On Mon, Apr 08, 2019 at 07:04:18PM +0200, Alexander Potapenko wrote:
> This config option enables CONFIG_SLUB_DEBUG and CONFIG_PAGE_POISONING
> without the need to pass any boot parameters.
>
> No performance optimizations are done at the moment to reduce double
> initialization of memory regions.
>
> Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> Cc: James Morris <jmorris@xxxxxxxxx>
> Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Cc: Kostya Serebryany <kcc@xxxxxxxxxx>
> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Sandeep Patil <sspatil@xxxxxxxxxxx>
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> Cc: linux-kbuild@xxxxxxxxxxxxxxx
> Cc: kernel-hardening@xxxxxxxxxxxxxxxxxx
> ---
> v3:
> - addressed comments by Masahiro Yamada (Kconfig fixes)
> ---
> mm/page_poison.c | 5 +++++
> mm/slub.c | 2 ++
> security/Kconfig.initmem | 11 +++++++++++
> 3 files changed, 18 insertions(+)
>
> diff --git a/mm/page_poison.c b/mm/page_poison.c
> index 21d4f97cb49b..a1985f33f635 100644
> --- a/mm/page_poison.c
> +++ b/mm/page_poison.c
> @@ -12,9 +12,14 @@ static bool want_page_poisoning __read_mostly;
>
> static int __init early_page_poison_param(char *buf)
> {
> +#ifdef CONFIG_INIT_ALL_HEAP
> + want_page_poisoning = true;
> + return 0;
> +#else
> if (!buf)
> return -EINVAL;
> return strtobool(buf, &want_page_poisoning);
> +#endif
> }
> early_param("page_poison", early_page_poison_param);
IIUC this is only called if page_poison is passed on the command line,
so want_page_poisoning won't be set automatically unless that's passed.
Presumably you want to initialize it at definition with:
static bool want_page_poisoning __read_mostly = IS_ENABLED(CONFIG_INIT_ALL_HEAP);
with:
#ifndef CONFIG_INIT_ALL_HEAP
static int __init early_page_poison_param(char *buf)
{
...
}
early_param("page_poison", early_page_poison_param);
#endif
... so that it can't be disabled?
Thanks,
Mark.
