1 files changed, 8 insertions, 4 deletions

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index e5222b5fb4fe..923414a246e9 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -974,10 +974,6 @@ 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.
@@ -1004,6 +1000,14 @@ 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,