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