[PATCH] D20024: [ELF] - Protect first entries of got.plt with RelRo.

[Rafael Espíndola via llvm-commits]

Remind me again how the first entry works. From the ABI it looks like
.got has to have the first entry be the value of _DYNAMIC and the
dynamic linker can use that.

But, it looks like it is actually .got.plt that has that. Also, if the
dynamic linker can find the .got, it can find the .dynamic section,
no?

On 6 May 2016 at 13:09, George Rimar <grimar at accesssoftek.com> wrote:
> grimar created this revision.
> grimar added reviewers: ruiu, rafael.
> grimar added subscribers: grimar, llvm-commits.
> Herald added a subscriber: joker.eph.
>
> First entries of got.plt can be protected using RelRo technique,
> this patch implements this by shifting got.plt to the memory page,
> where relro is active.
>
> Both gold and bfd do that and it should be good for security.
>
> http://reviews.llvm.org/D20024
>
> Files:
>   ELF/OutputSections.h
>   ELF/Writer.cpp
>   test/ELF/aarch64-condb-reloc.s
>   test/ELF/aarch64-gnu-ifunc.s
>   test/ELF/aarch64-tstbr14-reloc.s
>   test/ELF/copy-rel-pie.s
>   test/ELF/dynamic-reloc-index.s
>   test/ELF/dynamic-reloc.s
>   test/ELF/gnu-ifunc-i386.s
>   test/ELF/gnu-ifunc.s
>   test/ELF/lto/undefined-puts.ll
>   test/ELF/mips-26.s
>   test/ELF/plt-aarch64.s
>   test/ELF/plt-i686.s
>   test/ELF/plt.s
>   test/ELF/relocation.s
>   test/ELF/relro.s
>   test/ELF/undef-with-plt-addr.s
>