linux-stable.git/net/ipv4/netfilter, branch v5.13.2

netfilter: arptables: use pernet ops struct during unregister

2021-05-03T21:04:01+00:00

Like with iptables and ebtables, hook unregistration has to use the
pernet ops struct, not the template.

This triggered following splat:
  hook not found, pf 3 num 0
  WARNING: CPU: 0 PID: 224 at net/netfilter/core.c:480 __nf_unregister_net_hook+0x1eb/0x610 net/netfilter/core.c:480
[..]
 nf_unregister_net_hook net/netfilter/core.c:502 [inline]
 nf_unregister_net_hooks+0x117/0x160 net/netfilter/core.c:576
 arpt_unregister_table_pre_exit+0x67/0x80 net/ipv4/netfilter/arp_tables.c:1565

Fixes: f9006acc8dfe5 ("netfilter: arp_tables: pass table pointer via nf_hook_ops")
Reported-by: syzbot+dcccba8a1e41a38cb9df@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: allow to turn off xtables compat layer

2021-04-26T16:16:56+00:00

The compat layer needs to parse untrusted input (the ruleset)
to translate it to a 64bit compatible format.

We had a number of bugs in this department in the past, so allow users
to turn this feature off.

Add CONFIG_NETFILTER_XTABLES_COMPAT kconfig knob and make it default to y
to keep existing behaviour.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: arp_tables: pass table pointer via nf_hook_ops

2021-04-26T01:20:46+00:00

Same change as previous patch.  Only difference:
no need to handle NULL template_ops parameter, the only caller
(arptable_filter) always passes non-NULL argument.

This removes all remaining accesses to net->ipv4.arptable_filter.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: ip_tables: pass table pointer via nf_hook_ops

2021-04-26T01:20:46+00:00

iptable_x modules rely on 'struct net' to contain a pointer to the
table that should be evaluated.

In order to remove these pointers from struct net, pass them via
the 'priv' pointer in a similar fashion as nf_tables passes the
rule data.

To do that, duplicate the nf_hook_info array passed in from the
iptable_x modules, update the ops->priv pointers of the copy to
refer to the table and then change the hookfn implementations to
just pass the 'priv' argument to the traverser.

After this patch, the xt_table pointers can already be removed
from struct net.

However, changes to struct net result in re-compile of the entire
network stack, so do the removal after arptables and ip6tables
have been converted as well.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: xt_nat: pass table to hookfn

2021-04-26T01:20:46+00:00

This changes how ip(6)table nat passes the ruleset/table to the
evaluation loop.

At the moment, it will fetch the table from struct net.

This change stores the table in the hook_ops 'priv' argument
instead.

This requires to duplicate the hook_ops for each netns, so
they can store the (per-net) xt_table structure.

The dupliated nat hook_ops get stored in net_generic data area.
They are free'd in the namespace exit path.

This is a pre-requisite to remove the xt_table/ruleset pointers
from struct net.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: x_tables: remove paranoia tests

2021-04-26T01:20:46+00:00

No need for these.
There is only one caller, the xtables core, when the table is registered
for the first time with a particular network namespace.

After ->table_init() call, the table is linked into the tables[af] list,
so next call to that function will skip the ->table_init().

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: arptables: unregister the tables by name

2021-04-26T01:20:46+00:00

and again, this time for arptables.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: iptables: unregister the tables by name

2021-04-26T01:20:46+00:00

xtables stores the xt_table structs in the struct net.  This isn't
needed anymore, the structures could be passed via the netfilter hook
'private' pointer to the hook functions, which would allow us to remove
those pointers from struct net.

As a first step, reduce the number of accesses to the
net->ipv4.ip6table_{raw,filter,...} pointers.
This allows the tables to get unregistered by name instead of having to
pass the raw address.

The xt_table structure cane looked up by name+address family instead.

This patch is useless as-is (the backends still have the raw pointer
address), but it lowers the bar to remove those.

It also allows to put the 'was table registered in the first place' check
into ip_tables.c rather than have it in each table sub module.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: x_tables: remove ipt_unregister_table

2021-04-26T01:20:08+00:00

Its the same function as ipt_unregister_table_exit.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: disable defrag once its no longer needed

2021-04-26T01:20:07+00:00

When I changed defrag hooks to no longer get registered by default I
intentionally made it so that registration can only be un-done by unloading
the nf_defrag_ipv4/6 module.

In hindsight this was too conservative; there is no reason to keep defrag
on while there is no feature dependency anymore.

Moreover, this won't work if user isn't allowed to remove nf_defrag module.

This adds the disable() functions for both ipv4 and ipv6 and calls them
from conntrack, TPROXY and the xtables socket module.

ipvs isn't converted here, it will behave as before this patch and
will need module removal.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso