auth logging: Extract common audit logging code

Extract the common audit logging code into a library to allow it's
re-use in other logging modules.

Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

4 files changed, 1441 insertions, 0 deletions

diff --git a/lib/audit_logging/audit_logging.c b/lib/audit_logging/audit_logging.c
new file mode 100644
index 00000000000..7da161cd204
--- /dev/null
+++ b/lib/audit_logging/audit_logging.c
@@ -0,0 +1,771 @@
+/*
+   common routines for audit logging
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2018
+
+   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/>.
+*/
+
+/*
+ * Error handling:
+ *
+ * The json_object structure contains a boolean 'error'.  This is set whenever
+ * an error is detected. All the library functions check this flag and return
+ * immediately if it is set.
+ *
+ *	if (object->error) {
+ *		return;
+ *	}
+ *
+ * This allows the operations to be sequenced naturally with out the clutter
+ * of error status checks.
+ *
+ *	audit = json_new_object();
+ *	json_add_version(&audit, OPERATION_MAJOR, OPERATION_MINOR);
+ *	json_add_int(&audit, "statusCode", ret);
+ *	json_add_string(&audit, "status", ldb_strerror(ret));
+ *	json_add_string(&audit, "operation", operation);
+ *	json_add_address(&audit, "remoteAddress", remote);
+ *	json_add_sid(&audit, "userSid", sid);
+ *	json_add_string(&audit, "dn", dn);
+ *	json_add_guid(&audit, "transactionId", &ac->transaction_guid);
+ *	json_add_guid(&audit, "sessionId", unique_session_token);
+ *
+ * The assumptions are that errors will be rare, and that the audit logging
+ * code should not cause failures. So errors are logged but processing
+ * continues on a best effort basis.
+ */
+
+#include "includes.h"
+
+#include "librpc/ndr/libndr.h"
+#include "lib/tsocket/tsocket.h"
+#include "libcli/security/dom_sid.h"
+#include "lib/messaging/messaging.h"
+#include "auth/common_auth.h"
+#include "audit_logging.h"
+
+/*
+ * @brief Get a human readable timestamp.
+ *
+ * Returns the current time formatted as
+ *  "Tue, 14 Mar 2017 08:38:42.209028 NZDT"
+ *
+ * The returned string is allocated by talloc in the supplied context.
+ * It is the callers responsibility to free it.
+ *
+ * @param mem_ctx talloc memory context that owns the returned string.
+ *
+ * @return a human readable time stamp.
+ *
+ */
+char* audit_get_timestamp(TALLOC_CTX *frame)
+{
+	char buffer[40];	/* formatted time less usec and timezone */
+	char tz[10];		/* formatted time zone			 */
+	struct tm* tm_info;	/* current local time			 */
+	struct timeval tv;	/* current system time			 */
+	int r;			/* response code from gettimeofday	 */
+	char * ts;		/* formatted time stamp			 */
+
+	r = gettimeofday(&tv, NULL);
+	if (r) {
+		DBG_ERR("Unable to get time of day: (%d) %s\n",
+			errno,
+			strerror(errno));
+		return NULL;
+	}
+
+	tm_info = localtime(&tv.tv_sec);
+	if (tm_info == NULL) {
+		DBG_ERR("Unable to determine local time\n");
+		return NULL;
+	}
+
+	strftime(buffer, sizeof(buffer)-1, "%a, %d %b %Y %H:%M:%S", tm_info);
+	strftime(tz, sizeof(tz)-1, "%Z", tm_info);
+	ts = talloc_asprintf(frame, "%s.%06ld %s", buffer, tv.tv_usec, tz);
+	if (ts == NULL) {
+		DBG_ERR("Out of memory formatting time stamp\n");
+	}
+	return ts;
+}
+
+#ifdef HAVE_JANSSON
+
+#include "system/time.h"
+
+/*
+ * @brief get a connection to the messaging event server.
+ *
+ * Get a connection to the messaging event server registered by server_name.
+ *
+ * @param msg_ctx a valid imessaging_context.
+ * @param server_name name of messaging event server to connect to.
+ * @param server_id The event server details to populate
+ *
+ * @return NTSTATUS
+ */
+static NTSTATUS get_event_server(
+	struct imessaging_context *msg_ctx,
+	const char *server_name,
+	struct server_id *event_server)
+{
+	NTSTATUS status;
+	TALLOC_CTX *frame = talloc_stackframe();
+	unsigned num_servers, i;
+	struct server_id *servers;
+
+	status = irpc_servers_byname(
+		msg_ctx,
+		frame,
+		server_name,
+		&num_servers,
+		&servers);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_NOTICE(
+			"Failed to find '%s' registered on the message bus to "
+			"send audit events to: %s\n",
+			server_name,
+			nt_errstr(status));
+		TALLOC_FREE(frame);
+		return status;
+	}
+
+	/*
+	 * Select the first server that is listening, because we get
+	 * connection refused as NT_STATUS_OBJECT_NAME_NOT_FOUND
+	 * without waiting
+	 */
+	for (i = 0; i < num_servers; i++) {
+		status = imessaging_send(
+			msg_ctx,
+			servers[i],
+			MSG_PING,
+			&data_blob_null);
+		if (NT_STATUS_IS_OK(status)) {
+			*event_server = servers[i];
+			TALLOC_FREE(frame);
+			return NT_STATUS_OK;
+		}
+	}
+	DBG_NOTICE(
+		"Failed to find '%s' registered on the message bus to "
+		"send audit events to: %s\n",
+		server_name,
+		nt_errstr(status));
+	TALLOC_FREE(frame);
+	return NT_STATUS_OBJECT_NAME_NOT_FOUND;
+}
+
+/*
+ * @brief send an audit message to a messaging event server.
+ *
+ * Send the message to a registered and listening event server.
+ * Note: Any errors are logged, and the message is not sent.  This is to ensure
+ *       that a poorly behaved event server does not impact Samba.
+ *
+ *       As it is possible to lose messages, especially during server
+ *       shut down, currently this function is primarily intended for use
+ *       in integration tests.
+ *
+ * @param msg_ctx an imessaging_context, can be NULL in which case no message
+ *                will be sent.
+ * @param server_name the naname of the event server to send the message to.
+ * @param messag_type A message type defined in librpc/idl/messaging.idl
+ * @param message The message to send.
+ *
+ */
+void audit_message_send(
+	struct imessaging_context *msg_ctx,
+	const char *server_name,
+	uint32_t message_type,
+	const char *message)
+{
+	struct server_id event_server;
+	NTSTATUS status;
+	DATA_BLOB message_blob = data_blob_string_const(message);
+
+	if (msg_ctx == NULL) {
+		DBG_DEBUG("No messaging context\n");
+		return;
+	}
+
+	/* Need to refetch the address each time as the destination server may
+	 * have disconnected and reconnected in the interim, in which case
+	 * messages may get lost
+	 */
+	status = get_event_server(msg_ctx, server_name, &event_server);
+	if (!NT_STATUS_IS_OK(status) &&
+	    !NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
+		DBG_ERR("get_event_server for %s returned (%s)\n",
+			server_name,
+			nt_errstr(status));
+		return;
+	}
+
+	status = imessaging_send(
+		msg_ctx,
+		event_server,
+		message_type,
+		&message_blob);
+
+	/*
+	 * If the server crashed, try to find it again
+	 */
+	if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
+		status = get_event_server(msg_ctx, server_name, &event_server);
+		if (!NT_STATUS_IS_OK(status) &&
+		    !NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
+			DBG_ERR("get_event_server for %s returned (%s)\n",
+				server_name,
+				nt_errstr(status));
+			return;
+		}
+		imessaging_send(
+			msg_ctx,
+			event_server,
+			message_type,
+			&message_blob);
+	}
+}
+
+/*
+ * @brief Create a new struct json_object, wrapping a JSON Object.
+ *
+ * Create a new json object, the json_object wraps the underlying json
+ * implementations JSON Object representation.
+ *
+ * Free with a call to json_free_object, note that the jansson inplementation
+ * allocates memory with malloc and not talloc.
+ *
+ * @return a struct json_object, error will be set to true if the object
+ *         could not be created.
+ *
+ */
+struct json_object json_new_object(void) {
+
+	struct json_object object;
+	object.error = false;
+
+	object.root = json_object();
+	if (object.root == NULL) {
+		object.error = true;
+		DBG_ERR("Unable to create json_object\n");
+	}
+	return object;
+}
+
+/*
+ * @brief Create a new struct json_object wrapping a JSON Array.
+ *
+ * Create a new json object, the json_object wraps the underlying json
+ * implementations JSON Array representation.
+ *
+ * Free with a call to json_free_object, note that the jansson inplementation
+ * allocates memory with malloc and not talloc.
+ *
+ * @return a struct json_object, error will be set to true if the array
+ *         could not be created.
+ *
+ */
+struct json_object json_new_array(void) {
+
+	struct json_object array;
+	array.error = false;
+
+	array.root = json_array();
+	if (array.root == NULL) {
+		array.error = true;
+		DBG_ERR("Unable to create json_array\n");
+	}
+	return array;
+}
+
+
+/*
+ * @brief free and invalidate a previously created JSON object.
+ *
+ * Release any resources owned by a json_object, and then mark the structure
+ * as invalid.  It is safe to call this multiple times on an object.
+ *
+ */
+void json_free(struct json_object *object)
+{
+	if (object->root != NULL) {
+		json_decref(object->root);
+	}
+	object->root = NULL;
+	object->error = true;
+}
+
+/*
+ * @brief is the current JSON object invalid?
+ *
+ * Check the state of the object to determine if it is invalid.
+ *
+ * @return is the object valid?
+ *
+ */
+bool json_is_invalid(struct json_object *object)
+{
+	return object->error;
+}
+
+/*
+ * @brief Add an integer value to a JSON object.
+ *
+ * Add an integer value named 'name' to the json object.
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name of the value.
+ * @param value the value.
+ *
+ */
+void json_add_int(struct json_object *object,
+		  const char* name,
+		  const int value)
+{
+	int rc = 0;
+
+	if (object->error) {
+		return;
+	}
+
+	rc = json_object_set_new(object->root, name, json_integer(value));
+	if (rc) {
+		DBG_ERR("Unable to set name [%s] value [%d]\n", name, value);
+		object->error = true;
+	}
+}
+
+/*
+ * @brief Add a boolean value to a JSON object.
+ *
+ * Add a boolean value named 'name' to the json object.
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name.
+ * @param value the value.
+ *
+ */
+void json_add_bool(struct json_object *object,
+		   const char* name,
+		   const bool value)
+{
+	int rc = 0;
+
+	if (object->error) {
+		return;
+	}
+
+	rc = json_object_set_new(object->root, name, json_boolean(value));
+	if (rc) {
+		DBG_ERR("Unable to set name [%s] value [%d]\n", name, value);
+		object->error = true;
+	}
+
+}
+
+/*
+ * @brief Add a string value to a JSON object.
+ *
+ * Add a string value named 'name' to the json object.
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name.
+ * @param value the value.
+ *
+ */
+void json_add_string(struct json_object *object,
+		     const char* name,
+		     const char* value)
+{
+	int rc = 0;
+
+	if (object->error) {
+		return;
+	}
+
+	if (value) {
+		rc = json_object_set_new(
+			object->root,
+			name,
+			json_string(value));
+	} else {
+		rc = json_object_set_new(object->root, name, json_null());
+	}
+	if (rc) {
+		DBG_ERR("Unable to set name [%s] value [%s]\n", name, value);
+		object->error = true;
+	}
+}
+
+/*
+ * @brief Assert that the current JSON object is an array.
+ *
+ * Check that the current object is a JSON array, and if not
+ * invalidate the object. We also log an error message as this indicates
+ * bug in the calling code.
+ *
+ * @param object the JSON object to be validated.
+ */
+void json_assert_is_array(struct json_object *array) {
+
+	if (array->error) {
+		return;
+	}
+
+	if (json_is_array(array->root) == false) {
+		DBG_ERR("JSON object is not an array\n");
+		array->error = true;
+		return;
+	}
+}
+
+/*
+ * @brief Add a JSON object to a JSON object.
+ *
+ * Add a JSON object named 'name' to the json object.
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name.
+ * @param value the value.
+ *
+ */
+void json_add_object(struct json_object *object,
+		const char* name,
+		struct json_object *value)
+{
+	int rc = 0;
+	json_t *jv = NULL;
+
+	if (object->error) {
+		return;
+	}
+
+	if (value != NULL && value->error) {
+		object->error = true;
+		return;
+	}
+
+	jv = value == NULL ? json_null() : value->root;
+
+	if (json_is_array(object->root)) {
+		rc = json_array_append_new(object->root, jv);
+	} else if (json_is_object(object->root)) {
+		rc = json_object_set_new(object->root, name,  jv);
+	} else {
+		DBG_ERR("Invalid JSON object type\n");
+		object->error = true;
+	}
+	if (rc) {
+		DBG_ERR("Unable to add object [%s]\n", name);
+		object->error = true;
+	}
+}
+
+/*
+ * @brief Add a string to a JSON object, truncating if necessary.
+ *
+ *
+ * Add a string value named 'name' to the json object, the string will be
+ * truncated if it is more than len characters long. If len is 0 the value
+ * is encoded as a JSON null.
+ *
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name.
+ * @param value the value.
+ * @param len the maximum number of characters to be copied.
+ *
+ */
+void json_add_stringn(
+	struct json_object *object,
+	const char *name,
+	const char *value,
+	const size_t len)
+{
+
+	int rc = 0;
+	if (object->error) {
+		return;
+	}
+
+	if (value != NULL && len > 0) {
+		char buffer[len+1];
+		strncpy(buffer, value, len);
+		buffer[len] = '\0';
+		rc = json_object_set_new(object->root,
+					 name,
+					 json_string(buffer));
+	} else {
+		rc = json_object_set_new(object->root, name, json_null());
+	}
+	if (rc) {
+		DBG_ERR("Unable to set name [%s] value [%s]\n", name, value);
+		object->error = true;
+	}
+}
+
+/*
+ * @brief Add a version object to a JSON object
+ *
+ * Add a version object to the JSON object
+ * 	"version":{"major":1, "minor":0}
+ *
+ * The version tag is intended to aid the processing of the JSON messages
+ * The major version number should change when an attribute is:
+ *  - renamed
+ *  - removed
+ *  - its meaning changes
+ *  - its contents change format
+ * The minor version should change whenever a new attribute is added and for
+ * minor bug fixes to an attributes content.
+ *
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param major the major version number
+ * @param minor the minor version number
+ */
+void json_add_version(struct json_object *object, int major, int minor)
+{
+	struct json_object version = json_new_object();
+	json_add_int(&version, "major", major);
+	json_add_int(&version, "minor", minor);
+	json_add_object(object, "version", &version);
+}
+
+/*
+ * @brief add an ISO 8601 timestamp to the object.
+ *
+ * Add the current date and time as a timestamp in ISO 8601 format
+ * to a JSON object
+ *
+ * "timestamp":"2017-03-06T17:18:04.455081+1300"
+ *
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ */
+void json_add_timestamp(struct json_object *object)
+{
+	char buffer[40];	/* formatted time less usec and timezone */
+	char timestamp[50];	/* the formatted ISO 8601 time stamp	 */
+	char tz[10];		/* formatted time zone			 */
+	struct tm* tm_info;	/* current local time			 */
+	struct timeval tv;	/* current system time			 */
+	int r;			/* response code from gettimeofday	 */
+
+	if (object->error) {
+		return;
+	}
+
+	r = gettimeofday(&tv, NULL);
+	if (r) {
+		DBG_ERR("Unable to get time of day: (%d) %s\n",
+			errno,
+			strerror(errno));
+		object->error = true;
+		return;
+	}
+
+	tm_info = localtime(&tv.tv_sec);
+	if (tm_info == NULL) {
+		DBG_ERR("Unable to determine local time\n");
+		object->error = true;
+		return;
+	}
+
+	strftime(buffer, sizeof(buffer)-1, "%Y-%m-%dT%T", tm_info);
+	strftime(tz, sizeof(tz)-1, "%z", tm_info);
+	snprintf(
+		timestamp,
+		sizeof(timestamp),
+		"%s.%06ld%s",
+		buffer,
+		tv.tv_usec,
+		tz);
+	json_add_string(object, "timestamp", timestamp);
+}
+
+
+/*
+ *@brief Add a tsocket_address to a JSON object
+ *
+ * Add the string representation of a Samba tsocket_address to the object.
+ *
+ * "localAddress":"ipv6::::0"
+ *
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name.
+ * @param address the tsocket_address.
+ *
+ */
+void json_add_address(
+	struct json_object *object,
+	const char *name,
+	const struct tsocket_address *address)
+{
+
+	if (object->error) {
+		return;
+	}
+	if (address == NULL) {
+		int rc = json_object_set_new(object->root, name, json_null());
+		if (rc) {
+			DBG_ERR("Unable to set address [%s] to null\n", name);
+			object->error = true;
+		}
+	} else {
+		TALLOC_CTX *ctx = talloc_new(NULL);
+		char *s = NULL;
+
+		s = tsocket_address_string(address, ctx);
+		json_add_string(object, name, s);
+		TALLOC_FREE(ctx);
+	}
+}
+
+/*
+ * @brief Add a formatted string representation of a sid to a json object.
+ *
+ * Add the string representation of a Samba sid to the object.
+ *
+ * "sid":"S-1-5-18"
+ *
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name.
+ * @param sid the sid
+ *
+ */
+void json_add_sid(
+	struct json_object *object,
+	const char *name,
+	const struct dom_sid *sid)
+{
+
+	if (object->error) {
+		return;
+	}
+	if (sid == NULL) {
+		int rc = json_object_set_new(object->root, name, json_null());
+		if (rc) {
+			DBG_ERR("Unable to set SID [%s] to null\n", name);
+			object->error = true;
+		}
+	} else {
+		char sid_buf[DOM_SID_STR_BUFLEN];
+
+		dom_sid_string_buf(sid, sid_buf, sizeof(sid_buf));
+		json_add_string(object, name, sid_buf);
+	}
+}
+
+/*
+ * @brief Add a formatted string representation of a guid to a json object.
+ *
+ * Add the string representation of a Samba GUID to the object.
+ *
+ * "guid":"1fb9f2ee-2a4d-4bf8-af8b-cb9d4529a9ab"
+ *
+ * In the event of an error object will be invalidated.
+ *
+ * @param object the JSON object to be updated.
+ * @param name the name.
+ * @param guid the guid.
+ *
+ *
+ */
+void json_add_guid(
+	struct json_object *object,
+	const char *name,
+	const struct GUID *guid)
+{
+
+
+	if (object->error) {
+		return;
+	}
+	if (guid == NULL) {
+		int rc = json_object_set_new(object->root, name, json_null());
+		if (rc) {
+			DBG_ERR("Unable to set GUID [%s] to null\n", name);
+			object->error = true;
+		}
+	} else {
+		char *guid_str;
+		struct GUID_txt_buf guid_buff;
+
+		guid_str = GUID_buf_string(guid, &guid_buff);
+		json_add_string(object, name, guid_str);
+	}
+}
+
+
+/*
+ * @brief Convert a JSON object into a string
+ *
+ * Convert the jsom object into a string suitable for printing on a log line,
+ * i.e. with no embedded line breaks.
+ *
+ * If the object is invalid it returns NULL.
+ *
+ * @param mem_ctx the talloc memory context owning the returned string
+ * @param object the json object.
+ *
+ * @return A string representation of the object or NULL if the object
+ *         is invalid.
+ */
+char *json_to_string(TALLOC_CTX *mem_ctx, struct json_object *object)
+{
+	char *json = NULL;
+	char *json_string = NULL;
+
+	if (object->error) {
+		return NULL;
+	}
+
+	/*
+	 * json_dumps uses malloc, so need to call free(json) to release
+	 * the memory
+	 */
+	json = json_dumps(object->root, 0);
+	if (json == NULL) {
+		DBG_ERR("Unable to convert JSON object to string\n");
+		return NULL;
+	}
+
+	json_string = talloc_strdup(mem_ctx, json);
+	if (json_string == NULL) {
+		free(json);
+		DBG_ERR("Unable to copy JSON object string to talloc string\n");
+		return NULL;
+	}
+	free(json);
+
+	return json_string;
+}
+#endif
diff --git a/lib/audit_logging/audit_logging.h b/lib/audit_logging/audit_logging.h
new file mode 100644
index 00000000000..763f3ed5d9c
--- /dev/null
+++ b/lib/audit_logging/audit_logging.h
@@ -0,0 +1,89 @@
+/*
+   common routines for audit logging
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2018
+
+   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 <talloc.h>
+#include "lib/messaging/irpc.h"
+#include "lib/tsocket/tsocket.h"
+
+char* audit_get_timestamp(
+	TALLOC_CTX *frame);
+
+void audit_message_send(
+	struct imessaging_context *msg_ctx,
+	const char *server_name,
+	uint32_t message_type,
+	const char *message);
+#ifdef HAVE_JANSSON
+#include <jansson.h>
+/*
+ * Wrapper for jannson JSON object
+ *
+ */
+struct json_object {
+	json_t *root;
+	bool error;
+};
+
+struct json_object json_new_object(void);
+struct json_object json_new_array(void);
+void json_free(struct json_object *object);
+void json_assert_is_array(struct json_object *array);
+bool json_is_invalid(struct json_object *object);
+
+void json_add_int(
+	struct json_object *object,
+	const char* name,
+	const int value);
+void json_add_bool(
+	struct json_object *object,
+	const char* name,
+	const bool value);
+void json_add_string(
+	struct json_object *object,
+	const char* name,
+	const char* value);
+void json_add_object(
+	struct json_object *object,
+	const char* name,
+	struct json_object *value);
+void json_add_stringn(
+	struct json_object *object,
+	const char *name,
+	const char *value,
+	const size_t len);
+void json_add_version(
+	struct json_object *object,
+	int major,
+	int minor);
+void json_add_timestamp(struct json_object *object);
+void json_add_address(
+	struct json_object *object,
+	const char *name,
+	const struct tsocket_address *address);
+void json_add_sid(
+	struct json_object *object,
+	const char *name,
+	const struct dom_sid *sid);
+void json_add_guid(
+	struct json_object *object,
+	const char *name,
+	const struct GUID *guid);
+
+char *json_to_string(TALLOC_CTX *mem_ctx, struct json_object *object);
+#endif
diff --git a/lib/audit_logging/tests/audit_logging_test.c b/lib/audit_logging/tests/audit_logging_test.c
new file mode 100644
index 00000000000..9ba71fb60d7
--- /dev/null
+++ b/lib/audit_logging/tests/audit_logging_test.c
@@ -0,0 +1,557 @@
+/*
+ * Unit tests for the audit_logging library.
+ *
+ *  Copyright (C) Andrew Bartlett <abartlet@samba.org> 2018
+ *
+ * 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/>.
+ *
+ */
+
+/*
+ * from cmocka.c:
+ * These headers or their equivalents should be included prior to
+ * including
+ * this header file.
+ *
+ * #include <stdarg.h>
+ * #include <stddef.h>
+ * #include <setjmp.h>
+ *
+ * This allows test applications to use custom definitions of C standard
+ * library functions and types.
+ *
+ */
+
+/*
+ * Note that the messaging routines (audit_message_send and get_event_server)
+ * are not tested by these unit tests.  Currently they are for integration
+ * test support, and as such are exercised by the integration tests.
+ */
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+#include <string.h>
+#include <time.h>
+#include <tevent.h>
+#include <config.h>
+#include <talloc.h>
+#include "lib/util/talloc_stack.h"
+
+#include "lib/util/data_blob.h"
+#include "lib/util/time.h"
+#include "libcli/util/werror.h"
+#include "lib/param/loadparm.h"
+#include "libcli/security/dom_sid.h"
+#include "librpc/ndr/libndr.h"
+
+#include "lib/audit_logging/audit_logging.h"
+
+#ifdef HAVE_JANSSON
+static void test_json_add_int(void **state)
+{
+	struct json_object object;
+	struct json_t *value = NULL;
+	double n;
+
+	object = json_new_object();
+	json_add_int(&object, "positive_one", 1);
+	json_add_int(&object, "zero", 0);
+	json_add_int(&object, "negative_one", -1);
+
+
+	assert_int_equal(3, json_object_size(object.root));
+
+	value = json_object_get(object.root, "positive_one");
+	assert_true(json_is_integer(value));
+	n = json_number_value(value);
+	assert_true(n == 1.0);
+
+	value = json_object_get(object.root, "zero");
+	assert_true(json_is_integer(value));
+	n = json_number_value(value);
+	assert_true(n == 0.0);
+
+	value = json_object_get(object.root, "negative_one");
+	assert_true(json_is_integer(value));
+	n = json_number_value(value);
+	assert_true(n == -1.0);
+
+	json_free(&object);
+}
+
+static void test_json_add_bool(void **state)
+{
+	struct json_object object;
+	struct json_t *value = NULL;
+
+	object = json_new_object();
+	json_add_bool(&object, "true", true);
+	json_add_bool(&object, "false", false);
+
+
+	assert_int_equal(2, json_object_size(object.root));
+
+	value = json_object_get(object.root, "true");
+	assert_true(json_is_boolean(value));
+	assert_true(value == json_true());
+
+	value = json_object_get(object.root, "false");
+	assert_true(json_is_boolean(value));
+	assert_true(value == json_false());
+
+	json_free(&object);
+}
+
+static void test_json_add_string(void **state)
+{
+	struct json_object object;
+	struct json_t *value = NULL;
+	const char *s = NULL;
+
+	object = json_new_object();
+	json_add_string(&object, "null", NULL);
+	json_add_string(&object, "empty", "");
+	json_add_string(&object, "name", "value");
+
+
+
+	assert_int_equal(3, json_object_size(object.root));
+
+	value = json_object_get(object.root, "null");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "empty");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("", s);
+
+	value = json_object_get(object.root, "name");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("value", s);
+	json_free(&object);
+}
+
+static void test_json_add_object(void **state)
+{
+	struct json_object object;
+	struct json_object other;
+	struct json_t *value = NULL;
+
+	object = json_new_object();
+	other  = json_new_object();
+	json_add_object(&object, "null", NULL);
+	json_add_object(&object, "other", &other);
+
+
+
+	assert_int_equal(2, json_object_size(object.root));
+
+	value = json_object_get(object.root, "null");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "other");
+	assert_true(json_is_object(value));
+	assert_ptr_equal(other.root, value);
+
+	json_free(&object);
+}
+
+static void test_json_add_to_array(void **state)
+{
+	struct json_object array;
+	struct json_object o1;
+	struct json_object o2;
+	struct json_object o3;
+	struct json_t *value = NULL;
+
+	array = json_new_array();
+	assert_true(json_is_array(array.root));
+
+	o1 = json_new_object();
+	o2 = json_new_object();
+	o3 = json_new_object();
+
+	json_add_object(&array, NULL, &o3);
+	json_add_object(&array, "", &o2);
+	json_add_object(&array, "will-be-ignored", &o1);
+	json_add_object(&array, NULL, NULL);
+
+	assert_int_equal(4, json_array_size(array.root));
+
+	value = json_array_get(array.root, 0);
+	assert_ptr_equal(o3.root, value);
+
+	value = json_array_get(array.root, 1);
+	assert_ptr_equal(o2.root, value);
+
+	value = json_array_get(array.root, 2);
+	assert_ptr_equal(o1.root, value);
+
+	value = json_array_get(array.root, 3);
+	assert_true(json_is_null(value));
+
+	json_free(&array);
+
+}
+
+static void test_json_add_timestamp(void **state)
+{
+	struct json_object object;
+	struct json_t *ts = NULL;
+	const char *t = NULL;
+	int rc;
+	int usec, tz;
+	char c[2];
+	struct tm tm;
+	time_t before;
+	time_t after;
+	time_t actual;
+
+
+	object = json_new_object();
+	before = time(NULL);
+	json_add_timestamp(&object);
+	after = time(NULL);
+
+	ts = json_object_get(object.root, "timestamp");
+	assert_true(json_is_string(ts));
+
+	/*
+	 * Convert the returned ISO 8601 timestamp into a time_t
+	 * Note for convenience we ignore the value of the microsecond
+	 * part of the time stamp.
+	 */
+	t = json_string_value(ts);
+	rc = sscanf(
+		t,
+		"%4d-%2d-%2dT%2d:%2d:%2d.%6d%1c%4d",
+		&tm.tm_year,
+		&tm.tm_mon,
+		&tm.tm_mday,
+		&tm.tm_hour,
+		&tm.tm_min,
+		&tm.tm_sec,
+		&usec,
+		c,
+		&tz);
+	assert_int_equal(9, rc);
+	tm.tm_year = tm.tm_year - 1900;
+	tm.tm_mon = tm.tm_mon - 1;
+	tm.tm_isdst = -1;
+	actual = mktime(&tm);
+
+	/*
+	 * The timestamp should be before <= actual <= after
+	 */
+	assert_true(difftime(actual, before) >= 0);
+	assert_true(difftime(after, actual) >= 0);
+
+	json_free(&object);
+}
+
+static void test_json_add_stringn(void **state)
+{
+	struct json_object object;
+	struct json_t *value = NULL;
+	const char *s = NULL;
+
+	object = json_new_object();
+	json_add_stringn(&object, "null", NULL, 10);
+	json_add_stringn(&object, "null-zero-len", NULL, 0);
+	json_add_stringn(&object, "empty", "", 1);
+	json_add_stringn(&object, "empty-zero-len", "", 0);
+	json_add_stringn(&object, "value-less-than-len", "123456", 7);
+	json_add_stringn(&object, "value-greater-than-len", "abcd", 3);
+	json_add_stringn(&object, "value-equal-len", "ZYX", 3);
+	json_add_stringn(&object, "value-len-is-zero", "this will be null", 0);
+
+
+	assert_int_equal(8, json_object_size(object.root));
+
+	value = json_object_get(object.root, "null");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "null-zero-len");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "empty");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("", s);
+
+	value = json_object_get(object.root, "empty-zero-len");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "value-greater-than-len");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("abc", s);
+	assert_int_equal(3, strlen(s));
+
+	value = json_object_get(object.root, "value-equal-len");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("ZYX", s);
+	assert_int_equal(3, strlen(s));
+
+	value = json_object_get(object.root, "value-len-is-zero");
+	assert_true(json_is_null(value));
+
+	json_free(&object);
+}
+
+static void test_json_add_version(void **state)
+{
+	struct json_object object;
+	struct json_t *version = NULL;
+	struct json_t *v = NULL;
+	double n;
+
+	object = json_new_object();
+	json_add_version(&object, 3, 1);
+
+	assert_int_equal(1, json_object_size(object.root));
+
+	version = json_object_get(object.root, "version");
+	assert_true(json_is_object(version));
+	assert_int_equal(2, json_object_size(version));
+
+	v = json_object_get(version, "major");
+	assert_true(json_is_integer(v));
+	n = json_number_value(v);
+	assert_true(n == 3.0);
+
+	v = json_object_get(version, "minor");
+	assert_true(json_is_integer(v));
+	n = json_number_value(v);
+	assert_true(n == 1.0);
+
+	json_free(&object);
+}
+
+static void test_json_add_address(void **state)
+{
+	struct json_object object;
+	struct json_t *value = NULL;
+	struct tsocket_address *ip4  = NULL;
+	struct tsocket_address *ip6  = NULL;
+	struct tsocket_address *pipe = NULL;
+	const char *s = NULL;
+	int rc;
+
+	TALLOC_CTX *ctx = talloc_new(NULL);
+
+	object = json_new_object();
+
+	json_add_address(&object, "null", NULL);
+
+	rc = tsocket_address_inet_from_strings(
+		ctx,
+		"ip",
+		"127.0.0.1",
+		21,
+		&ip4);
+	assert_int_equal(0, rc);
+	json_add_address(&object, "ip4", ip4);
+
+	rc = tsocket_address_inet_from_strings(
+		ctx,
+		"ip",
+		"2001:db8:0:0:1:0:0:1",
+		42,
+		&ip6);
+	assert_int_equal(0, rc);
+	json_add_address(&object, "ip6", ip6);
+
+	rc = tsocket_address_unix_from_path(ctx, "/samba/pipe", &pipe);
+	assert_int_equal(0, rc);
+	json_add_address(&object, "pipe", pipe);
+
+	assert_int_equal(4, json_object_size(object.root));
+
+	value = json_object_get(object.root, "null");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "ip4");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("ipv4:127.0.0.1:21", s);
+
+	value = json_object_get(object.root, "ip6");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("ipv6:2001:db8::1:0:0:1:42", s);
+
+	value = json_object_get(object.root, "pipe");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal("unix:/samba/pipe", s);
+
+	json_free(&object);
+	TALLOC_FREE(ctx);
+}
+
+static void test_json_add_sid(void **state)
+{
+	struct json_object object;
+	struct json_t *value = NULL;
+	const char *SID = "S-1-5-21-2470180966-3899876309-2637894779";
+	struct dom_sid sid;
+	const char *s = NULL;
+
+
+	object = json_new_object();
+
+	json_add_sid(&object, "null", NULL);
+
+	assert_true(string_to_sid(&sid, SID));
+	json_add_sid(&object, "sid", &sid);
+
+	assert_int_equal(2, json_object_size(object.root));
+
+	value = json_object_get(object.root, "null");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "sid");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal(SID, s);
+	json_free(&object);
+}
+
+static void test_json_add_guid(void **state)
+{
+	struct json_object object;
+	struct json_t *value = NULL;
+	const char *GUID = "3ab88633-1e57-4c1a-856c-d1bc4b15bbb1";
+	struct GUID guid;
+	const char *s = NULL;
+	NTSTATUS status;
+
+
+	object = json_new_object();
+
+	json_add_guid(&object, "null", NULL);
+
+	status = GUID_from_string(GUID, &guid);
+	assert_true(NT_STATUS_IS_OK(status));
+	json_add_guid(&object, "guid", &guid);
+
+	assert_int_equal(2, json_object_size(object.root));
+
+	value = json_object_get(object.root, "null");
+	assert_true(json_is_null(value));
+
+	value = json_object_get(object.root, "guid");
+	assert_true(json_is_string(value));
+	s = json_string_value(value);
+	assert_string_equal(GUID, s);
+
+	json_free(&object);
+}
+
+static void test_json_to_string(void **state)
+{
+	struct json_object object;
+	char *s = NULL;
+
+	TALLOC_CTX *ctx = talloc_new(NULL);
+
+	object = json_new_object();
+	object.error = true;
+
+	s = json_to_string(ctx, &object);
+	assert_null(s);
+
+	object.error = false;
+	s = json_to_string(ctx, &object);
+	assert_string_equal("{}", s);
+	TALLOC_FREE(s);
+
+	json_add_string(&object, "name", "value");
+	s = json_to_string(ctx, &object);
+	assert_string_equal("{\"name\": \"value\"}", s);
+	TALLOC_FREE(s);
+
+	json_free(&object);
+	TALLOC_FREE(ctx);
+}
+#endif
+
+static void test_audit_get_timestamp(void **state)
+{
+	const char *t = NULL;
+	char *c;
+	struct tm tm;
+	time_t before;
+	time_t after;
+	time_t actual;
+
+	TALLOC_CTX *ctx = talloc_new(NULL);
+
+	before = time(NULL);
+	t = audit_get_timestamp(ctx);
+	after = time(NULL);
+
+
+	c = strptime(t, "%a, %d %b %Y %H:%M:%S", &tm);
+	tm.tm_isdst = -1;
+	if (c != NULL && *c == '.') {
+		char *e;
+		strtod(c, &e);
+		c = e;
+	}
+	if (c != NULL && *c == ' ') {
+		struct tm tz;
+		c = strptime(c, " %Z", &tz);
+	}
+	assert_int_equal(0, strlen(c));
+
+	actual = mktime(&tm);
+
+	/*
+	 * The timestamp should be before <= actual <= after
+	 */
+	assert_true(difftime(actual, before) >= 0);
+	assert_true(difftime(after, actual) >= 0);
+
+	TALLOC_FREE(ctx);
+}
+
+int main(int argc, const char **argv)
+{
+	const struct CMUnitTest tests[] = {
+#ifdef HAVE_JANSSON
+		cmocka_unit_test(test_json_add_int),
+		cmocka_unit_test(test_json_add_bool),
+		cmocka_unit_test(test_json_add_string),
+		cmocka_unit_test(test_json_add_object),
+		cmocka_unit_test(test_json_add_to_array),
+		cmocka_unit_test(test_json_add_timestamp),
+		cmocka_unit_test(test_json_add_stringn),
+		cmocka_unit_test(test_json_add_version),
+		cmocka_unit_test(test_json_add_address),
+		cmocka_unit_test(test_json_add_sid),
+		cmocka_unit_test(test_json_add_guid),
+		cmocka_unit_test(test_json_to_string),
+#endif
+		cmocka_unit_test(test_audit_get_timestamp),
+	};
+
+	cmocka_set_message_output(CM_OUTPUT_SUBUNIT);
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}
diff --git a/lib/audit_logging/wscript_build b/lib/audit_logging/wscript_build
new file mode 100644
index 00000000000..4022d9031f6
--- /dev/null
+++ b/lib/audit_logging/wscript_build
@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+
+bld.SAMBA_SUBSYSTEM(
+    'audit_logging',
+    deps='''MESSAGING_SEND
+            jansson
+            samba-debug
+            LIBTSOCKET''',
+    source='audit_logging.c'
+)
+
+bld.SAMBA_BINARY(
+    'audit_logging_test',
+    source='tests/audit_logging_test.c',
+    deps='''
+        audit_logging
+        jansson
+        cmocka
+        talloc
+        samba-util
+        LIBTSOCKET
+    ''',
+    install=False
+)