */
 124         if (token->mechTypes && *token->mechTypes) {
 125                 int i;
 126
 127                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 128                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 129                 for (i = 0; token->mechTypes[i]; i++) {
 130                         asn1_write_OID(asn1, token->mechTypes[i]);
 131                 }
 132                 asn1_pop_tag(asn1);
 133                 asn1_pop_tag(asn1);
 134         }
 135
 136         /* write reqFlags */
 137         if (token->reqFlags & SPNEGO_REQ_FLAG) {
 138                 int flags = token->reqFlags & ~SPNEGO_REQ_FLAG;
 139
 140                 asn1_push_tag(asn1, ASN1_CONTEXT(1));
 141                 asn1_write_Integer(asn1, flags);
 142                 asn1_pop_tag(asn1);
 143         }
 144
 145         /* write mechToken */
 146         if (token->mechToken.data) {
 147                 asn1_push_tag(asn1, ASN1_CONTEXT(2));
 148                 asn1_write_OctetString(asn1, token->mechToken.data,
 149                                        token->mechToken.length);
 150                 asn1_pop_tag(asn1);
 151         }
 152
 153         /* write mechListMIC */
 154         if (token->mechListMIC.data) {
 155                 asn1_push_tag(asn1, ASN1_CONTEXT(3));
 156 #if 0
 157                 /* This is what RFC 2478 says ... */
 158                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 159                                        token->mechListMIC.length);
 160 #else
 161                 /* ... but unfortunately this is what Windows
 162                    sends/expects */
 163                 asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 164                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 165                 asn1_push_tag(asn1, ASN1_GENERAL_STRING);
 166                 asn1_write(asn1, token->mechListMIC.data,
 167                            token->mechListMIC.length);
 168                 asn1_pop_tag(asn1);
 169                 asn1_pop_tag(asn1);
 170                 asn1_pop_tag(asn1);
 171 #endif
 172                 asn1_pop_tag(asn1);
 173         }
 174
 175         asn1_pop_tag(asn1);
 176         asn1_pop_tag(asn1);
 177
 178         return !asn1->has_error;
 179 }
 180
 181 static BOOL read_negTokenTarg(struct asn1_data *asn1, struct spnego_negTokenTarg *token)
 182 {
 183         ZERO_STRUCTP(token);
 184
 185         asn1_start_tag(asn1, ASN1_CONTEXT(1));
 186         asn1_start_tag(asn1, ASN1_SEQUENCE(0));
 187
 188         while (!asn1->has_error && 0 < asn1_tag_remaining(asn1)) {
 189                 uint8_t context;
 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, &token->supportedMech);
 206                         asn1_end_tag(asn1);
 207                         break;
 208                 case ASN1_CONTEXT(2):
 209                         asn1_start_tag(asn1, ASN1_CONTEXT(2));
 210                         asn1_read_OctetString(asn1, &token->responseToken);
 211                         asn1_end_tag(asn1);
 212                         break;
 213                 case ASN1_CONTEXT(3):
 214                         asn1_start_tag(asn1, ASN1_CONTEXT(3));
 215                         asn1_read_OctetString(asn1, &token->mechListMIC);
 216                         asn1_end_tag(asn1);
 217                         break;
 218                 default:
 219                         asn1->has_error = True;
 220                         break;
 221                 }
 222         }
 223
 224         asn1_end_tag(asn1);
 225         asn1_end_tag(asn1);
 226
 227         return !asn1->has_error;
 228 }
 229
 230 static BOOL write_negTokenTarg(struct asn1_data *asn1, struct spnego_negTokenTarg *token)
 231 {
 232         asn1_push_tag(asn1, ASN1_CONTEXT(1));
 233         asn1_push_tag(asn1, ASN1_SEQUENCE(0));
 234
 235         if (token->negResult != SPNEGO_NONE_RESULT) {
 236                 asn1_push_tag(asn1, ASN1_CONTEXT(0));
 237                 asn1_write_enumerated(asn1, token->negResult);
 238                 asn1_pop_tag(asn1);
 239         }
 240
 241         if (token->supportedMech) {
 242                 asn1_push_tag(asn1, ASN1_CONTEXT(1));
 243                 asn1_write_OID(asn1, token->supportedMech);
 244                 asn1_pop_tag(asn1);
 245         }
 246
 247         if (token->responseToken.data) {
 248                 asn1_push_tag(asn1, ASN1_CONTEXT(2));
 249                 asn1_write_OctetString(asn1, token->responseToken.data,
 250                                        token->responseToken.length);
 251                 asn1_pop_tag(asn1);
 252         }
 253
 254         if (token->mechListMIC.data) {
 255                 asn1_push_tag(asn1, ASN1_CONTEXT(3));
 256                 asn1_write_OctetString(asn1, token->mechListMIC.data,
 257                                       token->mechListMIC.length);
 258                 asn1_pop_tag(asn1);
 259         }
 260
 261         asn1_pop_tag(asn1);
 262         asn1_pop_tag(asn1);
 263
 264         return !asn1->has_error;
 265 }
 266
 267 ssize_t spnego_read_data(DATA_BLOB data, struct spnego_data *token)
 268 {
 269         struct asn1_data asn1;
 270         ssize_t ret = -1;
 271         uint8_t context;
 272
 273         ZERO_STRUCTP(token);
 274         ZERO_STRUCT(asn1);
 275
 276         if (data.length == 0) {
 277                 return ret;
 278         }
 279
 280         asn1_load(&asn1, data);
 281
 282         if (!asn1_peek_uint8(&asn1, &context)) {
 283                 asn1.has_error = True;
 284         } else {
 285                 switch (context) {
 286                 case ASN1_APPLICATION(0):
 287                         asn1_start_tag(&asn1, ASN1_APPLICATION(0));
 288                         asn1_check_OID(&asn1, GENSEC_OID_SPNEGO);
 289                         if (read_negTokenInit(&asn1, &token->negTokenInit)) {
 290                                 token->type = SPNEGO_NEG_TOKEN_INIT;
 291                         }
 292                         asn1_end_tag(&asn1);
 293                         break;
 294                 case ASN1_CONTEXT(1):
 295                         if (read_negTokenTarg(&asn1, &token->negTokenTarg)) {
 296                                 token->type = SPNEGO_NEG_TOKEN_TARG;
 297                         }
 298                         break;
 299                 default:
 300                         asn1.has_error = True;
 301                         break;
 302                 }
 303         }
 304
 305         if (!asn1.has_error) ret = asn1.ofs;
 306         asn1_free(&asn1);
 307
 308         return ret;
 309 }
 310
 311 ssize_t spnego_write_data(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, struct spnego_data *spnego)
 312 {
 313         struct asn1_data asn1;
 314         ssize_t ret = -1;
 315
 316         ZERO_STRUCT(asn1);
 317
 318         switch (spnego->type) {
 319         case SPNEGO_NEG_TOKEN_INIT:
 320                 asn1_push_tag(&asn1, ASN1_APPLICATION(0));
 321                 asn1_write_OID(&asn1, GENSEC_OID_SPNEGO);
 322                 write_negTokenInit(&asn1, &spnego->negTokenInit);
 323                 asn1_pop_tag(&asn1);
 324                 break;
 325         case SPNEGO_NEG_TOKEN_TARG:
 326                 write_negTokenTarg(&asn1, &spnego->negTokenTarg);
 327                 break;
 328         default:
 329                 asn1.has_error = True;
 330                 break;
 331         }
 332
 333         if (!asn1.has_error) {
 334                 *blob = data_blob_talloc(mem_ctx, asn1.data, asn1.length);
 335                 ret = asn1.ofs;
 336         }
 337         asn1_free(&asn1);
 338
 339         return ret;
 340 }
 341
 342 BOOL spnego_free_data(struct spnego_data *spnego)
 343 {
 344         BOOL ret = True;
 345
 346         if (!spnego) goto out;
 347
 348         switch(spnego->type) {
 349         case SPNEGO_NEG_TOKEN_INIT:
 350                 if (spnego->negTokenInit.mechTypes) {
 351                         talloc_free(spnego->negTokenInit.mechTypes);
 352                 }
 353                 data_blob_free(&spnego->negTokenInit.mechToken);
 354                 data_blob_free(&spnego->negTokenInit.mechListMIC);
 355                 talloc_free(spnego->negTokenInit.targetPrincipal);
 356                 break;
 357         case SPNEGO_NEG_TOKEN_TARG:
 358                 if (spnego->negTokenTarg.supportedMech) {
 359                         talloc_free(discard_const(spnego->negTokenTarg.supportedMech));
 360                 }
 361                 data_blob_free(&spnego->negTokenTarg.responseToken);
 362                 data_blob_free(&spnego->negTokenTarg.mechListMIC);
 363                 break;
 364         default:
 365                 ret = False;
 366                 break;
 367         }
 368         ZERO_STRUCTP(spnego);
 369 out:
 370         return ret;
 371 }
 372