[src/trunk]: src/sys/rump/dev/lib/librnd Add workaround for PR kern/51135

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

details:   https://anonhg.NetBSD.org/src/rev/020c72a59944
branches:  trunk
changeset: 345280:020c72a59944
user:      pooka <pooka%NetBSD.org@localhost>
date:      Mon May 16 16:31:07 2016 +0000

description:
Add workaround for PR kern/51135

If the rnd component is present, load extra initial entropy to avoid
/dev/random not being able to request it on demand.  The extra initial
entropy will allow a few instances of /dev/random, but will eventually
go into the failure mode described in the PR.

diffstat:

 sys/rump/dev/lib/librnd/rnd_component.c |  31 +++++++++++++++++++++++++++++--
 1 files changed, 29 insertions(+), 2 deletions(-)

diffs (49 lines):

diff -r 84c36ffe9f09 -r 020c72a59944 sys/rump/dev/lib/librnd/rnd_component.c
--- a/sys/rump/dev/lib/librnd/rnd_component.c   Mon May 16 15:09:29 2016 +0000
+++ b/sys/rump/dev/lib/librnd/rnd_component.c   Mon May 16 16:31:07 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rnd_component.c,v 1.3 2016/01/26 23:12:16 pooka Exp $  */
+/*     $NetBSD: rnd_component.c,v 1.4 2016/05/16 16:31:07 pooka Exp $  */
 
 /*
  * Copyright (c) 2009 Antti Kantee.  All Rights Reserved.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rnd_component.c,v 1.3 2016/01/26 23:12:16 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rnd_component.c,v 1.4 2016/05/16 16:31:07 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/conf.h>
@@ -63,3 +63,30 @@
        rump_pdev_add(rndattach, 4);
        rnd_init();
 }
+
+/*
+ * XXX: the following hack works around PR kern/51135 and should ASAP be
+ * nuked to and then from orbit.
+ */
+#define RNDPRELOAD 256
+#include <sys/rndio.h>
+RUMP_COMPONENT(RUMP_COMPONENT_POSTINIT)
+{
+       rnddata_t *rd;
+       size_t dsize, i;
+
+       CTASSERT(RNDPRELOAD <= sizeof(rd->data));
+
+       aprint_verbose("/dev/random: "
+           "loading initial entropy to workaround PR kern/51135\n");
+       rd = kmem_alloc(sizeof(*rd), KM_SLEEP);
+       for (i = 0; i < RNDPRELOAD; i += dsize) {
+               if (rumpuser_getrandom(rd->data,
+                   RNDPRELOAD-i, RUMPUSER_RANDOM_HARD, &dsize) != 0)
+                       panic("rumpuser_getrandom failed"); /* XXX */
+               rd->len = dsize;
+               rd->entropy = dsize*NBBY;
+               if (rnd_system_ioctl(NULL, RNDADDDATA, rd))
+                       panic("rnd_system_ioctl failed"); /* XXX */
+       }
+}