138939e066
Regarding RFC3775, MH payload proto field should be IPPROTO_NONE. Otherwise it must be discarded (and the receiver should send ICMP error). We assume filter should drop such piggyback everytime to disallow slipping through firewall rules, even the final receiver will discard it. Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
116 lines
2.6 KiB
C
116 lines
2.6 KiB
C
/*
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* Copyright (C)2006 USAGI/WIDE Project
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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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* Author:
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* Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com>
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*
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* Based on net/netfilter/xt_tcpudp.c
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*
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*/
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#include <linux/types.h>
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#include <linux/module.h>
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#include <net/ip.h>
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#include <linux/ipv6.h>
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#include <net/ipv6.h>
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#include <net/mip6.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_ipv6/ip6t_mh.h>
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MODULE_DESCRIPTION("ip6t_tables match for MH");
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MODULE_LICENSE("GPL");
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#ifdef DEBUG_IP_FIREWALL_USER
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#define duprintf(format, args...) printk(format , ## args)
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#else
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#define duprintf(format, args...)
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#endif
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/* Returns 1 if the type is matched by the range, 0 otherwise */
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static inline int
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type_match(u_int8_t min, u_int8_t max, u_int8_t type, int invert)
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{
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int ret;
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ret = (type >= min && type <= max) ^ invert;
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return ret;
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}
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static int
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const struct xt_match *match,
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const void *matchinfo,
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int offset,
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unsigned int protoff,
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int *hotdrop)
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{
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struct ip6_mh _mh, *mh;
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const struct ip6t_mh *mhinfo = matchinfo;
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/* Must not be a fragment. */
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if (offset)
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return 0;
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mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh);
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if (mh == NULL) {
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/* We've been asked to examine this packet, and we
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can't. Hence, no choice but to drop. */
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duprintf("Dropping evil MH tinygram.\n");
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*hotdrop = 1;
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return 0;
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}
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if (mh->ip6mh_proto != IPPROTO_NONE) {
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duprintf("Dropping invalid MH Payload Proto: %u\n",
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mh->ip6mh_proto);
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*hotdrop = 1;
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return 0;
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}
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return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type,
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!!(mhinfo->invflags & IP6T_MH_INV_TYPE));
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}
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/* Called when user tries to insert an entry of this type. */
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static int
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mh_checkentry(const char *tablename,
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const void *entry,
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const struct xt_match *match,
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void *matchinfo,
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unsigned int hook_mask)
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{
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const struct ip6t_mh *mhinfo = matchinfo;
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/* Must specify no unknown invflags */
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return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);
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}
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static struct xt_match mh_match = {
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.name = "mh",
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.family = AF_INET6,
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.checkentry = mh_checkentry,
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.match = match,
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.matchsize = sizeof(struct ip6t_mh),
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.proto = IPPROTO_MH,
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.me = THIS_MODULE,
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};
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static int __init ip6t_mh_init(void)
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{
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return xt_register_match(&mh_match);
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}
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static void __exit ip6t_mh_fini(void)
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{
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xt_unregister_match(&mh_match);
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}
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module_init(ip6t_mh_init);
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module_exit(ip6t_mh_fini);
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