netdev - Re: [PATCH for 2.6.33] conntrack: restrict runtime hashsize modifications

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: <4B6BFE29.1040204@trash.net>
Date:	Fri, 05 Feb 2010 12:16:57 +0100
From:	Patrick McHardy <kaber@...sh.net>
To:	Alexey Dobriyan <adobriyan@...il.com>
CC:	davem@...emloft.net, jonathan@...masters.org,
	eric.dumazet@...il.com, netdev@...r.kernel.org,
	netfilter-devel@...r.kernel.org
Subject: Re: [PATCH for 2.6.33] conntrack: restrict runtime hashsize modifications

Patrick McHardy wrote:
> Alexey Dobriyan wrote:
>>> How about this (so far untested) patch? The htable_size is moved into
>>> the per-namespace struct and initialized from the current (global)
>>> value of nf_conntrack_htable_size. Changes through sysfs are still
>>> permitted, but only affect the init namespace and newly created ones.
>> No matter what we do, it's a hack!
>>
>>> Additionally I removed reinitializing the hash random value when
>>> changing the hash size since that also requires to rehash in all
>>> namespaces.
>> I'm not fond of this, because we're not even closely going to allow changing
>> hashtable size per-netns. As such having actual per-netns hashtable size
>> just slows down everything.
> 
> Actually it doesn't seem like much more work to allow changing
> table size, the main problem is that sysfs module parameters
> don't seem to fit into the network namespace model at all.
> 
> Please be more specific about your suspected slowdowns.
> What's "everything"? What's different about the hashsize
> compared to the many members we already moved to per-netns
> structs?

OK testing looks fine, although I'm quite surprised that its actually
possible to change module parameters from within non-init namespaces.
How is this supposed to work at all? I don't see how sysfs could
possibly provide a network namespace context ...
--
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