From: Stephen Hemminger <stephen@networkplumber.org>
To: Salam Noureddine <noureddine@aristanetworks.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
James Morris <jmorris@namei.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Patrick McHardy <kaber@trash.net>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
netdev@vger.kernel.org
Subject: Re: [PATCH 1/1] ipv4: arp: Always update neighbour address when a gratuitous arp is received
Date: Fri, 20 Dec 2013 14:06:17 -0800 [thread overview]
Message-ID: <20131220140617.09a672f7@nehalam.linuxnetplumber.net> (raw)
In-Reply-To: <1387565962-9357-1-git-send-email-noureddine@aristanetworks.com>
On Fri, 20 Dec 2013 10:59:22 -0800
Salam Noureddine <noureddine@aristanetworks.com> wrote:
> Gratuitous arp packets are useful in switchover scenarios to update
> client arp tables as quickly as possible. Currently, the mac address
> of a neighbour is only updated after a locktime period has elapsed
> since the last update. In most use cases such delays are unacceptable
> for network admins. Moreover, the "updated" field of the neighbour
> stucture doesn't record the last time the address of a neighbour
> changed but records any change that happens to the neighbour. This is
> clearly a bug since locktime uses that field as meaning "addr_updated".
> With this observation, I was able to perpetuate a stale address by
> sending a stream of gratuitous arp packets spaced less than locktime
> apart.
>
> Signed-off-by: Salam Noureddine <noureddine@aristanetworks.com>
Doesn't this make the system more vulnerable to ARP spoofing?
next prev parent reply other threads:[~2013-12-20 22:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-20 18:59 [PATCH 1/1] ipv4: arp: Always update neighbour address when a gratuitous arp is received Salam Noureddine
2013-12-20 22:06 ` Stephen Hemminger [this message]
2013-12-20 22:25 ` Salam Noureddine
2013-12-20 22:30 ` Hannes Frederic Sowa
2013-12-21 0:36 ` Hannes Frederic Sowa
-- strict thread matches above, loose matches on Subject: below --
2013-12-20 5:41 Salam Noureddine
2013-12-20 14:00 ` Hannes Frederic Sowa
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