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<div class="moz-cite-prefix">On 7/11/2018 4:02 AM, Chandler Carruth
via llvm-dev wrote:<br>
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cite="mid:CAGCO0Kjst2Ope31kQXV_k=Cqw0CbSfd4VXTvY=XWAmEFc22dmg@mail.gmail.com">
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<div>Â </div>
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<div>I believe this approach has the advantage that:<br>
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<div>a) it makes it possible to only insert a mitigation
in specific locations if</div>
<div>Â Â the programmer is capable of inserting
intrinsics manually.</div>
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<div>This is definitely an area of great interest long-term.</div>
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Annotating specific loads that need to be protected seems like a
trap to me. See <a class="moz-txt-link-freetext" href="https://reviews.llvm.org/D41761#989799">https://reviews.llvm.org/D41761#989799</a> . (And
Bounds Check Bypass Store variants open up other possibilities, like
overwriting a spill slot.)<br>
<br>
Maybe we can come up with some workable approach to "whitelist"
certain pointers: a pointer could be marked
"speculatively-dereferenceable(N)" if it points to N bytes of
non-secret data. (We could apply this as load metadata, like
!dereferenceable, or it could be explicitly applied using an
intrinsic.)<br>
<br>
-Eli<br>
<pre class="moz-signature" cols="72">--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project</pre>
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