Re: [PATCH net-next] net: qrtr: make checks in qrtr_endpoint_post() stricter

[Dan Carpenter <dan.carpenter@oracle.com>]

On Fri, Aug 27, 2021 at 11:35:31PM +0800, butt3rflyh4ck wrote:
> On Fri, Aug 27, 2021 at 9:24 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
> >
> > These checks are still not strict enough.  The main problem is that if
> > "cb->type == QRTR_TYPE_NEW_SERVER" is true then "len - hdrlen" is
> > guaranteed to be 4 but we need to be at least 16 bytes.  In fact, we
> > can reject everything smaller than sizeof(*pkt) which is 20 bytes.
> >
> > Also I don't like the ALIGN(size, 4).  It's better to just insist that
> > data is needs to be aligned at the start.
> >
> > Fixes: 0baa99ee353c ("net: qrtr: Allow non-immediate node routing")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > This was from review.  Not tested.
> >
> >  net/qrtr/qrtr.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
> > index b8508e35d20e..dbb647f5481b 100644
> > --- a/net/qrtr/qrtr.c
> > +++ b/net/qrtr/qrtr.c
> > @@ -493,7 +493,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
> >                 goto err;
> >         }
> >
> 
> > -       if (!size || len != ALIGN(size, 4) + hdrlen)
> > +       if (!size || size % 3 || len != size + hdrlen)
> 
> Hi, (size % 3)  is wrong, is it (size & 3), right ?
> 

Yeah.  Thanks for catching that.  I means & 3.

regards,
dan carpenter