![Jan Engelhardt](/assets/img/avatar_default.png)
This patch does this for match extensions' checkentry functions. Signed-off-by: Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Patrick McHardy <kaber@trash.net>
397 lines
11 KiB
C
397 lines
11 KiB
C
/*
|
|
* xt_conntrack - Netfilter module to match connection tracking
|
|
* information. (Superset of Rusty's minimalistic state match.)
|
|
*
|
|
* (C) 2001 Marc Boucher (marc@mbsi.ca).
|
|
* Copyright © CC Computer Consultants GmbH, 2007 - 2008
|
|
*
|
|
* 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 <net/ipv6.h>
|
|
#include <linux/netfilter/x_tables.h>
|
|
#include <linux/netfilter/xt_conntrack.h>
|
|
#include <net/netfilter/nf_conntrack.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
|
|
MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
|
|
MODULE_DESCRIPTION("Xtables: connection tracking state match");
|
|
MODULE_ALIAS("ipt_conntrack");
|
|
MODULE_ALIAS("ip6t_conntrack");
|
|
|
|
static bool
|
|
conntrack_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
|
|
{
|
|
const struct xt_conntrack_info *sinfo = par->matchinfo;
|
|
const struct nf_conn *ct;
|
|
enum ip_conntrack_info ctinfo;
|
|
unsigned int statebit;
|
|
|
|
ct = nf_ct_get(skb, &ctinfo);
|
|
|
|
#define FWINV(bool, invflg) ((bool) ^ !!(sinfo->invflags & (invflg)))
|
|
|
|
if (ct == &nf_conntrack_untracked)
|
|
statebit = XT_CONNTRACK_STATE_UNTRACKED;
|
|
else if (ct)
|
|
statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
|
|
else
|
|
statebit = XT_CONNTRACK_STATE_INVALID;
|
|
|
|
if (sinfo->flags & XT_CONNTRACK_STATE) {
|
|
if (ct) {
|
|
if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
|
|
statebit |= XT_CONNTRACK_STATE_SNAT;
|
|
if (test_bit(IPS_DST_NAT_BIT, &ct->status))
|
|
statebit |= XT_CONNTRACK_STATE_DNAT;
|
|
}
|
|
if (FWINV((statebit & sinfo->statemask) == 0,
|
|
XT_CONNTRACK_STATE))
|
|
return false;
|
|
}
|
|
|
|
if (ct == NULL) {
|
|
if (sinfo->flags & ~XT_CONNTRACK_STATE)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
if (sinfo->flags & XT_CONNTRACK_PROTO &&
|
|
FWINV(nf_ct_protonum(ct) !=
|
|
sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum,
|
|
XT_CONNTRACK_PROTO))
|
|
return false;
|
|
|
|
if (sinfo->flags & XT_CONNTRACK_ORIGSRC &&
|
|
FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip &
|
|
sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
|
|
sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip,
|
|
XT_CONNTRACK_ORIGSRC))
|
|
return false;
|
|
|
|
if (sinfo->flags & XT_CONNTRACK_ORIGDST &&
|
|
FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip &
|
|
sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
|
|
sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip,
|
|
XT_CONNTRACK_ORIGDST))
|
|
return false;
|
|
|
|
if (sinfo->flags & XT_CONNTRACK_REPLSRC &&
|
|
FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip &
|
|
sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) !=
|
|
sinfo->tuple[IP_CT_DIR_REPLY].src.ip,
|
|
XT_CONNTRACK_REPLSRC))
|
|
return false;
|
|
|
|
if (sinfo->flags & XT_CONNTRACK_REPLDST &&
|
|
FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip &
|
|
sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) !=
|
|
sinfo->tuple[IP_CT_DIR_REPLY].dst.ip,
|
|
XT_CONNTRACK_REPLDST))
|
|
return false;
|
|
|
|
if (sinfo->flags & XT_CONNTRACK_STATUS &&
|
|
FWINV((ct->status & sinfo->statusmask) == 0,
|
|
XT_CONNTRACK_STATUS))
|
|
return false;
|
|
|
|
if(sinfo->flags & XT_CONNTRACK_EXPIRES) {
|
|
unsigned long expires = timer_pending(&ct->timeout) ?
|
|
(ct->timeout.expires - jiffies)/HZ : 0;
|
|
|
|
if (FWINV(!(expires >= sinfo->expires_min &&
|
|
expires <= sinfo->expires_max),
|
|
XT_CONNTRACK_EXPIRES))
|
|
return false;
|
|
}
|
|
return true;
|
|
#undef FWINV
|
|
}
|
|
|
|
static bool
|
|
conntrack_addrcmp(const union nf_inet_addr *kaddr,
|
|
const union nf_inet_addr *uaddr,
|
|
const union nf_inet_addr *umask, unsigned int l3proto)
|
|
{
|
|
if (l3proto == NFPROTO_IPV4)
|
|
return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
|
|
else if (l3proto == NFPROTO_IPV6)
|
|
return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
|
|
&uaddr->in6) == 0;
|
|
else
|
|
return false;
|
|
}
|
|
|
|
static inline bool
|
|
conntrack_mt_origsrc(const struct nf_conn *ct,
|
|
const struct xt_conntrack_mtinfo1 *info,
|
|
u_int8_t family)
|
|
{
|
|
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
|
|
&info->origsrc_addr, &info->origsrc_mask, family);
|
|
}
|
|
|
|
static inline bool
|
|
conntrack_mt_origdst(const struct nf_conn *ct,
|
|
const struct xt_conntrack_mtinfo1 *info,
|
|
u_int8_t family)
|
|
{
|
|
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3,
|
|
&info->origdst_addr, &info->origdst_mask, family);
|
|
}
|
|
|
|
static inline bool
|
|
conntrack_mt_replsrc(const struct nf_conn *ct,
|
|
const struct xt_conntrack_mtinfo1 *info,
|
|
u_int8_t family)
|
|
{
|
|
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3,
|
|
&info->replsrc_addr, &info->replsrc_mask, family);
|
|
}
|
|
|
|
static inline bool
|
|
conntrack_mt_repldst(const struct nf_conn *ct,
|
|
const struct xt_conntrack_mtinfo1 *info,
|
|
u_int8_t family)
|
|
{
|
|
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
|
|
&info->repldst_addr, &info->repldst_mask, family);
|
|
}
|
|
|
|
static inline bool
|
|
ct_proto_port_check(const struct xt_conntrack_mtinfo1 *info,
|
|
const struct nf_conn *ct)
|
|
{
|
|
const struct nf_conntrack_tuple *tuple;
|
|
|
|
tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
|
|
if ((info->match_flags & XT_CONNTRACK_PROTO) &&
|
|
(nf_ct_protonum(ct) == info->l4proto) ^
|
|
!(info->invert_flags & XT_CONNTRACK_PROTO))
|
|
return false;
|
|
|
|
/* Shortcut to match all recognized protocols by using ->src.all. */
|
|
if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&
|
|
(tuple->src.u.all == info->origsrc_port) ^
|
|
!(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))
|
|
return false;
|
|
|
|
if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&
|
|
(tuple->dst.u.all == info->origdst_port) ^
|
|
!(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))
|
|
return false;
|
|
|
|
tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
|
|
|
|
if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&
|
|
(tuple->src.u.all == info->replsrc_port) ^
|
|
!(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))
|
|
return false;
|
|
|
|
if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&
|
|
(tuple->dst.u.all == info->repldst_port) ^
|
|
!(info->invert_flags & XT_CONNTRACK_REPLDST_PORT))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool
|
|
conntrack_mt(const struct sk_buff *skb, const struct xt_match_param *par)
|
|
{
|
|
const struct xt_conntrack_mtinfo1 *info = par->matchinfo;
|
|
enum ip_conntrack_info ctinfo;
|
|
const struct nf_conn *ct;
|
|
unsigned int statebit;
|
|
|
|
ct = nf_ct_get(skb, &ctinfo);
|
|
|
|
if (ct == &nf_conntrack_untracked)
|
|
statebit = XT_CONNTRACK_STATE_UNTRACKED;
|
|
else if (ct != NULL)
|
|
statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
|
|
else
|
|
statebit = XT_CONNTRACK_STATE_INVALID;
|
|
|
|
if (info->match_flags & XT_CONNTRACK_STATE) {
|
|
if (ct != NULL) {
|
|
if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
|
|
statebit |= XT_CONNTRACK_STATE_SNAT;
|
|
if (test_bit(IPS_DST_NAT_BIT, &ct->status))
|
|
statebit |= XT_CONNTRACK_STATE_DNAT;
|
|
}
|
|
if (!!(info->state_mask & statebit) ^
|
|
!(info->invert_flags & XT_CONNTRACK_STATE))
|
|
return false;
|
|
}
|
|
|
|
if (ct == NULL)
|
|
return info->match_flags & XT_CONNTRACK_STATE;
|
|
if ((info->match_flags & XT_CONNTRACK_DIRECTION) &&
|
|
(CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^
|
|
!!(info->invert_flags & XT_CONNTRACK_DIRECTION))
|
|
return false;
|
|
|
|
if (info->match_flags & XT_CONNTRACK_ORIGSRC)
|
|
if (conntrack_mt_origsrc(ct, info, par->match->family) ^
|
|
!(info->invert_flags & XT_CONNTRACK_ORIGSRC))
|
|
return false;
|
|
|
|
if (info->match_flags & XT_CONNTRACK_ORIGDST)
|
|
if (conntrack_mt_origdst(ct, info, par->match->family) ^
|
|
!(info->invert_flags & XT_CONNTRACK_ORIGDST))
|
|
return false;
|
|
|
|
if (info->match_flags & XT_CONNTRACK_REPLSRC)
|
|
if (conntrack_mt_replsrc(ct, info, par->match->family) ^
|
|
!(info->invert_flags & XT_CONNTRACK_REPLSRC))
|
|
return false;
|
|
|
|
if (info->match_flags & XT_CONNTRACK_REPLDST)
|
|
if (conntrack_mt_repldst(ct, info, par->match->family) ^
|
|
!(info->invert_flags & XT_CONNTRACK_REPLDST))
|
|
return false;
|
|
|
|
if (!ct_proto_port_check(info, ct))
|
|
return false;
|
|
|
|
if ((info->match_flags & XT_CONNTRACK_STATUS) &&
|
|
(!!(info->status_mask & ct->status) ^
|
|
!(info->invert_flags & XT_CONNTRACK_STATUS)))
|
|
return false;
|
|
|
|
if (info->match_flags & XT_CONNTRACK_EXPIRES) {
|
|
unsigned long expires = 0;
|
|
|
|
if (timer_pending(&ct->timeout))
|
|
expires = (ct->timeout.expires - jiffies) / HZ;
|
|
if ((expires >= info->expires_min &&
|
|
expires <= info->expires_max) ^
|
|
!(info->invert_flags & XT_CONNTRACK_EXPIRES))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static bool conntrack_mt_check(const struct xt_mtchk_param *par)
|
|
{
|
|
if (nf_ct_l3proto_try_module_get(par->match->family) < 0) {
|
|
printk(KERN_WARNING "can't load conntrack support for "
|
|
"proto=%u\n", par->match->family);
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static void
|
|
conntrack_mt_destroy(const struct xt_match *match, void *matchinfo)
|
|
{
|
|
nf_ct_l3proto_module_put(match->family);
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
struct compat_xt_conntrack_info
|
|
{
|
|
compat_uint_t statemask;
|
|
compat_uint_t statusmask;
|
|
struct ip_conntrack_old_tuple tuple[IP_CT_DIR_MAX];
|
|
struct in_addr sipmsk[IP_CT_DIR_MAX];
|
|
struct in_addr dipmsk[IP_CT_DIR_MAX];
|
|
compat_ulong_t expires_min;
|
|
compat_ulong_t expires_max;
|
|
u_int8_t flags;
|
|
u_int8_t invflags;
|
|
};
|
|
|
|
static void conntrack_mt_compat_from_user_v0(void *dst, void *src)
|
|
{
|
|
const struct compat_xt_conntrack_info *cm = src;
|
|
struct xt_conntrack_info m = {
|
|
.statemask = cm->statemask,
|
|
.statusmask = cm->statusmask,
|
|
.expires_min = cm->expires_min,
|
|
.expires_max = cm->expires_max,
|
|
.flags = cm->flags,
|
|
.invflags = cm->invflags,
|
|
};
|
|
memcpy(m.tuple, cm->tuple, sizeof(m.tuple));
|
|
memcpy(m.sipmsk, cm->sipmsk, sizeof(m.sipmsk));
|
|
memcpy(m.dipmsk, cm->dipmsk, sizeof(m.dipmsk));
|
|
memcpy(dst, &m, sizeof(m));
|
|
}
|
|
|
|
static int conntrack_mt_compat_to_user_v0(void __user *dst, void *src)
|
|
{
|
|
const struct xt_conntrack_info *m = src;
|
|
struct compat_xt_conntrack_info cm = {
|
|
.statemask = m->statemask,
|
|
.statusmask = m->statusmask,
|
|
.expires_min = m->expires_min,
|
|
.expires_max = m->expires_max,
|
|
.flags = m->flags,
|
|
.invflags = m->invflags,
|
|
};
|
|
memcpy(cm.tuple, m->tuple, sizeof(cm.tuple));
|
|
memcpy(cm.sipmsk, m->sipmsk, sizeof(cm.sipmsk));
|
|
memcpy(cm.dipmsk, m->dipmsk, sizeof(cm.dipmsk));
|
|
return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
|
|
}
|
|
#endif
|
|
|
|
static struct xt_match conntrack_mt_reg[] __read_mostly = {
|
|
{
|
|
.name = "conntrack",
|
|
.revision = 0,
|
|
.family = NFPROTO_IPV4,
|
|
.match = conntrack_mt_v0,
|
|
.checkentry = conntrack_mt_check,
|
|
.destroy = conntrack_mt_destroy,
|
|
.matchsize = sizeof(struct xt_conntrack_info),
|
|
.me = THIS_MODULE,
|
|
#ifdef CONFIG_COMPAT
|
|
.compatsize = sizeof(struct compat_xt_conntrack_info),
|
|
.compat_from_user = conntrack_mt_compat_from_user_v0,
|
|
.compat_to_user = conntrack_mt_compat_to_user_v0,
|
|
#endif
|
|
},
|
|
{
|
|
.name = "conntrack",
|
|
.revision = 1,
|
|
.family = NFPROTO_IPV4,
|
|
.matchsize = sizeof(struct xt_conntrack_mtinfo1),
|
|
.match = conntrack_mt,
|
|
.checkentry = conntrack_mt_check,
|
|
.destroy = conntrack_mt_destroy,
|
|
.me = THIS_MODULE,
|
|
},
|
|
{
|
|
.name = "conntrack",
|
|
.revision = 1,
|
|
.family = NFPROTO_IPV6,
|
|
.matchsize = sizeof(struct xt_conntrack_mtinfo1),
|
|
.match = conntrack_mt,
|
|
.checkentry = conntrack_mt_check,
|
|
.destroy = conntrack_mt_destroy,
|
|
.me = THIS_MODULE,
|
|
},
|
|
};
|
|
|
|
static int __init conntrack_mt_init(void)
|
|
{
|
|
return xt_register_matches(conntrack_mt_reg,
|
|
ARRAY_SIZE(conntrack_mt_reg));
|
|
}
|
|
|
|
static void __exit conntrack_mt_exit(void)
|
|
{
|
|
xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
|
|
}
|
|
|
|
module_init(conntrack_mt_init);
|
|
module_exit(conntrack_mt_exit);
|