Re: ausearch checkpoint capability

[Steve Grubb <sgrubb@redhat.com>]

Hello,

On Saturday, August 16, 2014 09:25:16 AM Burn Alting wrote:
> One of the issues with ausearch's checkpoint code is how to recover from
> failures. A classic failure is to perform a checkpoint on a busy system
> and then delay too long before running the next invocation of ausearch
> and as a result of the delay, the checkpointed event cannot be found in
> the files in /var/log/audit. There are other failures, such as re-use of
> inodes etc.
> 
> For those of you who haven't noted the ausearch --checkpoint change, it
> basically records the details of the last complete audit event it
> processed or printed in a checkpoint file. It records not only the event
> time, but also the event node, serial, type and the file device and
> inode. Thus, when you next invoke ausearch with this option, the next
> event to process is the next complete event since the one recorded.
> 
> Should an error occur when attempting to find the next complete event to
> process, ausearch will exit. At this point, I believe the best recovery
> action is to extract only the event time from the checkpoint file and
> ask for all complete events after that time (i.e. as opposed to the
> usual action of comparing time, event id, type, log file details etc).

Would anyone be opposed to making that the default behavior?


> There are at last two solutions:
> a. We can patch ausearch to take a --checkpoint-time-only flag which
> means ausearch will look for all events since the time in the checkpoint
> file. This provides the best granularity in time as it goes down to
> msecs.

I am worried about the proliferation of command line switches. I'd rather make 
a new --start target. e.g. --start checkpoint-time.

> b. We extract the timestamp from the checkpoint file, convert it to a
> date and time and use ausearch's --start option to find all events since
> the time in the checkpoint file.
> 
> The first provides greater granularity in time as it goes to msecs.

If one is the timestamp of the file, that might be misleading. I don't know if 
touching a file is an auditable event. No time to investigate right now either. 
I'd rather see the time taken from within the file.

> I can provide a patch. Do you want it?

Sure, if its based on a --start target.

-Steve