// SPDX-License-Identifier: GPL-2.0-only
/*
* ebt_ip
*
* Authors:
* Bart De Schuymer <[email protected]>
*
* April, 2002
*
* Changes:
* added ip-sport and ip-dport
* Innominate Security Technologies AG <[email protected]>
* September, 2002
*/
#include <linux/ip.h>
#include <net/ip.h>
#include <linux/in.h>
#include <linux/module.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_ip.h>
union pkthdr {
struct {
__be16 src;
__be16 dst;
} tcpudphdr;
struct {
u8 type;
u8 code;
} icmphdr;
struct {
u8 type;
} igmphdr;
};
static bool
ebt_ip_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct ebt_ip_info *info = par->matchinfo;
const struct iphdr *ih;
struct iphdr _iph;
const union pkthdr *pptr;
union pkthdr _pkthdr;
ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
if (ih == NULL)
return false;
if ((info->bitmask & EBT_IP_TOS) &&
NF_INVF(info, EBT_IP_TOS, info->tos != ih->tos))
return false;
if ((info->bitmask & EBT_IP_SOURCE) &&
NF_INVF(info, EBT_IP_SOURCE,
(ih->saddr & info->smsk) != info->saddr))
return false;
if ((info->bitmask & EBT_IP_DEST) &&
NF_INVF(info, EBT_IP_DEST,
(ih->daddr & info->dmsk) != info->daddr))
return false;
if (info->bitmask & EBT_IP_PROTO) {
if (NF_INVF(info, EBT_IP_PROTO, info->protocol != ih->protocol))
return false;
if (!(info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT |
EBT_IP_ICMP | EBT_IP_IGMP)))
return true;
if (ntohs(ih->frag_off) & IP_OFFSET)
return false;
/* min icmp/igmp headersize is 4, so sizeof(_pkthdr) is ok. */
pptr = skb_header_pointer(skb, ih->ihl*4,
sizeof(_pkthdr), &_pkthdr);
if (pptr == NULL)
return false;
if (info->bitmask & EBT_IP_DPORT) {
u32 dst = ntohs(pptr->tcpudphdr.dst);
if (NF_INVF(info, EBT_IP_DPORT,
dst < info->dport[0] ||
dst > info->dport[1]))
return false;
}
if (info->bitmask & EBT_IP_SPORT) {
u32 src = ntohs(pptr->tcpudphdr.src);
if (NF_INVF(info, EBT_IP_SPORT,
src < info->sport[0] ||
src > info->sport[1]))
return false;
}
if ((info->bitmask & EBT_IP_ICMP) &&
NF_INVF(info, EBT_IP_ICMP,
pptr->icmphdr.type < info->icmp_type[0] ||
pptr->icmphdr.type > info->icmp_type[1] ||
pptr->icmphdr.code < info->icmp_code[0] ||
pptr->icmphdr.code > info->icmp_code[1]))
return false;
if ((info->bitmask & EBT_IP_IGMP) &&
NF_INVF(info, EBT_IP_IGMP,
pptr->igmphdr.type < info->igmp_type[0] ||
pptr->igmphdr.type > info->igmp_type[1]))
return false;
}
return true;
}
static int ebt_ip_mt_check(const struct xt_mtchk_param *par)
{
const struct ebt_ip_info *info = par->matchinfo;
const struct ebt_entry *e = par->entryinfo;
if (e->ethproto != htons(ETH_P_IP) ||
e->invflags & EBT_IPROTO)
return -EINVAL;
if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK)
return -EINVAL;
if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) {
if (info->invflags & EBT_IP_PROTO)
return -EINVAL;
if (info->protocol != IPPROTO_TCP &&
info->protocol != IPPROTO_UDP &&
info->protocol != IPPROTO_UDPLITE &&
info->protocol != IPPROTO_SCTP &&
info->protocol != IPPROTO_DCCP)
return -EINVAL;
}
if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1])
return -EINVAL;
if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1])
return -EINVAL;
if (info->bitmask & EBT_IP_ICMP) {
if ((info->invflags & EBT_IP_PROTO) ||
info->protocol != IPPROTO_ICMP)
return -EINVAL;
if (info->icmp_type[0] > info->icmp_type[1] ||
info->icmp_code[0] > info->icmp_code[1])
return -EINVAL;
}
if (info->bitmask & EBT_IP_IGMP) {
if ((info->invflags & EBT_IP_PROTO) ||
info->protocol != IPPROTO_IGMP)
return -EINVAL;
if (info->igmp_type[0] > info->igmp_type[1])
return -EINVAL;
}
return 0;
}
static struct xt_match ebt_ip_mt_reg __read_mostly = {
.name = "ip",
.revision = 0,
.family = NFPROTO_BRIDGE,
.match = ebt_ip_mt,
.checkentry = ebt_ip_mt_check,
.matchsize = sizeof(struct ebt_ip_info),
.me = THIS_MODULE,
};
static int __init ebt_ip_init(void)
{
return xt_register_match(&ebt_ip_mt_reg);
}
static void __exit ebt_ip_fini(void)
{
xt_unregister_match(&ebt_ip_mt_reg);
}
module_init(ebt_ip_init);
module_exit(ebt_ip_fini);
MODULE_DESCRIPTION("Ebtables: IPv4 protocol packet match");
MODULE_LICENSE("GPL");