On 04/28/2013 04:40 PM, Jason Wang wrote:
> On 04/28/2013 04:32 PM, Michael S. Tsirkin wrote:
>> On Fri, Apr 26, 2013 at 04:34:03PM +0800, Jason Wang wrote:
>>> virtio-rng-ccw has zero config length, so we need validate the config length
>>> before trying to access it. Otherwise we may crash since vdev->config is
>>> NULL.
>>>
>>> Cc: Cornelia Huck <cornelia.h...@de.ibm.com>
>>> Cc: Richard Henderson <r...@twiddle.net>
>>> Cc: Alexander Graf <ag...@suse.de>
>>> Signed-off-by: Jason Wang <jasow...@redhat.com>
>> The real problem is dev->vdev->get_config being NULL,
>> isn't it? So why not validate it and be done with it?
> Ok, this looks more clear. Will do it in V2.
Recheck the code, looks like {get|set}_config() has been validated in
virtio_bus_get_vdev_config(). So the codes were ok here, will drop this
patch also.
>>> ---
>>> hw/s390x/virtio-ccw.c | 4 ++--
>>> 1 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
>>> index 56539d3..8d0dff5 100644
>>> --- a/hw/s390x/virtio-ccw.c
>>> +++ b/hw/s390x/virtio-ccw.c
>>> @@ -260,7 +260,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
>>> }
>>> }
>>> len = MIN(ccw.count, dev->vdev->config_len);
>>> - if (!ccw.cda) {
>>> + if (!ccw.cda || !len) {
>>> ret = -EFAULT;
>>> } else {
>>> dev->vdev->get_config(dev->vdev, dev->vdev->config);
>>> @@ -279,7 +279,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
>>> }
>>> len = MIN(ccw.count, dev->vdev->config_len);
>>> hw_len = len;
>>> - if (!ccw.cda) {
>>> + if (!ccw.cda || !len) {
>>> ret = -EFAULT;
>>> } else {
>>> config = cpu_physical_memory_map(ccw.cda, &hw_len, 0);
>>> --
>>> 1.7.1
>
