Re: [PATCH 2/5] fork,random: use get_random_canary to set tsk->stack_canary

[Kees Cook]

On Wed, May 24, 2017 at 8:57 AM,  <riel@xxxxxxxxxx> wrote:
> From: Rik van Riel <riel@xxxxxxxxxx>
>
> Use the ascii-armor canary to prevent unterminated C string overflows
> from being able to successfully overwrite the canary, even if they
> somehow obtain the canary value.
>
> Inspired by execshield ascii-armor and Daniel Micay's linux-hardened tree.
>
> Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

> ---
>  kernel/fork.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/fork.c b/kernel/fork.c
> index aa1076c5e4a9..b3591e9250a8 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -560,7 +560,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
>         set_task_stack_end_magic(tsk);
>
>  #ifdef CONFIG_CC_STACKPROTECTOR
> -       tsk->stack_canary = get_random_long();
> +       tsk->stack_canary = get_random_canary();
>  #endif
>
>         /*
> --
> 2.9.3
>



-- 
Kees Cook
Pixel Security