Re: PowerDNS Security Advisory 2014-02

[Peter van Dijk <peter.van.dijk () netherlabs nl>]

Hello,

On 09 Dec 2014, at 8:16 , Peter van Dijk <peter.van.dijk () netherlabs nl> wrote:

> Somebody asked me to (help him) check djbdns today, which we’ll do. Any other implementations you are interested in?

Vanilla djbdns 1.05 manages a counter called ‘loop’ (look for ‘z->loop’ in the code); if this counter hits 100, it 
simply aborts the current query. This is similar to the fixes now present in PowerDNS, BIND and Unbound.

Breakpoint 4, doit (z=0x611660 <u>, state=1) at query.c:452
452       if (++z->loop == 100) goto DIE;
1: z->loop = 99
(gdb) cont
Continuing.

It then logs 'drop 1 input/output error’ and aborts resolution of this query. Note that it actually drops the query, 
the client will eventually timeout; PowerDNS Recursor sends a SERVFAIL, and I presume so do BIND and Unbound.

Kind regards,
-- 
Peter van Dijk
Netherlabs Computer Consulting BV - http://www.netherlabs.nl/

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