From 08ef412169e7d1b670ae8d57bfd6adfdace32ca4 Mon Sep 17 00:00:00 2001
From: delphij <delphij@FreeBSD.org>
Date: Tue, 2 Apr 2013 23:41:20 +0000
Subject: Replace access to /dev/random with the kernel pseudo-random number
source sysctl(KERN_ARND) and remove the fallback code.
Obtained from: OpenBSD
Reviewed by: secteam
MFC after: 1 month
---
lib/libc/stdlib/random.c | 42 +++++++++++++++---------------------------
1 file changed, 15 insertions(+), 27 deletions(-)
(limited to 'lib/libc/stdlib/random.c')
diff --git a/lib/libc/stdlib/random.c b/lib/libc/stdlib/random.c
index a3c054e..4c88ecb 100644
--- a/lib/libc/stdlib/random.c
+++ b/lib/libc/stdlib/random.c
@@ -34,12 +34,11 @@ static char sccsid[] = "@(#)random.c 8.2 (Berkeley) 5/19/95";
__FBSDID("$FreeBSD$");
#include "namespace.h"
-#include <sys/time.h> /* for srandomdev() */
-#include <fcntl.h> /* for srandomdev() */
+#include <sys/param.h>
+#include <sys/sysctl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
-#include <unistd.h> /* for srandomdev() */
#include "un-namespace.h"
/*
@@ -284,39 +283,28 @@ srandom(unsigned long x)
* srandomdev:
*
* Many programs choose the seed value in a totally predictable manner.
- * This often causes problems. We seed the generator using the much more
- * secure random(4) interface. Note that this particular seeding
- * procedure can generate states which are impossible to reproduce by
- * calling srandom() with any value, since the succeeding terms in the
- * state buffer are no longer derived from the LC algorithm applied to
- * a fixed seed.
+ * This often causes problems. We seed the generator using pseudo-random
+ * data from the kernel.
+ *
+ * Note that this particular seeding procedure can generate states
+ * which are impossible to reproduce by calling srandom() with any
+ * value, since the succeeding terms in the state buffer are no longer
+ * derived from the LC algorithm applied to a fixed seed.
*/
void
srandomdev(void)
{
- int fd, done;
+ int mib[2];
size_t len;
if (rand_type == TYPE_0)
- len = sizeof state[0];
+ len = sizeof(state[0]);
else
- len = rand_deg * sizeof state[0];
-
- done = 0;
- fd = _open("/dev/random", O_RDONLY | O_CLOEXEC, 0);
- if (fd >= 0) {
- if (_read(fd, (void *) state, len) == (ssize_t) len)
- done = 1;
- _close(fd);
- }
+ len = rand_deg * sizeof(state[0]);
- if (!done) {
- struct timeval tv;
-
- gettimeofday(&tv, NULL);
- srandom((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec);
- return;
- }
+ mib[0] = CTL_KERN;
+ mib[1] = KERN_ARND;
+ sysctl(mib, 2, state, &len, NULL, 0);
if (rand_type != TYPE_0) {
fptr = &state[rand_sep];
--
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