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    SubjectRe: [PATCH] net: sched: Fix memory exposure from short TCA_U32_SEL
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    On 2018-08-26 6:57 p.m., Al Viro wrote:
    > On Sun, Aug 26, 2018 at 06:32:37PM +0100, Al Viro wrote:
    >
    >> As far as I can tell, the solution is
    > [snip long and painful reasoning]
    >> pointers, and not in provably opaque fashion. Theoretically, the three tcf_...
    >> inlines above need another look; fortunately, they don't use ->next at all, not to
    >> mention not being used anywhere outside of net/sched/*.c
    >>
    >> The 80 lines above prove that we only need to grep net/sched/*.c for
    >> tcf_proto_ops method calls. And only because we don't have (thank $DEITY)
    >> anything that could deconstruct types - as soon as some bastard grows means
    >> to say "type of the second argument of the function pointed to by p", this
    >> kind of analysis, painful as it is, goes out of window. Even as it is,
    >> do you really like the idea of newbies trying to get through the exercises
    >> like the one above?
    >
    > BTW, would there be any problem if we took the definitions of tcf_proto and
    > tcf_proto_ops to e.g. net/sched/tcf_proto.h (along with the three inlines in
    > in pkt_cls.h), left forwards in sch_generic.h and added includes of "tcf_proto.h"
    > where needed in net/sched/*.c?
    >

    I cant think of any challenges. Cong/Jiri? Would it require development
    time classifiers/actions/qdiscs to sit in that directory (I suspect you
    dont want them in include/net).
    BTW, the idea of improving grep-ability of the code by prefixing the
    ops appropriately makes sense. i.e we should have ops->cls_init,
    ops->act_init etc.

    cheers,
    jamal

    > That would make tcf_proto/tcf_proto_ops opaque outside of net/sched, reducing
    > the exposure of internals. Something like a diff below (against net/master,
    > builds clean, ought to result in identical binary):
    >

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