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    SubjectRe: Misc Fixes
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    >Tried getting this patch through during 1.3; Linus rejected it as making
    >it too easy for module to circumvent securelevel. The fix he wanted was
    >write a functional interfaces so that it would be possible for ext2 to
    >obtain the current securelevel settings, without being able to set it.

    Unless I'm gravely mistaken about the nature of Linux modules, any
    loaded module can *actually* modify securelevel -- or indeed do
    anything that the current securelevel would normally prohibit --
    regardless of this patch. The only difference is that without this
    patch (a) a lot of things are not easily modularised and (b) it's
    non-trivial to write a module to maliciously change the securelevel
    (though still easy to do other nasty things).

    A function such as you describe will effectively give away the address
    of securelevel to malicious code (it knows where the function is and
    doesn't need to do as much as a disassembly), but will still hinder
    legitimate code. The obvious solution is to disallow loading/unloading
    of modules at a sufficiently high securelevel.

    -zefram


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