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![Hans Schillstrom](/assets/img/avatar_default.png)
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>
225 lines
5.8 KiB
C
225 lines
5.8 KiB
C
/* Kernel module to match ROUTING 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/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 <asm/byteorder.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_rt.h>
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Xtables: IPv6 Routing Header match");
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MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
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/* Returns 1 if the id is matched by the range, 0 otherwise */
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static inline bool
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segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert)
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{
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bool r;
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pr_debug("segsleft_match:%c 0x%x <= 0x%x <= 0x%x\n",
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invert ? '!' : ' ', min, id, max);
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r = (id >= min && id <= 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 rt_mt6(const struct sk_buff *skb, struct xt_action_param *par)
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{
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struct ipv6_rt_hdr _route;
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const struct ipv6_rt_hdr *rh;
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const struct ip6t_rt *rtinfo = par->matchinfo;
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unsigned int temp;
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unsigned int ptr = 0;
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unsigned int hdrlen = 0;
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bool ret = false;
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struct in6_addr _addr;
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const struct in6_addr *ap;
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int err;
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err = ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, 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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rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route);
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if (rh == NULL) {
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par->hotdrop = true;
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return false;
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}
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hdrlen = ipv6_optlen(rh);
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if (skb->len - ptr < hdrlen) {
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/* Pcket smaller than its length field */
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return false;
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}
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pr_debug("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen);
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pr_debug("TYPE %04X ", rh->type);
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pr_debug("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left);
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pr_debug("IPv6 RT segsleft %02X ",
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segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
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rh->segments_left,
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!!(rtinfo->invflags & IP6T_RT_INV_SGS)));
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pr_debug("type %02X %02X %02X ",
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rtinfo->rt_type, rh->type,
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(!(rtinfo->flags & IP6T_RT_TYP) ||
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((rtinfo->rt_type == rh->type) ^
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!!(rtinfo->invflags & IP6T_RT_INV_TYP))));
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pr_debug("len %02X %04X %02X ",
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rtinfo->hdrlen, hdrlen,
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!(rtinfo->flags & IP6T_RT_LEN) ||
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((rtinfo->hdrlen == hdrlen) ^
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!!(rtinfo->invflags & IP6T_RT_INV_LEN)));
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pr_debug("res %02X %02X %02X ",
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rtinfo->flags & IP6T_RT_RES,
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((const struct rt0_hdr *)rh)->reserved,
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!((rtinfo->flags & IP6T_RT_RES) &&
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(((const struct rt0_hdr *)rh)->reserved)));
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ret = (rh != NULL) &&
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(segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
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rh->segments_left,
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!!(rtinfo->invflags & IP6T_RT_INV_SGS))) &&
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(!(rtinfo->flags & IP6T_RT_LEN) ||
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((rtinfo->hdrlen == hdrlen) ^
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!!(rtinfo->invflags & IP6T_RT_INV_LEN))) &&
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(!(rtinfo->flags & IP6T_RT_TYP) ||
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((rtinfo->rt_type == rh->type) ^
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!!(rtinfo->invflags & IP6T_RT_INV_TYP)));
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if (ret && (rtinfo->flags & IP6T_RT_RES)) {
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const u_int32_t *rp;
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u_int32_t _reserved;
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rp = skb_header_pointer(skb,
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ptr + offsetof(struct rt0_hdr,
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reserved),
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sizeof(_reserved),
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&_reserved);
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ret = (*rp == 0);
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}
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pr_debug("#%d ", rtinfo->addrnr);
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if (!(rtinfo->flags & IP6T_RT_FST)) {
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return ret;
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} else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) {
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pr_debug("Not strict ");
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if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
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pr_debug("There isn't enough space\n");
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return false;
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} else {
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unsigned int i = 0;
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pr_debug("#%d ", rtinfo->addrnr);
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for (temp = 0;
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temp < (unsigned int)((hdrlen - 8) / 16);
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temp++) {
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ap = skb_header_pointer(skb,
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ptr
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+ sizeof(struct rt0_hdr)
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+ temp * sizeof(_addr),
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sizeof(_addr),
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&_addr);
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BUG_ON(ap == NULL);
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if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {
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pr_debug("i=%d temp=%d;\n", i, temp);
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i++;
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}
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if (i == rtinfo->addrnr)
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break;
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}
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pr_debug("i=%d #%d\n", i, rtinfo->addrnr);
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if (i == rtinfo->addrnr)
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return ret;
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else
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return false;
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}
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} else {
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pr_debug("Strict ");
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if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
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pr_debug("There isn't enough space\n");
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return false;
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} else {
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pr_debug("#%d ", rtinfo->addrnr);
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for (temp = 0; temp < rtinfo->addrnr; temp++) {
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ap = skb_header_pointer(skb,
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ptr
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+ sizeof(struct rt0_hdr)
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+ temp * sizeof(_addr),
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sizeof(_addr),
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&_addr);
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BUG_ON(ap == NULL);
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if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp]))
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break;
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}
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pr_debug("temp=%d #%d\n", temp, rtinfo->addrnr);
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if (temp == rtinfo->addrnr &&
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temp == (unsigned int)((hdrlen - 8) / 16))
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return ret;
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else
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return false;
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}
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}
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return false;
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}
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static int rt_mt6_check(const struct xt_mtchk_param *par)
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{
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const struct ip6t_rt *rtinfo = par->matchinfo;
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if (rtinfo->invflags & ~IP6T_RT_INV_MASK) {
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pr_debug("unknown flags %X\n", rtinfo->invflags);
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return -EINVAL;
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}
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if ((rtinfo->flags & (IP6T_RT_RES | IP6T_RT_FST_MASK)) &&
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(!(rtinfo->flags & IP6T_RT_TYP) ||
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(rtinfo->rt_type != 0) ||
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(rtinfo->invflags & IP6T_RT_INV_TYP))) {
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pr_debug("`--rt-type 0' required before `--rt-0-*'");
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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 rt_mt6_reg __read_mostly = {
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.name = "rt",
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.family = NFPROTO_IPV6,
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.match = rt_mt6,
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.matchsize = sizeof(struct ip6t_rt),
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.checkentry = rt_mt6_check,
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.me = THIS_MODULE,
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};
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static int __init rt_mt6_init(void)
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{
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return xt_register_match(&rt_mt6_reg);
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}
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static void __exit rt_mt6_exit(void)
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{
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xt_unregister_match(&rt_mt6_reg);
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}
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module_init(rt_mt6_init);
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module_exit(rt_mt6_exit);
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