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    SubjectRe: capabilities carried over execve()
    Hi!

    > I am attempting to write an init replacement that is capability-smart.
    > Though I'm pleased that prctl() lets me keep capabilities across a
    > setreuid(), maintaining caps over execve() seems impossible to do right.
    >
    > I currently see a few options:
    > - use the CLOEXEC-pipe hack that execcap uses (parent notices
    > when pipe closes then rushes to set caps on child before
    > child notices they're gone). This looks like a race to me.
    > - tweak linux/fs/exec.c (prepare_binprm) to pretend that all
    > files have cap_inheritable and cap_effective fully set.
    > This seems a more elegant solution, but requires a kernel
    > patch.
    > - exec the child in a stopped state, mess with caps, then
    > send it SIGCONT. AFAIK, there is no way to do
    > execve_and_stop.

    What about ptrace? It should be able to do this kind of stuff... but
    it is going to be messy.
    Pavel
    --
    I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care."
    Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org
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