RE: [PATCH V5] net/colo.c: Fix the pointer issue reported by Coverity.

[Zhang, Chen]

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Tuesday, August 23, 2022 10:03 AM
> 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 V5] net/colo.c: Fix the pointer issue reported by 
> Coverity.
> 
> On Mon, Aug 22, 2022 at 4:29 PM Zhang Chen <chen.zhang@intel.com> wrote:
> >
> > 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 needs 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>
> 
> Not sure it's worth 7.1. So I queued this for 7.2.

It's fine for me.

Thanks
Chen

> 
> Thanks
> 
> > ---
> >  net/colo.c       | 25 ++++++++++++++++---------
> >  net/colo.h       |  1 +
> >  net/trace-events |  2 +-
> >  3 files changed, 18 insertions(+), 10 deletions(-)
> >
> > diff --git a/net/colo.c b/net/colo.c
> > index 6b0ff562ad..fb2c36a026 100644
> > --- a/net/colo.c
> > +++ b/net/colo.c
> > @@ -44,21 +44,28 @@ 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, "
> > -                                        "pkt->vnet_hdr_len", 
> > pkt->vnet_hdr_len);
> > +    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)) {
> > +        /*
> > +         * 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->size);
> >          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
> >
> > diff --git a/net/trace-events b/net/trace-events index
> > 6af927b4b9..823a071bdc 100644
> > --- a/net/trace-events
> > +++ b/net/trace-events
> > @@ -9,7 +9,7 @@ vhost_user_event(const char *chr, int event) "chr: %s got
> event: %d"
> >
> >  # colo.c
> >  colo_proxy_main(const char *chr) ": %s"
> > -colo_proxy_main_vnet_info(const char *sta, int size) ": %s = %d"
> > +colo_proxy_main_vnet_info(const char *sta, uint32_t vnet_hdr, int size)
> ": %s pkt->vnet_hdr_len = %u, pkt->size = %d"
> >
> >  # colo-compare.c
> >  colo_compare_main(const char *chr) ": %s"
> > --
> > 2.25.1
> >