2 files changed, 81 insertions, 0 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index a05d191ffdd9..5424e37673ed 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -22,6 +22,9 @@
 #include <linux/pid_namespace.h>
 #include <net/net_namespace.h>
 #include <linux/ipc_namespace.h>
+#include <linux/proc_fs.h>
+#include <linux/file.h>
+#include <linux/syscalls.h>
 
 static struct kmem_cache *nsproxy_cachep;
 
@@ -233,6 +236,45 @@ void exit_task_namespaces(struct task_struct *p)
 	switch_task_namespaces(p, NULL);
 }
 
+SYSCALL_DEFINE2(setns, int, fd, int, nstype)
+{
+	const struct proc_ns_operations *ops;
+	struct task_struct *tsk = current;
+	struct nsproxy *new_nsproxy;
+	struct proc_inode *ei;
+	struct file *file;
+	int err;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	file = proc_ns_fget(fd);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	err = -EINVAL;
+	ei = PROC_I(file->f_dentry->d_inode);
+	ops = ei->ns_ops;
+	if (nstype && (ops->type != nstype))
+		goto out;
+
+	new_nsproxy = create_new_namespaces(0, tsk, tsk->fs);
+	if (IS_ERR(new_nsproxy)) {
+		err = PTR_ERR(new_nsproxy);
+		goto out;
+	}
+
+	err = ops->install(new_nsproxy, ei->ns);
+	if (err) {
+		free_nsproxy(new_nsproxy);
+		goto out;
+	}
+	switch_task_namespaces(tsk, new_nsproxy);
+out:
+	fput(file);
+	return err;
+}
+
 static int __init nsproxy_cache_init(void)
 {
 	nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 44646179eaba..bff131b9510a 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -15,6 +15,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/user_namespace.h>
+#include <linux/proc_fs.h>
 
 static struct uts_namespace *create_uts_ns(void)
 {
@@ -79,3 +80,41 @@ void free_uts_ns(struct kref *kref)
 	put_user_ns(ns->user_ns);
 	kfree(ns);
 }
+
+static void *utsns_get(struct task_struct *task)
+{
+	struct uts_namespace *ns = NULL;
+	struct nsproxy *nsproxy;
+
+	rcu_read_lock();
+	nsproxy = task_nsproxy(task);
+	if (nsproxy) {
+		ns = nsproxy->uts_ns;
+		get_uts_ns(ns);
+	}
+	rcu_read_unlock();
+
+	return ns;
+}
+
+static void utsns_put(void *ns)
+{
+	put_uts_ns(ns);
+}
+
+static int utsns_install(struct nsproxy *nsproxy, void *ns)
+{
+	get_uts_ns(ns);
+	put_uts_ns(nsproxy->uts_ns);
+	nsproxy->uts_ns = ns;
+	return 0;
+}
+
+const struct proc_ns_operations utsns_operations = {
+	.name		= "uts",
+	.type		= CLONE_NEWUTS,
+	.get		= utsns_get,
+	.put		= utsns_put,
+	.install	= utsns_install,
+};
+