tree 405d95ae4a6c1caae2692f30f423288ee2844664
parent 6bc282bedfc988db493ee69232ecb35fc0f91226
author Jason A. Donenfeld <Jason@zx2c4.com> 1644320668 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1656150307 +0200

random: ensure early RDSEED goes through mixer on init

commit a02cf3d0dd77244fd5333ac48d78871de459ae6d upstream.

Continuing the reasoning of "random: use RDSEED instead of RDRAND in
entropy extraction" from this series, at init time we also don't want to
be xoring RDSEED directly into the crng. Instead it's safer to put it
into our entropy collector and then re-extract it, so that it goes
through a hash function with preimage resistance. As a matter of hygiene,
we also order these now so that the RDSEED byte are hashed in first,
followed by the bytes that are likely more predictable (e.g. utsname()).

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>