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    SubjectRe: patch to make Linux capabilities into something useful (v 0.3.1)
    Hi!

    > > > How about another gid, then? Should we reset all caps on sgid exec?
    > >
    > > Yes. Any setuid/setgid exec is a security barrier, and weird (or new)
    > > semantics may not cross that barrier.
    >
    > Right, so what I was saying was: if you reset all regular caps on sgid
    > exec, anyone can trivially reset all regular caps by creating a sgid
    > program (users are always members of a great many groups so "finding
    > another gid to hijack" is trivial). So CAP_REG_SXID needs to be off
    > all the time, so we lose again.
    >
    > But I'll make this a securebit ("unsanitized sxid"), with the behavior
    > you advertise as default (0).

    I'm not sure if fundamental security semantics should be optional, but
    it is certainly better than before.

    > > > Ultimately a compromise is to be reached between security and
    > > > flexibility... The problem is, I don't know who should make the
    > > > decision.
    > >
    > > Go for security here. (Normally, consensus on the list is needed for
    > > merging the patch).
    >
    > I am now completely convinced the patch will never be merged. :-(
    > Linux will have useless caps forever...

    Well, merging the patches is not that hard.

    tytso actually shown a clever way: add per-filesystem 'default
    capability masks'. That should be fairly easy to merge, and
    automatically back-compatible.

    (And it would get tou semantics you wanted in inheritance area,
    right?)
    Pavel
    --
    Thanks for all the (sleeping) penguins.
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