source4/kdc/wdc-samba4.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    PAC Glue between Samba and the KDC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2009
   7    Copyright (C) Simo Sorce <idra@samba.org> 2010
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "kdc/kdc-glue.h"
  26 #include "kdc/pac-glue.h"
  27
  28 /*
  29  * Given the right private pointer from hdb_samba4,
  30  * get a PAC from the attached ldb messages.
  31  *
  32  * For PKINIT we also get pk_reply_key and can add PAC_CREDENTIAL_INFO.
  33  */
  34 static krb5_error_code samba_wdc_get_pac(void *priv, krb5_context context,
  35                                          struct hdb_entry_ex *client,
  36                                          const krb5_keyblock *pk_reply_key,
  37                                          krb5_pac *pac)
  38 {
  39         TALLOC_CTX *mem_ctx;
  40         DATA_BLOB *pac_blob;
  41         krb5_error_code ret;
  42         NTSTATUS nt_status;
  43         struct samba_kdc_entry *skdc_entry =
  44                 talloc_get_type_abort(client->ctx,
  45                 struct samba_kdc_entry);
  46
  47         mem_ctx = talloc_named(client->ctx, 0, "samba_get_pac context");
  48         if (!mem_ctx) {
  49                 return ENOMEM;
  50         }
  51
  52         nt_status = samba_kdc_get_pac_blob(mem_ctx, skdc_entry, &pac_blob);
  53         if (!NT_STATUS_IS_OK(nt_status)) {
  54                 talloc_free(mem_ctx);
  55                 return EINVAL;
  56         }
  57
  58         ret = samba_make_krb5_pac(context, pac_blob, NULL, pac);
  59
  60         talloc_free(mem_ctx);
  61         return ret;
  62 }
  63
  64 static krb5_error_code samba_wdc_get_pac_compat(void *priv, krb5_context context,
  65                                                 struct hdb_entry_ex *client,
  66                                                 krb5_pac *pac)
  67 {
  68         return samba_wdc_get_pac(priv, context, client, NULL, pac);
  69 }
  70
  71 /* Resign (and reform, including possibly new groups) a PAC */
  72
  73 static krb5_error_code samba_wdc_reget_pac(void *priv, krb5_context context,
  74                                            const krb5_principal client_principal,
  75                                            const krb5_principal delegated_proxy_principal,
  76                                            struct hdb_entry_ex *client,
  77                                            struct hdb_entry_ex *server,
  78                                            struct hdb_entry_ex *krbtgt,
  79                                            krb5_pac *pac)
  80 {
  81         struct samba_kdc_entry *p =
  82                 talloc_get_type_abort(server->ctx,
  83                 struct samba_kdc_entry);
  84         struct samba_kdc_entry *krbtgt_skdc_entry =
  85                 talloc_get_type_abort(krbtgt->ctx,
  86                 struct samba_kdc_entry);
  87         TALLOC_CTX *mem_ctx = talloc_named(p, 0, "samba_kdc_reget_pac context");
  88         DATA_BLOB *pac_blob;
  89         DATA_BLOB *deleg_blob = NULL;
  90         krb5_error_code ret;
  91         NTSTATUS nt_status;
  92         struct PAC_SIGNATURE_DATA *pac_srv_sig;
  93         struct PAC_SIGNATURE_DATA *pac_kdc_sig;
  94         bool is_in_db, is_untrusted;
  95
  96         if (!mem_ctx) {
  97                 return ENOMEM;
  98         }
  99
 100         /* The user account may be set not to want the PAC */
 101         if (!samba_princ_needs_pac(p)) {
 102                 talloc_free(mem_ctx);
 103                 return EINVAL;
 104         }
 105
 106         /* If the krbtgt was generated by an RODC, and we are not that
 107          * RODC, then we need to regenerate the PAC - we can't trust
 108          * it */
 109         ret = samba_krbtgt_is_in_db(krbtgt_skdc_entry, &is_in_db, &is_untrusted);
 110         if (ret != 0) {
 111                 talloc_free(mem_ctx);
 112                 return ret;
 113         }
 114
 115         if (is_untrusted) {
 116                 struct samba_kdc_entry *client_skdc_entry = NULL;
 117
 118                 if (client == NULL) {
 119                         return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
 120                 }
 121
 122                 client_skdc_entry = talloc_get_type_abort(client->ctx,
 123                                                           struct samba_kdc_entry);
 124
 125                 nt_status = samba_kdc_get_pac_blob(mem_ctx, client_skdc_entry, &pac_blob);
 126                 if (!NT_STATUS_IS_OK(nt_status)) {
 127                         talloc_free(mem_ctx);
 128                         return EINVAL;
 129                 }
 130         } else {
 131                 pac_blob = talloc_zero(mem_ctx, DATA_BLOB);
 132                 if (!pac_blob) {
 133                         talloc_free(mem_ctx);
 134                         return ENOMEM;
 135                 }
 136
 137                 pac_srv_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 138                 if (!pac_srv_sig) {
 139                         talloc_free(mem_ctx);
 140                         return ENOMEM;
 141                 }
 142
 143                 pac_kdc_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 144                 if (!pac_kdc_sig) {
 145                         talloc_free(mem_ctx);
 146                         return ENOMEM;
 147                 }
 148
 149                 nt_status = samba_kdc_update_pac_blob(mem_ctx, context,
 150                                                       *pac, pac_blob,
 151                                                       pac_srv_sig, pac_kdc_sig);
 152                 if (!NT_STATUS_IS_OK(nt_status)) {
 153                         DEBUG(0, ("Building PAC failed: %s\n",
 154                                   nt_errstr(nt_status)));
 155                         talloc_free(mem_ctx);
 156                         return EINVAL;
 157                 }
 158
 159                 if (is_in_db) {
 160                         /* Now check the KDC signature, fetching the correct key based on the enc type */
 161                         ret = kdc_check_pac(context, pac_srv_sig->signature, pac_kdc_sig, krbtgt);
 162                         if (ret != 0) {
 163                                 DEBUG(1, ("PAC KDC signature failed to verify\n"));
 164                                 talloc_free(mem_ctx);
 165                                 return ret;
 166                         }
 167                 }
 168         }
 169
 170         if (delegated_proxy_principal) {
 171                 deleg_blob = talloc_zero(mem_ctx, DATA_BLOB);
 172                 if (!deleg_blob) {
 173                         talloc_free(mem_ctx);
 174                         return ENOMEM;
 175                 }
 176
 177                 nt_status = samba_kdc_update_delegation_info_blob(mem_ctx,
 178                                         context, *pac,
 179                                         server->entry.principal,
 180                                         delegated_proxy_principal,
 181                                         deleg_blob);
 182                 if (!NT_STATUS_IS_OK(nt_status)) {
 183                         DEBUG(0, ("Building PAC failed: %s\n",
 184                                   nt_errstr(nt_status)));
 185                         talloc_free(mem_ctx);
 186                         return EINVAL;
 187                 }
 188         }
 189
 190         /* We now completely regenerate this pac */
 191         krb5_pac_free(context, *pac);
 192
 193         ret = samba_make_krb5_pac(context, pac_blob, deleg_blob, pac);
 194
 195         talloc_free(mem_ctx);
 196         return ret;
 197 }
 198
 199 static char *get_netbios_name(TALLOC_CTX *mem_ctx, HostAddresses *addrs)
 200 {
 201         char *nb_name = NULL;
 202         size_t len;
 203         unsigned int i;
 204
 205         for (i = 0; addrs && i < addrs->len; i++) {
 206                 if (addrs->val[i].addr_type != KRB5_ADDRESS_NETBIOS) {
 207                         continue;
 208                 }
 209                 len = MIN(addrs->val[i].address.length, 15);
 210                 nb_name = talloc_strndup(mem_ctx,
 211                                          addrs->val[i].address.data, len);
 212                 if (nb_name) {
 213                         break;
 214                 }
 215         }
 216
 217         if ((nb_name == NULL) || (nb_name[0] == '\0')) {
 218                 return NULL;
 219         }
 220
 221         /* Strip space padding */
 222         for (len = strlen(nb_name) - 1;
 223              (len > 0) && (nb_name[len] == ' ');
 224              --len) {
 225                 nb_name[len] = '\0';
 226         }
 227
 228         return nb_name;
 229 }
 230
 231 static krb5_data fill_krb5_data(void *data, size_t length)
 232 {
 233         krb5_data kdata;
 234
 235         kdata.data = data;
 236         kdata.length = length;
 237
 238         return kdata;
 239 }
 240
 241 /* this function allocates 'data' using malloc.
 242  * The caller is responsible for freeing it */
 243 static void samba_kdc_build_edata_reply(NTSTATUS nt_status, DATA_BLOB *e_data)
 244 {
 245         krb5_error_code ret = 0;
 246         PA_DATA pa;
 247         unsigned char *buf;
 248         size_t len;
 249
 250         if (!e_data)
 251                 return;
 252
 253         e_data->data   = NULL;
 254         e_data->length = 0;
 255
 256         pa.padata_type          = KRB5_PADATA_PW_SALT;
 257         pa.padata_value.length  = 12;
 258         pa.padata_value.data    = malloc(pa.padata_value.length);
 259         if (!pa.padata_value.data) {
 260                 e_data->length = 0;
 261                 e_data->data = NULL;
 262                 return;
 263         }
 264
 265         SIVAL(pa.padata_value.data, 0, NT_STATUS_V(nt_status));
 266         SIVAL(pa.padata_value.data, 4, 0);
 267         SIVAL(pa.padata_value.data, 8, 1);
 268
 269         ASN1_MALLOC_ENCODE(PA_DATA, buf, len, &pa, &len, ret);
 270         free(pa.padata_value.data);
 271         if (ret) {
 272                 return;
 273         }
 274
 275         e_data->data   = buf;
 276         e_data->length = len;
 277
 278         return;
 279 }
 280
 281
 282 static krb5_error_code samba_wdc_check_client_access(void *priv,
 283                                                      krb5_context context,
 284                                                      krb5_kdc_configuration *config,
 285                                                      hdb_entry_ex *client_ex, const char *client_name,
 286                                                      hdb_entry_ex *server_ex, const char *server_name,
 287                                                      KDC_REQ *req,
 288                                                      krb5_data *e_data)
 289 {
 290         struct samba_kdc_entry *kdc_entry;
 291         bool password_change;
 292         char *workstation;
 293         NTSTATUS nt_status;
 294
 295         kdc_entry = talloc_get_type(client_ex->ctx, struct samba_kdc_entry);
 296         password_change = (server_ex && server_ex->entry.flags.change_pw);
 297         workstation = get_netbios_name((TALLOC_CTX *)client_ex->ctx,
 298                                         req->req_body.addresses);
 299
 300         nt_status = samba_kdc_check_client_access(kdc_entry,
 301                                                   client_name,
 302                                                   workstation,
 303                                                   password_change);
 304
 305         if (!NT_STATUS_IS_OK(nt_status)) {
 306                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) {
 307                         return ENOMEM;
 308                 }
 309
 310                 if (e_data) {
 311                         DATA_BLOB data;
 312
 313                         samba_kdc_build_edata_reply(nt_status, &data);
 314                         *e_data = fill_krb5_data(data.data, data.length);
 315                 }
 316
 317                 return samba_kdc_map_policy_err(nt_status);
 318         }
 319
 320         /* Now do the standard Heimdal check */
 321         return kdc_check_flags(context, config,
 322                                client_ex, client_name,
 323                                server_ex, server_name,
 324                                req->msg_type == krb_as_req);
 325 }
 326
 327 static krb5_error_code samba_wdc_plugin_init(krb5_context context, void **ptr)
 328 {
 329         *ptr = NULL;
 330         return 0;
 331 }
 332
 333 static void samba_wdc_plugin_fini(void *ptr)
 334 {
 335         return;
 336 }
 337
 338 struct krb5plugin_windc_ftable windc_plugin_table = {
 339         .minor_version = KRB5_WINDC_PLUGIN_MINOR,
 340         .init = samba_wdc_plugin_init,
 341         .fini = samba_wdc_plugin_fini,
 342         .pac_generate = samba_wdc_get_pac_compat,
 343         .pac_verify = samba_wdc_reget_pac,
 344         .client_access = samba_wdc_check_client_access,
 345         .pac_pk_generate = samba_wdc_get_pac,
 346 };
 347
 348