netfilter: audit target to record accepted/dropped packets

This patch adds a new netfilter target which creates audit records
for packets traversing a certain chain.

It can be used to record packets which are rejected administraively
as follows:

  -N AUDIT_DROP
  -A AUDIT_DROP -j AUDIT --type DROP
  -A AUDIT_DROP -j DROP

a rule which would typically drop or reject a packet would then
invoke the new chain to record packets before dropping them.

  -j AUDIT_DROP

The module is protocol independant and works for iptables, ip6tables
and ebtables.

The following information is logged:
 - netfilter hook
 - packet length
 - incomming/outgoing interface
 - MAC src/dst/proto for ethernet packets
 - src/dst/protocol address for IPv4/IPv6
 - src/dst port for TCP/UDP/UDPLITE
 - icmp type/code

Cc: Patrick McHardy <kaber@trash.net>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Thomas Graf <tgraf@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

3 files changed, 32 insertions, 0 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 8b5c0620abf9..ae227dfcf9c6 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -103,6 +103,7 @@
 #define AUDIT_BPRM_FCAPS	1321	/* Information about fcaps increasing perms */
 #define AUDIT_CAPSET		1322	/* Record showing argument to sys_capset */
 #define AUDIT_MMAP		1323	/* Record showing descriptor and flags in mmap */
+#define AUDIT_NETFILTER_PKT	1324	/* Packets traversing netfilter chains */
 
 #define AUDIT_AVC		1400	/* SE Linux avc denial or grant */
 #define AUDIT_SELINUX_ERR	1401	/* Internal SE Linux Errors */
diff --git a/include/linux/netfilter/Kbuild b/include/linux/netfilter/Kbuild
index 9d40effe7ca7..9f11fbc377e2 100644
--- a/include/linux/netfilter/Kbuild
+++ b/include/linux/netfilter/Kbuild
@@ -9,6 +9,7 @@ header-y += nfnetlink_conntrack.h
 header-y += nfnetlink_log.h
 header-y += nfnetlink_queue.h
 header-y += x_tables.h
+header-y += xt_AUDIT.h
 header-y += xt_CHECKSUM.h
 header-y += xt_CLASSIFY.h
 header-y += xt_CONNMARK.h
diff --git a/include/linux/netfilter/xt_AUDIT.h b/include/linux/netfilter/xt_AUDIT.h
new file mode 100644
index 000000000000..38751d2ea52b
--- /dev/null
+++ b/include/linux/netfilter/xt_AUDIT.h
@@ -0,0 +1,30 @@
+/*
+ * Header file for iptables xt_AUDIT target
+ *
+ * (C) 2010-2011 Thomas Graf <tgraf@redhat.com>
+ * (C) 2010-2011 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _XT_AUDIT_TARGET_H
+#define _XT_AUDIT_TARGET_H
+
+#include <linux/types.h>
+
+enum {
+	XT_AUDIT_TYPE_ACCEPT = 0,
+	XT_AUDIT_TYPE_DROP,
+	XT_AUDIT_TYPE_REJECT,
+	__XT_AUDIT_TYPE_MAX,
+};
+
+#define XT_AUDIT_TYPE_MAX (__XT_AUDIT_TYPE_MAX - 1)
+
+struct xt_audit_info {
+	__u8 type; /* XT_AUDIT_TYPE_* */
+};
+
+#endif /* _XT_AUDIT_TARGET_H */