Re: [PATCH v4 1/6] x86/elf: Add table to document READ_IMPLIES_EXEC

[Borislav Petkov]

Ozenn Mon, Feb 24, 2020 at 09:13:02PM -0800, Kees Cook wrote:
> Add a table to document the current behavior of READ_IMPLIES_EXEC in
> preparation for changing the behavior.
> 
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> ---
>  arch/x86/include/asm/elf.h | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
> index 69c0f892e310..733f69c2b053 100644
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -281,6 +281,25 @@ extern u32 elf_hwcap2;
>  /*
>   * An executable for which elf_read_implies_exec() returns TRUE will
>   * have the READ_IMPLIES_EXEC personality flag set automatically.
> + *
> + * The decision process for determining the results are:
> + *
> + * Â Â Â Â Â Â ÂCPU: | lacks NX* Â| has NX, ia32 Â Â | has NX, x86_64 |
> + * ELF: Â Â Â Â Â Â Â| Â Â Â Â Â Â| Â Â Â Â Â Â Â Â Â| Â Â Â Â Â Â Â Â|
> + * -------------------------------|------------------|----------------|
> + * missing GNU_STACK | exec-all  | exec-all     | exec-all    |
> + * GNU_STACK == RWX Â| exec-all  | exec-all     | exec-all    |
> + * GNU_STACK == RW  | exec-none Â| exec-none    Â| exec-none   Â|

In all those tables, you wanna do:

s/GNU_STACK/PT_GNU_STACK/g

so that it is clear what this define is.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette