From: "Russ Cox" <rsc@swtch.com>
To: 9fans@9fans.net
Subject: Re: [9fans] dns exploits (self-promotion remix)
Date: Sun, 27 Jul 2008 12:19:42 -0400 [thread overview]
Message-ID: <20080727161735.B8D881E8C1C@holo.morphisms.net> (raw)
In-Reply-To: <ce3cd2eb74d8211244db56f5ab952f9d@quanstro.net>
>> those things combined mean that you get 15 bits of randomness
>> from query id and 15 from source port, giving 30 bits,
>> so ndb/dns is okay (for now).
>
> why only 15 in the query id? that's an artifact of rand()
> which returns 0 ≤ n ≤ 0x7fff. why not return numbers
> between 0 and 0xffff?
one might change rand or dns to get 16 bits, and that'd be fine.
i doubt many programs depend on rand not returning
numbers bigger than 32767. or you could use fastrand()&0xffff
in dns, which would be even better.
it's just one bit though. getting the other 15 was more important.
russ
next prev parent reply other threads:[~2008-07-27 16:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <261342.6156.qm@web27004.mail.ukl.yahoo.com>
2008-07-27 13:18 ` erik quanstrom
2008-07-27 15:56 ` Russ Cox
2008-07-27 15:57 ` erik quanstrom
2008-07-27 16:19 ` Russ Cox [this message]
2008-07-27 22:20 ` don bailey
2008-07-28 1:16 ` erik quanstrom
2008-07-28 2:53 ` a
2008-07-28 2:57 ` don bailey
2008-07-28 3:48 ` erik quanstrom
2008-07-28 20:53 ` Wes Kussmaul
2008-07-27 22:22 ` don bailey
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