Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfd

* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfd:
  net: fix get_net_ns_by_fd for !CONFIG_NET_NS
  ns proc: Return -ENOENT for a nonexistent /proc/self/ns/ entry.
  ns: Declare sys_setns in syscalls.h
  net: Allow setting the network namespace by fd
  ns proc: Add support for the ipc namespace
  ns proc: Add support for the uts namespace
  ns proc: Add support for the network namespace.
  ns: Introduce the setns syscall
  ns: proc files for namespace naming policy.

2 files changed, 81 insertions, 0 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index a05d191ffdd..5424e37673e 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 44646179eab..bff131b9510 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,
+};
+