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![James Morris](/assets/img/avatar_default.png)
The following patch implements a new "security" table for iptables, so that MAC (SELinux etc.) networking rules can be managed separately to standard DAC rules. This is to help with distro integration of the new secmark-based network controls, per various previous discussions. The need for a separate table arises from the fact that existing tools and usage of iptables will likely clash with centralized MAC policy management. The SECMARK and CONNSECMARK targets will still be valid in the mangle table to prevent breakage of existing users. Signed-off-by: James Morris <jmorris@namei.org> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
161 lines
4.2 KiB
C
161 lines
4.2 KiB
C
/*
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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 <http://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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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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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#define PFX "CONNSECMARK: "
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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, skb);
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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 net_device *in,
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const struct net_device *out, unsigned int hooknum,
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const struct xt_target *target, const void *targinfo)
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{
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const struct xt_connsecmark_target_info *info = 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 bool
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connsecmark_tg_check(const char *tablename, const void *entry,
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const struct xt_target *target, void *targinfo,
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unsigned int hook_mask)
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{
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const struct xt_connsecmark_target_info *info = targinfo;
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if (strcmp(tablename, "mangle") && strcmp(tablename, "security")) {
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printk(KERN_INFO PFX "target only valid in the \'mangle\' "
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"or \'security\' tables, not \'%s\'.\n", tablename);
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return false;
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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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printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode);
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return false;
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}
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if (nf_ct_l3proto_try_module_get(target->family) < 0) {
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printk(KERN_WARNING "can't load conntrack support for "
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"proto=%u\n", target->family);
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return false;
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}
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return true;
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}
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static void
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connsecmark_tg_destroy(const struct xt_target *target, void *targinfo)
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{
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nf_ct_l3proto_module_put(target->family);
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}
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static struct xt_target connsecmark_tg_reg[] __read_mostly = {
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{
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.name = "CONNSECMARK",
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.family = AF_INET,
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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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{
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.name = "CONNSECMARK",
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.family = AF_INET6,
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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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};
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static int __init connsecmark_tg_init(void)
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{
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return xt_register_targets(connsecmark_tg_reg,
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ARRAY_SIZE(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_targets(connsecmark_tg_reg,
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ARRAY_SIZE(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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