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Subject[ 17/44] random: Use arch-specific RNG to initialize the entropy store
Date
From: Greg KH <gregkh@linuxfoundation.org>

3.0-stable review patch. If anyone has any objections, please let me know.

------------------
From: Theodore Ts'o <tytso@mit.edu>

commit 3e88bdff1c65145f7ba297ccec69c774afe4c785 upstream.

If there is an architecture-specific random number generator (such as
RDRAND for Intel architectures), use it to initialize /dev/random's
entropy stores. Even in the worst case, if RDRAND is something like
AES(NSA_KEY, counter++), it won't hurt, and it will definitely help
against any other adversaries.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Link: http://lkml.kernel.org/r/1324589281-31931-1-git-send-email-tytso@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/char/random.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -965,6 +965,7 @@ EXPORT_SYMBOL(get_random_bytes);
*/
static void init_std_data(struct entropy_store *r)
{
+ int i;
ktime_t now;
unsigned long flags;

@@ -974,6 +975,11 @@ static void init_std_data(struct entropy

now = ktime_get_real();
mix_pool_bytes(r, &now, sizeof(now));
+ for (i = r->poolinfo->poolwords; i; i--) {
+ if (!arch_get_random_long(&flags))
+ break;
+ mix_pool_bytes(r, &flags, sizeof(flags));
+ }
mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
}




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