Re: [PATCH 31/32] x86, pkeys: execute-only support

[Andy Lutomirski]

On Mon, Dec 14, 2015 at 3:44 PM, Dave Hansen <dave@xxxxxxxx> wrote:
> On 12/14/2015 03:39 PM, Andy Lutomirski wrote:
>>> > Nope.  My linker-fu is weak.
>>> >
>>> > Can we even depend on the linker by itself?  Even if the sections were
>>> > marked --x, we can't actually use them with those permissions unless we
>>> > have protection keys.
>>> >
>>> > Do we need some special tag on the section to tell the linker to map it
>>> > as --x under some conditions and r-x for others?
>>> >
>> Why?  Wouldn't --x just end up acting like r-x if PKRU is absent?
>
> An app doing --x would expect it to be unreadable.  I don't think we can
> just silently turn it in to r-x.

I don't see why.  After all, an app doing --x right now gets rx.  An
app doing r-- still gets r-x on some systems.

--Andy


-- 
Andy Lutomirski
AMA Capital Management, LLC
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/