Re: [PATCH v4 1/2] powerpc/32: add stack protector support

From: Segher Boessenkool
Date: Wed Sep 26 2018 - 15:17:06 EST


On Wed, Sep 26, 2018 at 11:40:38AM +0000, Christophe Leroy wrote:
> +static __always_inline void boot_init_stack_canary(void)
> +{
> + unsigned long canary;
> +
> + /* Try to get a semi random initial value. */
> + get_random_bytes(&canary, sizeof(canary));
> + canary ^= mftb();
> + canary ^= LINUX_VERSION_CODE;
> +
> + current->stack_canary = canary;
> +}

I still think you should wait until there is entropy available. You
haven't answered my questions about that (or I didn't see them): what
does the kernel do in other similar cases?

Looks great otherwise!


Segher