[MPlayer-dev-eng] [PATCH] compile as PIE by default

[Ivan Kalvachev]

On 5/21/12, Reimar Döffinger <Reimar.Doeffinger at gmx.de> wrote:
> Hello,
> below patch would compile MPlayer as PIE on x86 by default.
> On 32 bit, the cost would only be in a larger binary size and having to do
> relocations at startup, but no real cost at runtime.
> On 64 bit, there is almost no size or runtime overhead, mostly that
> in some cases PIC-relative addressing has to be used.
> I believe that none of the assembler code will be disabled by either.
> I have not made any changes to other architectures since I can't
> judge the impact.
> A side effect of the 64 bit case is that MPlayer will refuse to link
> against some static libraries (those not compiled with PIC and thus
> violating
> the ABI), one example (which only exists as static library) is LIVE555
> as provided by Debian.
> Another point is that backtraces without debug info will probably be
> even less useful.
> Any comments? My belief is that there is negligible if any disadvantage
> for a sometimes significant win in security.
>
> Index: configure
> ===================================================================
> --- configure	(revision 34955)
> +++ configure	(working copy)
> @@ -2643,6 +2643,22 @@
>  fi
>
>
> +# try to create a relocatable binary by default
> +echocheck "relocatable binary"
> +if x86_32 && cflag_check -pie ; then
> +  extra_ldflags="$extra_ldflags -pie"
> +  relocatable=yes
> +  res_comment="non-PIC"
> +elif x86_64 && cflag_check -fpie -pie ; then
> +  extra_ldflags="$extra_ldflags -fpie -pie"
> +  extra_cflags="$extra_cflags -fpie"
> +  relocatable=yes
> +  res_comment="fast PIC"
> +else
> +  relocatable=no
> +  res_comment="unavailable or untested architecture"
> +fi
> +echores $relocatable
>
>  if x86_32 ; then
>    # Checking assembler (_as) compatibility...

Without researching the topic.
Would the above check fail if --enable-static is used?
I think there must be a way to disable this with configure option,
e.g. --disable-pie

Have you tested it with the win32loader?