On Wed, Feb 03, 2021 at 11:45:44AM +0100, Andrea Parri wrote:
> Hi Dan,
>
> On Wed, Feb 03, 2021 at 01:10:41PM +0300, Dan Carpenter wrote:
> > Hello Andrea Parri (Microsoft),
> >
> > This is a semi-automatic email about new static checker warnings.
> >
> > The patch 0ba35fe91ce3: "hv_netvsc: Copy packets sent by Hyper-V out
> > of the receive buffer" from Jan 26, 2021, leads to the following
> > Smatch complaint:
> >
> > drivers/net/hyperv/rndis_filter.c:468 rsc_add_data()
> > error: we previously assumed 'csum_info' could be null (see line 460)
> >
> > drivers/net/hyperv/rndis_filter.c
> > 459 }
> > 460 if (csum_info != NULL) {
> > ^^^^^^^^^^^^^^^^^
> > "csum_info" can be NULL.
> >
> > 461 memcpy(&nvchan->rsc.csum_info, csum_info, sizeof(*csum_info));
> > 462 nvchan->rsc.ppi_flags |= NVSC_RSC_CSUM_INFO;
> > 463 } else {
> > 464 nvchan->rsc.ppi_flags &= ~NVSC_RSC_CSUM_INFO;
> > 465 }
> > 466 nvchan->rsc.pktlen = len;
> > 467 if (hash_info != NULL) {
> > 468 nvchan->rsc.csum_info = *csum_info;
> > ^^^^^^^^^^^
> > Unchecked dereference. Plus this has "csum_info" on both sides of the
> > assignment so maybe it is a copy and paste error? This is equivalent to
> > the "memcpy(&nvchan->rsc.csum_info, csum_info, sizeof(*csum_info));"
> > in the ealier if statement but stated as an assignment instead of a
> > memcpy().
>
> Right, I did realize about the error and I'm about to send a fix for it.
For reference,
https://lkml.kernel.org/r/20210203113513.558864-3-parri.andrea@xxxxxxxxx/
Andrea
