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authorTheodore Ts'o <tytso@mit.edu>2013-11-03 00:15:05 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-11-03 18:18:47 -0500
commit40db23e5337d99fda05ee6cd18034b516f8f123d (patch)
tree3620424cec3d8df5ec5455335620e65b37a94909 /drivers/char
parentf80bbd8b92987f55f26691cd53785c4a54622eb0 (diff)
downloadlinux-40db23e5337d99fda05ee6cd18034b516f8f123d.tar.bz2
random: make add_timer_randomness() fill the nonblocking pool first
Change add_timer_randomness() so that it directs incoming entropy to the nonblocking pool first if it hasn't been fully initialized yet. This matches the strategy we use in add_interrupt_randomness(), which allows us to push the randomness where we need it the most during when the system is first booting up, so that get_random_bytes() and /dev/urandom become safe to use as soon as possible. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/random.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index f126bd2f69fe..62923138e77a 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -761,6 +761,7 @@ static struct timer_rand_state input_timer_state;
*/
static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
{
+ struct entropy_store *r;
struct {
long jiffies;
unsigned cycles;
@@ -773,7 +774,8 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
sample.jiffies = jiffies;
sample.cycles = random_get_entropy();
sample.num = num;
- mix_pool_bytes(&input_pool, &sample, sizeof(sample), NULL);
+ r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool;
+ mix_pool_bytes(r, &sample, sizeof(sample), NULL);
/*
* Calculate number of bits of randomness we probably added.
@@ -807,8 +809,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
* Round down by 1 bit on general principles,
* and limit entropy entimate to 12 bits.
*/
- credit_entropy_bits(&input_pool,
- min_t(int, fls(delta>>1), 11));
+ credit_entropy_bits(r, min_t(int, fls(delta>>1), 11));
}
preempt_enable();
}