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 /* Given the right private pointer from hdb_samba4, get a PAC from the attached ldb messages */
  29 static krb5_error_code samba_wdc_get_pac(void *priv, krb5_context context,
  30                                          struct hdb_entry_ex *client,
  31                                          krb5_pac *pac)
  32 {
  33         TALLOC_CTX *mem_ctx;
  34         DATA_BLOB *pac_blob;
  35         krb5_error_code ret;
  36         NTSTATUS nt_status;
  37         struct samba_kdc_entry *skdc_entry =
  38                 talloc_get_type_abort(client->ctx,
  39                 struct samba_kdc_entry);
  40
  41         mem_ctx = talloc_named(client->ctx, 0, "samba_get_pac context");
  42         if (!mem_ctx) {
  43                 return ENOMEM;
  44         }
  45
  46         nt_status = samba_kdc_get_pac_blob(mem_ctx, skdc_entry, &pac_blob);
  47         if (!NT_STATUS_IS_OK(nt_status)) {
  48                 talloc_free(mem_ctx);
  49                 return EINVAL;
  50         }
  51
  52         ret = samba_make_krb5_pac(context, pac_blob, NULL, pac);
  53
  54         talloc_free(mem_ctx);
  55         return ret;
  56 }
  57
  58 /* Resign (and reform, including possibly new groups) a PAC */
  59
  60 static krb5_error_code samba_wdc_reget_pac(void *priv, krb5_context context,
  61                                            const krb5_principal client_principal,
  62                                            const krb5_principal delegated_proxy_principal,
  63                                            struct hdb_entry_ex *client,
  64                                            struct hdb_entry_ex *server,
  65                                            struct hdb_entry_ex *krbtgt,
  66                                            krb5_pac *pac)
  67 {
  68         struct samba_kdc_entry *p =
  69                 talloc_get_type_abort(server->ctx,
  70                 struct samba_kdc_entry);
  71         TALLOC_CTX *mem_ctx = talloc_named(p, 0, "samba_kdc_reget_pac context");
  72         DATA_BLOB *pac_blob;
  73         DATA_BLOB *deleg_blob = NULL;
  74         krb5_error_code ret;
  75         NTSTATUS nt_status;
  76         struct PAC_SIGNATURE_DATA *pac_srv_sig;
  77         struct PAC_SIGNATURE_DATA *pac_kdc_sig;
  78         bool is_in_db, is_untrusted;
  79
  80         if (!mem_ctx) {
  81                 return ENOMEM;
  82         }
  83
  84         /* The user account may be set not to want the PAC */
  85         if (!samba_princ_needs_pac(p)) {
  86                 talloc_free(mem_ctx);
  87                 return EINVAL;
  88         }
  89
  90         /* If the krbtgt was generated by an RODC, and we are not that
  91          * RODC, then we need to regenerate the PAC - we can't trust
  92          * it */
  93         ret = samba_krbtgt_is_in_db(krbtgt, &is_in_db, &is_untrusted);
  94         if (ret != 0) {
  95                 talloc_free(mem_ctx);
  96                 return ret;
  97         }
  98
  99         if (is_untrusted) {
 100                 struct samba_kdc_entry *client_skdc_entry = NULL;
 101
 102                 if (client == NULL) {
 103                         return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
 104                 }
 105
 106                 client_skdc_entry = talloc_get_type_abort(client->ctx,
 107                                                           struct samba_kdc_entry);
 108
 109                 nt_status = samba_kdc_get_pac_blob(mem_ctx, client_skdc_entry, &pac_blob);
 110                 if (!NT_STATUS_IS_OK(nt_status)) {
 111                         talloc_free(mem_ctx);
 112                         return EINVAL;
 113                 }
 114         } else {
 115                 pac_blob = talloc_zero(mem_ctx, DATA_BLOB);
 116                 if (!pac_blob) {
 117                         talloc_free(mem_ctx);
 118                         return ENOMEM;
 119                 }
 120
 121                 pac_srv_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 122                 if (!pac_srv_sig) {
 123                         talloc_free(mem_ctx);
 124                         return ENOMEM;
 125                 }
 126
 127                 pac_kdc_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 128                 if (!pac_kdc_sig) {
 129                         talloc_free(mem_ctx);
 130                         return ENOMEM;
 131                 }
 132
 133                 nt_status = samba_kdc_update_pac_blob(mem_ctx, context,
 134                                                       *pac, pac_blob,
 135                                                       pac_srv_sig, pac_kdc_sig);
 136                 if (!NT_STATUS_IS_OK(nt_status)) {
 137                         DEBUG(0, ("Building PAC failed: %s\n",
 138                                   nt_errstr(nt_status)));
 139                         talloc_free(mem_ctx);
 140                         return EINVAL;
 141                 }
 142
 143                 if (is_in_db) {
 144                         /* Now check the KDC signature, fetching the correct key based on the enc type */
 145                         ret = kdc_check_pac(context, pac_srv_sig->signature, pac_kdc_sig, krbtgt);
 146                         if (ret != 0) {
 147                                 DEBUG(1, ("PAC KDC signature failed to verify\n"));
 148                                 talloc_free(mem_ctx);
 149                                 return ret;
 150                         }
 151                 }
 152         }
 153
 154         if (delegated_proxy_principal) {
 155                 deleg_blob = talloc_zero(mem_ctx, DATA_BLOB);
 156                 if (!deleg_blob) {
 157                         talloc_free(mem_ctx);
 158                         return ENOMEM;
 159                 }
 160
 161                 nt_status = samba_kdc_update_delegation_info_blob(mem_ctx,
 162                                         context, *pac,
 163                                         server->entry.principal,
 164                                         delegated_proxy_principal,
 165                                         deleg_blob);
 166                 if (!NT_STATUS_IS_OK(nt_status)) {
 167                         DEBUG(0, ("Building PAC failed: %s\n",
 168                                   nt_errstr(nt_status)));
 169                         talloc_free(mem_ctx);
 170                         return EINVAL;
 171                 }
 172         }
 173
 174         /* We now completely regenerate this pac */
 175         krb5_pac_free(context, *pac);
 176
 177         ret = samba_make_krb5_pac(context, pac_blob, deleg_blob, pac);
 178
 179         talloc_free(mem_ctx);
 180         return ret;
 181 }
 182
 183 static char *get_netbios_name(TALLOC_CTX *mem_ctx, HostAddresses *addrs)
 184 {
 185         char *nb_name = NULL;
 186         size_t len;
 187         unsigned int i;
 188
 189         for (i = 0; addrs && i < addrs->len; i++) {
 190                 if (addrs->val[i].addr_type != KRB5_ADDRESS_NETBIOS) {
 191                         continue;
 192                 }
 193                 len = MIN(addrs->val[i].address.length, 15);
 194                 nb_name = talloc_strndup(mem_ctx,
 195                                          addrs->val[i].address.data, len);
 196                 if (nb_name) {
 197                         break;
 198                 }
 199         }
 200
 201         if ((nb_name == NULL) || (nb_name[0] == '\0')) {
 202                 return NULL;
 203         }
 204
 205         /* Strip space padding */
 206         for (len = strlen(nb_name) - 1;
 207              (len > 0) && (nb_name[len] == ' ');
 208              --len) {
 209                 nb_name[len] = '\0';
 210         }
 211
 212         return nb_name;
 213 }
 214
 215 static krb5_data fill_krb5_data(void *data, size_t length)
 216 {
 217         krb5_data kdata;
 218
 219         kdata.data = data;
 220         kdata.length = length;
 221
 222         return kdata;
 223 }
 224
 225 static krb5_error_code samba_wdc_check_client_access(void *priv,
 226                                                      krb5_context context,
 227                                                      krb5_kdc_configuration *config,
 228                                                      hdb_entry_ex *client_ex, const char *client_name,
 229                                                      hdb_entry_ex *server_ex, const char *server_name,
 230                                                      KDC_REQ *req,
 231                                                      krb5_data *e_data)
 232 {
 233         struct samba_kdc_entry *kdc_entry;
 234         bool password_change;
 235         char *workstation;
 236         NTSTATUS nt_status;
 237
 238         kdc_entry = talloc_get_type(client_ex->ctx, struct samba_kdc_entry);
 239         password_change = (server_ex && server_ex->entry.flags.change_pw);
 240         workstation = get_netbios_name((TALLOC_CTX *)client_ex->ctx,
 241                                         req->req_body.addresses);
 242
 243         nt_status = samba_kdc_check_client_access(kdc_entry,
 244                                                   client_name,
 245                                                   workstation,
 246                                                   password_change);
 247
 248         if (!NT_STATUS_IS_OK(nt_status)) {
 249                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) {
 250                         return ENOMEM;
 251                 }
 252
 253                 if (e_data) {
 254                         DATA_BLOB data;
 255
 256                         samba_kdc_build_edata_reply(nt_status, &data);
 257                         *e_data = fill_krb5_data(data.data, data.length);
 258                 }
 259
 260                 return samba_kdc_map_policy_err(nt_status);
 261         }
 262
 263         /* Now do the standard Heimdal check */
 264         return kdc_check_flags(context, config,
 265                                client_ex, client_name,
 266                                server_ex, server_name,
 267                                req->msg_type == krb_as_req);
 268 }
 269
 270 static krb5_error_code samba_wdc_plugin_init(krb5_context context, void **ptr)
 271 {
 272         *ptr = NULL;
 273         return 0;
 274 }
 275
 276 static void samba_wdc_plugin_fini(void *ptr)
 277 {
 278         return;
 279 }
 280
 281 struct krb5plugin_windc_ftable windc_plugin_table = {
 282         .minor_version = KRB5_WINDC_PLUGIN_MINOR,
 283         .init = samba_wdc_plugin_init,
 284         .fini = samba_wdc_plugin_fini,
 285         .pac_generate = samba_wdc_get_pac,
 286         .pac_verify = samba_wdc_reget_pac,
 287         .client_access = samba_wdc_check_client_access,
 288 };
 289
 290