BACKPORT: random32: add periodic reseeding
Clean cherry pick of commmit 6d31920246a9fc80be4f16acd27c0bbe8d7b8494.
The current Tausworthe PRNG is never reseeded with truly random data after
the first attempt in late_initcall. As this PRNG is used for some critical
random data as e.g. UDP port randomization we should try better and reseed
the PRNG once in a while with truly random data from get_random_bytes().
When we reseed with prandom_seed we now make also sure to throw the first
output away. This suffices the reseeding procedure.
The delay calculation is based on a proposal from Eric Dumazet.
Joint work with Daniel Borkmann.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bug: http://b/29621447
Change-Id: I990d00f4a29a56a22357cec1c17477c4721054ae
(cherry picked from commit 6d31920246a9fc80be4f16acd27c0bbe8d7b8494)
Signed-off-by: Kevin F. Haggerty <haggertk@lineageos.org>
1 file changed