Re: [PATCH net-next] netfilter: arptables: use xt_entry_foreach() in copy_entries_to_user()

[Florian Westphal]

Simon Horman <horms@xxxxxxxxxx> wrote:
> On Mon, Jan 19, 2026 at 12:07:04PM +0530, Kshitiz Bartariya wrote:
> > Replace the manual offset-based iteration with xt_entry_foreach(),
> > thereby removing FIXME. The byte offset semantics and user ABI
> > are preserved.
> > 
> > Signed-off-by: Kshitiz Bartariya <kshitiz.bartariya@xxxxxxxxxxx>
> > ---
> >  net/ipv4/netfilter/arp_tables.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
> > index 1cdd9c28ab2d..9f82ce0fcaa5 100644
> > --- a/net/ipv4/netfilter/arp_tables.c
> > +++ b/net/ipv4/netfilter/arp_tables.c
> > @@ -684,12 +684,11 @@ static int copy_entries_to_user(unsigned int total_size,
> >  
> >  	loc_cpu_entry = private->entries;
> >  
> > -	/* FIXME: use iterator macros --RR */
> > -	/* ... then go back and fix counters and names */
> > -	for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
> > +	num = 0;
> > +	xt_entry_foreach(e, loc_cpu_entry, total_size) {
> >  		const struct xt_entry_target *t;
> >  
> > -		e = loc_cpu_entry + off;
> > +		off = (unsigned char *)e - (unsigned char *)loc_cpu_entry;
> 
> This offset calculation makes me feel queasy.
> 
> Can the code start with off = 0 and increment it by e->next_offset
> as the loop iterates, as was the case before this patch?
> It would be similar to how num is handled.

I think this file should just be left alone resp. should be restricted
to bug fixes only.  Same for ip/ip6/ebtables.

Its too early to remove this file from the tree, but I don't see
value in making cosmetic improvements, sorry.