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Full Discussion: Sandboxing
Top Forums Programming Sandboxing Post 302965396 by jim mcnamara on Thursday 28th of January 2016 11:23:50 AM
Old 01-28-2016
The reason this is not feasible is that the "API" or syscall responsible for connecting to the internat is open(). I'm not sure that a restricted shell will help with this. I hope jgt will chime in on this....

tcp sockets are treated as files by the OS. Of course the drivers are totally different. The reason iptables "works" is because it intercepts traffic at a very low level. The -j DROP will just disconnect any tcp request, based on using the -A chain specification OPEN.
 
IPTABLES-XML(1) 						  iptables 1.4.21						   IPTABLES-XML(1)

NAME
iptables-xml -- Convert iptables-save format to XML SYNOPSIS
iptables-xml [-c] [-v] DESCRIPTION
iptables-xml is used to convert the output of iptables-save into an easily manipulatable XML format to STDOUT. Use I/O-redirection pro- vided by your shell to write to a file. -c, --combine combine consecutive rules with the same matches but different targets. iptables does not currently support more than one target per match, so this simulates that by collecting the targets from consecutive iptables rules into one action tag, but only when the rule matches are identical. Terminating actions like RETURN, DROP, ACCEPT and QUEUE are not combined with subsequent targets. -v, --verbose Output xml comments containing the iptables line from which the XML is derived iptables-xml does a mechanistic conversion to a very expressive xml format; the only semantic considerations are for -g and -j targets in order to discriminate between <call> <goto> and <nane-of-target> as it helps xml processing scripts if they can tell the difference between a target like SNAT and another chain. Some sample output is: <iptables-rules> <table name="mangle"> <chain name="PREROUTING" policy="ACCEPT" packet-count="63436" byte-count="7137573"> <rule> <conditions> <match> <p>tcp</p> </match> <tcp> <sport>8443</sport> </tcp> </conditions> <actions> <call> <check_ip/> </call> <ACCEPT/> </actions> </rule> </chain> </table> </iptables-rules> Conversion from XML to iptables-save format may be done using the iptables.xslt script and xsltproc, or a custom program using libxsltproc or similar; in this fashion: xsltproc iptables.xslt my-iptables.xml | iptables-restore BUGS
None known as of iptables-1.3.7 release AUTHOR
Sam Liddicott <azez@ufomechanic.net> SEE ALSO
iptables-save(8), iptables-restore(8), iptables(8) iptables 1.4.21 IPTABLES-XML(1)
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