Messages in this thread |  | | From | Systemkennung Linux <> | Subject | Re: boot parameters, init= and security issues | Date | Wed, 5 Jun 1996 23:54:16 +0200 (MET DST) |
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Hi,
> >> Generally, though I am in favor of your proposal. Providing as many > >> boot-time security measures as possible sounds like a *very* good idea > >> --- but maybe I am just a little bit paranoid :-)
this reminds me of root NFS which tries to fallback to a floppy boot when it doesn't get a RARP/BOOTP answer after a certain time. I think this feature is a bad idea in terms of security:
- let a diskless machine boot its kernel - unplug the network cable before the kernel tries to get RARP/BOOTP answers - wait the the kernel gives up waiting for a RARP/BOOTP answer - insert your favourite bootdisk
You may say given physical access to a machine this class of attacks is always easy. Well, you're right. It's just that the NFS root stuff just makes it *too* easy. There is a big difference between just removing and reattaching a network cable (no tools required) and other, more conspicuous, manipulations.
Aside of this this fallback action when no RARP/BOOTP answer is received is in my experience never a helpful action; in case of a large network like my university's it's even the wrong thing after a complete power failure. (The right thing would be to wait for the servers coming back online. Given the problems with our larger servers this might mean waiting for hours.)
Ralf
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