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![Mr Dash Four](/assets/img/avatar_default.png)
In this revision the conversion of secid to SELinux context and adding it to the audit log is moved from xt_AUDIT.c to audit.c with the aid of a separate helper function - audit_log_secctx - which does both the conversion and logging of SELinux context, thus also preventing internal secid number being leaked to userspace. If conversion is not successful an error is raised. With the introduction of this helper function the work done in xt_AUDIT.c is much more simplified. It also opens the possibility of this helper function being used by other modules (including auditd itself), if desired. With this addition, typical (raw auditd) output after applying the patch would be: type=NETFILTER_PKT msg=audit(1305852240.082:31012): action=0 hook=1 len=52 inif=? outif=eth0 saddr=10.1.1.7 daddr=10.1.2.1 ipid=16312 proto=6 sport=56150 dport=22 obj=system_u:object_r:ssh_client_packet_t:s0 type=NETFILTER_PKT msg=audit(1306772064.079:56): action=0 hook=3 len=48 inif=eth0 outif=? smac=00:05:5d:7c:27:0b dmac=00:02:b3:0a:7f:81 macproto=0x0800 saddr=10.1.2.1 daddr=10.1.1.7 ipid=462 proto=6 sport=22 dport=3561 obj=system_u:object_r:ssh_server_packet_t:s0 Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Mr Dash Four <mr.dash.four@googlemail.com> Signed-off-by: Patrick McHardy <kaber@trash.net>
227 lines
5 KiB
C
227 lines
5 KiB
C
/*
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* Creates audit record for dropped/accepted packets
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*
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* (C) 2010-2011 Thomas Graf <tgraf@redhat.com>
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* (C) 2010-2011 Red Hat, Inc.
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/audit.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <linux/if_arp.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_AUDIT.h>
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#include <linux/netfilter_bridge/ebtables.h>
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#include <net/ipv6.h>
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#include <net/ip.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Thomas Graf <tgraf@redhat.com>");
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MODULE_DESCRIPTION("Xtables: creates audit records for dropped/accepted packets");
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MODULE_ALIAS("ipt_AUDIT");
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MODULE_ALIAS("ip6t_AUDIT");
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MODULE_ALIAS("ebt_AUDIT");
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MODULE_ALIAS("arpt_AUDIT");
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static void audit_proto(struct audit_buffer *ab, struct sk_buff *skb,
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unsigned int proto, unsigned int offset)
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{
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switch (proto) {
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case IPPROTO_TCP:
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case IPPROTO_UDP:
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case IPPROTO_UDPLITE: {
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const __be16 *pptr;
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__be16 _ports[2];
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pptr = skb_header_pointer(skb, offset, sizeof(_ports), _ports);
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if (pptr == NULL) {
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audit_log_format(ab, " truncated=1");
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return;
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}
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audit_log_format(ab, " sport=%hu dport=%hu",
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ntohs(pptr[0]), ntohs(pptr[1]));
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}
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break;
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case IPPROTO_ICMP:
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case IPPROTO_ICMPV6: {
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const u8 *iptr;
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u8 _ih[2];
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iptr = skb_header_pointer(skb, offset, sizeof(_ih), &_ih);
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if (iptr == NULL) {
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audit_log_format(ab, " truncated=1");
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return;
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}
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audit_log_format(ab, " icmptype=%hhu icmpcode=%hhu",
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iptr[0], iptr[1]);
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}
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break;
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}
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}
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static void audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
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{
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struct iphdr _iph;
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const struct iphdr *ih;
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ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
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if (!ih) {
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audit_log_format(ab, " truncated=1");
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return;
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}
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audit_log_format(ab, " saddr=%pI4 daddr=%pI4 ipid=%hu proto=%hhu",
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&ih->saddr, &ih->daddr, ntohs(ih->id), ih->protocol);
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if (ntohs(ih->frag_off) & IP_OFFSET) {
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audit_log_format(ab, " frag=1");
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return;
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}
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audit_proto(ab, skb, ih->protocol, ih->ihl * 4);
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}
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static void audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
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{
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struct ipv6hdr _ip6h;
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const struct ipv6hdr *ih;
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u8 nexthdr;
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int offset;
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ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
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if (!ih) {
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audit_log_format(ab, " truncated=1");
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return;
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}
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nexthdr = ih->nexthdr;
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offset = ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h),
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&nexthdr);
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audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
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&ih->saddr, &ih->daddr, nexthdr);
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if (offset)
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audit_proto(ab, skb, nexthdr, offset);
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}
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static unsigned int
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audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_audit_info *info = par->targinfo;
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struct audit_buffer *ab;
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ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
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if (ab == NULL)
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goto errout;
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audit_log_format(ab, "action=%hhu hook=%u len=%u inif=%s outif=%s",
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info->type, par->hooknum, skb->len,
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par->in ? par->in->name : "?",
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par->out ? par->out->name : "?");
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if (skb->mark)
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audit_log_format(ab, " mark=%#x", skb->mark);
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if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
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audit_log_format(ab, " smac=%pM dmac=%pM macproto=0x%04x",
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eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
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ntohs(eth_hdr(skb)->h_proto));
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if (par->family == NFPROTO_BRIDGE) {
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switch (eth_hdr(skb)->h_proto) {
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case __constant_htons(ETH_P_IP):
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audit_ip4(ab, skb);
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break;
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case __constant_htons(ETH_P_IPV6):
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audit_ip6(ab, skb);
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break;
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}
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}
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}
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switch (par->family) {
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case NFPROTO_IPV4:
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audit_ip4(ab, skb);
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break;
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case NFPROTO_IPV6:
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audit_ip6(ab, skb);
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break;
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}
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#ifdef CONFIG_NETWORK_SECMARK
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if (skb->secmark)
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audit_log_secctx(ab, skb->secmark);
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#endif
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audit_log_end(ab);
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errout:
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return XT_CONTINUE;
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}
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static unsigned int
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audit_tg_ebt(struct sk_buff *skb, const struct xt_action_param *par)
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{
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audit_tg(skb, par);
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return EBT_CONTINUE;
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}
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static int audit_tg_check(const struct xt_tgchk_param *par)
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{
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const struct xt_audit_info *info = par->targinfo;
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if (info->type > XT_AUDIT_TYPE_MAX) {
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pr_info("Audit type out of range (valid range: 0..%hhu)\n",
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XT_AUDIT_TYPE_MAX);
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return -ERANGE;
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}
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return 0;
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}
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static struct xt_target audit_tg_reg[] __read_mostly = {
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{
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.name = "AUDIT",
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.family = NFPROTO_UNSPEC,
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.target = audit_tg,
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.targetsize = sizeof(struct xt_audit_info),
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.checkentry = audit_tg_check,
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.me = THIS_MODULE,
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},
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{
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.name = "AUDIT",
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.family = NFPROTO_BRIDGE,
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.target = audit_tg_ebt,
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.targetsize = sizeof(struct xt_audit_info),
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.checkentry = audit_tg_check,
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.me = THIS_MODULE,
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},
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};
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static int __init audit_tg_init(void)
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{
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return xt_register_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
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}
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static void __exit audit_tg_exit(void)
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{
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xt_unregister_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
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}
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module_init(audit_tg_init);
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module_exit(audit_tg_exit);
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