Re: [PATCH v3] elf: Stop with zero entry point value [BZ #28453]

[Florian Weimer <fweimer@redhat.com>]

* H. J. Lu:

> diff --git a/elf/rtld.c b/elf/rtld.c
> index 6ce1e07dc0..7d1801c51c 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -2491,6 +2491,12 @@ dl_main (const ElfW(Phdr) *phdr,
>        rtld_timer_accum (&relocate_time, start);
>      }
>  
> +  /* Stop if there is no associated entry point.  */
> +  if (rtld_is_main && main_map->l_entry == main_map->l_addr)
> +    _dl_fatal_printf("%s: cannot execute shared object '%s' directly "
> +		     "without entry point\n",
> +		     ld_so_name, rtld_progname);
> +
>    /* Relocation is complete.  Perform early libc initialization.  This
>       is the initial libc, even if audit modules have been loaded with
>       other libcs.  */

I think this is still too early for full backwards compatibility.

However, the bug you are actually trying to fix occurs during
relocation, so it looks to me as if using entry point addresses as an
indicator will not actually work.  And entry point zero is generated by
recent binutils only anyway.

Thanks,
Florian