// SPDX-License-Identifier: GPL-2.0-only
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/*
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* This module is used to copy security markings from packets
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* to connections, and restore security markings from connections
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* back to packets. This would normally be performed in conjunction
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* with the SECMARK target and state match.
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*
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* Based somewhat on CONNMARK:
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* Copyright (C) 2002,2004 MARA Systems AB <https://www.marasystems.com>
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* by Henrik Nordstrom <hno@marasystems.com>
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*
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* (C) 2006,2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
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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/skbuff.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_CONNSECMARK.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_ecache.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
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MODULE_DESCRIPTION("Xtables: target for copying between connection and security mark");
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MODULE_ALIAS("ipt_CONNSECMARK");
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MODULE_ALIAS("ip6t_CONNSECMARK");
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/*
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* If the packet has a security mark and the connection does not, copy
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* the security mark from the packet to the connection.
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*/
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static void secmark_save(const struct sk_buff *skb)
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{
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if (skb->secmark) {
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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ct = nf_ct_get(skb, &ctinfo);
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if (ct && !ct->secmark) {
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ct->secmark = skb->secmark;
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nf_conntrack_event_cache(IPCT_SECMARK, ct);
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}
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}
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}
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/*
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* If packet has no security mark, and the connection does, restore the
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* security mark from the connection to the packet.
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*/
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static void secmark_restore(struct sk_buff *skb)
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{
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if (!skb->secmark) {
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const struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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ct = nf_ct_get(skb, &ctinfo);
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if (ct && ct->secmark)
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skb->secmark = ct->secmark;
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}
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}
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static unsigned int
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connsecmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_connsecmark_target_info *info = par->targinfo;
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switch (info->mode) {
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case CONNSECMARK_SAVE:
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secmark_save(skb);
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break;
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case CONNSECMARK_RESTORE:
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secmark_restore(skb);
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break;
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default:
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BUG();
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}
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return XT_CONTINUE;
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}
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static int connsecmark_tg_check(const struct xt_tgchk_param *par)
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{
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const struct xt_connsecmark_target_info *info = par->targinfo;
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int ret;
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if (strcmp(par->table, "mangle") != 0 &&
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strcmp(par->table, "security") != 0) {
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pr_info_ratelimited("only valid in \'mangle\' or \'security\' table, not \'%s\'\n",
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par->table);
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return -EINVAL;
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}
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switch (info->mode) {
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case CONNSECMARK_SAVE:
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case CONNSECMARK_RESTORE:
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break;
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default:
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pr_info_ratelimited("invalid mode: %hu\n", info->mode);
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return -EINVAL;
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}
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ret = nf_ct_netns_get(par->net, par->family);
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if (ret < 0)
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pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
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par->family);
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return ret;
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}
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static void connsecmark_tg_destroy(const struct xt_tgdtor_param *par)
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{
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nf_ct_netns_put(par->net, par->family);
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}
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static struct xt_target connsecmark_tg_reg __read_mostly = {
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.name = "CONNSECMARK",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.checkentry = connsecmark_tg_check,
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.destroy = connsecmark_tg_destroy,
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.target = connsecmark_tg,
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.targetsize = sizeof(struct xt_connsecmark_target_info),
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.me = THIS_MODULE,
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};
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static int __init connsecmark_tg_init(void)
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{
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return xt_register_target(&connsecmark_tg_reg);
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}
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static void __exit connsecmark_tg_exit(void)
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{
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xt_unregister_target(&connsecmark_tg_reg);
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}
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module_init(connsecmark_tg_init);
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module_exit(connsecmark_tg_exit);
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