Re: [Qemu-devel] [PATCH for 3.1 4/4] virtio-net-test: add large tx buffer test

[Jason Wang]

On 2018/11/29 下午2:21, Thomas Huth wrote:
> On 2018-11-29 04:12, Jason Wang wrote:
> > This test tries to build a packet whose size is greater than INT_MAX
> > which tries to trigger integer overflow in qemu_net_queue_append_iov()
> > which may result OOB.
> >
> > Signed-off-by: Jason Wang <address@hidden>
> > ---
> >   tests/virtio-net-test.c | 46 +++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 46 insertions(+)
> >
> > diff --git a/tests/virtio-net-test.c b/tests/virtio-net-test.c
> > index 33d26ab079..09c220c2fa 100644
> > --- a/tests/virtio-net-test.c
> > +++ b/tests/virtio-net-test.c
> > @@ -245,6 +245,51 @@ static void pci_basic(gconstpointer data)
> >       g_free(dev);
> >       qtest_shutdown(qs);
> >   }
> > +
> > +static void large_tx(gconstpointer data)
> > +{
> > +    QVirtioPCIDevice *dev;
> > +    QOSState *qs;
> > +    QVirtQueuePCI *tx, *rx;
> > +    QVirtQueue *vq;
> > +    const char *cmd = "-netdev hubport,id=hp0,hubid=0 "
> > +                      "-device virtio-net-pci,netdev=hp0 ";
> > +    uint64_t req_addr;
> > +    uint32_t free_head;
> > +    size_t alloc_size = UINT_MAX / 64;
> > +    int i;
> > +
> > +    qs = pci_test_start(cmd);
> > +    dev = virtio_net_pci_init(qs->pcibus, PCI_SLOT);
> > +
> > +    rx = (QVirtQueuePCI *)qvirtqueue_setup(&dev->vdev, qs->alloc, 0);
> > +    tx = (QVirtQueuePCI *)qvirtqueue_setup(&dev->vdev, qs->alloc, 1);
> > +
> > +    driver_init(&dev->vdev);
> > +    vq = &tx->vq;
> > +
> > +    /* Bypass the limitation by pointing several descriptors to a single
> > +     * smaller area */
> > +    req_addr = guest_alloc(qs->alloc, alloc_size);
> > +    for (i = 0; i < 64; i ++) {
> > +        if (i == 0)
> > +            free_head = qvirtqueue_add(vq, req_addr, alloc_size, false, true);
> > +        else
> > +            qvirtqueue_add(vq, req_addr, alloc_size, false, true);
> QEMU coding style requires always curly braces. Maybe move the initial
> case before the for-loop and then start the for loop with i=1 instead?


Ok, fix and post V2.

Thanks


> > +    }
> > +    qvirtqueue_add(vq, req_addr, alloc_size, false, false);
> > +    qvirtqueue_kick(&dev->vdev, vq, free_head);
> > +
> > +    qvirtio_wait_used_elem(&dev->vdev, vq, free_head, NULL,
> > +                           QVIRTIO_NET_TIMEOUT_US);
> > +
> > +    qvirtqueue_cleanup(dev->vdev.bus, &tx->vq, qs->alloc);
> > +    qvirtqueue_cleanup(dev->vdev.bus, &rx->vq, qs->alloc);
> > +    qvirtio_pci_device_disable(dev);
> > +    g_free(dev->pdev);
> > +    g_free(dev);
> > +    qtest_shutdown(qs);
> > +}
> >   #endif
> >   
> >   static void hotplug(void)
> > @@ -270,6 +315,7 @@ int main(int argc, char **argv)
> >       qtest_add_data_func("/virtio/net/pci/basic", send_recv_test, pci_basic);
> >       qtest_add_data_func("/virtio/net/pci/rx_stop_cont",
> >                           stop_cont_test, pci_basic);
> > +    qtest_add_data_func("/virtio/net/pci/large_tx", NULL, large_tx);
> >   #endif
> >       qtest_add_func("/virtio/net/pci/hotplug", hotplug);
>   Thomas