source3/libads/kerberos.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 3.0
   4    kerberos utility library
   5    Copyright (C) Andrew Tridgell 2001
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 #ifdef HAVE_KRB5
  25
  26 /*
  27   verify an incoming ticket and parse out the principal name and
  28   authorization_data if available
  29 */
  30 NTSTATUS ads_verify_ticket(const DATA_BLOB *ticket,
  31                            char **principal, DATA_BLOB *auth_data)
  32 {
  33         krb5_context context;
  34         krb5_auth_context auth_context = NULL;
  35         krb5_keytab keytab = NULL;
  36         krb5_data packet;
  37         krb5_ticket *tkt = NULL;
  38         krb5_data salt;
  39         krb5_encrypt_block eblock;
  40         int ret;
  41         krb5_keyblock * key;
  42         krb5_principal host_princ;
  43         char *host_princ_s;
  44         extern pstring global_myname;
  45         fstring myname;
  46         char *password_s;
  47         krb5_data password;
  48
  49         if (!secrets_init()) {
  50                 DEBUG(1,("secrets_init failed\n"));
  51                 return NT_STATUS_LOGON_FAILURE;
  52         }
  53
  54         password_s = secrets_fetch_machine_password();
  55         if (!password_s) {
  56                 DEBUG(1,("failed to fetch machine password\n"));
  57                 return NT_STATUS_LOGON_FAILURE;
  58         }
  59
  60         password.data = password_s;
  61         password.length = strlen(password_s);
  62
  63         ret = krb5_init_context(&context);
  64         if (ret) {
  65                 DEBUG(1,("krb5_init_context failed (%s)\n", error_message(ret)));
  66                 return NT_STATUS_LOGON_FAILURE;
  67         }
  68
  69         ret = krb5_set_default_realm(context, lp_realm());
  70         if (ret) {
  71                 DEBUG(1,("krb5_set_default_realm failed (%s)\n", error_message(ret)));
  72                 return NT_STATUS_LOGON_FAILURE;
  73         }
  74
  75         /* this whole process is far more complex than I would
  76            like. We have to go through all this to allow us to store
  77            the secret internally, instead of using /etc/krb5.keytab */
  78         ret = krb5_auth_con_init(context, &auth_context);
  79         if (ret) {
  80                 DEBUG(1,("krb5_auth_con_init failed (%s)\n", error_message(ret)));
  81                 return NT_STATUS_LOGON_FAILURE;
  82         }
  83
  84         fstrcpy(myname, global_myname);
  85         strlower(myname);
  86         asprintf(&host_princ_s, "HOST/%s@%s", myname, lp_realm());
  87         ret = krb5_parse_name(context, host_princ_s, &host_princ);
  88         if (ret) {
  89                 DEBUG(1,("krb5_parse_name(%s) failed (%s)\n", host_princ_s, error_message(ret)));
  90                 return NT_STATUS_LOGON_FAILURE;
  91         }
  92
  93         ret = krb5_principal2salt(context, host_princ, &salt);
  94         if (ret) {
  95                 DEBUG(1,("krb5_principal2salt failed (%s)\n", error_message(ret)));
  96                 return NT_STATUS_LOGON_FAILURE;
  97         }
  98
  99         if (!(key = (krb5_keyblock *)malloc(sizeof(*key)))) {
 100                 return NT_STATUS_NO_MEMORY;
 101         }
 102
 103         krb5_use_enctype(context, &eblock, ENCTYPE_DES_CBC_MD5);
 104
 105         ret = krb5_string_to_key(context, &eblock, key, &password, &salt);
 106         if (ret) {
 107                 DEBUG(1,("krb5_string_to_key failed (%s)\n", error_message(ret)));
 108                 return NT_STATUS_LOGON_FAILURE;
 109         }
 110
 111         krb5_auth_con_setuseruserkey(context, auth_context, key);
 112
 113         packet.length = ticket->length;
 114         packet.data = (krb5_pointer)ticket->data;
 115
 116 #if 0
 117         file_save("/tmp/ticket.dat", ticket->data, ticket->length);
 118 #endif
 119
 120         if ((ret = krb5_rd_req(context, &auth_context, &packet,
 121                                NULL, keytab, NULL, &tkt))) {
 122                 DEBUG(3,("krb5_rd_req with auth failed (%s)\n",
 123                          error_message(ret)));
 124                 return NT_STATUS_LOGON_FAILURE;
 125         }
 126
 127         if (tkt->enc_part2) {
 128                 *auth_data = data_blob(tkt->enc_part2->authorization_data[0]->contents,
 129                                        tkt->enc_part2->authorization_data[0]->length);
 130         }
 131
 132 #if 0
 133         if (tkt->enc_part2) {
 134                 file_save("/tmp/authdata.dat",
 135                           tkt->enc_part2->authorization_data[0]->contents,
 136                           tkt->enc_part2->authorization_data[0]->length);
 137         }
 138 #endif
 139
 140         if ((ret = krb5_unparse_name(context, tkt->enc_part2->client, principal))) {
 141                 DEBUG(3,("krb5_unparse_name failed (%s)\n",
 142                          error_message(ret)));
 143                 return NT_STATUS_LOGON_FAILURE;
 144         }
 145
 146         return NT_STATUS_OK;
 147 }
 148
 149 #endif