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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ipt_ah.c (2190B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* Kernel module to match AH parameters. */
      3/* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
      4 */
      5#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
      6#include <linux/in.h>
      7#include <linux/module.h>
      8#include <linux/skbuff.h>
      9#include <linux/ip.h>
     10
     11#include <linux/netfilter_ipv4/ipt_ah.h>
     12#include <linux/netfilter/x_tables.h>
     13
     14MODULE_LICENSE("GPL");
     15MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
     16MODULE_DESCRIPTION("Xtables: IPv4 IPsec-AH SPI match");
     17
     18/* Returns 1 if the spi is matched by the range, 0 otherwise */
     19static inline bool
     20spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
     21{
     22	bool r;
     23	pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n",
     24		 invert ? '!' : ' ', min, spi, max);
     25	r = (spi >= min && spi <= max) ^ invert;
     26	pr_debug(" result %s\n", r ? "PASS" : "FAILED");
     27	return r;
     28}
     29
     30static bool ah_mt(const struct sk_buff *skb, struct xt_action_param *par)
     31{
     32	struct ip_auth_hdr _ahdr;
     33	const struct ip_auth_hdr *ah;
     34	const struct ipt_ah *ahinfo = par->matchinfo;
     35
     36	/* Must not be a fragment. */
     37	if (par->fragoff != 0)
     38		return false;
     39
     40	ah = skb_header_pointer(skb, par->thoff, sizeof(_ahdr), &_ahdr);
     41	if (ah == NULL) {
     42		/* We've been asked to examine this packet, and we
     43		 * can't.  Hence, no choice but to drop.
     44		 */
     45		pr_debug("Dropping evil AH tinygram.\n");
     46		par->hotdrop = true;
     47		return false;
     48	}
     49
     50	return spi_match(ahinfo->spis[0], ahinfo->spis[1],
     51			 ntohl(ah->spi),
     52			 !!(ahinfo->invflags & IPT_AH_INV_SPI));
     53}
     54
     55static int ah_mt_check(const struct xt_mtchk_param *par)
     56{
     57	const struct ipt_ah *ahinfo = par->matchinfo;
     58
     59	/* Must specify no unknown invflags */
     60	if (ahinfo->invflags & ~IPT_AH_INV_MASK) {
     61		pr_debug("unknown flags %X\n", ahinfo->invflags);
     62		return -EINVAL;
     63	}
     64	return 0;
     65}
     66
     67static struct xt_match ah_mt_reg __read_mostly = {
     68	.name		= "ah",
     69	.family		= NFPROTO_IPV4,
     70	.match		= ah_mt,
     71	.matchsize	= sizeof(struct ipt_ah),
     72	.proto		= IPPROTO_AH,
     73	.checkentry	= ah_mt_check,
     74	.me		= THIS_MODULE,
     75};
     76
     77static int __init ah_mt_init(void)
     78{
     79	return xt_register_match(&ah_mt_reg);
     80}
     81
     82static void __exit ah_mt_exit(void)
     83{
     84	xt_unregister_match(&ah_mt_reg);
     85}
     86
     87module_init(ah_mt_init);
     88module_exit(ah_mt_exit);