Module Name: src
Committed By: riastradh
Date: Sat May 21 15:27:15 UTC 2016
Modified Files:
src/sys/kern: kern_rndq.c
Log Message:
Ask on-demand entropy sources to produce enough data to fill buffer.
Remainder of fix for PR kern/51135: if there is an entropy source
that can produce arbitrarily much data, as in rump, then nothing
should ever block indefinitely waiting for data.
To generate a diff of this commit:
cvs rdiff -u -r1.88 -r1.89 src/sys/kern/kern_rndq.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_rndq.c
diff -u src/sys/kern/kern_rndq.c:1.88 src/sys/kern/kern_rndq.c:1.89
--- src/sys/kern/kern_rndq.c:1.88 Mon Feb 29 01:57:30 2016
+++ src/sys/kern/kern_rndq.c Sat May 21 15:27:15 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_rndq.c,v 1.88 2016/02/29 01:57:30 riastradh Exp $ */
+/* $NetBSD: kern_rndq.c,v 1.89 2016/05/21 15:27:15 riastradh Exp $ */
/*-
* Copyright (c) 1997-2013 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.88 2016/02/29 01:57:30 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.89 2016/05/21 15:27:15 riastradh Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
@@ -258,6 +258,19 @@ rnd_getmore(size_t byteswanted)
{
krndsource_t *rs, *next;
+ /*
+ * Due to buffering in rnd_process_events, even if the entropy
+ * sources provide the requested number of bytes, users may not
+ * be woken because the data may be stuck in unfilled buffers.
+ * So ask for enough data to fill all the buffers.
+ *
+ * XXX Just get rid of this buffering and solve the
+ * /dev/random-as-side-channel-for-keystroke-timings a
+ * different way.
+ */
+ byteswanted = MAX(byteswanted,
+ MAX(RND_POOLBITS/NBBY, sizeof(uint32_t)*RND_SAMPLE_COUNT));
+
mutex_spin_enter(&rnd_global.lock);
LIST_FOREACH_SAFE(rs, &rnd_global.sources, list, next) {
/* Skip if the source is disabled. */
