Merge branch 'CVE-2014-7970' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux

Pull pivot_root() fix from Andy Lutomirski.

Prevent a leak of unreachable mounts.

* 'CVE-2014-7970' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux:
  mnt: Prevent pivot_root from creating a loop in the mount tree

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 2651328d1790..fbba8b17330d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2915,6 +2915,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
         /* make sure we can reach put_old from new_root */
         if (!is_path_reachable(old_mnt, old.dentry, &new))
                 goto out4;
+        /* make certain new is below the root */
+        if (!is_path_reachable(new_mnt, new.dentry, &root))
+                goto out4;
         root_mp->m_count++; /* pin it so it won't go away */
         lock_mount_hash();
         detach_mnt(new_mnt, &parent_path);