softirq: Reorder trace_softirqs_on to prevent lockdep splat

[mirror_ubuntu-bionic-kernel.git] / kernel / user_namespace.c

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 246d4d4ce5c70cde4b5c9ed7fd33f54c1efe5a3e..12de8c144db931d9f378700b8ed77f34463d7ae8 100644 (file)
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -26,6 +26,12 @@
 #include <linux/bsearch.h>
 #include <linux/sort.h>
 
+/*
+ * sysctl determining whether unprivileged users may unshare a new
+ * userns.  Allowed by default
+ */
+int unprivileged_userns_clone = 1;
+
 static struct kmem_cache *user_ns_cachep __read_mostly;
 static DEFINE_MUTEX(userns_state_mutex);
 
@@ -977,10 +983,6 @@ static ssize_t map_write(struct file *file, const char __user *buf,
        if (!new_idmap_permitted(file, ns, cap_setid, &new_map))
                goto out;
 
-       ret = sort_idmaps(&new_map);
-       if (ret < 0)
-               goto out;
-
        ret = -EPERM;
        /* Map the lower ids from the parent user namespace to the
         * kernel global id space.
@@ -1007,6 +1009,14 @@ static ssize_t map_write(struct file *file, const char __user *buf,
                e->lower_first = lower_first;
        }
 
+       /*
+        * If we want to use binary search for lookup, this clones the extent
+        * array and sorts both copies.
+        */
+       ret = sort_idmaps(&new_map);
+       if (ret < 0)
+               goto out;
+
        /* Install the map */
        if (new_map.nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS) {
                memcpy(map->extent, new_map.extent,
@@ -1235,6 +1245,7 @@ bool current_in_userns(const struct user_namespace *target_ns)
 {
        return in_userns(target_ns, current_user_ns());
 }
+EXPORT_SYMBOL(current_in_userns);
 
 static inline struct user_namespace *to_user_ns(struct ns_common *ns)
 {