cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ebt_arp.c (3689B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  ebt_arp
      4 *
      5 *	Authors:
      6 *	Bart De Schuymer <bdschuym@pandora.be>
      7 *	Tim Gardner <timg@tpi.com>
      8 *
      9 *  April, 2002
     10 *
     11 */
     12#include <linux/if_arp.h>
     13#include <linux/if_ether.h>
     14#include <linux/module.h>
     15#include <linux/netfilter/x_tables.h>
     16#include <linux/netfilter_bridge/ebtables.h>
     17#include <linux/netfilter_bridge/ebt_arp.h>
     18
     19static bool
     20ebt_arp_mt(const struct sk_buff *skb, struct xt_action_param *par)
     21{
     22	const struct ebt_arp_info *info = par->matchinfo;
     23	const struct arphdr *ah;
     24	struct arphdr _arph;
     25
     26	ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
     27	if (ah == NULL)
     28		return false;
     29	if ((info->bitmask & EBT_ARP_OPCODE) &&
     30	    NF_INVF(info, EBT_ARP_OPCODE, info->opcode != ah->ar_op))
     31		return false;
     32	if ((info->bitmask & EBT_ARP_HTYPE) &&
     33	    NF_INVF(info, EBT_ARP_HTYPE, info->htype != ah->ar_hrd))
     34		return false;
     35	if ((info->bitmask & EBT_ARP_PTYPE) &&
     36	    NF_INVF(info, EBT_ARP_PTYPE, info->ptype != ah->ar_pro))
     37		return false;
     38
     39	if (info->bitmask & (EBT_ARP_SRC_IP | EBT_ARP_DST_IP | EBT_ARP_GRAT)) {
     40		const __be32 *sap, *dap;
     41		__be32 saddr, daddr;
     42
     43		if (ah->ar_pln != sizeof(__be32) || ah->ar_pro != htons(ETH_P_IP))
     44			return false;
     45		sap = skb_header_pointer(skb, sizeof(struct arphdr) +
     46					ah->ar_hln, sizeof(saddr),
     47					&saddr);
     48		if (sap == NULL)
     49			return false;
     50		dap = skb_header_pointer(skb, sizeof(struct arphdr) +
     51					2*ah->ar_hln+sizeof(saddr),
     52					sizeof(daddr), &daddr);
     53		if (dap == NULL)
     54			return false;
     55		if ((info->bitmask & EBT_ARP_SRC_IP) &&
     56		    NF_INVF(info, EBT_ARP_SRC_IP,
     57			    info->saddr != (*sap & info->smsk)))
     58			return false;
     59		if ((info->bitmask & EBT_ARP_DST_IP) &&
     60		    NF_INVF(info, EBT_ARP_DST_IP,
     61			    info->daddr != (*dap & info->dmsk)))
     62			return false;
     63		if ((info->bitmask & EBT_ARP_GRAT) &&
     64		    NF_INVF(info, EBT_ARP_GRAT, *dap != *sap))
     65			return false;
     66	}
     67
     68	if (info->bitmask & (EBT_ARP_SRC_MAC | EBT_ARP_DST_MAC)) {
     69		const unsigned char *mp;
     70		unsigned char _mac[ETH_ALEN];
     71
     72		if (ah->ar_hln != ETH_ALEN || ah->ar_hrd != htons(ARPHRD_ETHER))
     73			return false;
     74		if (info->bitmask & EBT_ARP_SRC_MAC) {
     75			mp = skb_header_pointer(skb, sizeof(struct arphdr),
     76						sizeof(_mac), &_mac);
     77			if (mp == NULL)
     78				return false;
     79			if (NF_INVF(info, EBT_ARP_SRC_MAC,
     80				    !ether_addr_equal_masked(mp, info->smaddr,
     81							     info->smmsk)))
     82				return false;
     83		}
     84
     85		if (info->bitmask & EBT_ARP_DST_MAC) {
     86			mp = skb_header_pointer(skb, sizeof(struct arphdr) +
     87						ah->ar_hln + ah->ar_pln,
     88						sizeof(_mac), &_mac);
     89			if (mp == NULL)
     90				return false;
     91			if (NF_INVF(info, EBT_ARP_DST_MAC,
     92				    !ether_addr_equal_masked(mp, info->dmaddr,
     93							     info->dmmsk)))
     94				return false;
     95		}
     96	}
     97
     98	return true;
     99}
    100
    101static int ebt_arp_mt_check(const struct xt_mtchk_param *par)
    102{
    103	const struct ebt_arp_info *info = par->matchinfo;
    104	const struct ebt_entry *e = par->entryinfo;
    105
    106	if ((e->ethproto != htons(ETH_P_ARP) &&
    107	   e->ethproto != htons(ETH_P_RARP)) ||
    108	   e->invflags & EBT_IPROTO)
    109		return -EINVAL;
    110	if (info->bitmask & ~EBT_ARP_MASK || info->invflags & ~EBT_ARP_MASK)
    111		return -EINVAL;
    112	return 0;
    113}
    114
    115static struct xt_match ebt_arp_mt_reg __read_mostly = {
    116	.name		= "arp",
    117	.revision	= 0,
    118	.family		= NFPROTO_BRIDGE,
    119	.match		= ebt_arp_mt,
    120	.checkentry	= ebt_arp_mt_check,
    121	.matchsize	= sizeof(struct ebt_arp_info),
    122	.me		= THIS_MODULE,
    123};
    124
    125static int __init ebt_arp_init(void)
    126{
    127	return xt_register_match(&ebt_arp_mt_reg);
    128}
    129
    130static void __exit ebt_arp_fini(void)
    131{
    132	xt_unregister_match(&ebt_arp_mt_reg);
    133}
    134
    135module_init(ebt_arp_init);
    136module_exit(ebt_arp_fini);
    137MODULE_DESCRIPTION("Ebtables: ARP protocol packet match");
    138MODULE_LICENSE("GPL");