[PATCH] Disallow copy relocation against protected data symbol

[H.J. Lu]

On Thu, Aug 24, 2017 at 11:22 PM, Alan Modra <amodra@gmail.com> wrote:
> On Thu, Aug 24, 2017 at 09:13:15AM -0700, H.J. Lu wrote:
>> property.  This patch adds a bit to elf_link_hash_entry and elf_obj_tdata
>
> Why is def_protected needed?  Surely it is wrong to record the
> visibility of a symbol that may not even be the final definition?
> Why not just use visibility directly?

ELF_ST_VISIBILITY is only merged with relocatable input.  We don't
mark an undefined symbol as protected just because the definition comes
from a protected symbol in a shared object.  A protected symbol is
meaningful only for a definition with dynamic relocation.

def_protected is updated every time when def_regular or def_dynamic
is set.  It tracks the visibility of the symbol definition, which can be
different from the visibility of the symbol reference.  It reflects the
visibility of the final definition.

-- 
H.J.