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/*
Unix SMB/CIFS implementation.
kerberos utility library
Copyright (C) Andrew Tridgell 2001
Copyright (C) Remus Koos 2001
Copyright (C) Luke Howard 2003
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
#ifdef HAVE_KRB5
/*
verify an incoming ticket and parse out the principal name and
authorization_data if available
*/
NTSTATUS ads_verify_ticket(const char *realm, const DATA_BLOB *ticket,
char **principal, DATA_BLOB *auth_data,
DATA_BLOB *ap_rep,
uint8 session_key[16])
{
NTSTATUS sret = NT_STATUS_LOGON_FAILURE;
krb5_context context = NULL;
krb5_auth_context auth_context = NULL;
krb5_keytab keytab = NULL;
krb5_data packet;
krb5_ticket *tkt = NULL;
krb5_rcache rcache = NULL;
int ret, i;
krb5_keyblock *key = NULL;
krb5_principal host_princ;
char *host_princ_s = NULL;
fstring myname;
char *password_s = NULL;
krb5_data password;
krb5_enctype *enctypes = NULL;
#if 0
krb5_address local_addr;
krb5_address remote_addr;
#endif
BOOL auth_ok = False;
ZERO_STRUCT(packet);
ZERO_STRUCT(password);
ZERO_STRUCTP(auth_data);
ZERO_STRUCTP(ap_rep);
if (!secrets_init()) {
DEBUG(1,("ads_verify_ticket: secrets_init failed\n"));
return NT_STATUS_LOGON_FAILURE;
}
password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
if (!password_s) {
DEBUG(1,("ads_verify_ticket: failed to fetch machine password\n"));
return NT_STATUS_LOGON_FAILURE;
}
password.data = password_s;
password.length = strlen(password_s);
ret = krb5_init_context(&context);
if (ret) {
DEBUG(1,("ads_verify_ticket: krb5_init_context failed (%s)\n", error_message(ret)));
return NT_STATUS_LOGON_FAILURE;
}
ret = krb5_set_default_realm(context, realm);
if (ret) {
DEBUG(1,("ads_verify_ticket: krb5_set_default_realm failed (%s)\n", error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
/* This whole process is far more complex than I would
like. We have to go through all this to allow us to store
the secret internally, instead of using /etc/krb5.keytab */
ret = krb5_auth_con_init(context, &auth_context);
if (ret) {
DEBUG(1,("ads_verify_ticket: krb5_auth_con_init failed (%s)\n", error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
fstrcpy(myname, global_myname());
strlower_m(myname);
asprintf(&host_princ_s, "HOST/%s@%s", myname, lp_realm());
ret = krb5_parse_name(context, host_princ_s, &host_princ);
if (ret) {
DEBUG(1,("ads_verify_ticket: krb5_parse_name(%s) failed (%s)\n",
host_princ_s, error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
/*
* JRA. We must set the rcache here. This will prevent replay attacks.
*/
ret = krb5_get_server_rcache(context, krb5_princ_component(context, host_princ, 0), &rcache);
if (ret) {
DEBUG(1,("ads_verify_ticket: krb5_get_server_rcache failed (%s)\n", error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
ret = krb5_auth_con_setrcache(context, auth_context, rcache);
if (ret) {
DEBUG(1,("ads_verify_ticket: krb5_auth_con_setrcache failed (%s)\n", error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
/* CIFS doesn't use addresses in tickets. This would breat NAT. JRA */
if ((ret = get_kerberos_allowed_etypes(context, &enctypes))) {
DEBUG(1,("ads_verify_ticket: krb5_get_permitted_enctypes failed (%s)\n",
error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
/* Lock a mutex surrounding the replay as there is no locking in the MIT krb5
* code surrounding the replay cache... */
if (!grab_server_mutex("replay cache mutex")) {
DEBUG(1,("ads_verify_ticket: unable to protect replay cache with mutex.\n"));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
/* We need to setup a auth context with each possible encoding type in turn. */
for (i=0;enctypes[i];i++) {
if (!(key = (krb5_keyblock *)malloc(sizeof(*key)))) {
sret = NT_STATUS_NO_MEMORY;
goto out;
}
if (create_kerberos_key_from_string(context, host_princ, &password, key, enctypes[i])) {
continue;
}
krb5_auth_con_setuseruserkey(context, auth_context, key);
krb5_free_keyblock(context, key);
packet.length = ticket->length;
packet.data = (krb5_pointer)ticket->data;
if (!(ret = krb5_rd_req(context, &auth_context, &packet,
NULL, keytab, NULL, &tkt))) {
DEBUG(10,("ads_verify_ticket: enc type [%u] decrypted message !\n",
(unsigned int)enctypes[i] ));
auth_ok = True;
break;
}
DEBUG((ret != KRB5_BAD_ENCTYPE) ? 3 : 10,
("ads_verify_ticket: enc type [%u] failed to decrypt with error %s\n",
(unsigned int)enctypes[i], error_message(ret)));
}
release_server_mutex();
if (!auth_ok) {
DEBUG(3,("ads_verify_ticket: krb5_rd_req with auth failed (%s)\n",
error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
ret = krb5_mk_rep(context, auth_context, &packet);
if (ret) {
DEBUG(3,("ads_verify_ticket: Failed to generate mutual authentication reply (%s)\n",
error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
*ap_rep = data_blob(packet.data, packet.length);
free(packet.data);
get_krb5_smb_session_key(context, auth_context, session_key, True);
#ifdef DEBUG_PASSWORD
DEBUG(10,("SMB session key (from ticket) follows:\n"));
dump_data(10, session_key, 16);
#endif
#if 0
file_save("/tmp/ticket.dat", ticket->data, ticket->length);
#endif
get_auth_data_from_tkt(auth_data, tkt);
{
TALLOC_CTX *ctx = talloc_init("pac data");
decode_pac_data(auth_data, ctx);
talloc_destroy(ctx);
}
#if 0
if (tkt->enc_part2) {
file_save("/tmp/authdata.dat",
tkt->enc_part2->authorization_data[0]->contents,
tkt->enc_part2->authorization_data[0]->length);
#endif
if ((ret = krb5_unparse_name(context, get_principal_from_tkt(tkt),
principal))) {
DEBUG(3,("ads_verify_ticket: krb5_unparse_name failed (%s)\n",
error_message(ret)));
sret = NT_STATUS_LOGON_FAILURE;
goto out;
}
sret = NT_STATUS_OK;
out:
if (!NT_STATUS_IS_OK(sret))
data_blob_free(auth_data);
if (!NT_STATUS_IS_OK(sret))
data_blob_free(ap_rep);
krb5_free_principal(context, host_princ);
krb5_free_ticket(context, tkt);
free_kerberos_etypes(context, enctypes);
SAFE_FREE(password_s);
SAFE_FREE(host_princ_s);
if (auth_context)
krb5_auth_con_free(context, auth_context);
if (context)
krb5_free_context(context);
return sret;
}
#endif /* HAVE_KRB5 */
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