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