path: root/drivers/char
diff options
authorHannes Frederic Sowa <hannes@stressinduktion.org>2013-11-11 12:20:34 +0100
committerDavid S. Miller <davem@davemloft.net>2013-11-11 14:32:14 -0500
commit4af712e8df998475736f3e2727701bd31e3751a9 (patch)
tree315b7092cf6ee0aeb3a180a09f8d628984cd9ddf /drivers/char
parent6d31920246a9fc80be4f16acd27c0bbe8d7b8494 (diff)
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 <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> Acked-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/char')
1 files changed, 4 insertions, 1 deletions
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,