From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 net/netfilter/xt_owner.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 net/netfilter/xt_owner.c

(limited to 'net/netfilter/xt_owner.c')

diff --git a/net/netfilter/xt_owner.c b/net/netfilter/xt_owner.c
new file mode 100644
index 000000000..ca2e577ed
--- /dev/null
+++ b/net/netfilter/xt_owner.c
@@ -0,0 +1,100 @@
+/*
+ * Kernel module to match various things tied to sockets associated with
+ * locally generated outgoing packets.
+ *
+ * (C) 2000 Marc Boucher <marc@mbsi.ca>
+ *
+ * Copyright © CC Computer Consultants GmbH, 2007 - 2008
+ *
+ * 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/module.h>
+#include <linux/skbuff.h>
+#include <linux/file.h>
+#include <net/sock.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_owner.h>
+
+static int owner_check(const struct xt_mtchk_param *par)
+{
+	struct xt_owner_match_info *info = par->matchinfo;
+
+	/* For now only allow adding matches from the initial user namespace */
+	if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) &&
+	    (current_user_ns() != &init_user_ns))
+		return -EINVAL;
+	return 0;
+}
+
+static bool
+owner_mt(const struct sk_buff *skb, struct xt_action_param *par)
+{
+	const struct xt_owner_match_info *info = par->matchinfo;
+	const struct file *filp;
+
+	if (skb->sk == NULL || skb->sk->sk_socket == NULL)
+		return (info->match ^ info->invert) == 0;
+	else if (info->match & info->invert & XT_OWNER_SOCKET)
+		/*
+		 * Socket exists but user wanted ! --socket-exists.
+		 * (Single ampersands intended.)
+		 */
+		return false;
+
+	filp = skb->sk->sk_socket->file;
+	if (filp == NULL)
+		return ((info->match ^ info->invert) &
+		       (XT_OWNER_UID | XT_OWNER_GID)) == 0;
+
+	if (info->match & XT_OWNER_UID) {
+		kuid_t uid_min = make_kuid(&init_user_ns, info->uid_min);
+		kuid_t uid_max = make_kuid(&init_user_ns, info->uid_max);
+		if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
+		     uid_lte(filp->f_cred->fsuid, uid_max)) ^
+		    !(info->invert & XT_OWNER_UID))
+			return false;
+	}
+
+	if (info->match & XT_OWNER_GID) {
+		kgid_t gid_min = make_kgid(&init_user_ns, info->gid_min);
+		kgid_t gid_max = make_kgid(&init_user_ns, info->gid_max);
+		if ((gid_gte(filp->f_cred->fsgid, gid_min) &&
+		     gid_lte(filp->f_cred->fsgid, gid_max)) ^
+		    !(info->invert & XT_OWNER_GID))
+			return false;
+	}
+
+	return true;
+}
+
+static struct xt_match owner_mt_reg __read_mostly = {
+	.name       = "owner",
+	.revision   = 1,
+	.family     = NFPROTO_UNSPEC,
+	.checkentry = owner_check,
+	.match      = owner_mt,
+	.matchsize  = sizeof(struct xt_owner_match_info),
+	.hooks      = (1 << NF_INET_LOCAL_OUT) |
+	              (1 << NF_INET_POST_ROUTING),
+	.me         = THIS_MODULE,
+};
+
+static int __init owner_mt_init(void)
+{
+	return xt_register_match(&owner_mt_reg);
+}
+
+static void __exit owner_mt_exit(void)
+{
+	xt_unregister_match(&owner_mt_reg);
+}
+
+module_init(owner_mt_init);
+module_exit(owner_mt_exit);
+MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
+MODULE_DESCRIPTION("Xtables: socket owner matching");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_owner");
+MODULE_ALIAS("ip6t_owner");
-- 
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