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    SubjectRe: [PATCH] Capabilities, this time in elf section
    You need capabilities directly tied to the UID or you cannot
    securely eliminate root from the system. Whether program
    capabilities (which HAVE to be a subset of the capabilities
    of the owner) exist in the executable or the filesystem does
    not change this. One of the capabilities in question is the
    ability to override UID/permission protections on files.

    The possibility of creating a binary that
    posseses a capability that the owner does not
    is one definition of a security hole.

    Any given user is going to have a set of "standard capabilities".

    - create and modify files owned by the user in directories owned by
    the user.
    - run binaries that the user/group permissions allow them to run.

    An ordinary user is _NOT_ going to be able to set any capabilities
    on binaries they create other than those. However, they _may_ create
    a binary that has one or both of those capabilities turned off.

    A restricted user may have one or both of those capabilities turned off.

    A power/admin user may have additional capabilities, for example:

    - chown a file not owned by themselves
    - run a file that they do not have explicit permission to run,
    - perform other file operations where there is not explicit permission,
    - open a TCP socket below 1024,
    - assign another user the ability to use capabilities that the
    assigning user has permission for,
    - mount/unmount filesystems

    And others.

    Many (all?) of these capabilities are currently part of "root", and
    are only usable by root or SUID-root programs. For capabilities
    to work properly they still need to be tied directly to a user or
    you still need root to own and control all binaries that have capabilities
    beyond what an ordinary user may do.

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      Last update: 2005-03-22 13:51    [W:0.049 / U:1.776 seconds]
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