[Patch] kexec_load: check CAP_SYS_MODULE

[Cong Wang]

(Forgot Cc'ing Eric Paris, adding.)

> Eric pointed out that kexec_load() actually allows you to
> run any code you want in ring0, this is more like CAP_SYS_MODULE.
>
> Reported-by: Eric Paris<eparis at redhat.com>
> Signed-off-by: WANG Cong<amwang at redhat.com>
>
> ---
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index b55045b..c30d613 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -945,7 +945,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
>   	int result;
>
>   	/* We only trust the superuser with rebooting the system. */
> -	if (!capable(CAP_SYS_BOOT))
> +	if (!capable(CAP_SYS_BOOT) || !capable(CAP_SYS_MODULE))
>   		return -EPERM;
>
>   	/*