ns proc: Add support for the uts namespace

Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

3 files changed, 43 insertions, 0 deletions

diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index dcbd483e9915..b017181f1273 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -19,6 +19,9 @@ static const struct proc_ns_operations *ns_entries[] = {
 #ifdef CONFIG_NET_NS
         &netns_operations,
 #endif
+#ifdef CONFIG_UTS_NS
+        &utsns_operations,
+#endif
 };
 
 static const struct file_operations ns_file_operations = {
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 62126ec6ede9..52aa89df8a6d 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -266,6 +266,7 @@ struct proc_ns_operations {
         int (*install)(struct nsproxy *nsproxy, void *ns);
 };
 extern const struct proc_ns_operations netns_operations;
+extern const struct proc_ns_operations utsns_operations;
 
 union proc_op {
         int (*proc_get_link)(struct inode *, struct path *);
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,
+};
+