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|
/*
Unix SMB/CIFS implementation.
Create and parse the krb5 PAC
Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
Copyright (C) Andrew Tridgell 2001
Copyright (C) Luke Howard 2002-2003
Copyright (C) Stefan Metzmacher 2004-2005
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"
#include "system/kerberos.h"
#include "system/time.h"
#include "system/network.h"
#include "auth/auth.h"
#include "auth/kerberos/kerberos.h"
#include "librpc/gen_ndr/ndr_krb5pac.h"
#include "auth/auth.h"
static NTSTATUS check_pac_checksum(TALLOC_CTX *mem_ctx,
DATA_BLOB pac_data,
struct PAC_SIGNATURE_DATA *sig,
krb5_context context,
krb5_keyblock *keyblock)
{
krb5_error_code ret;
krb5_crypto crypto;
Checksum cksum;
cksum.cksumtype = (CKSUMTYPE)sig->type;
cksum.checksum.length = sizeof(sig->signature);
cksum.checksum.data = sig->signature;
ret = krb5_crypto_init(context,
keyblock,
0,
&crypto);
if (ret) {
DEBUG(0,("krb5_crypto_init() failed: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
return NT_STATUS_FOOBAR;
}
ret = krb5_verify_checksum(context,
crypto,
KRB5_KU_OTHER_CKSUM,
pac_data.data,
pac_data.length,
&cksum);
if (ret) {
DEBUG(2, ("PAC Verification failed: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
}
krb5_crypto_destroy(context, crypto);
if (ret) {
return NT_STATUS_ACCESS_DENIED;
}
return NT_STATUS_OK;
}
NTSTATUS kerberos_decode_pac(TALLOC_CTX *mem_ctx,
struct PAC_DATA **pac_data_out,
DATA_BLOB blob,
krb5_context context,
krb5_keyblock *krbtgt_keyblock,
krb5_keyblock *service_keyblock)
{
NTSTATUS status;
struct PAC_SIGNATURE_DATA srv_sig;
struct PAC_SIGNATURE_DATA *srv_sig_ptr = NULL;
struct PAC_SIGNATURE_DATA kdc_sig;
struct PAC_SIGNATURE_DATA *kdc_sig_ptr = NULL;
struct PAC_LOGON_INFO *logon_info = NULL;
struct PAC_DATA *pac_data;
DATA_BLOB modified_pac_blob = data_blob_talloc(mem_ctx, blob.data, blob.length);
int i;
pac_data = talloc(mem_ctx, struct PAC_DATA);
if (!pac_data) {
return NT_STATUS_NO_MEMORY;
}
status = ndr_pull_struct_blob(&blob, mem_ctx, pac_data,
(ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0,("can't parse the PAC\n"));
return status;
}
if (pac_data->num_buffers < 3) {
/* we need logon_ingo, service_key and kdc_key */
DEBUG(0,("less than 3 PAC buffers\n"));
return NT_STATUS_FOOBAR;
}
for (i=0; i < pac_data->num_buffers; i++) {
switch (pac_data->buffers[i].type) {
case PAC_TYPE_LOGON_INFO:
if (!pac_data->buffers[i].info) {
break;
}
logon_info = pac_data->buffers[i].info->logon_info.info;
break;
case PAC_TYPE_SRV_CHECKSUM:
if (!pac_data->buffers[i].info) {
break;
}
srv_sig_ptr = &pac_data->buffers[i].info->srv_cksum;
srv_sig = pac_data->buffers[i].info->srv_cksum;
break;
case PAC_TYPE_KDC_CHECKSUM:
if (!pac_data->buffers[i].info) {
break;
}
kdc_sig_ptr = &pac_data->buffers[i].info->kdc_cksum;
kdc_sig = pac_data->buffers[i].info->kdc_cksum;
break;
case PAC_TYPE_LOGON_NAME:
break;
default:
break;
}
}
if (!logon_info) {
DEBUG(0,("PAC no logon_info\n"));
return NT_STATUS_FOOBAR;
}
if (!srv_sig_ptr) {
DEBUG(0,("PAC no srv_key\n"));
return NT_STATUS_FOOBAR;
}
if (!kdc_sig_ptr) {
DEBUG(0,("PAC no kdc_key\n"));
return NT_STATUS_FOOBAR;
}
memset(&modified_pac_blob.data[modified_pac_blob.length - 20],
'\0', 16);
memset(&modified_pac_blob.data[modified_pac_blob.length - 44],
'\0', 16);
/* verify by service_key */
status = check_pac_checksum(mem_ctx,
modified_pac_blob, &srv_sig,
context,
service_keyblock);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("PAC Decode: Failed to verify the service signature\n"));
return status;
}
if (krbtgt_keyblock) {
DATA_BLOB service_checksum_blob
= data_blob_const(srv_sig_ptr->signature, sizeof(srv_sig_ptr->signature));
status = check_pac_checksum(mem_ctx,
service_checksum_blob, &kdc_sig,
context, krbtgt_keyblock);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("PAC Decode: Failed to verify the krbtgt signature\n"));
return status;
}
}
#if 0
if (strcasecmp(logon_info->info3.base.account_name.string,
"Administrator")== 0) {
file_save("tmp_pac_data-admin.dat",blob.data,blob.length);
}
#endif
DEBUG(0,("account_name: %s [%s]\n",
logon_info->info3.base.account_name.string,
logon_info->info3.base.full_name.string));
*pac_data_out = pac_data;
return status;
}
NTSTATUS kerberos_pac_logon_info(TALLOC_CTX *mem_ctx,
struct PAC_LOGON_INFO **logon_info,
DATA_BLOB blob,
krb5_context context,
krb5_keyblock *krbtgt_keyblock,
krb5_keyblock *service_keyblock)
{
NTSTATUS nt_status;
struct PAC_DATA *pac_data;
int i;
nt_status = kerberos_decode_pac(mem_ctx, &pac_data,
blob,
context,
krbtgt_keyblock,
service_keyblock);
if (!NT_STATUS_IS_OK(nt_status)) {
return nt_status;
}
*logon_info = NULL;
for (i=0; i < pac_data->num_buffers; i++) {
if (pac_data->buffers[i].type != PAC_TYPE_LOGON_INFO) {
continue;
}
*logon_info = pac_data->buffers[i].info->logon_info.info;
}
if (!*logon_info) {
return NT_STATUS_INVALID_PARAMETER;
}
return NT_STATUS_OK;
}
static krb5_error_code make_pac_checksum(TALLOC_CTX *mem_ctx,
DATA_BLOB *pac_data,
struct PAC_SIGNATURE_DATA *sig,
krb5_context context,
krb5_keyblock *keyblock)
{
krb5_error_code ret;
krb5_crypto crypto;
Checksum cksum;
ret = krb5_crypto_init(context,
keyblock,
0,
&crypto);
if (ret) {
DEBUG(0,("krb5_crypto_init() failed: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
return ret;
}
ret = krb5_create_checksum(context,
crypto,
KRB5_KU_OTHER_CKSUM,
0,
pac_data->data,
pac_data->length,
&cksum);
if (ret) {
DEBUG(2, ("PAC Verification failed: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
}
krb5_crypto_destroy(context, crypto);
if (ret) {
return ret;
}
sig->type = cksum.cksumtype;
if (cksum.checksum.length == sizeof(sig->signature)) {
memcpy(sig->signature, cksum.checksum.data, sizeof(sig->signature));
}
return 0;
}
krb5_error_code kerberos_encode_pac(TALLOC_CTX *mem_ctx,
struct PAC_DATA *pac_data,
krb5_context context,
krb5_keyblock *krbtgt_keyblock,
krb5_keyblock *service_keyblock,
DATA_BLOB *pac)
{
NTSTATUS nt_status;
krb5_error_code ret;
DATA_BLOB zero_blob = data_blob(NULL, 0);
DATA_BLOB tmp_blob = data_blob(NULL, 0);
DATA_BLOB service_checksum_blob;
struct PAC_SIGNATURE_DATA *kdc_checksum = NULL;
struct PAC_SIGNATURE_DATA *srv_checksum = NULL;
int i;
/* First, just get the keytypes filled in (and lengths right, eventually) */
for (i=0; i < pac_data->num_buffers; i++) {
if (pac_data->buffers[i].type != PAC_TYPE_KDC_CHECKSUM) {
continue;
}
kdc_checksum = &pac_data->buffers[i].info->kdc_cksum,
ret = make_pac_checksum(mem_ctx, &zero_blob,
kdc_checksum,
context, krbtgt_keyblock);
if (ret) {
DEBUG(2, ("making krbtgt PAC checksum failed: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
talloc_free(pac_data);
return ret;
}
}
for (i=0; i < pac_data->num_buffers; i++) {
if (pac_data->buffers[i].type != PAC_TYPE_SRV_CHECKSUM) {
continue;
}
srv_checksum = &pac_data->buffers[i].info->srv_cksum;
ret = make_pac_checksum(mem_ctx, &zero_blob,
srv_checksum,
context, service_keyblock);
if (ret) {
DEBUG(2, ("making service PAC checksum failed: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
talloc_free(pac_data);
return ret;
}
}
if (!kdc_checksum) {
DEBUG(2, ("Invalid PAC constructed for signing, no KDC checksum present!"));
return EINVAL;
}
if (!srv_checksum) {
DEBUG(2, ("Invalid PAC constructed for signing, no SRV checksum present!"));
return EINVAL;
}
/* But wipe out the actual signatures */
ZERO_STRUCT(kdc_checksum->signature);
ZERO_STRUCT(srv_checksum->signature);
nt_status = ndr_push_struct_blob(&tmp_blob, mem_ctx, pac_data,
(ndr_push_flags_fn_t)ndr_push_PAC_DATA);
if (!NT_STATUS_IS_OK(nt_status)) {
DEBUG(1, ("PAC (presig) push failed: %s\n", nt_errstr(nt_status)));
talloc_free(pac_data);
return EINVAL;
}
/* Then sign the result of the previous push, where the sig was zero'ed out */
ret = make_pac_checksum(mem_ctx, &tmp_blob, srv_checksum,
context, service_keyblock);
service_checksum_blob
= data_blob_const(srv_checksum->signature, sizeof(srv_checksum->signature));
/* Then sign Server checksum */
ret = make_pac_checksum(mem_ctx, &service_checksum_blob, kdc_checksum, context, krbtgt_keyblock);
if (ret) {
DEBUG(2, ("making krbtgt PAC checksum failed: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
talloc_free(pac_data);
return ret;
}
/* And push it out again, this time to the world. This relies on determanistic pointer values */
nt_status = ndr_push_struct_blob(&tmp_blob, mem_ctx, pac_data,
(ndr_push_flags_fn_t)ndr_push_PAC_DATA);
if (!NT_STATUS_IS_OK(nt_status)) {
DEBUG(1, ("PAC (final) push failed: %s\n", nt_errstr(nt_status)));
talloc_free(pac_data);
return EINVAL;
}
*pac = tmp_blob;
return ret;
}
krb5_error_code kerberos_create_pac(TALLOC_CTX *mem_ctx,
struct auth_serversupplied_info *server_info,
krb5_context context,
krb5_keyblock *krbtgt_keyblock,
krb5_keyblock *service_keyblock,
time_t tgs_authtime,
DATA_BLOB *pac)
{
NTSTATUS nt_status;
krb5_error_code ret;
struct PAC_DATA *pac_data = talloc(mem_ctx, struct PAC_DATA);
struct netr_SamInfo3 *sam3;
struct timeval tv = timeval_current();
union PAC_INFO *u_LOGON_INFO;
struct PAC_LOGON_INFO *LOGON_INFO;
union PAC_INFO *u_LOGON_NAME;
struct PAC_LOGON_NAME *LOGON_NAME;
union PAC_INFO *u_KDC_CHECKSUM;
union PAC_INFO *u_SRV_CHECKSUM;
enum {
PAC_BUF_LOGON_INFO = 0,
PAC_BUF_LOGON_NAME = 1,
PAC_BUF_SRV_CHECKSUM = 2,
PAC_BUF_KDC_CHECKSUM = 3,
PAC_BUF_NUM_BUFFERS = 4
};
if (!pac_data) {
return ENOMEM;
}
pac_data->num_buffers = PAC_BUF_NUM_BUFFERS;
pac_data->version = 0;
pac_data->buffers = talloc_array(pac_data,
struct PAC_BUFFER,
pac_data->num_buffers);
if (!pac_data->buffers) {
talloc_free(pac_data);
return ENOMEM;
}
/* LOGON_INFO */
u_LOGON_INFO = talloc_zero(pac_data->buffers, union PAC_INFO);
if (!u_LOGON_INFO) {
talloc_free(pac_data);
return ENOMEM;
}
pac_data->buffers[PAC_BUF_LOGON_INFO].type = PAC_TYPE_LOGON_INFO;
pac_data->buffers[PAC_BUF_LOGON_INFO].info = u_LOGON_INFO;
/* LOGON_NAME */
u_LOGON_NAME = talloc_zero(pac_data->buffers, union PAC_INFO);
if (!u_LOGON_NAME) {
talloc_free(pac_data);
return ENOMEM;
}
pac_data->buffers[PAC_BUF_LOGON_NAME].type = PAC_TYPE_LOGON_NAME;
pac_data->buffers[PAC_BUF_LOGON_NAME].info = u_LOGON_NAME;
LOGON_NAME = &u_LOGON_NAME->logon_name;
/* SRV_CHECKSUM */
u_SRV_CHECKSUM = talloc_zero(pac_data->buffers, union PAC_INFO);
if (!u_SRV_CHECKSUM) {
talloc_free(pac_data);
return ENOMEM;
}
pac_data->buffers[PAC_BUF_SRV_CHECKSUM].type = PAC_TYPE_SRV_CHECKSUM;
pac_data->buffers[PAC_BUF_SRV_CHECKSUM].info = u_SRV_CHECKSUM;
/* KDC_CHECKSUM */
u_KDC_CHECKSUM = talloc_zero(pac_data->buffers, union PAC_INFO);
if (!u_KDC_CHECKSUM) {
talloc_free(pac_data);
return ENOMEM;
}
pac_data->buffers[PAC_BUF_KDC_CHECKSUM].type = PAC_TYPE_KDC_CHECKSUM;
pac_data->buffers[PAC_BUF_KDC_CHECKSUM].info = u_KDC_CHECKSUM;
/* now the real work begins... */
LOGON_INFO = talloc_zero(u_LOGON_INFO, struct PAC_LOGON_INFO);
if (!LOGON_INFO) {
talloc_free(pac_data);
return ENOMEM;
}
nt_status = auth_convert_server_info_saminfo3(LOGON_INFO, server_info, &sam3);
if (!NT_STATUS_IS_OK(nt_status)) {
DEBUG(1, ("Getting Samba info failed: %s\n", nt_errstr(nt_status)));
talloc_free(pac_data);
return EINVAL;
}
u_LOGON_INFO->logon_info.info = LOGON_INFO;
LOGON_INFO->info3 = *sam3;
LOGON_INFO->info3.base.last_logon = timeval_to_nttime(&tv);
LOGON_NAME->account_name = server_info->account_name;
/*
this logon_time field is absolutely critical. This is what
caused all our pac troubles :-)
*/
unix_to_nt_time(&LOGON_NAME->logon_time, tgs_authtime);
ret = kerberos_encode_pac(mem_ctx,
pac_data,
context,
krbtgt_keyblock,
service_keyblock,
pac);
talloc_free(pac_data);
return ret;
}
|