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    SubjectRe: kdbus_proc_permission (Re: [GIT PULL] kdbus updates for Greg)
    On Mon, Aug 31, 2015 at 9:22 AM, David Herrmann <dh.herrmann@gmail.com> wrote:
    > Hi
    >
    > On Mon, Aug 31, 2015 at 5:37 PM, Andy Lutomirski <luto@amacapital.net> wrote:
    >> On Mon, Aug 24, 2015 at 2:52 AM, David Herrmann <dh.herrmann@gmail.com> wrote:
    >>> On Mon, Aug 10, 2015 at 4:42 AM, Andy Lutomirski <luto@amacapital.net> wrote:
    >>>> I haven't checked the context in which it's used, but in order for
    >>>> kdbus_proc_permission to do what it claims to do, it appears to be
    >>>> missing calls to security_inode_permission and
    >>>> security_file_permission.
    >>>
    >>> Both are expected to be added by lsm patches (both hooks you mentioned
    >>> are empty if no lsm is selected).
    >>
    >> Will that mean that existing MAC policies stop being fully enforced
    >> (in effect) if kdbus is installed?
    >
    > It means kdbus messages carry information about the sender, which LSMs
    > might prevent you to read via /proc. Just like you can send dbus
    > messages to a peer, which LSM-enhanced dbus-daemon might not allow.

    It's a security-sensitive function that doesn't do what the name and
    description suggest. Whether that's an active problem or not is
    unknown, but it's certainly a maintainability problem.

    > If
    > you use LSMs, we clearly advise you to wait for kdbus to gain LSM
    > support. We explicitly support legacy dbus1-compat for exactly such
    > reasons.

    This is not an acceptable attitude for security.

    There are so many things wrong with your statement that I'll limit
    myself to one of them: Fedora 23/Rawhide, which is the *reference*
    platform, uses SELinux.

    --Andy

    >
    > Thanks
    > David



    --
    Andy Lutomirski
    AMA Capital Management, LLC


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