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    Copyright (C) Luke Howard 2003
   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                            DATA_BLOB *ap_rep,
  34                            uint8 session_key[16])
  35 {
  36         krb5_context context;
  37         krb5_auth_context auth_context = NULL;
  38         krb5_keytab keytab = NULL;
  39         krb5_data packet;
  40         krb5_ticket *tkt = NULL;
  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(lp_workgroup(), NULL, NULL);
  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         if (!(key = (krb5_keyblock *)malloc(sizeof(*key)))) {
  96                 return NT_STATUS_NO_MEMORY;
  97         }
  98
  99         if ((ret = get_kerberos_allowed_etypes(context, &enctypes))) {
 100                 DEBUG(1,("krb5_get_permitted_enctypes failed (%s)\n",
 101                          error_message(ret)));
 102                 return NT_STATUS_LOGON_FAILURE;
 103         }
 104
 105         /* we need to setup a auth context with each possible encoding type in turn */
 106         for (i=0;enctypes[i];i++) {
 107                 if (create_kerberos_key_from_string(context, host_princ, &password, key, enctypes[i])) {
 108                         continue;
 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 (!(ret = krb5_rd_req(context, &auth_context, &packet,
 117                                        NULL, keytab, NULL, &tkt))) {
 118                         free_kerberos_etypes(context, enctypes);
 119                         auth_ok = True;
 120                         break;
 121                 }
 122         }
 123
 124         if (!auth_ok) {
 125                 DEBUG(3,("krb5_rd_req with auth failed (%s)\n",
 126                          error_message(ret)));
 127                 return NT_STATUS_LOGON_FAILURE;
 128         }
 129
 130         ret = krb5_mk_rep(context, auth_context, &packet);
 131         if (ret) {
 132                 DEBUG(3,("Failed to generate mutual authentication reply (%s)\n",
 133                         error_message(ret)));
 134                 krb5_auth_con_free(context, auth_context);
 135                 return NT_STATUS_LOGON_FAILURE;
 136         }
 137
 138         *ap_rep = data_blob(packet.data, packet.length);
 139         free(packet.data);
 140
 141         krb5_get_smb_session_key(context, auth_context, session_key);
 142         DEBUG(0,("SMB session key (from ticket) follows:\n"));
 143         dump_data(0, session_key, 16);
 144
 145 #if 0
 146         file_save("/tmp/ticket.dat", ticket->data, ticket->length);
 147 #endif
 148
 149         get_auth_data_from_tkt(auth_data, tkt);
 150
 151         {
 152                 TALLOC_CTX *ctx = talloc_init("pac data");
 153                 decode_pac_data(auth_data, ctx);
 154                 talloc_destroy(ctx);
 155         }
 156
 157 #if 0
 158         if (tkt->enc_part2) {
 159                 file_save("/tmp/authdata.dat",
 160                           tkt->enc_part2->authorization_data[0]->contents,
 161                           tkt->enc_part2->authorization_data[0]->length);
 162 #endif
 163
 164         if ((ret = krb5_unparse_name(context, get_principal_from_tkt(tkt),
 165                                      principal))) {
 166                 DEBUG(3,("krb5_unparse_name failed (%s)\n",
 167                          error_message(ret)));
 168                 data_blob_free(auth_data);
 169                 data_blob_free(ap_rep);
 170                 krb5_auth_con_free(context, auth_context);
 171                 return NT_STATUS_LOGON_FAILURE;
 172         }
 173
 174         krb5_auth_con_free(context, auth_context);
 175
 176         return NT_STATUS_OK;
 177 }
 178
 179 #endif /* HAVE_KRB5 */