source3/libads/kerberos_verify.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    kerberos utility library
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Remus Koos 2001
   6
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 #ifdef HAVE_KRB5
  26
  27 /*
  28   verify an incoming ticket and parse out the principal name and
  29   authorization_data if available
  30 */
  31 NTSTATUS ads_verify_ticket(ADS_STRUCT *ads, const DATA_BLOB *ticket,
  32                            char **principal, DATA_BLOB *auth_data)
  33 {
  34         krb5_context context;
  35         krb5_auth_context auth_context = NULL;
  36         krb5_keytab keytab = NULL;
  37         krb5_data packet;
  38         krb5_ticket *tkt = NULL;
  39         krb5_data salt;
  40         krb5_encrypt_block eblock;
  41         int ret, i;
  42         krb5_keyblock * key;
  43         krb5_principal host_princ;
  44         char *host_princ_s;
  45         fstring myname;
  46         char *password_s;
  47         krb5_data password;
  48         krb5_enctype *enctypes = NULL;
  49
  50         if (!secrets_init()) {
  51                 DEBUG(1,("secrets_init failed\n"));
  52                 return NT_STATUS_LOGON_FAILURE;
  53         }
  54
  55         password_s = secrets_fetch_machine_password();
  56         if (!password_s) {
  57                 DEBUG(1,("failed to fetch machine password\n"));
  58                 return NT_STATUS_LOGON_FAILURE;
  59         }
  60
  61         password.data = password_s;
  62         password.length = strlen(password_s);
  63
  64         ret = krb5_init_context(&context);
  65         if (ret) {
  66                 DEBUG(1,("krb5_init_context failed (%s)\n", error_message(ret)));
  67                 return NT_STATUS_LOGON_FAILURE;
  68         }
  69
  70         ret = krb5_set_default_realm(context, ads->auth.realm);
  71         if (ret) {
  72                 DEBUG(1,("krb5_set_default_realm failed (%s)\n", error_message(ret)));
  73                 return NT_STATUS_LOGON_FAILURE;
  74         }
  75
  76         /* this whole process is far more complex than I would
  77            like. We have to go through all this to allow us to store
  78            the secret internally, instead of using /etc/krb5.keytab */
  79         ret = krb5_auth_con_init(context, &auth_context);
  80         if (ret) {
  81                 DEBUG(1,("krb5_auth_con_init failed (%s)\n", error_message(ret)));
  82                 return NT_STATUS_LOGON_FAILURE;
  83         }
  84
  85         fstrcpy(myname, global_myname());
  86         strlower(myname);
  87         asprintf(&host_princ_s, "HOST/%s@%s", myname, lp_realm());
  88         ret = krb5_parse_name(context, host_princ_s, &host_princ);
  89         if (ret) {
  90                 DEBUG(1,("krb5_parse_name(%s) failed (%s)\n", host_princ_s, error_message(ret)));
  91                 return NT_STATUS_LOGON_FAILURE;
  92         }
  93
  94         ret = krb5_principal2salt(context, host_princ, &salt);
  95         if (ret) {
  96                 DEBUG(1,("krb5_principal2salt failed (%s)\n", error_message(ret)));
  97                 return NT_STATUS_LOGON_FAILURE;
  98         }
  99
 100         if (!(key = (krb5_keyblock *)malloc(sizeof(*key)))) {
 101                 return NT_STATUS_NO_MEMORY;
 102         }
 103
 104         if ((ret = krb5_get_permitted_enctypes(context, &enctypes))) {
 105                 DEBUG(1,("krb5_get_permitted_enctypes failed (%s)\n",
 106                          error_message(ret)));
 107                 return NT_STATUS_LOGON_FAILURE;
 108         }
 109
 110         /* we need to setup a auth context with each possible encoding type in turn */
 111         for (i=0;enctypes[i];i++) {
 112                 krb5_use_enctype(context, &eblock, enctypes[i]);
 113
 114                 ret = krb5_string_to_key(context, &eblock, key, &password, &salt);
 115                 if (ret) {
 116                         continue;
 117                 }
 118
 119                 krb5_auth_con_setuseruserkey(context, auth_context, key);
 120
 121                 packet.length = ticket->length;
 122                 packet.data = (krb5_pointer)ticket->data;
 123
 124                 if (!(ret = krb5_rd_req(context, &auth_context, &packet,
 125                                        NULL, keytab, NULL, &tkt))) {
 126                         krb5_free_ktypes(context, enctypes);
 127                         break;
 128                 }
 129         }
 130
 131         if (!enctypes[i]) {
 132                 DEBUG(3,("krb5_rd_req with auth failed (%s)\n",
 133                          error_message(ret)));
 134                 return NT_STATUS_LOGON_FAILURE;
 135         }
 136
 137 #if 0
 138         file_save("/tmp/ticket.dat", ticket->data, ticket->length);
 139 #endif
 140
 141
 142         if (tkt->enc_part2) {
 143                 *auth_data = data_blob(tkt->enc_part2->authorization_data[0]->contents,
 144                                        tkt->enc_part2->authorization_data[0]->length);
 145         }
 146
 147 #if 0
 148         if (tkt->enc_part2) {
 149                 file_save("/tmp/authdata.dat",
 150                           tkt->enc_part2->authorization_data[0]->contents,
 151                           tkt->enc_part2->authorization_data[0]->length);
 152         }
 153 #endif
 154
 155         if ((ret = krb5_unparse_name(context, tkt->enc_part2->client, principal))) {
 156                 DEBUG(3,("krb5_unparse_name failed (%s)\n",
 157                          error_message(ret)));
 158                 return NT_STATUS_LOGON_FAILURE;
 159         }
 160
 161         return NT_STATUS_OK;
 162 }
 163
 164 #endif