[PATCH 3.12 65/86] netfilter: arp_tables: fix invoking 32bit "iptable -P INPUT ACCEPT" failed in 64bit kernel

From: Jiri Slaby
Date: Thu May 04 2017 - 05:13:58 EST

From: Hongxu Jia <hongxu.jia@xxxxxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


commit 17a49cd549d9dc8707dc9262210166455c612dde upstream.

Since 09d9686047db ("netfilter: x_tables: do compat validation via
translate_table"), it used compatr structure to assign newinfo
structure. In translate_compat_table of ip_tables.c and ip6_tables.c,
it used compatr->hook_entry to replace info->hook_entry and
compatr->underflow to replace info->underflow, but not do the same
replacement in arp_tables.c.

It caused invoking 32-bit "arptbale -P INPUT ACCEPT" failed in 64bit
root@qemux86-64:~# arptables -P INPUT ACCEPT
root@qemux86-64:~# arptables -P INPUT ACCEPT
ERROR: Policy for `INPUT' offset 448 != underflow 0
arptables: Incompatible with this kernel

Fixes: 09d9686047db ("netfilter: x_tables: do compat validation via translate_table")
Signed-off-by: Hongxu Jia <hongxu.jia@xxxxxxxxxxxxx>
Acked-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
net/ipv4/netfilter/arp_tables.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index ab16b5c195da..3e3b3f75b3a0 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -1328,8 +1328,8 @@ static int translate_compat_table(struct xt_table_info **pinfo,

newinfo->number = compatr->num_entries;
for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
- newinfo->hook_entry[i] = info->hook_entry[i];
- newinfo->underflow[i] = info->underflow[i];
+ newinfo->hook_entry[i] = compatr->hook_entry[i];
+ newinfo->underflow[i] = compatr->underflow[i];
entry1 = newinfo->entries[raw_smp_processor_id()];
pos = entry1;