// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#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 bool 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, skb_network_offset(skb), sizeof(_iph), &_iph);
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if (!ih)
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return false;
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audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
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&ih->saddr, &ih->daddr, ih->protocol);
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return true;
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}
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static bool 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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__be16 frag_off;
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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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return false;
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nexthdr = ih->nexthdr;
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ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off);
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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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return true;
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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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struct audit_buffer *ab;
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int fam = -1;
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if (audit_enabled == AUDIT_OFF)
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goto errout;
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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, "mark=%#x", skb->mark);
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switch (xt_family(par)) {
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case NFPROTO_BRIDGE:
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switch (eth_hdr(skb)->h_proto) {
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case htons(ETH_P_IP):
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fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
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break;
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case htons(ETH_P_IPV6):
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fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
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break;
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}
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break;
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case NFPROTO_IPV4:
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fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
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break;
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case NFPROTO_IPV6:
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fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
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break;
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}
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if (fam == -1)
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audit_log_format(ab, " saddr=? daddr=? proto=-1");
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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_ratelimited("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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