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-rw-r--r--fs/proc/namespaces.c3
-rw-r--r--include/linux/proc_fs.h1
-rw-r--r--kernel/pid_namespace.c54
3 files changed, 58 insertions, 0 deletions
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index b178ed733c36..85ca047e35f1 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -24,6 +24,9 @@ static const struct proc_ns_operations *ns_entries[] = {
#ifdef CONFIG_IPC_NS
&ipcns_operations,
#endif
+#ifdef CONFIG_PID_NS
+ &pidns_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 3fd2e871ff1b..acaafcd40aa5 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -251,6 +251,7 @@ struct proc_ns_operations {
extern const struct proc_ns_operations netns_operations;
extern const struct proc_ns_operations utsns_operations;
extern const struct proc_ns_operations ipcns_operations;
+extern const struct proc_ns_operations pidns_operations;
union proc_op {
int (*proc_get_link)(struct dentry *, struct path *);
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 0dbbc66b6ec6..f78fc48c86bc 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -301,6 +301,60 @@ int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
return 0;
}
+static void *pidns_get(struct task_struct *task)
+{
+ struct pid_namespace *ns;
+
+ rcu_read_lock();
+ ns = get_pid_ns(task_active_pid_ns(task));
+ rcu_read_unlock();
+
+ return ns;
+}
+
+static void pidns_put(void *ns)
+{
+ put_pid_ns(ns);
+}
+
+static int pidns_install(struct nsproxy *nsproxy, void *ns)
+{
+ struct pid_namespace *active = task_active_pid_ns(current);
+ struct pid_namespace *ancestor, *new = ns;
+
+ if (!ns_capable(new->user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /*
+ * Only allow entering the current active pid namespace
+ * or a child of the current active pid namespace.
+ *
+ * This is required for fork to return a usable pid value and
+ * this maintains the property that processes and their
+ * children can not escape their current pid namespace.
+ */
+ if (new->level < active->level)
+ return -EINVAL;
+
+ ancestor = new;
+ while (ancestor->level > active->level)
+ ancestor = ancestor->parent;
+ if (ancestor != active)
+ return -EINVAL;
+
+ put_pid_ns(nsproxy->pid_ns);
+ nsproxy->pid_ns = get_pid_ns(new);
+ return 0;
+}
+
+const struct proc_ns_operations pidns_operations = {
+ .name = "pid",
+ .type = CLONE_NEWPID,
+ .get = pidns_get,
+ .put = pidns_put,
+ .install = pidns_install,
+};
+
static __init int pid_namespaces_init(void)
{
pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC);