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Re: Read-only data in ELF libraries may be remapped writable at runtime (upcoming NDSS'17 paper)
On December 23, 2016 7:18:29 PM GMT+01:00, Florian Weimer <email@example.com> wrote:
>On 12/23/2016 07:04 PM, Mathias Payer wrote:
>> At the linker level you likely don't know if the referenced symbol is
>> or not (as it could come from any object) -- only the runtime loader
>> this knowledge and at that time it is too late as PIE uses relative
>> addressing inside the object.
>The static linker necessarily sees a definition, otherwise it cannot
>produce a copy relocation because copy relocations must refer to
>of known size.
Agreed. The static linker knows about the symbol and size but not the permission. That information is discarded after compilation.
Sent from the road.