Re: [PATCH] KVM: validate userspace input in kvm_clear_dirty_log_protect()

[Paolo Bonzini <pbonzini@xxxxxxxxxx>]

On 02/01/19 18:29, Tomas Bortoli wrote:
>  	n = kvm_dirty_bitmap_bytes(memslot);
> +
> +	if (n << 3 < log->num_pages || log->first_page > log->num_pages)
> +		return -EINVAL;
> +

This should be

	if (log->first_page > memslot->npages ||
	    log->num_pages > memslot->npages - log->first_page)
		return -EINVAL;

i.e. the comparison should check the last page in the range, not the
number of pages.  In addition, using "n" is unnecessary since we do have
the memslot.  I'll do the changes myself if you prefer, but an ack would
be nice.

Paolo