auth/kerberos Move all the PAC handling functions to auth/kerberos

2 files changed, 365 insertions, 1 deletions

diff --git a/auth/kerberos/kerberos_pac.c b/auth/kerberos/kerberos_pac.c
new file mode 100644
index 0000000000..79d51b2645
--- /dev/null
+++ b/auth/kerberos/kerberos_pac.c
@@ -0,0 +1,364 @@
+/*
+   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;
+	}
+
+	if (service_keyblock) {
+		/* 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;
+			}
+		}
+	}
+
+	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(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;
+		}
+	}
+
+	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)));
+			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
diff --git a/auth/kerberos/wscript_build b/auth/kerberos/wscript_build
index c289aab839..10707708f0 100644
--- a/auth/kerberos/wscript_build
+++ b/auth/kerberos/wscript_build
@@ -1,3 +1,3 @@
 bld.SAMBA_SUBSYSTEM('KRB5_PAC',
-                    source='gssapi_pac.c',
+                    source='gssapi_pac.c kerberos_pac.c',
                     deps='gssapi_krb5 krb5 ndr-krb5pac')