On Mon, 18 Nov 2019 17:51:15 +0300 Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:
> PT_GNU_STACK is fail open design,
Not sure what this means. Please expand on the motivation for this
change.
> at least warn people that something
> isn't right.
People who use an executable stack get a kernel splat. How is that
useful?
> ...
>
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -762,6 +762,13 @@ int setup_arg_pages(struct linux_binprm *bprm,
> goto out_unlock;
> BUG_ON(prev != vma);
>
> +#ifdef CONFIG_MMU
> + if (vm_flags & VM_EXEC) {
> + pr_warn_once("process '%s'/%u started with executable stack\n",
> + current->comm, current->pid);
> + }
> +#endif
>
> /* Move stack pages down in memory. */
> if (stack_shift) {
> ret = shift_arg_pages(vma, stack_shift);
