Re: [PATCH v2] loongarch: Support RANDOMIZE_KSTACK_OFFSET

[Kees Cook]

On Fri, Jul 19, 2024 at 11:14:27AM +0800, Jinjie Ruan wrote:
> Add support of kernel stack offset randomization while handling syscall,
> the offset is defaultly limited by KSTACK_OFFSET_MAX().
> 
> In order to avoid trigger stack canaries (due to __builtin_alloca) and
> slowing down the entry path, use __no_stack_protector attribute to
> disable stack protector for do_syscall() at function level.
> 
> With this patch, the REPORT_STACK test show that:
> 	`loongarch64 bits of stack entropy: 7`

I suspect this will report the correct "6" after now that this commit
has landed:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=872bb37f6829d4f7f3ed5afe2786add3d4384b4b

> 
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
> Suggested-by: Huacai Chen <chenhuacai@xxxxxxxxxx>

Thanks for adding this and getting it tested!

Reviewed-by: Kees Cook <kees@xxxxxxxxxx>

-- 
Kees Cook