Messages in this thread | | | From | Kyle Moffett <> | Subject | Re: NFS4 authentification / fsuid | Date | Thu, 6 Sep 2007 19:30:25 -0400 |
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On Sep 06, 2007, at 11:06:16, J. Bruce Fields wrote: > On Thu, Sep 06, 2007 at 01:44:05PM +0530, Satyam Sharma wrote: >> Like Trond said, there are very high number of ways in which >> privileged userspace can compromise a running kernel if it really >> wants to do that, root-is-God has always been *the* major problem >> with Unix :-) >> >> The only _real_ way a kernel can lock itself completely against >> malicious userspace involves trusted tamperproof hardware, > > The question of how to protect against someone with *physical* > access certainly is more difficult, but surely that's a separate > problem.
Actually, that's a fairly simple problem (barring disassembling the system and attaching a hardware debugger). You encrypt the root filesystem and require a password to boot (See: LUKS). Debian has built-in support for installing onto fs-on-LVM-on-crypt-on-RAID, and it works quite well on all the laptops I use regularly. It's not even much of a speed penalty; once you take the overhead of hitting a 5400RPM laptop drive you can chew thousands of cycles of CPU without anybody noticing (much). Then all you have to do is burn a copy of your /boot with bootloader onto some read-only media (like a finalized CDROM/DVDROM) and you're set to go.
Cheers, Kyle Moffett - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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