1dc5ab2faSYasuyuki Kozakai /* Kernel module to match ESP parameters. */ 2dc5ab2faSYasuyuki Kozakai 3dc5ab2faSYasuyuki Kozakai /* (C) 1999-2000 Yon Uriarte <yon@astaro.de> 4dc5ab2faSYasuyuki Kozakai * 5dc5ab2faSYasuyuki Kozakai * This program is free software; you can redistribute it and/or modify 6dc5ab2faSYasuyuki Kozakai * it under the terms of the GNU General Public License version 2 as 7dc5ab2faSYasuyuki Kozakai * published by the Free Software Foundation. 8dc5ab2faSYasuyuki Kozakai */ 9be91fd5eSJan Engelhardt #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10dc5ab2faSYasuyuki Kozakai #include <linux/module.h> 11dc5ab2faSYasuyuki Kozakai #include <linux/skbuff.h> 12dc5ab2faSYasuyuki Kozakai #include <linux/in.h> 13dc5ab2faSYasuyuki Kozakai #include <linux/ip.h> 14dc5ab2faSYasuyuki Kozakai 15dc5ab2faSYasuyuki Kozakai #include <linux/netfilter/xt_esp.h> 16dc5ab2faSYasuyuki Kozakai #include <linux/netfilter/x_tables.h> 17dc5ab2faSYasuyuki Kozakai 18dc5ab2faSYasuyuki Kozakai #include <linux/netfilter_ipv4/ip_tables.h> 19dc5ab2faSYasuyuki Kozakai #include <linux/netfilter_ipv6/ip6_tables.h> 20dc5ab2faSYasuyuki Kozakai 21dc5ab2faSYasuyuki Kozakai MODULE_LICENSE("GPL"); 22dc5ab2faSYasuyuki Kozakai MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>"); 232ae15b64SJan Engelhardt MODULE_DESCRIPTION("Xtables: IPsec-ESP packet match"); 24dc5ab2faSYasuyuki Kozakai MODULE_ALIAS("ipt_esp"); 25dc5ab2faSYasuyuki Kozakai MODULE_ALIAS("ip6t_esp"); 26dc5ab2faSYasuyuki Kozakai 27dc5ab2faSYasuyuki Kozakai /* Returns 1 if the spi is matched by the range, 0 otherwise */ 281d93a9cbSJan Engelhardt static inline bool 291d93a9cbSJan Engelhardt spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert) 30dc5ab2faSYasuyuki Kozakai { 311d93a9cbSJan Engelhardt bool r; 32ff67e4e4SJan Engelhardt pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n", 33be91fd5eSJan Engelhardt invert ? '!' : ' ', min, spi, max); 34dc5ab2faSYasuyuki Kozakai r = (spi >= min && spi <= max) ^ invert; 35be91fd5eSJan Engelhardt pr_debug(" result %s\n", r ? "PASS" : "FAILED"); 36dc5ab2faSYasuyuki Kozakai return r; 37dc5ab2faSYasuyuki Kozakai } 38dc5ab2faSYasuyuki Kozakai 39f7108a20SJan Engelhardt static bool esp_mt(const struct sk_buff *skb, const struct xt_match_param *par) 40dc5ab2faSYasuyuki Kozakai { 413cf93c96SJan Engelhardt const struct ip_esp_hdr *eh; 423cf93c96SJan Engelhardt struct ip_esp_hdr _esp; 43f7108a20SJan Engelhardt const struct xt_esp *espinfo = par->matchinfo; 44dc5ab2faSYasuyuki Kozakai 45dc5ab2faSYasuyuki Kozakai /* Must not be a fragment. */ 46f7108a20SJan Engelhardt if (par->fragoff != 0) 471d93a9cbSJan Engelhardt return false; 48dc5ab2faSYasuyuki Kozakai 49f7108a20SJan Engelhardt eh = skb_header_pointer(skb, par->thoff, sizeof(_esp), &_esp); 50dc5ab2faSYasuyuki Kozakai if (eh == NULL) { 51dc5ab2faSYasuyuki Kozakai /* We've been asked to examine this packet, and we 52dc5ab2faSYasuyuki Kozakai * can't. Hence, no choice but to drop. 53dc5ab2faSYasuyuki Kozakai */ 54be91fd5eSJan Engelhardt pr_debug("Dropping evil ESP tinygram.\n"); 55f7108a20SJan Engelhardt *par->hotdrop = true; 561d93a9cbSJan Engelhardt return false; 57dc5ab2faSYasuyuki Kozakai } 58dc5ab2faSYasuyuki Kozakai 59dc5ab2faSYasuyuki Kozakai return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi), 60dc5ab2faSYasuyuki Kozakai !!(espinfo->invflags & XT_ESP_INV_SPI)); 61dc5ab2faSYasuyuki Kozakai } 62dc5ab2faSYasuyuki Kozakai 639b4fce7aSJan Engelhardt static bool esp_mt_check(const struct xt_mtchk_param *par) 64dc5ab2faSYasuyuki Kozakai { 659b4fce7aSJan Engelhardt const struct xt_esp *espinfo = par->matchinfo; 66dc5ab2faSYasuyuki Kozakai 67dc5ab2faSYasuyuki Kozakai if (espinfo->invflags & ~XT_ESP_INV_MASK) { 68be91fd5eSJan Engelhardt pr_debug("unknown flags %X\n", espinfo->invflags); 69ccb79bdcSJan Engelhardt return false; 70dc5ab2faSYasuyuki Kozakai } 71dc5ab2faSYasuyuki Kozakai 72ccb79bdcSJan Engelhardt return true; 73dc5ab2faSYasuyuki Kozakai } 74dc5ab2faSYasuyuki Kozakai 75d3c5ee6dSJan Engelhardt static struct xt_match esp_mt_reg[] __read_mostly = { 764470bbc7SPatrick McHardy { 77dc5ab2faSYasuyuki Kozakai .name = "esp", 78ee999d8bSJan Engelhardt .family = NFPROTO_IPV4, 79d3c5ee6dSJan Engelhardt .checkentry = esp_mt_check, 80d3c5ee6dSJan Engelhardt .match = esp_mt, 81dc5ab2faSYasuyuki Kozakai .matchsize = sizeof(struct xt_esp), 824470bbc7SPatrick McHardy .proto = IPPROTO_ESP, 83dc5ab2faSYasuyuki Kozakai .me = THIS_MODULE, 844470bbc7SPatrick McHardy }, 854470bbc7SPatrick McHardy { 86dc5ab2faSYasuyuki Kozakai .name = "esp", 87ee999d8bSJan Engelhardt .family = NFPROTO_IPV6, 88d3c5ee6dSJan Engelhardt .checkentry = esp_mt_check, 89d3c5ee6dSJan Engelhardt .match = esp_mt, 90dc5ab2faSYasuyuki Kozakai .matchsize = sizeof(struct xt_esp), 914470bbc7SPatrick McHardy .proto = IPPROTO_ESP, 92dc5ab2faSYasuyuki Kozakai .me = THIS_MODULE, 934470bbc7SPatrick McHardy }, 94dc5ab2faSYasuyuki Kozakai }; 95dc5ab2faSYasuyuki Kozakai 96d3c5ee6dSJan Engelhardt static int __init esp_mt_init(void) 97dc5ab2faSYasuyuki Kozakai { 98d3c5ee6dSJan Engelhardt return xt_register_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg)); 99dc5ab2faSYasuyuki Kozakai } 100dc5ab2faSYasuyuki Kozakai 101d3c5ee6dSJan Engelhardt static void __exit esp_mt_exit(void) 102dc5ab2faSYasuyuki Kozakai { 103d3c5ee6dSJan Engelhardt xt_unregister_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg)); 104dc5ab2faSYasuyuki Kozakai } 105dc5ab2faSYasuyuki Kozakai 106d3c5ee6dSJan Engelhardt module_init(esp_mt_init); 107d3c5ee6dSJan Engelhardt module_exit(esp_mt_exit); 108