Subject: Re: kernel ip_randomid() and libc randomid(3) still "broken"
To: Jun-ichiro itojun Hagino <itojun@itojun.org>
From: Matt Thomas <matt@3am-software.com>
List: tech-net
Date: 11/26/2003 13:39:11
On Nov 26, 2003, at 1:12 PM, Jun-ichiro itojun Hagino wrote:
>>> ip_randomid() there's guaranteed recycle period, which is about
>>> 12000.
>>> yes, the likelihood of the problem like you stated will increase
>>> by factor of (64K/12K), but with that cost we can buy hard-to-guess
>>> fragment ID.
>>
>> You seem to take it as an article of faith that somewhat harder to
>> predict ip_ids is worth *all* the downsides it carries with it. I
>> haven't noticed anyone else here who shares that opinion.
>>
>> Instead, I see several different people articulating the same
>> fundamental issue, all saying that the alleged security from
>> randomized IP IDs just isnt worth it -- in some cases, saying that
>> even if the random-id algoithm cost no more than the prior linear
>> incrementing IDs, it *still* isn't worth it.
>>
>> Shouldn't that be telling you something?
>
> nope.
>
> anyways, i will remove the RANDOM_IP_ID #ifdef, as less #ifdef is
> always
> better, and we have sysctl for controlling it. the default value for
> the sysctl would still be debetable, but i leave it to 0, for now.
#ifdef's are not bad. It allows users to trim unneeded code from their
kernels. This is very important in embedded systems.
Put the ifdef's back, please.
--
Matt Thomas email: matt@3am-software.com
3am Software Foundry www: http://3am-software.com/bio/matt/
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