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From: David Miller <davem@davemloft.net>
To: kchen@synology.com
Cc: nikolay@cumulusnetworks.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] net: bridge: fix a bug on using a neighbour cache entry without checking its state
Date: Mon, 07 Jan 2019 09:10:31 -0800 (PST)	[thread overview]
Message-ID: <20190107.091031.100384065611982323.davem@davemloft.net> (raw)
In-Reply-To: <1546745293-5678-1-git-send-email-kchen@synology.com>

From: kchen <kchen@synology.com>
Date: Sun,  6 Jan 2019 11:28:13 +0800

> From: JianJhen Chen <kchen@synology.com>
> 
> When handling DNAT'ed packets on a bridge device, the neighbour cache entry
> from lookup was used without checking its state. It means that a cache entry
> in the NUD_STALE state will be used directly instead of entering the NUD_DELAY
> state to confirm the reachability of the neighbor.
> 
> This problem becomes worse after commit 2724680bceee ("neigh: Keep neighbour
> cache entries if number of them is small enough."), since all neighbour cache
> entries in the NUD_STALE state will be kept in the neighbour table as long as
> the number of cache entries does not exceed the value specified in gc_thresh1.
> 
> This commit validates the state of a neighbour cache entry before using
> the entry.
> 
> Signed-off-by: JianJhen Chen <kchen@synology.com>
> Reviewed-by: JinLin Chen <jlchen@synology.com>

Indeed, this looks correct.

Applied and queued up for -stable, thanks.

  reply	other threads:[~2019-01-07 17:10 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-06  3:28 kchen
2019-01-07 17:10 ` David Miller [this message]
2019-01-08  6:04   ` kchen

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