Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull namespace fixes from Eric Biederman:
 "I believe all of these are simple obviously correct bug fixes. These
  fall into two groups:

   - Fixing the implementation of MNT_LOCKED which prevents lesser
     privileged users from seeing unders mounts created by more
     privileged users.

   - Fixing the extended uid and group mapping in user namespaces.

  As well as ensuring the code looks correct I have spot tested these
  changes as well and in my testing the fixes are working"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  mount: Prevent MNT_DETACH from disconnecting locked mounts
  mount: Don't allow copying MNT_UNBINDABLE|MNT_LOCKED mounts
  mount: Retest MNT_LOCKED in do_umount
  userns: also map extents in the reverse map to kernel IDs

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,