ipv4: netfilter: arp_tables: fix information leak to userland

Structure arpt_getinfo is copied to userland with the field "name"
that has the last elements unitialized.  It leads to leaking of
contents of kernel stack memory.

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 3cad2591ace0c15fdad446ab528b0f40c2624d09..3fac340a28d5394bd95bd649d5bcee3dcb3d24df 100644 (file)
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -927,6 +927,7 @@ static int get_info(struct net *net, void __user *user,
                        private = &tmp;
                }
 #endif
+               memset(&info, 0, sizeof(info));
                info.valid_hooks = t->valid_hooks;
                memcpy(info.hook_entry, private->hook_entry,
                       sizeof(info.hook_entry));