diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2012-07-02 07:52:16 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-15 08:10:10 -0700 |
| commit | 0110bbfbc8ed1b5240a51e8c767c44a856424139 (patch) | |
| tree | f3ac162b4925c7e841413db59dabff88324640ae /drivers/mfd | |
| parent | cabf5b0af54cec6a2f9ce674cbc96fc8aa2fc468 (diff) | |
random: make 'add_interrupt_randomness()' do something sane
commit 775f4b297b780601e61787b766f306ed3e1d23eb upstream.
We've been moving away from add_interrupt_randomness() for various
reasons: it's too expensive to do on every interrupt, and flooding the
CPU with interrupts could theoretically cause bogus floods of entropy
from a somewhat externally controllable source.
This solves both problems by limiting the actual randomness addition
to just once a second or after 64 interrupts, whicever comes first.
During that time, the interrupt cycle data is buffered up in a per-cpu
pool. Also, we make sure the the nonblocking pool used by urandom is
initialized before we start feeding the normal input pool. This
assures that /dev/urandom is returning unpredictable data as soon as
possible.
(Based on an original patch by Linus, but significantly modified by
tytso.)
Tested-by: Eric Wustrow <ewust@umich.edu>
Reported-by: Eric Wustrow <ewust@umich.edu>
Reported-by: Nadia Heninger <nadiah@cs.ucsd.edu>
Reported-by: Zakir Durumeric <zakir@umich.edu>
Reported-by: J. Alex Halderman <jhalderm@umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/mfd')
| -rw-r--r-- | drivers/mfd/ab3100-core.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c index 1efad20fb17..9522d6bda4f 100644 --- a/drivers/mfd/ab3100-core.c +++ b/drivers/mfd/ab3100-core.c @@ -409,8 +409,6 @@ static irqreturn_t ab3100_irq_handler(int irq, void *data) u32 fatevent; int err; - add_interrupt_randomness(irq); - err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1, event_regs, 3); if (err) |