1 files changed, 129 insertions, 0 deletions
diff --git a/net/sysctl_net.c b/net/sysctl_net.c
new file mode 100644
index 000000000..d14dab8b6
--- /dev/null
+++ b/net/sysctl_net.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* -*- linux-c -*-
+ * sysctl_net.c: sysctl interface to net subsystem.
+ *
+ * Begun April 1, 1996, Mike Shaver.
+ * Added /proc/sys/net directories for each protocol family. [MS]
+ *
+ * Revision 1.2  1996/05/08  20:24:40  shaver
+ * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
+ * NET_IPV4_IP_FORWARD.
+ *
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/sysctl.h>
+#include <linux/nsproxy.h>
+
+#include <net/sock.h>
+
+#ifdef CONFIG_INET
+#include <net/ip.h>
+#endif
+
+#ifdef CONFIG_NET
+#include <linux/if_ether.h>
+#endif
+
+static struct ctl_table_set *
+net_ctl_header_lookup(struct ctl_table_root *root)
+{
+	return &current->nsproxy->net_ns->sysctls;
+}
+
+static int is_seen(struct ctl_table_set *set)
+{
+	return &current->nsproxy->net_ns->sysctls == set;
+}
+
+/* Return standard mode bits for table entry. */
+static int net_ctl_permissions(struct ctl_table_header *head,
+			       struct ctl_table *table)
+{
+	struct net *net = container_of(head->set, struct net, sysctls);
+
+	/* Allow network administrator to have same access as root. */
+	if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {
+		int mode = (table->mode >> 6) & 7;
+		return (mode << 6) | (mode << 3) | mode;
+	}
+
+	return table->mode;
+}
+
+static void net_ctl_set_ownership(struct ctl_table_header *head,
+				  struct ctl_table *table,
+				  kuid_t *uid, kgid_t *gid)
+{
+	struct net *net = container_of(head->set, struct net, sysctls);
+	kuid_t ns_root_uid;
+	kgid_t ns_root_gid;
+
+	ns_root_uid = make_kuid(net->user_ns, 0);
+	if (uid_valid(ns_root_uid))
+		*uid = ns_root_uid;
+
+	ns_root_gid = make_kgid(net->user_ns, 0);
+	if (gid_valid(ns_root_gid))
+		*gid = ns_root_gid;
+}
+
+static struct ctl_table_root net_sysctl_root = {
+	.lookup = net_ctl_header_lookup,
+	.permissions = net_ctl_permissions,
+	.set_ownership = net_ctl_set_ownership,
+};
+
+static int __net_init sysctl_net_init(struct net *net)
+{
+	setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
+	return 0;
+}
+
+static void __net_exit sysctl_net_exit(struct net *net)
+{
+	retire_sysctl_set(&net->sysctls);
+}
+
+static struct pernet_operations sysctl_pernet_ops = {
+	.init = sysctl_net_init,
+	.exit = sysctl_net_exit,
+};
+
+static struct ctl_table_header *net_header;
+__init int net_sysctl_init(void)
+{
+	static struct ctl_table empty[1];
+	int ret = -ENOMEM;
+	/* Avoid limitations in the sysctl implementation by
+	 * registering "/proc/sys/net" as an empty directory not in a
+	 * network namespace.
+	 */
+	net_header = register_sysctl("net", empty);
+	if (!net_header)
+		goto out;
+	ret = register_pernet_subsys(&sysctl_pernet_ops);
+	if (ret)
+		goto out1;
+out:
+	return ret;
+out1:
+	unregister_sysctl_table(net_header);
+	net_header = NULL;
+	goto out;
+}
+
+struct ctl_table_header *register_net_sysctl(struct net *net,
+	const char *path, struct ctl_table *table)
+{
+	return __register_sysctl_table(&net->sysctls, path, table);
+}
+EXPORT_SYMBOL_GPL(register_net_sysctl);
+
+void unregister_net_sysctl_table(struct ctl_table_header *header)
+{
+	unregister_sysctl_table(header);
+}
+EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);