[Qemu-devel] [PATCH] virtio: abort on zero config length

[Jason Wang <jasowang@redhat.com>]

In fact we don't support zero length config length for virtio device. And it can
lead outbound memory access. So abort on zero config length to catch the bug
earlier.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/virtio.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 1c2282c..a6fa667 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -923,6 +923,7 @@ void virtio_init(VirtIODevice *vdev, const char *name,
                  uint16_t device_id, size_t config_size)
 {
     int i;
+    assert(config_size);
     vdev->device_id = device_id;
     vdev->status = 0;
     vdev->isr = 0;
@@ -938,11 +939,7 @@ void virtio_init(VirtIODevice *vdev, const char *name,
 
     vdev->name = name;
     vdev->config_len = config_size;
-    if (vdev->config_len) {
-        vdev->config = g_malloc0(config_size);
-    } else {
-        vdev->config = NULL;
-    }
+    vdev->config = g_malloc0(config_size);
     vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
                                                      vdev);
 }
-- 
1.7.1