RE: [PATCH V4 RESEND] net/colo.c: Fix the pointer issue reported by Coverity.

[Zhang, Chen]

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Thursday, August 18, 2022 4:04 PM
> To: Zhang, Chen <chen.zhang@intel.com>
> Cc: Peter Maydell <peter.maydell@linaro.org>; Li Zhijian
> <lizhijian@fujitsu.com>; qemu-dev <qemu-devel@nongnu.org>
> Subject: Re: [PATCH V4 RESEND] net/colo.c: Fix the pointer issue reported by
> Coverity.
> 
> On Wed, Aug 17, 2022 at 3:45 PM Zhang, Chen <chen.zhang@intel.com> wrote:
> >
> > Ping....  Jason and Peter, any comments for this patch?
> >
> > Thanks
> > Chen
> >
> > > -----Original Message-----
> > > From: Zhang, Chen <chen.zhang@intel.com>
> > > Sent: Tuesday, August 9, 2022 4:49 PM
> > > To: Jason Wang <jasowang@redhat.com>; Peter Maydell
> > > <peter.maydell@linaro.org>; Li Zhijian <lizhijian@fujitsu.com>;
> > > qemu-dev <qemu-devel@nongnu.org>
> > > Cc: Zhang, Chen <chen.zhang@intel.com>
> > > Subject: [PATCH V4 RESEND] net/colo.c: Fix the pointer issue
> > > reported by Coverity.
> > >
> > > When enabled the virtio-net-pci, guest network packet will load the
> vnet_hdr.
> > > In COLO status, the primary VM's network packet maybe redirect to
> > > another VM, it need filter-redirect enable the vnet_hdr flag at the
> > > same time, COLO- proxy will correctly parse the original network
> > > packet. If have any misconfiguration here, the vnet_hdr_len is wrong
> > > for parse the packet, the
> > > data+offset will point to wrong place.
> > >
> > > Signed-off-by: Zhang Chen <chen.zhang@intel.com>
> > > ---
> > >  net/colo.c | 18 ++++++++++--------
> > >  net/colo.h |  1 +
> > >  2 files changed, 11 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/net/colo.c b/net/colo.c index 6b0ff562ad..2b5568fff4
> > > 100644
> > > --- a/net/colo.c
> > > +++ b/net/colo.c
> > > @@ -44,21 +44,23 @@ int parse_packet_early(Packet *pkt)  {
> > >      int network_length;
> > >      static const uint8_t vlan[] = {0x81, 0x00};
> > > -    uint8_t *data = pkt->data + pkt->vnet_hdr_len;
> > > +    uint8_t *data = pkt->data;
> > >      uint16_t l3_proto;
> > >      ssize_t l2hdr_len;
> > >
> > > -    if (data == NULL) {
> > > -        trace_colo_proxy_main_vnet_info("This packet is not parsed 
> > > correctly,
> "
> > > +    assert(data);
> > > +
> > > +    /* Check the received vnet_hdr_len then add the offset */
> > > +    if ((pkt->vnet_hdr_len > sizeof(struct virtio_net_hdr_v1_hash)) ||
> > > +        (pkt->size < sizeof(struct eth_header) + sizeof(struct 
> > > vlan_header)
> > > +        + pkt->vnet_hdr_len)) {
> > > +        trace_colo_proxy_main_vnet_info("This packet may be load wrong "
> > >                                          "pkt->vnet_hdr_len",
> > > pkt->vnet_hdr_len);
> 
> Nit: I think we need to be verbose here, e.g put the pkt_size here at least.

OK, I will change here to:
/*
  * The received remote packet maybe misconfiguration here,
  * Please enable/disable filter module's the vnet_hdr flag at the same time.
  */
trace_colo_proxy_main_vnet_info("This received packet load wrong "
                                                               
"pkt->vnet_hdr_len",  pkt->vnet_hdr_len, pkt->size);

Thanks
Chen

> 
> Thanks
> 
> > >          return 1;
> > >      }
> > > -    l2hdr_len = eth_get_l2_hdr_length(data);
> > > +    data += pkt->vnet_hdr_len;
> > >
> > > -    if (pkt->size < ETH_HLEN + pkt->vnet_hdr_len) {
> > > -        trace_colo_proxy_main("pkt->size < ETH_HLEN");
> > > -        return 1;
> > > -    }
> > > +    l2hdr_len = eth_get_l2_hdr_length(data);
> > >
> > >      /*
> > >       * TODO: support vlan.
> > > diff --git a/net/colo.h b/net/colo.h index 8b3e8d5a83..22fc3031f7
> > > 100644
> > > --- a/net/colo.h
> > > +++ b/net/colo.h
> > > @@ -18,6 +18,7 @@
> > >  #include "qemu/jhash.h"
> > >  #include "qemu/timer.h"
> > >  #include "net/eth.h"
> > > +#include "standard-headers/linux/virtio_net.h"
> > >
> > >  #define HASHTABLE_MAX_SIZE 16384
> > >
> > > --
> > > 2.25.1
> >