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         BOOL auth_ok = False;
  50
  51         if (!secrets_init()) {
  52                 DEBUG(1,("secrets_init failed\n"));
  53                 return NT_STATUS_LOGON_FAILURE;
  54         }
  55
  56         password_s = secrets_fetch_machine_password();
  57         if (!password_s) {
  58                 DEBUG(1,("failed to fetch machine password\n"));
  59                 return NT_STATUS_LOGON_FAILURE;
  60         }
  61
  62         password.data = password_s;
  63         password.length = strlen(password_s);
  64
  65         ret = krb5_init_context(&context);
  66         if (ret) {
  67                 DEBUG(1,("krb5_init_context failed (%s)\n", error_message(ret)));
  68                 return NT_STATUS_LOGON_FAILURE;
  69         }
  70
  71         ret = krb5_set_default_realm(context, ads->auth.realm);
  72         if (ret) {
  73                 DEBUG(1,("krb5_set_default_realm failed (%s)\n", error_message(ret)));
  74                 return NT_STATUS_LOGON_FAILURE;
  75         }
  76
  77         /* this whole process is far more complex than I would
  78            like. We have to go through all this to allow us to store
  79            the secret internally, instead of using /etc/krb5.keytab */
  80         ret = krb5_auth_con_init(context, &auth_context);
  81         if (ret) {
  82                 DEBUG(1,("krb5_auth_con_init failed (%s)\n", error_message(ret)));
  83                 return NT_STATUS_LOGON_FAILURE;
  84         }
  85
  86         fstrcpy(myname, global_myname());
  87         strlower(myname);
  88         asprintf(&host_princ_s, "HOST/%s@%s", myname, lp_realm());
  89         ret = krb5_parse_name(context, host_princ_s, &host_princ);
  90         if (ret) {
  91                 DEBUG(1,("krb5_parse_name(%s) failed (%s)\n", host_princ_s, error_message(ret)));
  92                 return NT_STATUS_LOGON_FAILURE;
  93         }
  94
  95         ret = krb5_principal2salt(context, host_princ, &salt);
  96         if (ret) {
  97                 DEBUG(1,("krb5_principal2salt failed (%s)\n", error_message(ret)));
  98                 return NT_STATUS_LOGON_FAILURE;
  99         }
 100
 101         if (!(key = (krb5_keyblock *)malloc(sizeof(*key)))) {
 102                 return NT_STATUS_NO_MEMORY;
 103         }
 104
 105         if ((ret = krb5_get_permitted_enctypes(context, &enctypes))) {
 106                 DEBUG(1,("krb5_get_permitted_enctypes failed (%s)\n",
 107                          error_message(ret)));
 108                 return NT_STATUS_LOGON_FAILURE;
 109         }
 110
 111         /* we need to setup a auth context with each possible encoding type in turn */
 112         for (i=0;enctypes[i];i++) {
 113                 krb5_use_enctype(context, &eblock, enctypes[i]);
 114
 115                 ret = krb5_string_to_key(context, &eblock, key, &password, &salt);
 116                 if (ret) {
 117                         continue;
 118                 }
 119
 120                 krb5_auth_con_setuseruserkey(context, auth_context, key);
 121
 122                 packet.length = ticket->length;
 123                 packet.data = (krb5_pointer)ticket->data;
 124
 125                 if (!(ret = krb5_rd_req(context, &auth_context, &packet,
 126                                        NULL, keytab, NULL, &tkt))) {
 127                         krb5_free_ktypes(context, enctypes);
 128                         auth_ok = True;
 129                         break;
 130                 }
 131         }
 132
 133         if (!auth_ok) {
 134                 DEBUG(3,("krb5_rd_req with auth failed (%s)\n",
 135                          error_message(ret)));
 136                 return NT_STATUS_LOGON_FAILURE;
 137         }
 138
 139 #if 0
 140         file_save("/tmp/ticket.dat", ticket->data, ticket->length);
 141 #endif
 142
 143
 144         if (tkt->enc_part2) {
 145                 *auth_data = data_blob(tkt->enc_part2->authorization_data[0]->contents,
 146                                        tkt->enc_part2->authorization_data[0]->length);
 147         }
 148
 149 #if 0
 150         if (tkt->enc_part2) {
 151                 file_save("/tmp/authdata.dat",
 152                           tkt->enc_part2->authorization_data[0]->contents,
 153                           tkt->enc_part2->authorization_data[0]->length);
 154         }
 155 #endif
 156
 157         if ((ret = krb5_unparse_name(context, tkt->enc_part2->client, principal))) {
 158                 DEBUG(3,("krb5_unparse_name failed (%s)\n",
 159                          error_message(ret)));
 160                 return NT_STATUS_LOGON_FAILURE;
 161         }
 162
 163         return NT_STATUS_OK;
 164 }
 165
 166 #endif