3 files changed, 82 insertions, 0 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 6d8e48b376fc..c17902cb5df9 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -858,6 +858,16 @@ config NETFILTER_XT_MATCH_BPF
 
           To compile it as a module, choose M here.  If unsure, say N.
 
+config NETFILTER_XT_MATCH_CGROUP
+        tristate '"control group" match support'
+        depends on NETFILTER_ADVANCED
+        depends on CGROUPS
+        select CGROUP_NET_CLASSID
+        ---help---
+        Socket/process control group matching allows you to match locally
+        generated packets based on which net_cls control group processes
+        belong to.
+
 config NETFILTER_XT_MATCH_CLUSTER
         tristate '"cluster" match support'
         depends on NF_CONNTRACK
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 398cd709aa09..407fc232f625 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -143,6 +143,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_MULTIPORT) += xt_multiport.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_NFACCT) += xt_nfacct.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_OSF) += xt_osf.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_OWNER) += xt_owner.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_CGROUP) += xt_cgroup.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_PKTTYPE) += xt_pkttype.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_POLICY) += xt_policy.o
diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c
new file mode 100644
index 000000000000..9a8e77e7f8d4
--- /dev/null
+++ b/net/netfilter/xt_cgroup.c
@@ -0,0 +1,71 @@
+/*
+ * Xtables module to match the process control group.
+ *
+ * Might be used to implement individual "per-application" firewall
+ * policies in contrast to global policies based on control groups.
+ * Matching is based upon processes tagged to net_cls' classid marker.
+ *
+ * (C) 2013 Daniel Borkmann <dborkman@redhat.com>
+ *
+ * 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.
+ */
+
+#include <linux/skbuff.h>
+#include <linux/module.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_cgroup.h>
+#include <net/sock.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
+MODULE_DESCRIPTION("Xtables: process control group matching");
+MODULE_ALIAS("ipt_cgroup");
+MODULE_ALIAS("ip6t_cgroup");
+
+static int cgroup_mt_check(const struct xt_mtchk_param *par)
+{
+        struct xt_cgroup_info *info = par->matchinfo;
+
+        if (info->invert & ~1)
+                return -EINVAL;
+
+        return info->id ? 0 : -EINVAL;
+}
+
+static bool
+cgroup_mt(const struct sk_buff *skb, struct xt_action_param *par)
+{
+        const struct xt_cgroup_info *info = par->matchinfo;
+
+        if (skb->sk == NULL)
+                return false;
+
+        return (info->id == skb->sk->sk_classid) ^ info->invert;
+}
+
+static struct xt_match cgroup_mt_reg __read_mostly = {
+        .name       = "cgroup",
+        .revision   = 0,
+        .family     = NFPROTO_UNSPEC,
+        .checkentry = cgroup_mt_check,
+        .match      = cgroup_mt,
+        .matchsize  = sizeof(struct xt_cgroup_info),
+        .me         = THIS_MODULE,
+        .hooks      = (1 << NF_INET_LOCAL_OUT) |
+                      (1 << NF_INET_POST_ROUTING),
+};
+
+static int __init cgroup_mt_init(void)
+{
+        return xt_register_match(&cgroup_mt_reg);
+}
+
+static void __exit cgroup_mt_exit(void)
+{
+        xt_unregister_match(&cgroup_mt_reg);
+}
+
+module_init(cgroup_mt_init);
+module_exit(cgroup_mt_exit);