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    SubjectRe: unprivileged mounts git tree
    Quoting Miklos Szeredi (miklos@szeredi.hu):
    > On Wed, 27 Aug 2008, Serge E. Hallyn wrote:
    > > Quoting Miklos Szeredi (miklos@szeredi.hu):
    > > > Serge, thanks for spotting this: it looks indeed a nasty hole! I also
    > > > agree about the solution.
    > >
    > > Are you implementing it, or did you want me to?
    >
    > I'll implement it.

    Ok, thanks. I look forward to playing around with it when you publish
    the resulting git tree :)

    > > > But yeah, we should think this over very carefully. Especially
    > > > interaction with mount propagation, which has very complicated and
    > > > sometimes rather counter-intuitive semantics.
    > >
    > > I know we discussed before about whether a propagated mount from a
    > > non-user mount to a user mount should end up being owned by the user
    > > or not. I don't recall (and am not checking the code at the moment
    > > as your tree is sitting elsewhere) whether we mark the propagated
    > > tree with the right nosuid and nodev flags, or whether we call it
    > > a user mount or not.
    >
    > If the destination is a user mount, then
    >
    > - the propagated mount(s) will be owned by the same user as the destination
    > - the propagated mount(s) will inherit 'nosuid' from the destination
    >
    > I remember also thinking about 'nodev' and why it doesn't need similar
    > treatment to 'nosuid'. The reasoning was that 'nodev' is safe as long
    > as permissions are enforced, namespace shuffling cannot make it
    > insecure. Does that sound correct?

    Yes that sounds correct, thanks for the refresher.

    -serge


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