Re: [NSE] Undeclared variable in dns.processResponse()

[Patrik Karlsson <patrik () cqure net>]

On 29 okt 2010, at 15.02, Ron wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Fri, 29 Oct 2010 07:05:39 +0200 Patrik Karlsson <patrik () cqure net> wrote:
> > On 29 okt 2010, at 04.24, Ron wrote:
> >
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > >
> > > Hey,
> > >
> > > While writing some sample code for the DNS library, I wrote the
> > > following code: local status, result =
> > > dns.query('www.obscuredomain.com', {norecurse=true})
> > >
> > > It generates the following error:
> > > ./nselib/strict.lua:65: variable 'host' is not declared
> > > stack traceback:
> > >       [C]: in function 'error'
> > >       ./nselib/strict.lua:69: in function <./nselib/strict.lua:60>
> > >       ./nselib/strict.lua:65: in function <./nselib/strict.lua:60>
> > >       ./nselib/dns.lua:198: in function <./nselib/dns.lua:175>
> > >
> > > The line number's going to be wrong because I'm modifying dns.lua
> > > right now, but this is the line:
> > >
> > >      -- only ask next server in authority, if 
> > >      -- we got an auth dns and
> > >      -- it isn't the one we just asked
> > >      if next_server and next_server ~= host and options.tries > 1
> > > then   -- <---------- THIS LINE options.host = next_server
> > >         options.tries = option.tries - 1
> > >         return query(dname, options)
> > >      end
> > >
> > > I don't know the code well enough to fix it myself with any
> > > confidence, but I'm guessing that 'host' simply needs to be changed
> > > to 'options.host'. 
> > >
> > > Can somebody more familiar with the code confirm?
> >
> > I introduced this bug when I factored out the code in order to better
> > be able to process multiple responses when doing multicast DNS.
> > Looking at the code in r20446 we have the following at the top of the
> > query function:
> >
> >   local dtype, host, port, tries = options.dtype, options.host,
> > options.port, options.tries
> >
> > So, as far as I see it, your change should be correct. I've did the
> > same change and commited it as r20831.
> Cool, thanks! 
>
> After doing the fix, I noticed another error - a couple variables were misspelled. After fixing that (r20843), a more 
> obscure error popped up that I haven't had any luck tracking down:
> NSE: test threw an error!
> [string "local connect, socket_lock = ...;..."]:4: bad argument #2 to 'connect' (string expected, got boolean)
> stack traceback:
>        [C]: in function 'connect'
>        [string "local connect, socket_lock = ...;..."]:4: in function 'connect'
>        ./nselib/dns.lua:53: in function 'sendPackets'
>        ./nselib/dns.lua:252: in function <./nselib/dns.lua:215>
>        (tail call): ?
>        (tail call): ?
>        (tail call): ?
>        (tail call): ?
>        ././test.nse:41: in function <././test.nse:15>
>        (tail call): ?
>
> Ron
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v2.0.16 (GNU/Linux)
>
> iEYEARECAAYFAkzKxeUACgkQ2t2zxlt4g/TUYQCfeWg5eEFaL3RgPalnmRFzBDjb
> pqcAoIUKX9MueHIM4PvM/H2UaDC/pNbv
> =5mI7
> -----END PGP SIGNATURE-----


I haven't seen that before. Could you share your test script that triggers the error?

//Patrik
--
Patrik Karlsson
http://www.cqure.net
http://www.twitter.com/nevdull77





_______________________________________________
Sent through the nmap-dev mailing list
http://cgi.insecure.org/mailman/listinfo/nmap-dev
Archived at http://seclists.org/nmap-dev/