1 files changed, 405 insertions, 0 deletions
diff --git a/net/netfilter/xt_CT.c b/net/netfilter/xt_CT.c
new file mode 100644
index 000000000..2be2f7a7b
--- /dev/null
+++ b/net/netfilter/xt_CT.c
@@ -0,0 +1,405 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2010 Patrick McHardy <kaber@trash.net>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_CT.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_l4proto.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_ecache.h>
+#include <net/netfilter/nf_conntrack_timeout.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+
+static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct)
+{
+	/* Previously seen (loopback)? Ignore. */
+	if (skb->_nfct != 0)
+		return XT_CONTINUE;
+
+	if (ct) {
+		refcount_inc(&ct->ct_general.use);
+		nf_ct_set(skb, ct, IP_CT_NEW);
+	} else {
+		nf_ct_set(skb, ct, IP_CT_UNTRACKED);
+	}
+
+	return XT_CONTINUE;
+}
+
+static unsigned int xt_ct_target_v0(struct sk_buff *skb,
+				    const struct xt_action_param *par)
+{
+	const struct xt_ct_target_info *info = par->targinfo;
+	struct nf_conn *ct = info->ct;
+
+	return xt_ct_target(skb, ct);
+}
+
+static unsigned int xt_ct_target_v1(struct sk_buff *skb,
+				    const struct xt_action_param *par)
+{
+	const struct xt_ct_target_info_v1 *info = par->targinfo;
+	struct nf_conn *ct = info->ct;
+
+	return xt_ct_target(skb, ct);
+}
+
+static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
+{
+	if (par->family == NFPROTO_IPV4) {
+		const struct ipt_entry *e = par->entryinfo;
+
+		if (e->ip.invflags & IPT_INV_PROTO)
+			return 0;
+		return e->ip.proto;
+	} else if (par->family == NFPROTO_IPV6) {
+		const struct ip6t_entry *e = par->entryinfo;
+
+		if (e->ipv6.invflags & IP6T_INV_PROTO)
+			return 0;
+		return e->ipv6.proto;
+	} else
+		return 0;
+}
+
+static int
+xt_ct_set_helper(struct nf_conn *ct, const char *helper_name,
+		 const struct xt_tgchk_param *par)
+{
+	struct nf_conntrack_helper *helper;
+	struct nf_conn_help *help;
+	u8 proto;
+
+	proto = xt_ct_find_proto(par);
+	if (!proto) {
+		pr_info_ratelimited("You must specify a L4 protocol and not use inversions on it\n");
+		return -ENOENT;
+	}
+
+	helper = nf_conntrack_helper_try_module_get(helper_name, par->family,
+						    proto);
+	if (helper == NULL) {
+		pr_info_ratelimited("No such helper \"%s\"\n", helper_name);
+		return -ENOENT;
+	}
+
+	help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
+	if (help == NULL) {
+		nf_conntrack_helper_put(helper);
+		return -ENOMEM;
+	}
+
+	rcu_assign_pointer(help->helper, helper);
+	return 0;
+}
+
+static int
+xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par,
+		  const char *timeout_name)
+{
+#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
+	const struct nf_conntrack_l4proto *l4proto;
+	u8 proto;
+
+	proto = xt_ct_find_proto(par);
+	if (!proto) {
+		pr_info_ratelimited("You must specify a L4 protocol and not "
+				    "use inversions on it");
+		return -EINVAL;
+	}
+	l4proto = nf_ct_l4proto_find(proto);
+	return nf_ct_set_timeout(par->net, ct, par->family, l4proto->l4proto,
+				 timeout_name);
+
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info)
+{
+	switch (info->flags & (XT_CT_ZONE_DIR_ORIG |
+			       XT_CT_ZONE_DIR_REPL)) {
+	case XT_CT_ZONE_DIR_ORIG:
+		return NF_CT_ZONE_DIR_ORIG;
+	case XT_CT_ZONE_DIR_REPL:
+		return NF_CT_ZONE_DIR_REPL;
+	default:
+		return NF_CT_DEFAULT_ZONE_DIR;
+	}
+}
+
+static void xt_ct_put_helper(struct nf_conn_help *help)
+{
+	struct nf_conntrack_helper *helper;
+
+	if (!help)
+		return;
+
+	/* not yet exposed to other cpus, or ruleset
+	 * already detached (post-replacement).
+	 */
+	helper = rcu_dereference_raw(help->helper);
+	if (helper)
+		nf_conntrack_helper_put(helper);
+}
+
+static int xt_ct_tg_check(const struct xt_tgchk_param *par,
+			  struct xt_ct_target_info_v1 *info)
+{
+	struct nf_conntrack_zone zone;
+	struct nf_conn_help *help;
+	struct nf_conn *ct;
+	int ret = -EOPNOTSUPP;
+
+	if (info->flags & XT_CT_NOTRACK) {
+		ct = NULL;
+		goto out;
+	}
+
+#ifndef CONFIG_NF_CONNTRACK_ZONES
+	if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
+					 XT_CT_ZONE_DIR_REPL |
+					 XT_CT_ZONE_MARK))
+		goto err1;
+#endif
+
+	ret = nf_ct_netns_get(par->net, par->family);
+	if (ret < 0)
+		goto err1;
+
+	memset(&zone, 0, sizeof(zone));
+	zone.id = info->zone;
+	zone.dir = xt_ct_flags_to_dir(info);
+	if (info->flags & XT_CT_ZONE_MARK)
+		zone.flags |= NF_CT_FLAG_MARK;
+
+	ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
+	if (!ct) {
+		ret = -ENOMEM;
+		goto err2;
+	}
+
+	if ((info->ct_events || info->exp_events) &&
+	    !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
+				  GFP_KERNEL)) {
+		ret = -EINVAL;
+		goto err3;
+	}
+
+	if (info->helper[0]) {
+		if (strnlen(info->helper, sizeof(info->helper)) == sizeof(info->helper)) {
+			ret = -ENAMETOOLONG;
+			goto err3;
+		}
+
+		ret = xt_ct_set_helper(ct, info->helper, par);
+		if (ret < 0)
+			goto err3;
+	}
+
+	if (info->timeout[0]) {
+		if (strnlen(info->timeout, sizeof(info->timeout)) == sizeof(info->timeout)) {
+			ret = -ENAMETOOLONG;
+			goto err4;
+		}
+
+		ret = xt_ct_set_timeout(ct, par, info->timeout);
+		if (ret < 0)
+			goto err4;
+	}
+	__set_bit(IPS_CONFIRMED_BIT, &ct->status);
+out:
+	info->ct = ct;
+	return 0;
+
+err4:
+	help = nfct_help(ct);
+	xt_ct_put_helper(help);
+err3:
+	nf_ct_tmpl_free(ct);
+err2:
+	nf_ct_netns_put(par->net, par->family);
+err1:
+	return ret;
+}
+
+static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
+{
+	struct xt_ct_target_info *info = par->targinfo;
+	struct xt_ct_target_info_v1 info_v1 = {
+		.flags 		= info->flags,
+		.zone		= info->zone,
+		.ct_events	= info->ct_events,
+		.exp_events	= info->exp_events,
+	};
+	int ret;
+
+	if (info->flags & ~XT_CT_NOTRACK)
+		return -EINVAL;
+
+	memcpy(info_v1.helper, info->helper, sizeof(info->helper));
+
+	ret = xt_ct_tg_check(par, &info_v1);
+	if (ret < 0)
+		return ret;
+
+	info->ct = info_v1.ct;
+
+	return ret;
+}
+
+static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
+{
+	struct xt_ct_target_info_v1 *info = par->targinfo;
+
+	if (info->flags & ~XT_CT_NOTRACK)
+		return -EINVAL;
+
+	return xt_ct_tg_check(par, par->targinfo);
+}
+
+static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
+{
+	struct xt_ct_target_info_v1 *info = par->targinfo;
+
+	if (info->flags & ~XT_CT_MASK)
+		return -EINVAL;
+
+	return xt_ct_tg_check(par, par->targinfo);
+}
+
+static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
+			     struct xt_ct_target_info_v1 *info)
+{
+	struct nf_conn *ct = info->ct;
+	struct nf_conn_help *help;
+
+	if (ct) {
+		help = nfct_help(ct);
+		xt_ct_put_helper(help);
+
+		nf_ct_netns_put(par->net, par->family);
+
+		nf_ct_destroy_timeout(ct);
+		nf_ct_put(info->ct);
+	}
+}
+
+static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
+{
+	struct xt_ct_target_info *info = par->targinfo;
+	struct xt_ct_target_info_v1 info_v1 = {
+		.flags 		= info->flags,
+		.zone		= info->zone,
+		.ct_events	= info->ct_events,
+		.exp_events	= info->exp_events,
+		.ct		= info->ct,
+	};
+	memcpy(info_v1.helper, info->helper, sizeof(info->helper));
+
+	xt_ct_tg_destroy(par, &info_v1);
+}
+
+static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
+{
+	xt_ct_tg_destroy(par, par->targinfo);
+}
+
+static struct xt_target xt_ct_tg_reg[] __read_mostly = {
+	{
+		.name		= "CT",
+		.family		= NFPROTO_UNSPEC,
+		.targetsize	= sizeof(struct xt_ct_target_info),
+		.usersize	= offsetof(struct xt_ct_target_info, ct),
+		.checkentry	= xt_ct_tg_check_v0,
+		.destroy	= xt_ct_tg_destroy_v0,
+		.target		= xt_ct_target_v0,
+		.table		= "raw",
+		.me		= THIS_MODULE,
+	},
+	{
+		.name		= "CT",
+		.family		= NFPROTO_UNSPEC,
+		.revision	= 1,
+		.targetsize	= sizeof(struct xt_ct_target_info_v1),
+		.usersize	= offsetof(struct xt_ct_target_info, ct),
+		.checkentry	= xt_ct_tg_check_v1,
+		.destroy	= xt_ct_tg_destroy_v1,
+		.target		= xt_ct_target_v1,
+		.table		= "raw",
+		.me		= THIS_MODULE,
+	},
+	{
+		.name		= "CT",
+		.family		= NFPROTO_UNSPEC,
+		.revision	= 2,
+		.targetsize	= sizeof(struct xt_ct_target_info_v1),
+		.usersize	= offsetof(struct xt_ct_target_info, ct),
+		.checkentry	= xt_ct_tg_check_v2,
+		.destroy	= xt_ct_tg_destroy_v1,
+		.target		= xt_ct_target_v1,
+		.table		= "raw",
+		.me		= THIS_MODULE,
+	},
+};
+
+static unsigned int
+notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	/* Previously seen (loopback)? Ignore. */
+	if (skb->_nfct != 0)
+		return XT_CONTINUE;
+
+	nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
+
+	return XT_CONTINUE;
+}
+
+static struct xt_target notrack_tg_reg __read_mostly = {
+	.name		= "NOTRACK",
+	.revision	= 0,
+	.family		= NFPROTO_UNSPEC,
+	.target		= notrack_tg,
+	.table		= "raw",
+	.me		= THIS_MODULE,
+};
+
+static int __init xt_ct_tg_init(void)
+{
+	int ret;
+
+	ret = xt_register_target(&notrack_tg_reg);
+	if (ret < 0)
+		return ret;
+
+	ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
+	if (ret < 0) {
+		xt_unregister_target(&notrack_tg_reg);
+		return ret;
+	}
+	return 0;
+}
+
+static void __exit xt_ct_tg_exit(void)
+{
+	xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
+	xt_unregister_target(&notrack_tg_reg);
+}
+
+module_init(xt_ct_tg_init);
+module_exit(xt_ct_tg_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Xtables: connection tracking target");
+MODULE_ALIAS("ipt_CT");
+MODULE_ALIAS("ip6t_CT");
+MODULE_ALIAS("ipt_NOTRACK");
+MODULE_ALIAS("ip6t_NOTRACK");