Re: [PATCH net 1/1] netfilter: flowtable: Fix use after free after freeing flow table

[Pablo Neira Ayuso <pablo@netfilter.org>]

Hi Paul,

On Sun, Aug 21, 2022 at 12:23:39PM +0300, Paul Blakey wrote:
> Hi!
> 
> The only functional difference here (for HW table) is your patches call
> flush just for the del workqueue instead of del/stats/add, right?
> 
> Because in the end you do:
> cancel_delayed_work_sync(&flow_table->gc_work);
> nf_flow_table_offload_flush(flow_table);
> nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
> nf_flow_table_gc_run(flow_table);
> nf_flow_table_offload_flush_cleanup(flow_table);
> 
> 
> resulting in the following sequence (after expending flush_cleanup()):
> 
> cancel_delayed_work_sync(&flow_table->gc_work);
> nf_flow_table_offload_flush(flow_table);
> nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
> nf_flow_table_gc_run(flow_table);
> flush_workqueue(nf_flow_offload_del_wq);
> nf_flow_table_gc_run(flowtable);
> 
> 
> Where as my (and Volodymyr's) patch does:
> 
> cancel_delayed_work_sync(&flow_table->gc_work);
> nf_flow_table_offload_flush(flow_table);
> nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
> nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
> nf_flow_table_offload_flush(flow_table);
> nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
> 
> 
> so almost identical, I don't see "extra reiterative calls to flush" here,
> but I'm fine with just your patch as it's more efficient, can we take yours
> to both gits?

Yes, I'll submit them. I'll re-use your patch description.

Maybe I get a Tested-by: tag from you?

Thanks!