mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
![Jan Engelhardt](/assets/img/avatar_default.png)
Since xt_action_param is writable, let's use it. The pointer to 'bool hotdrop' always worried (8 bytes (64-bit) to write 1 byte!). Surprisingly results in a reduction in size: text data bss filename 5457066 692730 357892 vmlinux.o-prev 5456554 692730 357892 vmlinux.o Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
107 lines
2.6 KiB
C
107 lines
2.6 KiB
C
/* Kernel module to match ESP parameters. */
|
|
|
|
/* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
#include <linux/module.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/in.h>
|
|
#include <linux/ip.h>
|
|
|
|
#include <linux/netfilter/xt_esp.h>
|
|
#include <linux/netfilter/x_tables.h>
|
|
|
|
#include <linux/netfilter_ipv4/ip_tables.h>
|
|
#include <linux/netfilter_ipv6/ip6_tables.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
|
|
MODULE_DESCRIPTION("Xtables: IPsec-ESP packet match");
|
|
MODULE_ALIAS("ipt_esp");
|
|
MODULE_ALIAS("ip6t_esp");
|
|
|
|
/* Returns 1 if the spi is matched by the range, 0 otherwise */
|
|
static inline bool
|
|
spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
|
|
{
|
|
bool r;
|
|
pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n",
|
|
invert ? '!' : ' ', min, spi, max);
|
|
r = (spi >= min && spi <= max) ^ invert;
|
|
pr_debug(" result %s\n", r ? "PASS" : "FAILED");
|
|
return r;
|
|
}
|
|
|
|
static bool esp_mt(const struct sk_buff *skb, struct xt_action_param *par)
|
|
{
|
|
const struct ip_esp_hdr *eh;
|
|
struct ip_esp_hdr _esp;
|
|
const struct xt_esp *espinfo = par->matchinfo;
|
|
|
|
/* Must not be a fragment. */
|
|
if (par->fragoff != 0)
|
|
return false;
|
|
|
|
eh = skb_header_pointer(skb, par->thoff, sizeof(_esp), &_esp);
|
|
if (eh == NULL) {
|
|
/* We've been asked to examine this packet, and we
|
|
* can't. Hence, no choice but to drop.
|
|
*/
|
|
pr_debug("Dropping evil ESP tinygram.\n");
|
|
par->hotdrop = true;
|
|
return false;
|
|
}
|
|
|
|
return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi),
|
|
!!(espinfo->invflags & XT_ESP_INV_SPI));
|
|
}
|
|
|
|
static int esp_mt_check(const struct xt_mtchk_param *par)
|
|
{
|
|
const struct xt_esp *espinfo = par->matchinfo;
|
|
|
|
if (espinfo->invflags & ~XT_ESP_INV_MASK) {
|
|
pr_debug("unknown flags %X\n", espinfo->invflags);
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct xt_match esp_mt_reg[] __read_mostly = {
|
|
{
|
|
.name = "esp",
|
|
.family = NFPROTO_IPV4,
|
|
.checkentry = esp_mt_check,
|
|
.match = esp_mt,
|
|
.matchsize = sizeof(struct xt_esp),
|
|
.proto = IPPROTO_ESP,
|
|
.me = THIS_MODULE,
|
|
},
|
|
{
|
|
.name = "esp",
|
|
.family = NFPROTO_IPV6,
|
|
.checkentry = esp_mt_check,
|
|
.match = esp_mt,
|
|
.matchsize = sizeof(struct xt_esp),
|
|
.proto = IPPROTO_ESP,
|
|
.me = THIS_MODULE,
|
|
},
|
|
};
|
|
|
|
static int __init esp_mt_init(void)
|
|
{
|
|
return xt_register_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg));
|
|
}
|
|
|
|
static void __exit esp_mt_exit(void)
|
|
{
|
|
xt_unregister_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg));
|
|
}
|
|
|
|
module_init(esp_mt_init);
|
|
module_exit(esp_mt_exit);
|