linux-kernel - [PATCH 6/7] lib/random32.c: Randomize timeout to the millisecond, not the second

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140607082859.10162.qmail@ns.horizon.com>
Date:	7 Jun 2014 04:28:59 -0400
From:	"George Spelvin" <linux@...izon.com>
To:	davem@...emloft.net, dborkman@...hat.com, linux@...izon.com,
	shemminger@...l.org, tytso@....edu
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH 6/7] lib/random32.c: Randomize timeout to the millisecond, not the second

If you're going to bother randomizing it, do it right.
And use prandom_u32_max(), which is designed for the job, rather
than "% 40".

Signed-off-by: George Spelvin <linux@...izon.com>
---
 lib/random32.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/random32.c b/lib/random32.c
index eee60100..9cc410dd 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -208,14 +208,14 @@ static DEFINE_TIMER(seed_timer, __prandom_timer, 0, 0);
 static void __prandom_timer(unsigned long dontcare)
 {
 	u32 entropy;
-	unsigned long expires;
+	unsigned int expires;
 
 	get_random_bytes(&entropy, sizeof(entropy));
 	prandom_seed(entropy);
 
 	/* reseed every ~60 seconds, in [40 .. 80) interval with slack */
-	expires = 40 + (prandom_u32() % 40);
-	seed_timer.expires = jiffies + msecs_to_jiffies(expires * MSEC_PER_SEC);
+	expires = 40000 + prandom_u32_max(40000);
+	seed_timer.expires = jiffies + msecs_to_jiffies(expires);
 
 	add_timer(&seed_timer);
 }
-- 
2.0.0

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