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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ip6t_ipv6header.c (3416B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* ipv6header match - matches IPv6 packets based
      3   on whether they contain certain headers */
      4
      5/* Original idea: Brad Chapman
      6 * Rewritten by: Andras Kis-Szabo <kisza@sch.bme.hu> */
      7
      8/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
      9 */
     10
     11#include <linux/module.h>
     12#include <linux/skbuff.h>
     13#include <linux/ipv6.h>
     14#include <linux/types.h>
     15#include <net/checksum.h>
     16#include <net/ipv6.h>
     17
     18#include <linux/netfilter/x_tables.h>
     19#include <linux/netfilter_ipv6.h>
     20#include <linux/netfilter_ipv6/ip6t_ipv6header.h>
     21
     22MODULE_LICENSE("GPL");
     23MODULE_DESCRIPTION("Xtables: IPv6 header types match");
     24MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
     25
     26static bool
     27ipv6header_mt6(const struct sk_buff *skb, struct xt_action_param *par)
     28{
     29	const struct ip6t_ipv6header_info *info = par->matchinfo;
     30	unsigned int temp;
     31	int len;
     32	u8 nexthdr;
     33	unsigned int ptr;
     34
     35	/* Make sure this isn't an evil packet */
     36
     37	/* type of the 1st exthdr */
     38	nexthdr = ipv6_hdr(skb)->nexthdr;
     39	/* pointer to the 1st exthdr */
     40	ptr = sizeof(struct ipv6hdr);
     41	/* available length */
     42	len = skb->len - ptr;
     43	temp = 0;
     44
     45	while (nf_ip6_ext_hdr(nexthdr)) {
     46		const struct ipv6_opt_hdr *hp;
     47		struct ipv6_opt_hdr _hdr;
     48		int hdrlen;
     49
     50		/* No more exthdr -> evaluate */
     51		if (nexthdr == NEXTHDR_NONE) {
     52			temp |= MASK_NONE;
     53			break;
     54		}
     55		/* Is there enough space for the next ext header? */
     56		if (len < (int)sizeof(struct ipv6_opt_hdr))
     57			return false;
     58		/* ESP -> evaluate */
     59		if (nexthdr == NEXTHDR_ESP) {
     60			temp |= MASK_ESP;
     61			break;
     62		}
     63
     64		hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
     65		if (!hp) {
     66			par->hotdrop = true;
     67			return false;
     68		}
     69
     70		/* Calculate the header length */
     71		if (nexthdr == NEXTHDR_FRAGMENT)
     72			hdrlen = 8;
     73		else if (nexthdr == NEXTHDR_AUTH)
     74			hdrlen = ipv6_authlen(hp);
     75		else
     76			hdrlen = ipv6_optlen(hp);
     77
     78		/* set the flag */
     79		switch (nexthdr) {
     80		case NEXTHDR_HOP:
     81			temp |= MASK_HOPOPTS;
     82			break;
     83		case NEXTHDR_ROUTING:
     84			temp |= MASK_ROUTING;
     85			break;
     86		case NEXTHDR_FRAGMENT:
     87			temp |= MASK_FRAGMENT;
     88			break;
     89		case NEXTHDR_AUTH:
     90			temp |= MASK_AH;
     91			break;
     92		case NEXTHDR_DEST:
     93			temp |= MASK_DSTOPTS;
     94			break;
     95		default:
     96			return false;
     97		}
     98
     99		nexthdr = hp->nexthdr;
    100		len -= hdrlen;
    101		ptr += hdrlen;
    102		if (ptr > skb->len)
    103			break;
    104	}
    105
    106	if (nexthdr != NEXTHDR_NONE && nexthdr != NEXTHDR_ESP)
    107		temp |= MASK_PROTO;
    108
    109	if (info->modeflag)
    110		return !((temp ^ info->matchflags ^ info->invflags)
    111			 & info->matchflags);
    112	else {
    113		if (info->invflags)
    114			return temp != info->matchflags;
    115		else
    116			return temp == info->matchflags;
    117	}
    118}
    119
    120static int ipv6header_mt6_check(const struct xt_mtchk_param *par)
    121{
    122	const struct ip6t_ipv6header_info *info = par->matchinfo;
    123
    124	/* invflags is 0 or 0xff in hard mode */
    125	if ((!info->modeflag) && info->invflags != 0x00 &&
    126	    info->invflags != 0xFF)
    127		return -EINVAL;
    128
    129	return 0;
    130}
    131
    132static struct xt_match ipv6header_mt6_reg __read_mostly = {
    133	.name		= "ipv6header",
    134	.family		= NFPROTO_IPV6,
    135	.match		= ipv6header_mt6,
    136	.matchsize	= sizeof(struct ip6t_ipv6header_info),
    137	.checkentry	= ipv6header_mt6_check,
    138	.destroy	= NULL,
    139	.me		= THIS_MODULE,
    140};
    141
    142static int __init ipv6header_mt6_init(void)
    143{
    144	return xt_register_match(&ipv6header_mt6_reg);
    145}
    146
    147static void __exit ipv6header_mt6_exit(void)
    148{
    149	xt_unregister_match(&ipv6header_mt6_reg);
    150}
    151
    152module_init(ipv6header_mt6_init);
    153module_exit(ipv6header_mt6_exit);