netdev - [PATCH] Re: iproute2 / tbf with large burst seems broken again

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]

Date:	Wed, 26 Aug 2009 23:59:56 +0200
From:	Jarek Poplawski <jarkao2@...il.com>
To:	Denys Fedoryschenko <denys@...p.net.lb>
Cc:	netdev@...r.kernel.org
Subject: [PATCH] Re: iproute2 / tbf with large burst seems broken again

Denys Fedoryschenko wrote, On 08/25/2009 02:18 PM:
...
> Just maybe good idea in next kernels to document this or handle overflow, that 
> it will give warning in kernel. Otherwise user will have non-functional qdisc 
> that will not pass traffic.

OK, if this patch works for you send your Tested-by, please.

Thanks,
Jarek P.
---------------->
pkt_sched: Warn on tokens overflow in tbf_dequeue

After recent change of scheduling resolution some "extreme" configs
can cause token overflows with stalls. This patch warns when tokens
were negative before accounting for a packet length.

Reported-by: Denys Fedoryschenko <denys@...p.net.lb>
Signed-off-by: Jarek Poplawski <jarkao2@...il.com>
---

 net/sched/sch_tbf.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index e22dfe8..ef191c4 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -191,6 +191,12 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
 			return skb;
 		}
 
+		if (unlikely((long)(toks + L2T(q, len)) < 0 ||
+			     (long)(ptoks + L2T_P(q, len) < 0)))
+			if (net_ratelimit())
+				pr_warning("tbf: tokens overflow;"
+					   " fix limits.\n");
+
 		qdisc_watchdog_schedule(&q->watchdog,
 					now + max_t(long, -toks, -ptoks));
 
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html