1 files changed, 385 insertions, 0 deletions

diff --git a/net/netfilter/xt_conntrack.c b/net/netfilter/xt_conntrack.c
new file mode 100644
index 0000000..0b7139f
--- /dev/null
+++ b/net/netfilter/xt_conntrack.c
@@ -0,0 +1,385 @@
+/*
+ *	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->family) ^
+		    !(info->invert_flags & XT_CONNTRACK_ORIGSRC))
+			return false;
+
+	if (info->match_flags & XT_CONNTRACK_ORIGDST)
+		if (conntrack_mt_origdst(ct, info, par->family) ^
+		    !(info->invert_flags & XT_CONNTRACK_ORIGDST))
+			return false;
+
+	if (info->match_flags & XT_CONNTRACK_REPLSRC)
+		if (conntrack_mt_replsrc(ct, info, par->family) ^
+		    !(info->invert_flags & XT_CONNTRACK_REPLSRC))
+			return false;
+
+	if (info->match_flags & XT_CONNTRACK_REPLDST)
+		if (conntrack_mt_repldst(ct, info, par->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->family) < 0) {
+		printk(KERN_WARNING "can't load conntrack support for "
+				    "proto=%u\n", par->family);
+		return false;
+	}
+	return true;
+}
+
+static void conntrack_mt_destroy(const struct xt_mtdtor_param *par)
+{
+	nf_ct_l3proto_module_put(par->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_UNSPEC,
+		.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);