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    SubjectRe: [linux-fbdev] fbdev 2.4.0 cleanups

    On Wed, 15 Mar 2000, Russell King wrote:

    > James A Simmons writes:
    > > > But anyway, i don't agree with you, there is no reason that a lots of people
    > > > can open /dev/fb in read only mode, sure if some guys want to write to it at
    > > > the same time, it could cause problems, ...
    > >
    > > Security :) One of the goals is to allow anyone to run a app on /dev/fb.
    > > No more root.
    >
    > Erm, this is probably a silly question, especially as I haven't been following
    > this thread in depth.
    >
    > If you're concerned about security, then you don't really want anyone to be
    > able to open /dev/fb and read what you've got on your console. Think about
    > it - allowing anyone to open /dev/fb means that you might as well broadcast
    > the picture that is on your monitor to everyone who has access to your
    > machine.

    Yeah. Their are other issues I pointed out as well in my other postings.

    > I think think what you really want is to allow the user logged into the
    > console to be able to read/write the framebuffer, in much the same way that
    > /dev/console, /dev/dsp and friends are handled in a RedHat system - the
    > ownership of these "console" based devices is changed when a user logs in
    > at the console.

    Right. I going to have /dev/fb do this in the future. LIke what /dev/tty
    does.

    > Alternatively, the only other solution is to keep /dev/fb as "root only" and
    > have a suid program (tsk tsk) which drops it's privs directly after opening
    > /dev/fb. This allows "root" to control who can access /dev/fb.

    Yuk :(

    > Both of the above methods have their drawbacks in that neither of them can
    > be 100% secure when you may have multiple users logging in on the VCs, but
    > then that in itself is inherently insecure way of operating. ;)

    Well I have the vision in mind of when you open /dev/fb you switch to
    graphics mode (KD_GRAPHICS). No worries about VC in this case.

    "Look its a text editor, no its a OS, no its Emacs"
    James Simmons (o_
    fbdev/gfx developer (o_ (o_ //\
    http://www.linux-fbdev.org (/)_ (/)_ V_/_
    http://linuxgfx.sourceforge.net


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