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samba-mirror/auth/kerberos/kerberos_pac.c

391 lines
11 KiB
C

/*
Unix SMB/CIFS implementation.
kerberos authorization data (PAC) utility library
Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003
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
Copyright (C) Guenther Deschner 2005,2007,2008
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#ifdef HAVE_KRB5
#include "librpc/gen_ndr/ndr_krb5pac.h"
#include "libcli/auth/krb5_wrap.h"
krb5_error_code check_pac_checksum(DATA_BLOB pac_data,
struct PAC_SIGNATURE_DATA *sig,
krb5_context context,
const krb5_keyblock *keyblock)
{
krb5_error_code ret;
krb5_checksum cksum;
krb5_keyusage usage = 0;
smb_krb5_checksum_from_pac_sig(&cksum, sig);
#ifdef HAVE_KRB5_KU_OTHER_CKSUM /* Heimdal */
usage = KRB5_KU_OTHER_CKSUM;
#elif defined(HAVE_KRB5_KEYUSAGE_APP_DATA_CKSUM) /* MIT */
usage = KRB5_KEYUSAGE_APP_DATA_CKSUM;
#else
#error UNKNOWN_KRB5_KEYUSAGE
#endif
ret = smb_krb5_verify_checksum(context,
keyblock,
usage,
&cksum,
pac_data.data,
pac_data.length);
if (ret) {
DEBUG(2,("check_pac_checksum: PAC Verification failed: %s (%d)\n",
error_message(ret), ret));
return ret;
}
return ret;
}
/**
* @brief Decode a blob containing a NDR envoded PAC structure
*
* @param mem_ctx - The memory context
* @param pac_data_blob - The data blob containing the NDR encoded data
* @param context - The Kerberos Context
* @param service_keyblock - The Service Key used to verify the checksum
* @param client_principal - The client principal
* @param tgs_authtime - The ticket timestamp
* @param pac_data_out - [out] The decoded PAC
*
* @return - A NTSTATUS error code
*/
NTSTATUS kerberos_decode_pac(TALLOC_CTX *mem_ctx,
DATA_BLOB pac_data_blob,
krb5_context context,
const krb5_keyblock *krbtgt_keyblock,
const krb5_keyblock *service_keyblock,
krb5_const_principal client_principal,
time_t tgs_authtime,
struct PAC_DATA **pac_data_out)
{
NTSTATUS status;
enum ndr_err_code ndr_err;
krb5_error_code ret;
DATA_BLOB modified_pac_blob;
NTTIME tgs_authtime_nttime;
krb5_principal client_principal_pac = NULL;
int i;
struct PAC_SIGNATURE_DATA *srv_sig_ptr = NULL;
struct PAC_SIGNATURE_DATA *kdc_sig_ptr = NULL;
struct PAC_SIGNATURE_DATA *srv_sig_wipe = NULL;
struct PAC_SIGNATURE_DATA *kdc_sig_wipe = NULL;
struct PAC_LOGON_NAME *logon_name = NULL;
struct PAC_LOGON_INFO *logon_info = NULL;
struct PAC_DATA *pac_data = NULL;
struct PAC_DATA_RAW *pac_data_raw = NULL;
DATA_BLOB *srv_sig_blob = NULL;
DATA_BLOB *kdc_sig_blob = NULL;
bool bool_ret;
TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
if (!tmp_ctx) {
return NT_STATUS_NO_MEMORY;
}
if (pac_data_out) {
*pac_data_out = NULL;
}
pac_data = talloc(tmp_ctx, struct PAC_DATA);
pac_data_raw = talloc(tmp_ctx, struct PAC_DATA_RAW);
kdc_sig_wipe = talloc(tmp_ctx, struct PAC_SIGNATURE_DATA);
srv_sig_wipe = talloc(tmp_ctx, struct PAC_SIGNATURE_DATA);
if (!pac_data_raw || !pac_data || !kdc_sig_wipe || !srv_sig_wipe) {
talloc_free(tmp_ctx);
return NT_STATUS_NO_MEMORY;
}
ndr_err = ndr_pull_struct_blob(&pac_data_blob, pac_data, pac_data,
(ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
status = ndr_map_error2ntstatus(ndr_err);
DEBUG(0,("can't parse the PAC: %s\n",
nt_errstr(status)));
talloc_free(tmp_ctx);
return status;
}
if (pac_data->num_buffers < 4) {
/* we need logon_ingo, service_key and kdc_key */
DEBUG(0,("less than 4 PAC buffers\n"));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
ndr_err = ndr_pull_struct_blob(
&pac_data_blob, pac_data_raw, pac_data_raw,
(ndr_pull_flags_fn_t)ndr_pull_PAC_DATA_RAW);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
status = ndr_map_error2ntstatus(ndr_err);
DEBUG(0,("can't parse the PAC: %s\n",
nt_errstr(status)));
talloc_free(tmp_ctx);
return status;
}
if (pac_data_raw->num_buffers < 4) {
/* we need logon_ingo, service_key and kdc_key */
DEBUG(0,("less than 4 PAC buffers\n"));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
if (pac_data->num_buffers != pac_data_raw->num_buffers) {
/* we need logon_ingo, service_key and kdc_key */
DEBUG(0, ("misparse! PAC_DATA has %d buffers while "
"PAC_DATA_RAW has %d\n", pac_data->num_buffers,
pac_data_raw->num_buffers));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
for (i=0; i < pac_data->num_buffers; i++) {
struct PAC_BUFFER *data_buf = &pac_data->buffers[i];
struct PAC_BUFFER_RAW *raw_buf = &pac_data_raw->buffers[i];
if (data_buf->type != raw_buf->type) {
DEBUG(0, ("misparse! PAC_DATA buffer %d has type "
"%d while PAC_DATA_RAW has %d\n", i,
data_buf->type, raw_buf->type));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
switch (data_buf->type) {
case PAC_TYPE_LOGON_INFO:
if (!data_buf->info) {
break;
}
logon_info = data_buf->info->logon_info.info;
break;
case PAC_TYPE_SRV_CHECKSUM:
if (!data_buf->info) {
break;
}
srv_sig_ptr = &data_buf->info->srv_cksum;
srv_sig_blob = &raw_buf->info->remaining;
break;
case PAC_TYPE_KDC_CHECKSUM:
if (!data_buf->info) {
break;
}
kdc_sig_ptr = &data_buf->info->kdc_cksum;
kdc_sig_blob = &raw_buf->info->remaining;
break;
case PAC_TYPE_LOGON_NAME:
logon_name = &data_buf->info->logon_name;
break;
default:
break;
}
}
if (!logon_info) {
DEBUG(0,("PAC no logon_info\n"));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
if (!logon_name) {
DEBUG(0,("PAC no logon_name\n"));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
if (!srv_sig_ptr || !srv_sig_blob) {
DEBUG(0,("PAC no srv_key\n"));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
if (!kdc_sig_ptr || !kdc_sig_blob) {
DEBUG(0,("PAC no kdc_key\n"));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
/* Find and zero out the signatures,
* as required by the signing algorithm */
/* We find the data blobs above,
* now we parse them to get at the exact portion we should zero */
ndr_err = ndr_pull_struct_blob(
kdc_sig_blob, kdc_sig_wipe, kdc_sig_wipe,
(ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
status = ndr_map_error2ntstatus(ndr_err);
DEBUG(0,("can't parse the KDC signature: %s\n",
nt_errstr(status)));
talloc_free(tmp_ctx);
return status;
}
ndr_err = ndr_pull_struct_blob(
srv_sig_blob, srv_sig_wipe, srv_sig_wipe,
(ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
status = ndr_map_error2ntstatus(ndr_err);
DEBUG(0,("can't parse the SRV signature: %s\n",
nt_errstr(status)));
talloc_free(tmp_ctx);
return status;
}
/* Now zero the decoded structure */
memset(kdc_sig_wipe->signature.data,
'\0', kdc_sig_wipe->signature.length);
memset(srv_sig_wipe->signature.data,
'\0', srv_sig_wipe->signature.length);
/* and reencode, back into the same place it came from */
ndr_err = ndr_push_struct_blob(
kdc_sig_blob, pac_data_raw, kdc_sig_wipe,
(ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
status = ndr_map_error2ntstatus(ndr_err);
DEBUG(0,("can't repack the KDC signature: %s\n",
nt_errstr(status)));
talloc_free(tmp_ctx);
return status;
}
ndr_err = ndr_push_struct_blob(
srv_sig_blob, pac_data_raw, srv_sig_wipe,
(ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
status = ndr_map_error2ntstatus(ndr_err);
DEBUG(0,("can't repack the SRV signature: %s\n",
nt_errstr(status)));
talloc_free(tmp_ctx);
return status;
}
/* push out the whole structure, but now with zero'ed signatures */
ndr_err = ndr_push_struct_blob(
&modified_pac_blob, pac_data_raw, pac_data_raw,
(ndr_push_flags_fn_t)ndr_push_PAC_DATA_RAW);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
status = ndr_map_error2ntstatus(ndr_err);
DEBUG(0,("can't repack the RAW PAC: %s\n",
nt_errstr(status)));
talloc_free(tmp_ctx);
return status;
}
if (service_keyblock) {
/* verify by service_key */
ret = check_pac_checksum(modified_pac_blob, srv_sig_ptr,
context,
service_keyblock);
if (ret) {
DEBUG(1, ("PAC Decode: Failed to verify the service "
"signature: %s\n", error_message(ret)));
return NT_STATUS_ACCESS_DENIED;
}
if (krbtgt_keyblock) {
/* verify the service key checksum by krbtgt_key */
ret = check_pac_checksum(srv_sig_ptr->signature, kdc_sig_ptr,
context, krbtgt_keyblock);
if (ret) {
DEBUG(1, ("PAC Decode: Failed to verify the KDC signature: %s\n",
smb_get_krb5_error_message(context, ret, tmp_ctx)));
talloc_free(tmp_ctx);
return NT_STATUS_ACCESS_DENIED;
}
}
}
if (tgs_authtime) {
/* Convert to NT time, so as not to loose accuracy in comparison */
unix_to_nt_time(&tgs_authtime_nttime, tgs_authtime);
if (tgs_authtime_nttime != logon_name->logon_time) {
DEBUG(2, ("PAC Decode: "
"Logon time mismatch between ticket and PAC!\n"));
DEBUG(2, ("PAC Decode: PAC: %s\n",
nt_time_string(tmp_ctx, logon_name->logon_time)));
DEBUG(2, ("PAC Decode: Ticket: %s\n",
nt_time_string(tmp_ctx, tgs_authtime_nttime)));
talloc_free(tmp_ctx);
return NT_STATUS_ACCESS_DENIED;
}
}
if (client_principal) {
ret = smb_krb5_parse_name_norealm(context,
logon_name->account_name,
&client_principal_pac);
if (ret) {
DEBUG(2, ("Could not parse name from PAC: [%s]:%s\n",
logon_name->account_name, error_message(ret)));
talloc_free(tmp_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
bool_ret = smb_krb5_principal_compare_any_realm(context,
client_principal,
client_principal_pac);
krb5_free_principal(context, client_principal_pac);
if (!bool_ret) {
DEBUG(2, ("Name in PAC [%s] does not match principal name "
"in ticket\n", logon_name->account_name));
talloc_free(tmp_ctx);
return NT_STATUS_ACCESS_DENIED;
}
}
DEBUG(3,("Found account name from PAC: %s [%s]\n",
logon_info->info3.base.account_name.string,
logon_info->info3.base.full_name.string));
DEBUG(10,("Successfully validated Kerberos PAC\n"));
if (DEBUGLEVEL >= 10) {
const char *s;
s = NDR_PRINT_STRUCT_STRING(tmp_ctx, PAC_DATA, pac_data);
if (s) {
DEBUGADD(10,("%s\n", s));
}
}
if (pac_data_out) {
*pac_data_out = talloc_steal(mem_ctx, pac_data);
}
return NT_STATUS_OK;
}
#endif