Re: [PATCH v4 12/14] mips: Replace arch specific way to determine 32bit task with generic version

[Kees Cook]

On Sun, May 26, 2019 at 09:47:44AM -0400, Alexandre Ghiti wrote:
> Mips uses TASK_IS_32BIT_ADDR to determine if a task is 32bit, but
> this define is mips specific and other arches do not have it: instead,
> use !IS_ENABLED(CONFIG_64BIT) || is_compat_task() condition.
> 
> Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

> ---
>  arch/mips/mm/mmap.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
> index c052565b76fb..900670ea8531 100644
> --- a/arch/mips/mm/mmap.c
> +++ b/arch/mips/mm/mmap.c
> @@ -17,6 +17,7 @@
>  #include <linux/sched/signal.h>
>  #include <linux/sched/mm.h>
>  #include <linux/sizes.h>
> +#include <linux/compat.h>
>  
>  unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
>  EXPORT_SYMBOL(shm_align_mask);
> @@ -191,7 +192,7 @@ static inline unsigned long brk_rnd(void)
>  
>  	rnd = rnd << PAGE_SHIFT;
>  	/* 32MB for 32bit, 1GB for 64bit */
> -	if (TASK_IS_32BIT_ADDR)
> +	if (!IS_ENABLED(CONFIG_64BIT) || is_compat_task())
>  		rnd = rnd & SZ_32M;
>  	else
>  		rnd = rnd & SZ_1G;
> -- 
> 2.20.1
> 

-- 
Kees Cook