Loading...
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 | /* 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. */ #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("ah spi_match:%c 0x%x <= 0x%x <= 0x%x", 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, const struct net_device *in, const struct net_device *out, const struct xt_match *match, const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop) { struct ip_auth_hdr _ah; const struct ip_auth_hdr *ah; const struct ip6t_ah *ahinfo = matchinfo; unsigned int ptr; unsigned int hdrlen = 0; int err; err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL); if (err < 0) { if (err != -ENOENT) *hotdrop = true; return false; } ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah); if (ah == NULL) { *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); } /* Called when user tries to insert an entry of this type. */ static bool ah_mt6_check(const char *tablename, const void *entry, const struct xt_match *match, void *matchinfo, unsigned int hook_mask) { const struct ip6t_ah *ahinfo = matchinfo; if (ahinfo->invflags & ~IP6T_AH_INV_MASK) { pr_debug("ip6t_ah: unknown flags %X\n", ahinfo->invflags); return false; } return true; } static struct xt_match ah_mt6_reg __read_mostly = { .name = "ah", .family = AF_INET6, .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); |