[src/trunk]: src/sys/kern Fix hardware RNGs -- accept their entropy estimates...

[tls <tls%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/de6ccbbe9bff
branches:  trunk
changeset: 782303:de6ccbbe9bff
user:      tls <tls%NetBSD.org@localhost>
date:      Sat Oct 27 01:29:02 2012 +0000

description:
Fix hardware RNGs -- accept their entropy estimates *rather than* using
timestamps to estimate the entropy of their input.  I'd accidentally
made it so no entropy was ever counted from them at all.

diffstat:

 sys/kern/kern_rndq.c |  11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)

diffs (39 lines):

diff -r 6d7435e7533f -r de6ccbbe9bff sys/kern/kern_rndq.c
--- a/sys/kern/kern_rndq.c      Fri Oct 26 23:23:23 2012 +0000
+++ b/sys/kern/kern_rndq.c      Sat Oct 27 01:29:02 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_rndq.c,v 1.5 2012/09/05 18:57:34 tls Exp $        */
+/*     $NetBSD: kern_rndq.c,v 1.6 2012/10/27 01:29:02 tls Exp $        */
 
 /*-
  * Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.5 2012/09/05 18:57:34 tls Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.6 2012/10/27 01:29:02 tls Exp $");
 
 #include <sys/param.h>
 #include <sys/ioctl.h>
@@ -640,6 +640,11 @@
 rnd_add_data(krndsource_t *rs, const void *const data, uint32_t len,
             uint32_t entropy)
 {
+       /*
+        * This interface is meant for feeding data which is,
+        * itself, random.  Don't estimate entropy based on
+        * timestamp, just directly add the data.
+        */
        rnd_add_data_ts(rs, data, len, entropy, rnd_counter());
 }
 
@@ -835,8 +840,6 @@
                SIMPLEQ_REMOVE_HEAD(&dq_samples, next);
                source = sample->source;
                entropy = sample->entropy;
-               if (source->flags & RND_FLAG_NO_ESTIMATE)
-                       entropy = 0;
 
                /*
                 * Hardware generators are great but sometimes they