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    SubjectRe: RFC: disablenetwork facility. (v4)
    Quoting Bryan Donlan (bdonlan@gmail.com):
    > On Tue, Dec 29, 2009 at 10:11 AM, Serge E. Hallyn <serue@us.ibm.com> wrote:
    > > Eric, let me specifically point out a 'disable setuid-root'
    > > problem on linux: root still owns most of the system even when
    > > it's not privileged.  So does "disable setuid-root" mean
    > > we don't allow exec of setuid-root binaries at all, or that
    > > we don't setuid to root, or that we just don't raise privileges
    > > for setuid-root?
    >
    > I, for one, think it would be best to handle it exactly like the
    > nosuid mount option - that is, pretend the file doesn't have any
    > setuid bits set. There's no reason to deny execution; if the process
    > would otherwise be able to execute it, it can also copy the file to
    > make a non-suid version and execute that instead. And some programs
    > can operate with reduced function without setuid. For example, screen
    > comes to mind; it needs root to share screen sessions between multiple
    > users, but can operate for a single user just fine without root, and
    > indeed the latter is usually the default configuration.

    That's fine with me, seems safe for a fully unprivileged program to
    use, and would make sense to do through one of the securebits set
    with prctl(PR_SET_SECUREBITS).

    In addition, I assume we would also refuse to honor file capabilities?

    -serge
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