Re: `--script dns-client-subnet-scan' failed to work.

[Gyanendra Mishra <anomaly.the () gmail com>]

Hi,

As far as I see it the problem exists because line 327 returns nil instead
of an empty list and ipairs cant work on nil values. Simply adding {} after
return in line 327 works. Lets see what the main developers have to say.


> --- dns-client-subnet-scan.nse 2015-03-18 15:16:53.067082418 +0530
> +++ dns-client-subnet-scan-new.nse 2015-03-18 15:17:14.835081502 +0530
> @@ -324,7 +324,7 @@
> local subnet = { family = nmap.address_family(), address = address, mask =
> mask }
> local status, resp = dns.query(domain, {host = nameserver,
> port=port.number, protocol=port.protocol, retAll=true, subnet=subnet})
> if ( not(status) ) then
> - return
> + return {}
> end
> if ( "table" ~= type(resp) ) then resp = { resp } end
> return resp


Gyanendra


On Wed, Mar 18, 2015 at 8:42 AM, s0h3ck <s0h3ck () gmail com> wrote:

> Hi Hongyi (and mentors),
>
> Good news, I can reproduce the bug. This means whether we are doing a wrong
> manipulation or the script is not properly programmed. If a mentor think
> it's a bug, I would like to give a patch to prove myself as a valuable
> programmer to Nmap team. I did some test with the -d (debug) option to see
> what is going behind and I think I know what's wrong. The two critics parts
> that I doubt is where are gather the local value such as argDomain below
> the
> line where are described the categories. The second part I will look is the
> Generic for inside the action "function". I become more familiar with Lua,
> but I'm an expert, so I would like to dig something :)
>
> Thanks. I appreciate your feedback.
> s0h3ck.
>
> -----------------------------------------------------
> With -d (debug) option
>
> NSE: Script scanning 27.35.62.19.
> NSE: Starting runlevel 1 (of 1) scan.
> NSE: Starting dns-client-subnet-scan against 27.35.62.19:53.
> Initiating NSE at 23:06
> NSE: dns.query() got zero responses attempting to resolve query:
> www.google.com
> NSE: dns-client-subnet-scan against 27.35.62.19:53 threw an error!
> /usr/bin/../share/nmap/scripts/dns-client-subnet-scan.nse:356: bad argument
> #1 to 'ipairs' (table expected, got no value)
> stack traceback:
>         [C]: in function 'ipairs'
>         /usr/bin/../share/nmap/scripts/dns-client-subnet-scan.nse:356: in
> function
> </usr/bin/../share/nmap/scripts/dns-client-subnet-scan.nse:335>
>         (...tail calls...)
>
> Completed NSE at 23:06, 8.00s elapsed
> Nmap scan report for 27.35.62.19
> Host is up, received echo-reply (0.25s latency).
> Scanned at 2015-03-17 23:06:15 EDT for 11s
> PORT   STATE         SERVICE REASON
> 53/udp open|filtered domain  no-response
> Final times for host: srtt: 252274 rttvar: 252274  to: 1261370
>
>
>
>
> --
> View this message in context:
> http://nmap-dev.996309.n3.nabble.com/script-dns-client-subnet-scan-failed-to-work-tp25994p26000.html
> Sent from the Nmap - Dev mailing list archive at Nabble.com.
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-- 
Gyanendra Mishra
CS Sophomore
BITS PILANI, Pilani Campus
email-anomaly.the () gmail com

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