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    SubjectRe: LSM conversion to static interface

    On Oct 23 2007 10:20, Serge E. Hallyn wrote:
    >
    >Once the per-process capability bounding set is accepted
    >(http://lkml.org/lkml/2007/10/3/315) you will be able to do something
    >like:
    >
    > 1. Create user 'jdoe' with uid 0

    UID 0 is _not_ acceptable for me.

    > 2. write a pam module which, when jdoe logs in, takes
    > CAP_NET_ADMIN out of his capability bounding set
    > 3. Now jdoe can log in with the kind of capabilities subset
    > you describe.

    It is not that easy.
    CAP_DAC_OVERRIDE is given to the subadmin to bypass the pre-security
    checks in kernel code, and then the detailed implementation of
    limitation is done inside multiadm.
    This is not just raising or lowering capabilities.

    >It's not a perfect solution, since it doesn't allow jdoe any way at all
    >to directly execute a file with more caps (setuid and file capabilities
    >are subject to the capbound). So there is certainly still a place for
    >multiadm.

    A normal user can execute suid binaries today, and so can s/he with mtadm.
    I do not see where that will change - it does not need any caps atm.
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