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

[Tomas Bortoli]

Hi Paolo,

On 1/7/19 11:42 PM, Paolo Bonzini wrote:
> 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.
> 
> 


Yeah, I agree. Thanks for the reply and sure you can do the changes, np :)

Tomas