Re: [PATCH ghak124 v3] audit: log nftables configuration change events
Richard Guy Briggs <rgb(a)redhat.com> wrote:
Ok, can I get one more clarification on this "hierarchy"?
Is it roughly
in the order they appear in nf_tables_commit() after step 3? It appears
it might be mostly already. If it isn't already, would it be reasonable
to re-order them? Would you suggest a different order?
For audit purposes I think enum nf_tables_msg_types is already in the
most relevant order, the lower numbers being more imporant.
So e.g. NEWTABLE would be more interesting than DELRULE, if both
are in same batch.
> > such that it would be desirable to filter them out
> > to reduce noise in that single log line if it is attempted to list all
> > the change ops? It almost sounds like it would be better to do one
> > audit log line for each table for each family, and possibly for each op
> > to avoid the need to change userspace. This would already be a
> > significant improvement picking the highest ranking op.
>
> I think i understand what you'd like to do. Yes, that would reduce
> the log output a lot.
Would the generation change id be useful outside the kernel?
Yes, we already announce it to interested parties via nfnetlink.
What
exactly does it look like?
Its just a u64 counter that gets incremented whenever there is a change.
I don't quite understand the genmask purpose.
Thats an implementation detail only. When we process a transaction,
changes to the ruleset are being made but they should not have any
effect until the entire transaction is processed.
So there are two 'generations' at any time:
1. The active ruleset
2. The future ruleset
2) is what is being changed/modified.
When the transaction completes, then the future ruleset becomes
the active ruleset. If the transaction has to be aborted, the
pending changes are reverted and the genid/genmasks are not changed.