From: "Jason A. Donenfeld" Jason@zx2c4.com
commit cbe89e5a375a51bbb952929b93fa973416fea74e upstream.
It's too hard to keep the batches synchronized, and pointless anyway, since in !crng_ready(), we're updating the base_crng key really often, where batching only hurts. So instead, if the crng isn't ready, just call into get_random_bytes(). At this stage nothing is performance critical anyhow.
Cc: Theodore Ts'o tytso@mit.edu Reviewed-by: Dominik Brodowski linux@dominikbrodowski.net Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/random.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
--- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -467,10 +467,8 @@ static void crng_pre_init_inject(const v
if (account) { crng_init_cnt += min_t(size_t, len, CRNG_INIT_CNT_THRESH - crng_init_cnt); - if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) { - ++base_crng.generation; + if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) crng_init = 1; - } }
spin_unlock_irqrestore(&base_crng.lock, flags); @@ -626,6 +624,11 @@ u64 get_random_u64(void)
warn_unseeded_randomness(&previous);
+ if (!crng_ready()) { + _get_random_bytes(&ret, sizeof(ret)); + return ret; + } + local_lock_irqsave(&batched_entropy_u64.lock, flags); batch = raw_cpu_ptr(&batched_entropy_u64);
@@ -660,6 +663,11 @@ u32 get_random_u32(void)
warn_unseeded_randomness(&previous);
+ if (!crng_ready()) { + _get_random_bytes(&ret, sizeof(ret)); + return ret; + } + local_lock_irqsave(&batched_entropy_u32.lock, flags); batch = raw_cpu_ptr(&batched_entropy_u32);