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| author | Theodore Ts'o <tytso@mit.edu> | 2012-07-02 15:52:16 +0400 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2012-08-17 23:36:05 +0400 |
| commit | 17ef73f8c0be242d38efe9b28d9caaca9c3ef442 (patch) | |
| tree | 1a74e6fc35adb0a3ee19a21593eb5e2ce859d635 /include | |
| parent | a5c606bc8eef5c3153477f1eb0c6fbf54972e40a (diff) | |
| download | linux-17ef73f8c0be242d38efe9b28d9caaca9c3ef442.tar.xz | |
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>
[PG: minor adjustment required since .34 doesn't have f9e4989eb8
which renames "status" to "random" in kernel/irq/handle.c ]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/random.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/random.h b/include/linux/random.h index 0bf293697f09..8a8560257af5 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -48,7 +48,7 @@ extern void rand_initialize_irq(int irq); extern void add_input_randomness(unsigned int type, unsigned int code, unsigned int value); -extern void add_interrupt_randomness(int irq); +extern void add_interrupt_randomness(int irq, int irq_flags); extern void get_random_bytes(void *buf, int nbytes); void generate_random_uuid(unsigned char uuid_out[16]); |