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    SubjectRe: suidpid( UID, credential? ) ? secure IPC?
    kwrohrer@enteract.com wrote:
    >
    > And lo, Jim Dennis saith unto me:
    > > I was wondering if there is any mechanism for having some
    > > process (a daemon or kernel module perhaps) "touch" a process
    > > and set its *real* UID to a different value.
    > Probably not.
    >
    > > Would it make sense to add a suidpid() call?
    > What happens if, after authentication, the process dies and another
    > process pops up with the same PID? Hard to do nowadays, but I don't
    > believe it's guaranteed impossible, especially given some way of
    > bogging the authenticator down at the right moment...

    I don´t see this problem when the kernel handles this problem:
    - program calls kernel seteuid_auth(authinfo)
    - kernel blocks program and passes authinfo to authenticator
    - authenticator verifies authinfo and passes back status
    - kernel changes euid (or responds with error) of program
    - kernel releases program.

    A process can´t be killed while it is blocked in the kernel.
    The kernel would need to check the authenticator and i.e. signal
    init if the authenticator dies.

    My $0.02.

    Jochen

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