[syslinux] problem with PXElinux and security of local LAN - readonly double boot idea

Jason Keltz jas at cs.yorku.ca
Wed Dec 21 06:14:17 PST 2005

H. Peter Anvin wrote:
> Jason Keltz wrote:
>> H. Peter Anvin wrote:
>> Is there absolutely no way through comboot to query the DHCP server 
>> (or some other server like a web server) for a simple value through 
>> sys/extlinux is there?  This would just be very ideal.
> Sure, you can talk directly to the PXE stack, and send and receive UDP 
> traffic just fine.  You can also examine the DHCP packet.
> However, you have to make sure the enire path up to that point is 
> enforced, or they can just boot something else.

Is there any possible way you could give me much more detail on doing 
this?    How difficult is this task?  I would like to do something like 
boot a local copy of extlinux that runs a modified menu.c32 that gets an 
ip via DHCP, polls the DHCP server for an option, and based on the value 
of that option, I would boot.  I basically understand the code for 
menu.c32, and chain.c32, but I don't know how to handle the bios/dhcp stuff.


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