tree 5f506f0bd86918f14291bce8d6b17ee9401c0d7a
parent 2e2389a07923a888d6e22337391b08092f213416
author Theodore Ts'o <tytso@mit.edu> 1523467672 -0400
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1524555256 +0200

random: fix crng_ready() test

commit 43838a23a05fbd13e47d750d3dfd77001536dd33 upstream.

The crng_init variable has three states:

0: The CRNG is not initialized at all
1: The CRNG has a small amount of entropy, hopefully good enough for
   early-boot, non-cryptographical use cases
2: The CRNG is fully initialized and we are sure it is safe for
   cryptographic use cases.

The crng_ready() function should only return true once we are in the
last state.  This addresses CVE-2018-1108.

Reported-by: Jann Horn <jannh@google.com>
Fixes: e192be9d9a30 ("random: replace non-blocking pool...")
Cc: stable@kernel.org # 4.8+
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>