[RFC] elf: Add elf checks for main executable

[H.J. Lu]

On Thu, Nov 18, 2021 at 12:01 PM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> >  On Thu, Nov 18, 2021 at 11:55 AM Adhemerval Zanella
> > <adhemerval.zanella@linaro.org> wrote:
> >>
> >> The ELF header integrity check is only done on open_verify(), i.e,
> >> for objects explicitly loaded.  For main executable (issued with
> >> execve() for the binary) only kernel checks are done, which does
> >> not check EI_ABIVERSION.
> >
> > I believe the EI_ABIVERSION check on the executable should be
> > done in kernel, not in glibc, so that static PIE can be checked easily.
>
> There is no need to check statically linked binaries.  The kernel does
> not do any relocation processing.  The link editor plus the rest of the
> toolchain can make sure t hat the built-in relocator can process the
> relocations in the program.

You are right.   But if we want to change ld.so on all glibc branches
to check EI_ABIVERSION, won't it be easier to implement something
like DT_REQUIRED, DT_MANDATORY, DT_CRITICAL?

-- 
H.J.