+/*
+ 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(TALLOC_CTX *mem_ctx,
+ 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;
+
+ *pac_data_out = NULL;
+
+ pac_data = talloc(mem_ctx, struct PAC_DATA);
+ pac_data_raw = talloc(mem_ctx, struct PAC_DATA_RAW);
+ kdc_sig_wipe = talloc(mem_ctx, struct PAC_SIGNATURE_DATA);
+ srv_sig_wipe = talloc(mem_ctx, struct PAC_SIGNATURE_DATA);
+ if (!pac_data_raw || !pac_data || !kdc_sig_wipe || !srv_sig_wipe) {
+ 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)));
+ 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"));
+ 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)));
+ 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"));
+ 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));
+ 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));
+ 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"));
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ if (!logon_name) {
+ DEBUG(0,("PAC no logon_name\n"));
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ if (!srv_sig_ptr || !srv_sig_blob) {
+ DEBUG(0,("PAC no srv_key\n"));
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ if (!kdc_sig_ptr || !kdc_sig_blob) {
+ DEBUG(0,("PAC no kdc_key\n"));
+ 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)));
+ 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)));
+ 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)));
+ 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)));
+ 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)));
+ return status;
+ }
+
+ /* verify by service_key */
+ ret = check_pac_checksum(mem_ctx,
+ 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(mem_ctx,
+ 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, mem_ctx)));
+ return NT_STATUS_ACCESS_DENIED;
+ }
+ }
+
+ /* 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(mem_ctx, logon_name->logon_time)));
+ DEBUG(2, ("PAC Decode: Ticket: %s\n",
+ nt_time_string(mem_ctx, tgs_authtime_nttime)));
+ return NT_STATUS_ACCESS_DENIED;
+ }
+
+ 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)));
+ 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));
+ 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(mem_ctx, PAC_DATA, pac_data);
+ if (s) {
+ DEBUGADD(10,("%s\n", s));
+ }
+ }
+
+ *pac_data_out = pac_data;
+
+ return NT_STATUS_OK;
+}
+
+#endif
git.samba.org / samba.git / commitdiff