Bug#24493829 SETTING THE NULL_AUDIT_EVENT_RECORD CAUSES SEGMENTATION …

…FAULT

Problem:
========

null_audit_event_record variable is not intended to be modified outside
of the null_audit plugin. null_audit_event_record buffer must be allocated/deallocated
from within a plugin.

Fix:
====

null_audit_event_record is read only variable.

Reviewed-by:
============

Arun Kuruvila <arun.kuruvila@oracle.com>
Georgi Kodinov <georgi.kodinov@oracle.com>

mysql-test/r/audit_plugin_2.result

@@ -1840,6 +1840,20 @@ SELECT @@null_audit_event_order_check;
 @@null_audit_event_order_check
 EVENT-ORDER-ABORT
 ## CUSTOM ERROR MESSAGE - END ##
+##################
+## Event record ##
+##################
+SET @@null_audit_event_record_def = 'MYSQL_AUDIT_GENERAL_RESULT;MYSQL_AUDIT_COMMAND_END';
+SELECT 1;
+1
+1
+SELECT @@null_audit_event_record;
+@@null_audit_event_record
+MYSQL_AUDIT_GENERAL_RESULT;;
+MYSQL_AUDIT_GENERAL_STATUS;;
+MYSQL_AUDIT_COMMAND_END;command_id="<expected_command_id>";
+SET @@null_audit_event_record = '';
+ERROR HY000: Variable 'null_audit_event_record' is a read only variable
 UNINSTALL PLUGIN null_audit;
 Warnings:
 Warning	1620	Plugin is busy and will be uninstalled on shutdown

mysql-test/t/audit_plugin_2.test

@@ -1828,4 +1828,15 @@ SELECT 1;
 SELECT @@null_audit_event_order_check;
 --echo ## CUSTOM ERROR MESSAGE - END ##
 
+--echo ##################
+--echo ## Event record ##
+--echo ##################
+SET @@null_audit_event_record_def = 'MYSQL_AUDIT_GENERAL_RESULT;MYSQL_AUDIT_COMMAND_END';
+SELECT 1;
+--replace_regex /;command_id="[0-9]+"/;command_id="<expected_command_id>"/
+SELECT @@null_audit_event_record;
+
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@null_audit_event_record = '';
+
 eval UNINSTALL PLUGIN null_audit;

plugin/audit_null/audit_null.c

@@ -148,6 +148,7 @@ static MYSQL_THDVAR_STR(event_record_def,
                         "Event recording definition", NULL, NULL, NULL);
 
 static MYSQL_THDVAR_STR(event_record,
+                        PLUGIN_VAR_READONLY |
                         PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_MEMALLOC,
                         "Event recording", NULL, NULL, NULL);
 /*