random: Use arch-specific RNG to initialize the entropy store

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>
This commit is contained in:
Theodore Ts'o 2011-12-22 16:28:01 -05:00 committed by H. Peter Anvin
parent cf833d0b99
commit 3e88bdff1c

View file

@ -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_store *r)
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())));
}