[cfe-dev] Questions on Clang DataflowSanitizer Taint Propagation

[Peter Collingbourne via cfe-dev]

On Mon, Oct 10, 2016 at 2:12 AM, Jong-Ju Park via cfe-dev <
cfe-dev at lists.llvm.org> wrote:

> To whom it may concern:
>
> Greetings and happy Thanksgiving!
> I am using DataflowSanitizer to conduct software engineering-related
> research at Simon Fraser University, Canada.
>
> First off, why is it that for dfsan_create_label, the userdata is a
> pointer type,
> whereas for dfsan_get_label, the data is a long integer type? Not that I
> intend to
> confront or judge your wisdom in any way, but it seems more intuitive
> for the data type of dfsan_get_label and that in the dfsan_label_info
> structure to match.
>

The userdata stored in dfsan_label_info is unrelated to the value passed to
dfsan_get_label. Normally we would expect this value to be numeric, so the
function takes an integer as a parameter.

Also, after assigning a label to a byte, and copying the byte into another
> variable,
> I should get the label for the original byte if I try to fetch the labels
> on the said variable;
> however, no matter what I do, I get a (null) description and a (nil) data
> for the variable.
> The description and the data are just as expected when I use the original
> byte to
> fetch the label and the dfsan_label_info structure, though.
>

Can you please attach a small self contained example that demonstrates the
problem? Ideally something along the lines of the test cases in
compiler-rt/test/dfsan.

Peter

>
> My Clang version is 3.8, and I am using Lubutu 16.04.
>
> I have attached a PDF of some of the codes that I tried.
>
> DyTan has a dependency hell going on, not to mention being too tightly
> coupled with legacy technology (a very old version of Pin that has the
> files laid out in
> a very particular way) and TaintGrind is not quite what I am looking for,
> so I am really counting on getting DataFlowSanitizer to work as I want it
> to.
>
> Thank you for looking into this, and I would appreciate a reply as soon as
> possible.
>
>
> Sincerely,
>
> JongJu Park
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
>


-- 
-- 
Peter
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