[v2.6.34-stable 148/165] random: Use arch-specific RNG to initialize the entropy store

[Paul Gortmaker]

From: Theodore Ts'o <tytso@xxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

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@xxxxxxx>
Link: http://lkml.kernel.org/r/1324589281-31931-1-git-send-email-tytso@xxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/char/random.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index ed86cae..4874f55 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -958,6 +958,7 @@ EXPORT_SYMBOL(get_random_bytes);
  */
 static void init_std_data(struct entropy_store *r)
 {
+	int i;
 	ktime_t now;
 	unsigned long flags;
 
@@ -967,6 +968,11 @@ 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())));
 }
 
-- 
1.7.12.rc2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/