Re: [RFC PATCH 2/9] audit,io_uring,io-wq: add some basic audit support to io_uring

Jens Axboe
2021-05-26T01:11:05Z

On 5/24/21 1:59 PM, Paul Moore wrote:
> That said, audit is not for everyone, and we have build time and
> runtime options to help make life easier. Beyond simply disabling
> audit at compile time a number of Linux distributions effectively
> shortcut audit at runtime by adding a "never" rule to the audit
> filter, for example:
>
> % auditctl -a task,never

As has been brought up, the issue we're facing is that distros have
CONFIG_AUDIT=y and hence the above is the best real world case outside
of people doing custom kernels. My question would then be how much
overhead the above will add, considering it's an entry/exit call per op.
If auditctl is turned off, what is the expectation in turns of overhead?

My gut feeling tells me it's likely going to be too much. Keep in mind
that we're sometimes doing millions of operations per second, per core.

aio never had any audit logging as far as I can tell. I think it'd make
a lot more sense to selectively enable audit logging only for opcodes
that we care about. File open/create/unlink/mkdir etc, that kind of
thing. File level operations that people would care about logging. Would
they care about logging a buffer registration or a polled read from a
device/file? I highly doubt it, and we don't do that for alternative
methods either. Doesn't really make sense for a lot of the other
operations, imho.

--
Jens Axboe