Re: [PATCH 3.17-rc5] Fix confusing PFA_NO_NEW_PRIVS constant.

From: Kees Cook
Date: Sat Sep 20 2014 - 13:20:04 EST


On Sat, Sep 20, 2014 at 3:40 AM, Tetsuo Handa
<penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote:
> Can you apply below patch before new PFA_* are defined?
> Cgroups code might want to define PFA_SPREAD_PAGE as 1 and PFA_SPREAD_SLAB as 2.
> ----------------------------------------
> >From 8543e68adb210142fa347d8bc9d83df0bb2c5291 Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Date: Sat, 20 Sep 2014 19:24:23 +0900
> Subject: [PATCH 3.17-rc5] Fix confusing PFA_NO_NEW_PRIVS constant.
>
> Commit 1d4457f99928 ("sched: move no_new_privs into new atomic flags")
> defined PFA_NO_NEW_PRIVS as hexadecimal value, but it is confusing
> because it is used as bit number. Redefine it as decimal bit number.
>
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> ---
> include/linux/sched.h | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 5c2c885..4557765 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1957,7 +1957,7 @@ static inline void memalloc_noio_restore(unsigned int flags)
> }
>
> /* Per-process atomic flags. */
> -#define PFA_NO_NEW_PRIVS 0x00000001 /* May not gain new privileges. */
> +#define PFA_NO_NEW_PRIVS 0 /* May not gain new privileges. */
>
> static inline bool task_no_new_privs(struct task_struct *p)
> {

Thanks, good catch.

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

--
Kees Cook
Chrome OS Security
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/