1. Aug 06, 2018
  2. Aug 05, 2018
  3. Aug 04, 2018
    • Kees Cook's avatar
      jfs: Fix usercopy whitelist for inline inode data · 961b33c2
      Kees Cook authored
      
      
      Bart Massey reported what turned out to be a usercopy whitelist false
      positive in JFS when symlink contents exceeded 128 bytes. The inline
      inode data (i_inline) is actually designed to overflow into the "extended
      area" following it (i_inline_ea) when needed. So the whitelist needed to
      be expanded to include both i_inline and i_inline_ea (the whole size
      of which is calculated internally using IDATASIZE, 256, instead of
      sizeof(i_inline), 128).
      
      $ cd /mnt/jfs
      $ touch $(perl -e 'print "B" x 250')
      $ ln -s B* b
      $ ls -l >/dev/null
      
      [  249.436410] Bad or missing usercopy whitelist? Kernel memory exposure attempt detected from SLUB object 'jfs_ip' (offset 616, size 250)!
      
      Reported-by: default avatarBart Massey <bart.massey@gmail.com>
      Fixes: 8d2704d3
      
       ("jfs: Define usercopy region in jfs_ip slab cache")
      Cc: Dave Kleikamp <shaggy@kernel.org>
      Cc: jfs-discussion@lists.sourceforge.net
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      961b33c2