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    SubjectRe: [patch 1/2] [RFC] Simple tamper-proof device filesystem.

    On Sun, December 16, 2007 13:03, Tetsuo Handa wrote:
    > Hello.
    > David Newall wrote:
    >> > You won't be able to login to the system because /sbin/mingetty
    >> > fails to "chown/chmod" /dev/tty* if /dev is mounted for read-only mode.
    >> Good point. So, if only root can modify files in /dev, what's the
    >> problem you're fixing? (I'm sure you tried to explain this in your
    >> original post, but your reasons weren't clear to me.)
    > In 2003, I was trying to make / partition read-only to avoid tampering system
    > files.
    > Use of policy based mandatory access control (such as SELinux) is
    > one of ways to avoid tampering, but management of policy was a daunting task.
    > So, I tried to store / partition in a read-only medium so that
    > the system is free from tampering system files.
    > When I attended at Security Stadium 2003 as a defense side,
    > I was using devfs for /dev directory. The files in /dev directory
    > were deleted by attckers and the administrator was unable to login.
    > So I developed this filesystem so that attackers who got root privilege
    > can't tamper files in /dev directory.

    What prevents them from mounting tmpfs on top of /dev, bypassing your fs?

    Also, if they have root there are plenty of ways to prevent an administrator
    from logging in, e.g. using iptables or changing the password.



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