--- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -310,6 +310,33 @@ struct ipt_entry *ipt_next_entry(const s return (void *)entry + entry->next_offset; } +static bool +ipt_handle_default_rule(struct ipt_entry *e, unsigned int *verdict) +{ + struct xt_entry_target *t; + struct xt_standard_target *st; + + if (e->target_offset != sizeof(struct ipt_entry)) + return false; + + if (!(e->ip.flags & IPT_F_NO_DEF_MATCH)) + return false; + + t = ipt_get_target(e); + if (t->u.kernel.target->target) + return false; + + st = (struct xt_standard_target *) t; + if (st->verdict == XT_RETURN) + return false; + + if (st->verdict >= 0) + return false; + + *verdict = (unsigned)(-st->verdict) - 1; + return true; +} + /* Returns one of the generic firewall policies, like NF_ACCEPT. */ unsigned int ipt_do_table(struct sk_buff *skb, @@ -334,19 +361,6 @@ ipt_do_table(struct sk_buff *skb, ip = ip_hdr(skb); indev = in ? in->name : nulldevname; outdev = out ? out->name : nulldevname; - /* We handle fragments by dealing with the first fragment as - * if it was a normal packet. All other fragments are treated - * normally, except that they will NEVER match rules that ask - * things we don't know, ie. tcp syn flag or ports). If the - * rule is also a fragment-specific rule, non-fragments won't - * match it. */ - acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET; - acpar.thoff = ip_hdrlen(skb); - acpar.hotdrop = false; - acpar.in = in; - acpar.out = out; - acpar.family = NFPROTO_IPV4; - acpar.hooknum = hook; IP_NF_ASSERT(table->valid_hooks & (1 << hook)); local_bh_disable(); @@ -364,6 +378,26 @@ ipt_do_table(struct sk_buff *skb, origptr = *stackptr; e = get_entry(table_base, private->hook_entry[hook]); + if (ipt_handle_default_rule(e, &verdict)) { + ADD_COUNTER(e->counters, skb->len, 1); + xt_write_recseq_end(addend); + local_bh_enable(); + return verdict; + } + + /* We handle fragments by dealing with the first fragment as + * if it was a normal packet. All other fragments are treated + * normally, except that they will NEVER match rules that ask + * things we don't know, ie. tcp syn flag or ports). If the + * rule is also a fragment-specific rule, non-fragments won't + * match it. */ + acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET; + acpar.thoff = ip_hdrlen(skb); + acpar.hotdrop = false; + acpar.in = in; + acpar.out = out; + acpar.family = NFPROTO_IPV4; + acpar.hooknum = hook; pr_debug("Entering %s(hook %u); sp at %u (UF %p)\n", table->name, hook, origptr,