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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 | /* Kernel module to match AH parameters. */ /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> * * 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/ip.h> #include <linux/ipv6.h> #include <linux/types.h> #include <net/checksum.h> #include <net/ipv6.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter_ipv6/ip6_tables.h> #include <linux/netfilter_ipv6/ip6t_ah.h> MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Xtables: IPv6 IPsec-AH match"); MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); /* 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 ah_mt6(const struct sk_buff *skb, struct xt_action_param *par) { struct ip_auth_hdr _ah; const struct ip_auth_hdr *ah; const struct ip6t_ah *ahinfo = par->matchinfo; unsigned int ptr = 0; unsigned int hdrlen = 0; int err; err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL, NULL); if (err < 0) { if (err != -ENOENT) par->hotdrop = true; return false; } ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah); if (ah == NULL) { par->hotdrop = true; return false; } hdrlen = (ah->hdrlen + 2) << 2; pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen); pr_debug("RES %04X ", ah->reserved); pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi)); pr_debug("IPv6 AH spi %02X ", spi_match(ahinfo->spis[0], ahinfo->spis[1], ntohl(ah->spi), !!(ahinfo->invflags & IP6T_AH_INV_SPI))); pr_debug("len %02X %04X %02X ", ahinfo->hdrlen, hdrlen, (!ahinfo->hdrlen || (ahinfo->hdrlen == hdrlen) ^ !!(ahinfo->invflags & IP6T_AH_INV_LEN))); pr_debug("res %02X %04X %02X\n", ahinfo->hdrres, ah->reserved, !(ahinfo->hdrres && ah->reserved)); return (ah != NULL) && spi_match(ahinfo->spis[0], ahinfo->spis[1], ntohl(ah->spi), !!(ahinfo->invflags & IP6T_AH_INV_SPI)) && (!ahinfo->hdrlen || (ahinfo->hdrlen == hdrlen) ^ !!(ahinfo->invflags & IP6T_AH_INV_LEN)) && !(ahinfo->hdrres && ah->reserved); } static int ah_mt6_check(const struct xt_mtchk_param *par) { const struct ip6t_ah *ahinfo = par->matchinfo; if (ahinfo->invflags & ~IP6T_AH_INV_MASK) { pr_debug("unknown flags %X\n", ahinfo->invflags); return -EINVAL; } return 0; } static struct xt_match ah_mt6_reg __read_mostly = { .name = "ah", .family = NFPROTO_IPV6, .match = ah_mt6, .matchsize = sizeof(struct ip6t_ah), .checkentry = ah_mt6_check, .me = THIS_MODULE, }; static int __init ah_mt6_init(void) { return xt_register_match(&ah_mt6_reg); } static void __exit ah_mt6_exit(void) { xt_unregister_match(&ah_mt6_reg); } module_init(ah_mt6_init); module_exit(ah_mt6_exit); |