lib/addns/dnsgss.c

   1 /*
   2   Public Interface file for Linux DNS client library implementation
   3
   4   Copyright (C) 2006 Krishna Ganugapati <krishnag@centeris.com>
   5   Copyright (C) 2006 Gerald Carter <jerry@samba.org>
   6
   7      ** NOTE! The following LGPL license applies to the libaddns
   8      ** library. This does NOT imply that all of Samba is released
   9      ** under the LGPL
  10
  11   This library is free software; you can redistribute it and/or
  12   modify it under the terms of the GNU Lesser General Public
  13   License as published by the Free Software Foundation; either
  14   version 2.1 of the License, or (at your option) any later version.
  15
  16   This library is distributed in the hope that it will be useful,
  17   but WITHOUT ANY WARRANTY; without even the implied warranty of
  18   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19   Lesser General Public License for more details.
  20
  21   You should have received a copy of the GNU Lesser General Public
  22   License along with this library; if not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include "dns.h"
  26 #include <ctype.h>
  27
  28
  29 #ifdef HAVE_GSSAPI
  30
  31 /*********************************************************************
  32 *********************************************************************/
  33
  34 #ifndef HAVE_STRUPR
  35 static int strupr( char *szDomainName )
  36 {
  37         if ( !szDomainName ) {
  38                 return ( 0 );
  39         }
  40         while ( *szDomainName != '\0' ) {
  41                 *szDomainName = toupper( *szDomainName );
  42                 szDomainName++;
  43         }
  44         return ( 0 );
  45 }
  46 #endif
  47
  48 #if 0
  49 /*********************************************************************
  50 *********************************************************************/
  51
  52 static void display_status_1( const char *m, OM_uint32 code, int type )
  53 {
  54         OM_uint32 maj_stat, min_stat;
  55         gss_buffer_desc msg;
  56         OM_uint32 msg_ctx;
  57
  58         msg_ctx = 0;
  59         while ( 1 ) {
  60                 maj_stat = gss_display_status( &min_stat, code,
  61                                                type, GSS_C_NULL_OID,
  62                                                &msg_ctx, &msg );
  63                 fprintf( stdout, "GSS-API error %s: %s\n", m,
  64                          ( char * ) msg.value );
  65                 ( void ) gss_release_buffer( &min_stat, &msg );
  66
  67                 if ( !msg_ctx )
  68                         break;
  69         }
  70 }
  71
  72 /*********************************************************************
  73 *********************************************************************/
  74
  75 void display_status( const char *msg, OM_uint32 maj_stat, OM_uint32 min_stat )
  76 {
  77         display_status_1( msg, maj_stat, GSS_C_GSS_CODE );
  78         display_status_1( msg, min_stat, GSS_C_MECH_CODE );
  79 }
  80 #endif
  81
  82 static DNS_ERROR dns_negotiate_gss_ctx_int( TALLOC_CTX *mem_ctx,
  83                                             struct dns_connection *conn,
  84                                             const char *keyname,
  85                                             const gss_name_t target_name,
  86                                             gss_ctx_id_t *ctx,
  87                                             enum dns_ServerType srv_type )
  88 {
  89         struct gss_buffer_desc_struct input_desc, *input_ptr, output_desc;
  90         OM_uint32 major, minor;
  91         OM_uint32 ret_flags;
  92         struct dns_request *req = NULL;
  93         struct dns_buffer *buf = NULL;
  94         DNS_ERROR err;
  95
  96         gss_OID_desc krb5_oid_desc =
  97                 { 9, discard_const("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02") };
  98
  99         *ctx = GSS_C_NO_CONTEXT;
 100         input_ptr = NULL;
 101
 102         do {
 103                 major = gss_init_sec_context(
 104                         &minor, NULL, ctx, target_name, &krb5_oid_desc,
 105                         GSS_C_REPLAY_FLAG | GSS_C_MUTUAL_FLAG |
 106                         GSS_C_CONF_FLAG |
 107                         GSS_C_INTEG_FLAG,
 108                         0, NULL, input_ptr, NULL, &output_desc,
 109                         &ret_flags, NULL );
 110
 111                 if (input_ptr != NULL) {
 112                         TALLOC_FREE(input_desc.value);
 113                 }
 114
 115                 if (output_desc.length != 0) {
 116
 117                         struct dns_rrec *rec;
 118
 119                         time_t t = time(NULL);
 120
 121                         err = dns_create_query(mem_ctx, keyname, QTYPE_TKEY,
 122                                                DNS_CLASS_IN, &req);
 123                         if (!ERR_DNS_IS_OK(err)) goto error;
 124
 125                         err = dns_create_tkey_record(
 126                                 req, keyname, "gss.microsoft.com", t,
 127                                 t + 86400, DNS_TKEY_MODE_GSSAPI, 0,
 128                                 output_desc.length, (uint8_t *)output_desc.value,
 129                                 &rec );
 130                         if (!ERR_DNS_IS_OK(err)) goto error;
 131
 132                         /* Windows 2000 DNS is broken and requires the
 133                            TKEY payload in the Answer section instead
 134                            of the Additional section like Windows 2003 */
 135
 136                         if ( srv_type == DNS_SRV_WIN2000 ) {
 137                                 err = dns_add_rrec(req, rec, &req->num_answers,
 138                                                    &req->answers);
 139                         } else {
 140                                 err = dns_add_rrec(req, rec, &req->num_additionals,
 141                                                    &req->additionals);
 142                         }
 143
 144                         if (!ERR_DNS_IS_OK(err)) goto error;
 145
 146                         err = dns_marshall_request(mem_ctx, req, &buf);
 147                         if (!ERR_DNS_IS_OK(err)) goto error;
 148
 149                         err = dns_send(conn, buf);
 150                         if (!ERR_DNS_IS_OK(err)) goto error;
 151
 152                         TALLOC_FREE(buf);
 153                         TALLOC_FREE(req);
 154                 }
 155
 156                 gss_release_buffer(&minor, &output_desc);
 157
 158                 if ((major != GSS_S_COMPLETE) &&
 159                     (major != GSS_S_CONTINUE_NEEDED)) {
 160                         return ERROR_DNS_GSS_ERROR;
 161                 }
 162
 163                 if (major == GSS_S_CONTINUE_NEEDED) {
 164
 165                         struct dns_request *resp;
 166                         struct dns_tkey_record *tkey;
 167                         struct dns_rrec *tkey_answer = NULL;
 168                         uint16_t i;
 169
 170                         err = dns_receive(mem_ctx, conn, &buf);
 171                         if (!ERR_DNS_IS_OK(err)) goto error;
 172
 173                         err = dns_unmarshall_request(buf, buf, &resp);
 174                         if (!ERR_DNS_IS_OK(err)) goto error;
 175
 176                         /*
 177                          * TODO: Compare id and keyname
 178                          */
 179
 180                         for (i=0; i < resp->num_answers; i++) {
 181                                 if (resp->answers[i]->type != QTYPE_TKEY) {
 182                                         continue;
 183                                 }
 184
 185                                 tkey_answer = resp->answers[i];
 186                         }
 187
 188                         if (tkey_answer == NULL) {
 189                                 err = ERROR_DNS_INVALID_MESSAGE;
 190                                 goto error;
 191                         }
 192
 193                         err = dns_unmarshall_tkey_record(
 194                                 mem_ctx, resp->answers[0], &tkey);
 195                         if (!ERR_DNS_IS_OK(err)) goto error;
 196
 197                         input_desc.length = tkey->key_length;
 198                         input_desc.value = talloc_move(mem_ctx, &tkey->key);
 199
 200                         input_ptr = &input_desc;
 201
 202                         TALLOC_FREE(buf);
 203                 }
 204
 205         } while ( major == GSS_S_CONTINUE_NEEDED );
 206
 207         /* If we arrive here, we have a valid security context */
 208
 209         err = ERROR_DNS_SUCCESS;
 210
 211       error:
 212
 213         TALLOC_FREE(buf);
 214         TALLOC_FREE(req);
 215         return err;
 216 }
 217
 218 DNS_ERROR dns_negotiate_sec_ctx( const char *target_realm,
 219                                  const char *servername,
 220                                  const char *keyname,
 221                                  gss_ctx_id_t *gss_ctx,
 222                                  enum dns_ServerType srv_type )
 223 {
 224         OM_uint32 major, minor;
 225
 226         char *upcaserealm, *targetname;
 227         DNS_ERROR err;
 228
 229         gss_buffer_desc input_name;
 230         struct dns_connection *conn;
 231
 232         gss_name_t targ_name;
 233
 234         gss_OID_desc nt_host_oid_desc =
 235                 {10, discard_const("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x01")};
 236
 237         TALLOC_CTX *mem_ctx;
 238
 239         if (!(mem_ctx = talloc_init("dns_negotiate_sec_ctx"))) {
 240                 return ERROR_DNS_NO_MEMORY;
 241         }
 242
 243         err = dns_open_connection( servername, DNS_TCP, mem_ctx, &conn );
 244         if (!ERR_DNS_IS_OK(err)) goto error;
 245
 246         if (!(upcaserealm = talloc_strdup(mem_ctx, target_realm))) {
 247                 err = ERROR_DNS_NO_MEMORY;
 248                 goto error;
 249         }
 250
 251         strupr(upcaserealm);
 252
 253         if (!(targetname = talloc_asprintf(mem_ctx, "dns/%s@%s",
 254                                            servername, upcaserealm))) {
 255                 err = ERROR_DNS_NO_MEMORY;
 256                 goto error;
 257         }
 258
 259         input_name.value = targetname;
 260         input_name.length = strlen(targetname);
 261
 262         major = gss_import_name( &minor, &input_name,
 263                                  &nt_host_oid_desc, &targ_name );
 264
 265         if (major) {
 266                 err = ERROR_DNS_GSS_ERROR;
 267                 goto error;
 268         }
 269
 270         err = dns_negotiate_gss_ctx_int(mem_ctx, conn, keyname,
 271                                         targ_name, gss_ctx, srv_type );
 272
 273         gss_release_name( &minor, &targ_name );
 274
 275  error:
 276         TALLOC_FREE(mem_ctx);
 277
 278         return err;
 279 }
 280
 281 DNS_ERROR dns_sign_update(struct dns_update_request *req,
 282                           gss_ctx_id_t gss_ctx,
 283                           const char *keyname,
 284                           const char *algorithmname,
 285                           time_t time_signed, uint16_t fudge)
 286 {
 287         struct dns_buffer *buf;
 288         DNS_ERROR err;
 289         struct dns_domain_name *key, *algorithm;
 290         struct gss_buffer_desc_struct msg, mic;
 291         OM_uint32 major, minor;
 292         struct dns_rrec *rec;
 293
 294         err = dns_marshall_update_request(req, req, &buf);
 295         if (!ERR_DNS_IS_OK(err)) return err;
 296
 297         err = dns_domain_name_from_string(buf, keyname, &key);
 298         if (!ERR_DNS_IS_OK(err)) goto error;
 299
 300         err = dns_domain_name_from_string(buf, algorithmname, &algorithm);
 301         if (!ERR_DNS_IS_OK(err)) goto error;
 302
 303         dns_marshall_domain_name(buf, key);
 304         dns_marshall_uint16(buf, DNS_CLASS_ANY);
 305         dns_marshall_uint32(buf, 0); /* TTL */
 306         dns_marshall_domain_name(buf, algorithm);
 307         dns_marshall_uint16(buf, 0); /* Time prefix for 48-bit time_t */
 308         dns_marshall_uint32(buf, time_signed);
 309         dns_marshall_uint16(buf, fudge);
 310         dns_marshall_uint16(buf, 0); /* error */
 311         dns_marshall_uint16(buf, 0); /* other len */
 312
 313         err = buf->error;
 314         if (!ERR_DNS_IS_OK(buf->error)) goto error;
 315
 316         msg.value = (void *)buf->data;
 317         msg.length = buf->offset;
 318
 319         major = gss_get_mic(&minor, gss_ctx, 0, &msg, &mic);
 320         if (major != 0) {
 321                 err = ERROR_DNS_GSS_ERROR;
 322                 goto error;
 323         }
 324
 325         if (mic.length > 0xffff) {
 326                 gss_release_buffer(&minor, &mic);
 327                 err = ERROR_DNS_GSS_ERROR;
 328                 goto error;
 329         }
 330
 331         err = dns_create_tsig_record(buf, keyname, algorithmname, time_signed,
 332                                      fudge, mic.length, (uint8_t *)mic.value,
 333                                      req->id, 0, &rec);
 334         gss_release_buffer(&minor, &mic);
 335         if (!ERR_DNS_IS_OK(err)) goto error;
 336
 337         err = dns_add_rrec(req, rec, &req->num_additionals, &req->additionals);
 338
 339  error:
 340         TALLOC_FREE(buf);
 341         return err;
 342 }
 343
 344 #endif  /* HAVE_GSSAPI */