On Wed, Jul 31, 2013 at 11:11:56AM -0400, David Teigland wrote:
> On Wed, Jul 31, 2013 at 12:02:29PM +0300, Dan Carpenter wrote:
> > This is a static checker fix. We have several places here that check
> > the upper limit without checking for negative numbers. One example of
> > this is in find_rsb().
> >
> > My static checker marks endian data as user controled so. The
> > "ms->m_header.h_length" variable is tagged as user data because it
> > starts as little endian and we convert it at the start of
> > dlm_receive_buffer(). That means that receive_extralen() returns
> > user controlled data which could be negative. The call tree here is:
> >
> > -> dlm_receive_buffer()
> > -> dlm_receive_message()
> > -> _receive_message()
> > -> receive_request()
> >
> > We get "namelen" from receive_extralen(ms);
> >
> > -> find_rsb()
> >
> > It's never perfectly clear how invasive to make a fix like this. Many
> > of the changes in the patch are not needed but I wanted to make things
> > consistent.
>
> If it's negative, I don't think it would pass the h_length validation
> in dlm_process_incoming_buffer(), but I'm not certain...
Gar, yeah. We check that:
if (p->header.h_cmd == DLM_MSG) {
if (msglen < sizeof(struct dlm_message))
break;
Which means receive_extralen() can't return negative.
We can drop this patch.
regards,
dan carpenter
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