Re: disabling 'insecure' parts of gnuplot file

[Arun P. <ape...@lb...>]

Ethan Merritt wrote:
> On Tuesday 31 August 2004 12:47 pm, Edward Peschko wrote:
>>>[disabled pipes]
 >>not really true, IMO. In mediawiki we'd probably want to limit 
plotting to inline,
>>which I asked about the other time. IE: it would be up to the user to use programs
>>to create data, etc. which would then be uploaded to mediawiki.
> 
> ???
> What do you mean by "in line"?

I guess something like
plot "-"
followed by the data...

>>>[wrapper script issues]
> I don't think you would.  The wrapper script itself could save the
> output graph back to the user's own area.  Its flow would look like:
> 	stdin = open input
> 	stdout = open output
> 	drop privileges
> 	mkdir /tmp_<process_id>
> 	chroot /tmp_<process_id> gnuplot

this and a having the wiki (per php or similar) check the gnuplot input 
file for "!" "set output","print" and other commands which could be 
harmfull and not needed for just simple ploting etc. might be a good way 
to do it then...

perhaps you even want to be very restrictive anyway to get the same look 
for most of the graphs in the wiki and so the user would only need to 
supply the data and the plotstyle and then you would give gnuplot most 
of the input (e.g. use of grid yes/no, set terminal, etc) and
your plot command would always look like:

plot "-" $userplotstyle
$data

in that case you just have to scan those two variables for dangerous 
items or just allow for example numbers in $data and certain words in 
$userplotstyle

just my two cents

ARUN