netdev - Re: [net-next PATCH 2/3] net: fix enforcing of fragment queue hash list depth

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: <1366810523.26911.495.camel@localhost>
Date:	Wed, 24 Apr 2013 15:35:23 +0200
From:	Jesper Dangaard Brouer <brouer@...hat.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	"David S. Miller" <davem@...emloft.net>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>,
	netdev@...r.kernel.org
Subject: Re: [net-next PATCH 2/3] net: fix enforcing of fragment queue hash
 list depth

On Fri, 2013-04-19 at 07:49 -0700, Eric Dumazet wrote:
> On Fri, 2013-04-19 at 14:19 +0200, Jesper Dangaard Brouer wrote:
> 
> > When removing the LRU system (which is the real bottleneck, see perf
> > tests in cover mail), and doing direct hash cleaning we are trading-in
> > accuracy.
[...]
> > The reason I don't want a too big hash table is the following.
> > 
> > Worst case 1024 buckets * 130K bytes = 133 MBytes, which on smaller
> > embedded systems is a lot of kernel memory we are permitting a remote
> > host to "lock-down".
> 
> Thats pretty irrelevant, memory is limited by the total amount of memory
> used by fragments, not by hash table size.
>
> Its called /proc/sys/net/ipv4/ipfrag_high_thresh


I was talking about patch-03, where I do "direct hash cleaning", and
have moved the mem limit "ipfrag_high_thresh" into the hash cleaning
step.

It seems we are talking past each-other...

--Jesper


--
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