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         DNS_ERROR err;
  93
  94         gss_OID_desc krb5_oid_desc =
  95                 { 9, discard_const("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02") };
  96
  97         *ctx = GSS_C_NO_CONTEXT;
  98         input_ptr = NULL;
  99
 100         do {
 101                 major = gss_init_sec_context(
 102                         &minor, NULL, ctx, target_name, &krb5_oid_desc,
 103                         GSS_C_REPLAY_FLAG | GSS_C_MUTUAL_FLAG |
 104                         GSS_C_CONF_FLAG |
 105                         GSS_C_INTEG_FLAG,
 106                         0, NULL, input_ptr, NULL, &output_desc,
 107                         &ret_flags, NULL );
 108
 109                 if (input_ptr != NULL) {
 110                         TALLOC_FREE(input_desc.value);
 111                 }
 112
 113                 if (output_desc.length != 0) {
 114
 115                         struct dns_request *req;
 116                         struct dns_rrec *rec;
 117                         struct dns_buffer *buf;
 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 seciton 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(req, 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(req);
 153                 }
 154
 155                 gss_release_buffer(&minor, &output_desc);
 156
 157                 if ((major != GSS_S_COMPLETE) &&
 158                     (major != GSS_S_CONTINUE_NEEDED)) {
 159                         return ERROR_DNS_GSS_ERROR;
 160                 }
 161
 162                 if (major == GSS_S_CONTINUE_NEEDED) {
 163
 164                         struct dns_request *resp;
 165                         struct dns_buffer *buf;
 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         return err;
 214 }
 215
 216 DNS_ERROR dns_negotiate_sec_ctx( const char *target_realm,
 217                                  const char *servername,
 218                                  const char *keyname,
 219                                  gss_ctx_id_t *gss_ctx,
 220                                  enum dns_ServerType srv_type )
 221 {
 222         OM_uint32 major, minor;
 223
 224         char *upcaserealm, *targetname;
 225         DNS_ERROR err;
 226
 227         gss_buffer_desc input_name;
 228         struct dns_connection *conn;
 229
 230         gss_name_t targ_name;
 231
 232         gss_OID_desc nt_host_oid_desc =
 233                 {10, discard_const("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x01")};
 234
 235         TALLOC_CTX *mem_ctx;
 236
 237         if (!(mem_ctx = talloc_init("dns_negotiate_sec_ctx"))) {
 238                 return ERROR_DNS_NO_MEMORY;
 239         }
 240
 241         err = dns_open_connection( servername, DNS_TCP, mem_ctx, &conn );
 242         if (!ERR_DNS_IS_OK(err)) goto error;
 243
 244         if (!(upcaserealm = talloc_strdup(mem_ctx, target_realm))) {
 245                 err = ERROR_DNS_NO_MEMORY;
 246                 goto error;
 247         }
 248
 249         strupr(upcaserealm);
 250
 251         if (!(targetname = talloc_asprintf(mem_ctx, "dns/%s@%s",
 252                                            servername, upcaserealm))) {
 253                 err = ERROR_DNS_NO_MEMORY;
 254                 goto error;
 255         }
 256
 257         input_name.value = targetname;
 258         input_name.length = strlen(targetname);
 259
 260         major = gss_import_name( &minor, &input_name,
 261                                  &nt_host_oid_desc, &targ_name );
 262
 263         if (major) {
 264                 err = ERROR_DNS_GSS_ERROR;
 265                 goto error;
 266         }
 267
 268         err = dns_negotiate_gss_ctx_int(mem_ctx, conn, keyname,
 269                                         targ_name, gss_ctx, srv_type );
 270
 271         gss_release_name( &minor, &targ_name );
 272
 273  error:
 274         TALLOC_FREE(mem_ctx);
 275
 276         return err;
 277 }
 278
 279 DNS_ERROR dns_sign_update(struct dns_update_request *req,
 280                           gss_ctx_id_t gss_ctx,
 281                           const char *keyname,
 282                           const char *algorithmname,
 283                           time_t time_signed, uint16_t fudge)
 284 {
 285         struct dns_buffer *buf;
 286         DNS_ERROR err;
 287         struct dns_domain_name *key, *algorithm;
 288         struct gss_buffer_desc_struct msg, mic;
 289         OM_uint32 major, minor;
 290         struct dns_rrec *rec;
 291
 292         err = dns_marshall_update_request(req, req, &buf);
 293         if (!ERR_DNS_IS_OK(err)) return err;
 294
 295         err = dns_domain_name_from_string(buf, keyname, &key);
 296         if (!ERR_DNS_IS_OK(err)) goto error;
 297
 298         err = dns_domain_name_from_string(buf, algorithmname, &algorithm);
 299         if (!ERR_DNS_IS_OK(err)) goto error;
 300
 301         dns_marshall_domain_name(buf, key);
 302         dns_marshall_uint16(buf, DNS_CLASS_ANY);
 303         dns_marshall_uint32(buf, 0); /* TTL */
 304         dns_marshall_domain_name(buf, algorithm);
 305         dns_marshall_uint16(buf, 0); /* Time prefix for 48-bit time_t */
 306         dns_marshall_uint32(buf, time_signed);
 307         dns_marshall_uint16(buf, fudge);
 308         dns_marshall_uint16(buf, 0); /* error */
 309         dns_marshall_uint16(buf, 0); /* other len */
 310
 311         err = buf->error;
 312         if (!ERR_DNS_IS_OK(buf->error)) goto error;
 313
 314         msg.value = (void *)buf->data;
 315         msg.length = buf->offset;
 316
 317         major = gss_get_mic(&minor, gss_ctx, 0, &msg, &mic);
 318         if (major != 0) {
 319                 err = ERROR_DNS_GSS_ERROR;
 320                 goto error;
 321         }
 322
 323         if (mic.length > 0xffff) {
 324                 gss_release_buffer(&minor, &mic);
 325                 err = ERROR_DNS_GSS_ERROR;
 326                 goto error;
 327         }
 328
 329         err = dns_create_tsig_record(buf, keyname, algorithmname, time_signed,
 330                                      fudge, mic.length, (uint8_t *)mic.value,
 331                                      req->id, 0, &rec);
 332         gss_release_buffer(&minor, &mic);
 333         if (!ERR_DNS_IS_OK(err)) goto error;
 334
 335         err = dns_add_rrec(req, rec, &req->num_additionals, &req->additionals);
 336
 337  error:
 338         TALLOC_FREE(buf);
 339         return err;
 340 }
 341
 342 #endif  /* HAVE_GSSAPI */