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         struct samba_kdc_entry *krbtgt_skdc_entry =
  72                 talloc_get_type_abort(krbtgt->ctx,
  73                 struct samba_kdc_entry);
  74         TALLOC_CTX *mem_ctx = talloc_named(p, 0, "samba_kdc_reget_pac context");
  75         DATA_BLOB *pac_blob;
  76         DATA_BLOB *deleg_blob = NULL;
  77         krb5_error_code ret;
  78         NTSTATUS nt_status;
  79         struct PAC_SIGNATURE_DATA *pac_srv_sig;
  80         struct PAC_SIGNATURE_DATA *pac_kdc_sig;
  81         bool is_in_db, is_untrusted;
  82
  83         if (!mem_ctx) {
  84                 return ENOMEM;
  85         }
  86
  87         /* The user account may be set not to want the PAC */
  88         if (!samba_princ_needs_pac(p)) {
  89                 talloc_free(mem_ctx);
  90                 return EINVAL;
  91         }
  92
  93         /* If the krbtgt was generated by an RODC, and we are not that
  94          * RODC, then we need to regenerate the PAC - we can't trust
  95          * it */
  96         ret = samba_krbtgt_is_in_db(krbtgt_skdc_entry, &is_in_db, &is_untrusted);
  97         if (ret != 0) {
  98                 talloc_free(mem_ctx);
  99                 return ret;
 100         }
 101
 102         if (is_untrusted) {
 103                 struct samba_kdc_entry *client_skdc_entry = NULL;
 104
 105                 if (client == NULL) {
 106                         return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
 107                 }
 108
 109                 client_skdc_entry = talloc_get_type_abort(client->ctx,
 110                                                           struct samba_kdc_entry);
 111
 112                 nt_status = samba_kdc_get_pac_blob(mem_ctx, client_skdc_entry, &pac_blob);
 113                 if (!NT_STATUS_IS_OK(nt_status)) {
 114                         talloc_free(mem_ctx);
 115                         return EINVAL;
 116                 }
 117         } else {
 118                 pac_blob = talloc_zero(mem_ctx, DATA_BLOB);
 119                 if (!pac_blob) {
 120                         talloc_free(mem_ctx);
 121                         return ENOMEM;
 122                 }
 123
 124                 pac_srv_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 125                 if (!pac_srv_sig) {
 126                         talloc_free(mem_ctx);
 127                         return ENOMEM;
 128                 }
 129
 130                 pac_kdc_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 131                 if (!pac_kdc_sig) {
 132                         talloc_free(mem_ctx);
 133                         return ENOMEM;
 134                 }
 135
 136                 nt_status = samba_kdc_update_pac_blob(mem_ctx, context,
 137                                                       *pac, pac_blob,
 138                                                       pac_srv_sig, pac_kdc_sig);
 139                 if (!NT_STATUS_IS_OK(nt_status)) {
 140                         DEBUG(0, ("Building PAC failed: %s\n",
 141                                   nt_errstr(nt_status)));
 142                         talloc_free(mem_ctx);
 143                         return EINVAL;
 144                 }
 145
 146                 if (is_in_db) {
 147                         /* Now check the KDC signature, fetching the correct key based on the enc type */
 148                         ret = kdc_check_pac(context, pac_srv_sig->signature, pac_kdc_sig, krbtgt);
 149                         if (ret != 0) {
 150                                 DEBUG(1, ("PAC KDC signature failed to verify\n"));
 151                                 talloc_free(mem_ctx);
 152                                 return ret;
 153                         }
 154                 }
 155         }
 156
 157         if (delegated_proxy_principal) {
 158                 deleg_blob = talloc_zero(mem_ctx, DATA_BLOB);
 159                 if (!deleg_blob) {
 160                         talloc_free(mem_ctx);
 161                         return ENOMEM;
 162                 }
 163
 164                 nt_status = samba_kdc_update_delegation_info_blob(mem_ctx,
 165                                         context, *pac,
 166                                         server->entry.principal,
 167                                         delegated_proxy_principal,
 168                                         deleg_blob);
 169                 if (!NT_STATUS_IS_OK(nt_status)) {
 170                         DEBUG(0, ("Building PAC failed: %s\n",
 171                                   nt_errstr(nt_status)));
 172                         talloc_free(mem_ctx);
 173                         return EINVAL;
 174                 }
 175         }
 176
 177         /* We now completely regenerate this pac */
 178         krb5_pac_free(context, *pac);
 179
 180         ret = samba_make_krb5_pac(context, pac_blob, deleg_blob, pac);
 181
 182         talloc_free(mem_ctx);
 183         return ret;
 184 }
 185
 186 static char *get_netbios_name(TALLOC_CTX *mem_ctx, HostAddresses *addrs)
 187 {
 188         char *nb_name = NULL;
 189         size_t len;
 190         unsigned int i;
 191
 192         for (i = 0; addrs && i < addrs->len; i++) {
 193                 if (addrs->val[i].addr_type != KRB5_ADDRESS_NETBIOS) {
 194                         continue;
 195                 }
 196                 len = MIN(addrs->val[i].address.length, 15);
 197                 nb_name = talloc_strndup(mem_ctx,
 198                                          addrs->val[i].address.data, len);
 199                 if (nb_name) {
 200                         break;
 201                 }
 202         }
 203
 204         if ((nb_name == NULL) || (nb_name[0] == '\0')) {
 205                 return NULL;
 206         }
 207
 208         /* Strip space padding */
 209         for (len = strlen(nb_name) - 1;
 210              (len > 0) && (nb_name[len] == ' ');
 211              --len) {
 212                 nb_name[len] = '\0';
 213         }
 214
 215         return nb_name;
 216 }
 217
 218 static krb5_data fill_krb5_data(void *data, size_t length)
 219 {
 220         krb5_data kdata;
 221
 222         kdata.data = data;
 223         kdata.length = length;
 224
 225         return kdata;
 226 }
 227
 228 /* this function allocates 'data' using malloc.
 229  * The caller is responsible for freeing it */
 230 static void samba_kdc_build_edata_reply(NTSTATUS nt_status, DATA_BLOB *e_data)
 231 {
 232         krb5_error_code ret = 0;
 233         PA_DATA pa;
 234         unsigned char *buf;
 235         size_t len;
 236
 237         if (!e_data)
 238                 return;
 239
 240         e_data->data   = NULL;
 241         e_data->length = 0;
 242
 243         pa.padata_type          = KRB5_PADATA_PW_SALT;
 244         pa.padata_value.length  = 12;
 245         pa.padata_value.data    = malloc(pa.padata_value.length);
 246         if (!pa.padata_value.data) {
 247                 e_data->length = 0;
 248                 e_data->data = NULL;
 249                 return;
 250         }
 251
 252         SIVAL(pa.padata_value.data, 0, NT_STATUS_V(nt_status));
 253         SIVAL(pa.padata_value.data, 4, 0);
 254         SIVAL(pa.padata_value.data, 8, 1);
 255
 256         ASN1_MALLOC_ENCODE(PA_DATA, buf, len, &pa, &len, ret);
 257         free(pa.padata_value.data);
 258         if (ret) {
 259                 return;
 260         }
 261
 262         e_data->data   = buf;
 263         e_data->length = len;
 264
 265         return;
 266 }
 267
 268
 269 static krb5_error_code samba_wdc_check_client_access(void *priv,
 270                                                      krb5_context context,
 271                                                      krb5_kdc_configuration *config,
 272                                                      hdb_entry_ex *client_ex, const char *client_name,
 273                                                      hdb_entry_ex *server_ex, const char *server_name,
 274                                                      KDC_REQ *req,
 275                                                      krb5_data *e_data)
 276 {
 277         struct samba_kdc_entry *kdc_entry;
 278         bool password_change;
 279         char *workstation;
 280         NTSTATUS nt_status;
 281
 282         kdc_entry = talloc_get_type(client_ex->ctx, struct samba_kdc_entry);
 283         password_change = (server_ex && server_ex->entry.flags.change_pw);
 284         workstation = get_netbios_name((TALLOC_CTX *)client_ex->ctx,
 285                                         req->req_body.addresses);
 286
 287         nt_status = samba_kdc_check_client_access(kdc_entry,
 288                                                   client_name,
 289                                                   workstation,
 290                                                   password_change);
 291
 292         if (!NT_STATUS_IS_OK(nt_status)) {
 293                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) {
 294                         return ENOMEM;
 295                 }
 296
 297                 if (e_data) {
 298                         DATA_BLOB data;
 299
 300                         samba_kdc_build_edata_reply(nt_status, &data);
 301                         *e_data = fill_krb5_data(data.data, data.length);
 302                 }
 303
 304                 return samba_kdc_map_policy_err(nt_status);
 305         }
 306
 307         /* Now do the standard Heimdal check */
 308         return kdc_check_flags(context, config,
 309                                client_ex, client_name,
 310                                server_ex, server_name,
 311                                req->msg_type == krb_as_req);
 312 }
 313
 314 static krb5_error_code samba_wdc_plugin_init(krb5_context context, void **ptr)
 315 {
 316         *ptr = NULL;
 317         return 0;
 318 }
 319
 320 static void samba_wdc_plugin_fini(void *ptr)
 321 {
 322         return;
 323 }
 324
 325 struct krb5plugin_windc_ftable windc_plugin_table = {
 326         .minor_version = KRB5_WINDC_PLUGIN_MINOR,
 327         .init = samba_wdc_plugin_init,
 328         .fini = samba_wdc_plugin_fini,
 329         .pac_generate = samba_wdc_get_pac,
 330         .pac_verify = samba_wdc_reget_pac,
 331         .client_access = samba_wdc_check_client_access,
 332 };
 333
 334