From 4af712e8df998475736f3e2727701bd31e3751a9 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Mon, 11 Nov 2013 12:20:34 +0100 Subject: random32: add prandom_reseed_late() and call when nonblocking pool becomes initialized The Tausworthe PRNG is initialized at late_initcall time. At that time the entropy pool serving get_random_bytes is not filled sufficiently. This patch adds an additional reseeding step as soon as the nonblocking pool gets marked as initialized. On some machines it might be possible that late_initcall gets called after the pool has been initialized. In this situation we won't reseed again. (A call to prandom_seed_late blocks later invocations of early reseed attempts.) Joint work with Daniel Borkmann. Cc: Eric Dumazet Cc: Theodore Ts'o Signed-off-by: Hannes Frederic Sowa Signed-off-by: Daniel Borkmann Acked-by: "Theodore Ts'o" Signed-off-by: David S. Miller --- drivers/char/random.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/char/random.c b/drivers/char/random.c index 7a744d391756..4fe5609eeb72 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -603,8 +603,11 @@ retry: if (!r->initialized && nbits > 0) { r->entropy_total += nbits; - if (r->entropy_total > 128) + if (r->entropy_total > 128) { r->initialized = 1; + if (r == &nonblocking_pool) + prandom_reseed_late(); + } } trace_credit_entropy_bits(r->name, nbits, entropy_count, -- cgit v1.2.3