On Tue, Feb 08, 2022 at 04:53:33PM +0100, Jason A. Donenfeld wrote: > Continuing the reasoning of "random: ensure early RDSEED goes through > mixer on init", we don't want RDRAND interacting with anything without > going through the mixer function, as a backdoored CPU could presumably > cancel out data during an xor, which it'd have a harder time doing when > being forced through a cryptographic hash function. There's actually no > need at all to be calling RDRAND in write_pool(), because before we > extract from the pool, we always do so with 32 bytes of RDSEED hashed in > at that stage. Xoring at this stage is needless and introduces a minor > liability. > > Cc: Theodore Ts'o <tytso@xxxxxxx> > Cc: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx> > --- > drivers/char/random.c | 14 ++------------ > 1 file changed, 2 insertions(+), 12 deletions(-) Looks good, Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx> - Eric
