auth/kerberos/gssapi_helper.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    GSSAPI helper functions
   4
   5    Copyright (C) Stefan Metzmacher 2008,2015
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "system/gssapi.h"
  23 #include "auth/kerberos/pac_utils.h"
  24 #include "auth/kerberos/gssapi_helper.h"
  25
  26 #undef DBGC_CLASS
  27 #define DBGC_CLASS DBGC_AUTH
  28
  29 size_t gssapi_get_sig_size(gss_ctx_id_t gssapi_context,
  30                            const gss_OID mech,
  31                            uint32_t gss_want_flags,
  32                            size_t data_size)
  33 {
  34         TALLOC_CTX *frame = talloc_stackframe();
  35         size_t sig_size = 0;
  36
  37         if (gss_want_flags & GSS_C_CONF_FLAG) {
  38                 OM_uint32 min_stat, maj_stat;
  39                 bool want_sealing = true;
  40                 int sealed = 0;
  41                 gss_iov_buffer_desc iov[2];
  42
  43                 if (!(gss_want_flags & GSS_C_DCE_STYLE)) {
  44                         TALLOC_FREE(frame);
  45                         return 0;
  46                 }
  47
  48                 /*
  49                  * gss_wrap_iov_length() only needs the type and length
  50                  */
  51                 iov[0].type = GSS_IOV_BUFFER_TYPE_HEADER;
  52                 iov[0].buffer.value = NULL;
  53                 iov[0].buffer.length = 0;
  54                 iov[1].type = GSS_IOV_BUFFER_TYPE_DATA;
  55                 iov[1].buffer.value = NULL;
  56                 iov[1].buffer.length = data_size;
  57
  58                 maj_stat = gss_wrap_iov_length(&min_stat,
  59                                                gssapi_context,
  60                                                want_sealing,
  61                                                GSS_C_QOP_DEFAULT,
  62                                                &sealed,
  63                                                iov, ARRAY_SIZE(iov));
  64                 if (maj_stat) {
  65                         DEBUG(0, ("gss_wrap_iov_length failed with [%s]\n",
  66                                   gssapi_error_string(frame,
  67                                                       maj_stat,
  68                                                       min_stat,
  69                                                       mech)));
  70                         TALLOC_FREE(frame);
  71                         return 0;
  72                 }
  73
  74                 sig_size = iov[0].buffer.length;
  75         } else if (gss_want_flags & GSS_C_INTEG_FLAG) {
  76                 NTSTATUS status;
  77                 uint32_t keytype;
  78
  79                 status = gssapi_get_session_key(frame,
  80                                                 gssapi_context,
  81                                                 NULL, &keytype);
  82                 if (!NT_STATUS_IS_OK(status)) {
  83                         TALLOC_FREE(frame);
  84                         return 0;
  85                 }
  86
  87                 switch (keytype) {
  88                 case ENCTYPE_DES_CBC_MD5:
  89                 case ENCTYPE_DES_CBC_CRC:
  90                 case ENCTYPE_ARCFOUR_HMAC:
  91                 case ENCTYPE_ARCFOUR_HMAC_EXP:
  92                         sig_size = 37;
  93                         break;
  94                 default:
  95                         sig_size = 28;
  96                         break;
  97                 }
  98         }
  99
 100         TALLOC_FREE(frame);
 101         return sig_size;
 102 }
 103
 104 NTSTATUS gssapi_seal_packet(gss_ctx_id_t gssapi_context,
 105                             const gss_OID mech,
 106                             bool hdr_signing, size_t sig_size,
 107                             uint8_t *data, size_t length,
 108                             const uint8_t *whole_pdu, size_t pdu_length,
 109                             TALLOC_CTX *mem_ctx,
 110                             DATA_BLOB *sig)
 111 {
 112         OM_uint32 maj_stat, min_stat;
 113         gss_iov_buffer_desc iov[4];
 114         int req_seal = 1;
 115         int sealed = 0;
 116         const uint8_t *pre_sign_ptr = NULL;
 117         size_t pre_sign_len = 0;
 118         const uint8_t *post_sign_ptr = NULL;
 119         size_t post_sign_len = 0;
 120
 121         if (hdr_signing) {
 122                 const uint8_t *de = data + length;
 123                 const uint8_t *we = whole_pdu + pdu_length;
 124
 125                 if (data < whole_pdu) {
 126                         return NT_STATUS_INVALID_PARAMETER;
 127                 }
 128
 129                 if (de > we) {
 130                         return NT_STATUS_INVALID_PARAMETER;
 131                 }
 132
 133                 pre_sign_len = data - whole_pdu;
 134                 if (pre_sign_len > 0) {
 135                         pre_sign_ptr = whole_pdu;
 136                 }
 137                 post_sign_len = we - de;
 138                 if (post_sign_len > 0) {
 139                         post_sign_ptr = de;
 140                 }
 141         }
 142
 143         sig->length = sig_size;
 144         if (sig->length == 0) {
 145                 return NT_STATUS_ACCESS_DENIED;
 146         }
 147
 148         sig->data = talloc_zero_array(mem_ctx, uint8_t, sig->length);
 149         if (sig->data == NULL) {
 150                 return NT_STATUS_NO_MEMORY;
 151         }
 152
 153         iov[0].type          = GSS_IOV_BUFFER_TYPE_HEADER;
 154         iov[0].buffer.length = sig->length;
 155         iov[0].buffer.value  = sig->data;
 156
 157         if (pre_sign_ptr != NULL) {
 158                 iov[1].type = GSS_IOV_BUFFER_TYPE_SIGN_ONLY;
 159                 iov[1].buffer.length = pre_sign_len;
 160                 iov[1].buffer.value = discard_const(pre_sign_ptr);
 161         } else {
 162                 iov[1].type = GSS_IOV_BUFFER_TYPE_EMPTY;
 163                 iov[1].buffer.length = 0;
 164                 iov[1].buffer.value = NULL;
 165         }
 166
 167         /* data is encrypted in place, which is ok */
 168         iov[2].type          = GSS_IOV_BUFFER_TYPE_DATA;
 169         iov[2].buffer.length = length;
 170         iov[2].buffer.value  = data;
 171
 172         if (post_sign_ptr != NULL) {
 173                 iov[3].type = GSS_IOV_BUFFER_TYPE_SIGN_ONLY;
 174                 iov[3].buffer.length = post_sign_len;
 175                 iov[3].buffer.value = discard_const(post_sign_ptr);
 176         } else {
 177                 iov[3].type = GSS_IOV_BUFFER_TYPE_EMPTY;
 178                 iov[3].buffer.length = 0;
 179                 iov[3].buffer.value = NULL;
 180         }
 181
 182         maj_stat = gss_wrap_iov(&min_stat,
 183                                 gssapi_context,
 184                                 req_seal,
 185                                 GSS_C_QOP_DEFAULT,
 186                                 &sealed,
 187                                 iov, ARRAY_SIZE(iov));
 188         if (GSS_ERROR(maj_stat)) {
 189                 char *error_string = gssapi_error_string(mem_ctx,
 190                                                          maj_stat,
 191                                                          min_stat,
 192                                                          mech);
 193                 DEBUG(1, ("gss_wrap_iov failed: %s\n", error_string));
 194                 talloc_free(error_string);
 195                 data_blob_free(sig);
 196                 return NT_STATUS_ACCESS_DENIED;
 197         }
 198
 199         if (req_seal == 1 && sealed == 0) {
 200                 DEBUG(0, ("gss_wrap_iov says data was not sealed!\n"));
 201                 data_blob_free(sig);
 202                 return NT_STATUS_ACCESS_DENIED;
 203         }
 204
 205         dump_data_pw("gssapi_seal_packet: sig\n", sig->data, sig->length);
 206         dump_data_pw("gssapi_seal_packet: sealed\n", data, length);
 207
 208         DEBUG(10, ("Sealed %d bytes, and got %d bytes header/signature.\n",
 209                    (int)iov[2].buffer.length, (int)iov[0].buffer.length));
 210
 211         return NT_STATUS_OK;
 212 }
 213
 214 NTSTATUS gssapi_unseal_packet(gss_ctx_id_t gssapi_context,
 215                               const gss_OID mech,
 216                               bool hdr_signing,
 217                               uint8_t *data, size_t length,
 218                               const uint8_t *whole_pdu, size_t pdu_length,
 219                               const DATA_BLOB *sig)
 220 {
 221         OM_uint32 maj_stat, min_stat;
 222         gss_iov_buffer_desc iov[4];
 223         gss_qop_t qop_state;
 224         int sealed = 0;
 225         const uint8_t *pre_sign_ptr = NULL;
 226         size_t pre_sign_len = 0;
 227         const uint8_t *post_sign_ptr = NULL;
 228         size_t post_sign_len = 0;
 229
 230         if (hdr_signing) {
 231                 const uint8_t *de = data + length;
 232                 const uint8_t *we = whole_pdu + pdu_length;
 233
 234                 if (data < whole_pdu) {
 235                         return NT_STATUS_INVALID_PARAMETER;
 236                 }
 237
 238                 if (de > we) {
 239                         return NT_STATUS_INVALID_PARAMETER;
 240                 }
 241
 242                 pre_sign_len = data - whole_pdu;
 243                 if (pre_sign_len > 0) {
 244                         pre_sign_ptr = whole_pdu;
 245                 }
 246                 post_sign_len = we - de;
 247                 if (post_sign_len > 0) {
 248                         post_sign_ptr = de;
 249                 }
 250         }
 251
 252         dump_data_pw("gssapi_unseal_packet: sig\n", sig->data, sig->length);
 253         dump_data_pw("gssapi_unseal_packet: sealed\n", data, length);
 254
 255         iov[0].type          = GSS_IOV_BUFFER_TYPE_HEADER;
 256         iov[0].buffer.length = sig->length;
 257         iov[0].buffer.value  = sig->data;
 258
 259         if (pre_sign_ptr != NULL) {
 260                 iov[1].type = GSS_IOV_BUFFER_TYPE_SIGN_ONLY;
 261                 iov[1].buffer.length = pre_sign_len;
 262                 iov[1].buffer.value = discard_const(pre_sign_ptr);
 263         } else {
 264                 iov[1].type = GSS_IOV_BUFFER_TYPE_EMPTY;
 265                 iov[1].buffer.length = 0;
 266                 iov[1].buffer.value = NULL;
 267         }
 268
 269         /* data is encrypted in place, which is ok */
 270         iov[2].type          = GSS_IOV_BUFFER_TYPE_DATA;
 271         iov[2].buffer.length = length;
 272         iov[2].buffer.value  = data;
 273
 274         if (post_sign_ptr != NULL) {
 275                 iov[3].type = GSS_IOV_BUFFER_TYPE_SIGN_ONLY;
 276                 iov[3].buffer.length = post_sign_len;
 277                 iov[3].buffer.value = discard_const(post_sign_ptr);
 278         } else {
 279                 iov[3].type = GSS_IOV_BUFFER_TYPE_EMPTY;
 280                 iov[3].buffer.length = 0;
 281                 iov[3].buffer.value = NULL;
 282         }
 283
 284         maj_stat = gss_unwrap_iov(&min_stat,
 285                                   gssapi_context,
 286                                   &sealed,
 287                                   &qop_state,
 288                                   iov, ARRAY_SIZE(iov));
 289         if (GSS_ERROR(maj_stat)) {
 290                 char *error_string = gssapi_error_string(NULL,
 291                                                          maj_stat,
 292                                                          min_stat,
 293                                                          mech);
 294                 DEBUG(1, ("gss_unwrap_iov failed: %s\n", error_string));
 295                 talloc_free(error_string);
 296
 297                 return NT_STATUS_ACCESS_DENIED;
 298         }
 299
 300         if (sealed == 0) {
 301                 DEBUG(0, ("gss_unwrap_iov says data was not sealed!\n"));
 302                 return NT_STATUS_ACCESS_DENIED;
 303         }
 304
 305         DEBUG(10, ("Unsealed %d bytes, with %d bytes header/signature.\n",
 306                    (int)iov[2].buffer.length, (int)iov[0].buffer.length));
 307
 308         return NT_STATUS_OK;
 309 }
 310
 311 NTSTATUS gssapi_sign_packet(gss_ctx_id_t gssapi_context,
 312                             const gss_OID mech,
 313                             bool hdr_signing,
 314                             const uint8_t *data, size_t length,
 315                             const uint8_t *whole_pdu, size_t pdu_length,
 316                             TALLOC_CTX *mem_ctx,
 317                             DATA_BLOB *sig)
 318 {
 319         OM_uint32 maj_stat, min_stat;
 320         gss_buffer_desc input_token, output_token;
 321
 322         if (hdr_signing) {
 323                 input_token.length = pdu_length;
 324                 input_token.value = discard_const_p(uint8_t *, whole_pdu);
 325         } else {
 326                 input_token.length = length;
 327                 input_token.value = discard_const_p(uint8_t *, data);
 328         }
 329
 330         maj_stat = gss_get_mic(&min_stat,
 331                                gssapi_context,
 332                                GSS_C_QOP_DEFAULT,
 333                                &input_token,
 334                                &output_token);
 335         if (GSS_ERROR(maj_stat)) {
 336                 char *error_string = gssapi_error_string(mem_ctx,
 337                                                          maj_stat,
 338                                                          min_stat,
 339                                                          mech);
 340                 DEBUG(1, ("GSS GetMic failed: %s\n", error_string));
 341                 talloc_free(error_string);
 342                 return NT_STATUS_ACCESS_DENIED;
 343         }
 344
 345         *sig = data_blob_talloc(mem_ctx, (uint8_t *)output_token.value, output_token.length);
 346         gss_release_buffer(&min_stat, &output_token);
 347         if (sig->data == NULL) {
 348                 return NT_STATUS_NO_MEMORY;
 349         }
 350
 351         dump_data_pw("gssapi_sign_packet: sig\n", sig->data, sig->length);
 352
 353         return NT_STATUS_OK;
 354 }
 355
 356 NTSTATUS gssapi_check_packet(gss_ctx_id_t gssapi_context,
 357                              const gss_OID mech,
 358                              bool hdr_signing,
 359                              const uint8_t *data, size_t length,
 360                              const uint8_t *whole_pdu, size_t pdu_length,
 361                              const DATA_BLOB *sig)
 362 {
 363         OM_uint32 maj_stat, min_stat;
 364         gss_buffer_desc input_token;
 365         gss_buffer_desc input_message;
 366         gss_qop_t qop_state;
 367
 368         dump_data_pw("gssapi_check_packet: sig\n", sig->data, sig->length);
 369
 370         if (hdr_signing) {
 371                 input_message.length = pdu_length;
 372                 input_message.value = discard_const(whole_pdu);
 373         } else {
 374                 input_message.length = length;
 375                 input_message.value = discard_const(data);
 376         }
 377
 378         input_token.length = sig->length;
 379         input_token.value = sig->data;
 380
 381         maj_stat = gss_verify_mic(&min_stat,
 382                                   gssapi_context,
 383                                   &input_message,
 384                                   &input_token,
 385                                   &qop_state);
 386         if (GSS_ERROR(maj_stat)) {
 387                 char *error_string = gssapi_error_string(NULL,
 388                                                          maj_stat,
 389                                                          min_stat,
 390                                                          mech);
 391                 DEBUG(1, ("GSS VerifyMic failed: %s\n", error_string));
 392                 talloc_free(error_string);
 393
 394                 return NT_STATUS_ACCESS_DENIED;
 395         }
 396
 397         return NT_STATUS_OK;
 398 }