84018f55ab
This patch adds the flags parameter to ipv6_find_hdr. This flags allows us to: * know if this is a fragment. * stop at the AH header, so the information contained in that header can be used for some specific packet handling. This patch also adds the offset parameter for inspection of one inner IPv6 header that is contained in error messages. Signed-off-by: Hans Schillstrom <hans.schillstrom@ericsson.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
122 lines
3.1 KiB
C
122 lines
3.1 KiB
C
/* Kernel module to match AH parameters. */
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/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/types.h>
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#include <net/checksum.h>
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#include <net/ipv6.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter_ipv6/ip6t_ah.h>
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Xtables: IPv6 IPsec-AH match");
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MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
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/* Returns 1 if the spi is matched by the range, 0 otherwise */
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static inline bool
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spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
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{
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bool r;
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pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n",
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invert ? '!' : ' ', min, spi, max);
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r = (spi >= min && spi <= max) ^ invert;
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pr_debug(" result %s\n", r ? "PASS" : "FAILED");
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return r;
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}
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static bool ah_mt6(const struct sk_buff *skb, struct xt_action_param *par)
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{
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struct ip_auth_hdr _ah;
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const struct ip_auth_hdr *ah;
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const struct ip6t_ah *ahinfo = par->matchinfo;
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unsigned int ptr = 0;
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unsigned int hdrlen = 0;
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int err;
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err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL, NULL);
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if (err < 0) {
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if (err != -ENOENT)
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par->hotdrop = true;
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return false;
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}
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ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
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if (ah == NULL) {
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par->hotdrop = true;
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return false;
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}
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hdrlen = (ah->hdrlen + 2) << 2;
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pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
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pr_debug("RES %04X ", ah->reserved);
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pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
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pr_debug("IPv6 AH spi %02X ",
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spi_match(ahinfo->spis[0], ahinfo->spis[1],
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ntohl(ah->spi),
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!!(ahinfo->invflags & IP6T_AH_INV_SPI)));
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pr_debug("len %02X %04X %02X ",
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ahinfo->hdrlen, hdrlen,
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(!ahinfo->hdrlen ||
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(ahinfo->hdrlen == hdrlen) ^
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!!(ahinfo->invflags & IP6T_AH_INV_LEN)));
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pr_debug("res %02X %04X %02X\n",
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ahinfo->hdrres, ah->reserved,
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!(ahinfo->hdrres && ah->reserved));
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return (ah != NULL) &&
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spi_match(ahinfo->spis[0], ahinfo->spis[1],
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ntohl(ah->spi),
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!!(ahinfo->invflags & IP6T_AH_INV_SPI)) &&
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(!ahinfo->hdrlen ||
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(ahinfo->hdrlen == hdrlen) ^
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!!(ahinfo->invflags & IP6T_AH_INV_LEN)) &&
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!(ahinfo->hdrres && ah->reserved);
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}
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static int ah_mt6_check(const struct xt_mtchk_param *par)
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{
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const struct ip6t_ah *ahinfo = par->matchinfo;
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if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
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pr_debug("unknown flags %X\n", ahinfo->invflags);
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return -EINVAL;
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}
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return 0;
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}
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static struct xt_match ah_mt6_reg __read_mostly = {
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.name = "ah",
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.family = NFPROTO_IPV6,
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.match = ah_mt6,
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.matchsize = sizeof(struct ip6t_ah),
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.checkentry = ah_mt6_check,
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.me = THIS_MODULE,
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};
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static int __init ah_mt6_init(void)
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{
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return xt_register_match(&ah_mt6_reg);
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}
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static void __exit ah_mt6_exit(void)
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{
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xt_unregister_match(&ah_mt6_reg);
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}
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module_init(ah_mt6_init);
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module_exit(ah_mt6_exit);
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