[FFmpeg-devel] [PATCH 2/3 v2] configure: Support for HEASLR on mingw targets

[Hendrik Leppkes]

On Sat, Sep 26, 2015 at 8:43 AM, Alex Smith <alex.smith at warpsharp.info> wrote:
> From: Alex Smith <alex.smith at warpsharp.info>
>
> The appropriate flag for HEASLR (--high-entropy-va) was added in
> binutils 2.25.
>
> Also set the image base >4GB so higher entropy gets applied to image
> base randomization when used with HEASLR (8 -> 17 bits of
> randomization).  Windows does this for compatibility because of "latent
> pointer truncation issues".
>
> Signed-off-by: Alex Smith <alex.smith at warpsharp.info>
> ---
>  configure | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/configure b/configure
> index f6bc622..0a4b4ed 100755
> --- a/configure
> +++ b/configure
> @@ -4401,6 +4401,10 @@ case $target_os in
>              add_ldexeflags -Wl,--pic-executable,-e,_mainCRTStartup
>          elif enabled x86_64; then
>              add_ldexeflags -Wl,--pic-executable,-e,mainCRTStartup
> +            check_ldflags -Wl,--high-entropy-va # binutils 2.25
> +            # Set image base >4GB for extra entropy with HEASLR
> +            add_ldexeflags -Wl,--image-base,0x140000000
> +            append SHFLAGS -Wl,--image-base,0x180000000
>          fi
>          ;;
>      win32|win64)
> --
> 1.9.5.msysgit.0

LGTM, will push later.