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    SubjectRe: NFS4 authentification / fsuid


    On Thu, 6 Sep 2007, Kyle Moffett wrote:
    >
    > On Sep 06, 2007, at 19:35:14, Trond Myklebust wrote:
    > >
    > > On Thu, 2007-09-06 at 19:30 -0400, Kyle Moffett wrote:
    > > >
    > > > On Sep 06, 2007, at 11:06:16, J. Bruce Fields wrote:
    > > > > 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.
    > >
    > > Disconnect battery, and watch boot password go 'poof!'.
    >
    > Umm, I did say "encrypt the root filesystem", didn't I? Booting my laptops
    ^^^^^^^

    The whole *point* here is to secure against physical access -- then how
    can you assume "barring disassembling the system"? If you're not
    considering attacks such as those, then how _are_ you solving the
    physical access problem in the first place? :-)


    > this way follows this procedure:
    > 1) Enter BIOS boot menu
    > 2) Insert /boot CDROM
    > 3) Select the "CDROM" entry
    > 4) Wait for kernel to start and run through initramfs
    > 5) Type password into the initramfs prompt so that it can DECRYPT THE ROOT
    > FILESYSTEM
    > 6) Continue to boot the system.
    >
    > Under this setup, tinkering with my BIOS does virtually nothing; the only
    > avenues of attack are strictly of the "Install a hardware keylogger" variety.

    Doesn't flashing/replacing your BIOS firmware/chip count as tinkering?
    Then I don't really need a "hardware keylogger", do I ...
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