Re: Are the writing of an events records to audit.log atomic should a log rotation occur
On Saturday, February 02, 2013 10:51:29 AM Burn Alting wrote:
All,
When rotating log files due a USR1 signal being sent, or for any other
reason, does auditd finish writing all the
records that belong to the current event being written before starting
the new log file?
When it catches SIGUSR1, it sets a flag that is read by the event loop. So,
this serializes it with other events. It does write the record out before
rotating.
That is, will I find records belonging to a single event in two log
files?
That is a different question and a different answer. Events can be composed of
multiple records. It is possible for a record to be emitted and at that time a
check of the disk space used or file size may cause a rotation or some other
action.
If this is the case, would there be problems if auditd was changed
to
wait and 'flush' all an event's records before
rotating?
Auditd just writes to disk. It does not try to determine if anything is
pending because its in a race to dequeue as fast as possible before buffers fill
up. Any re-assembly of records into an event is done by aureport and ausearch.
One assumes auditd-event.c would need to be modified to be
more event aware. Perhaps make use of AUDIT_EOE or
other means of identifying the end of an event or a single event.
It might be helpful to describe the problem this is solving.
Thanks,
-Steve