[PATCH 0/4] explicit_bzero, this time for sure

Florian Weimer fweimer@redhat.com
Thu Aug 18 18:18:00 GMT 2016


On 08/18/2016 06:29 PM, Zack Weinberg wrote:
> On 08/17/2016 06:20 PM, Manuel López-Ibáñez wrote:
>> On 17/08/16 18:19, Zack Weinberg wrote:
>>> anything I would like to hear about it.  If anyone has any ideas for
>>> how to write a test that will start failing if a compiler ever learns
>>> to "see through" __glibc_read_memory, I would like to hear about that,
>>> too.  (I can imagine a way to do it with gcc's scan-assembler tests,
>>> but we don't have those here.)
>>
>> Perhaps? https://plus.google.com/+MatthewDempsky/posts/KQHFBouxurX
>
> Ingenious!  Done - patch 5/4 attached to this message, and also included
> in zack/explicit-bzero.  I would fold this into patch 2 for landing, but
> it may be easier to review this way.

GCC scans the generated assembly for such things.  It seems more 
reliable, particularly if we retain the explicit_bzero symbol.

> (What is the preferred way to deal with user-namespace project branches
> that get rebased?  The server won't let me push -f; I can delete the
> branch and recreate it but that seems ... not great.)

Yes, we should stop rebasing only on master and release/* branches. 
I'll send a separate mail about that.

Thanks,
Florian



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