On Tue, May 18, 2021 at 04:29:44PM +0800, Yongji Xie wrote: > On Tue, May 18, 2021 at 7:40 AM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > > > > On Mon, May 17, 2021 at 05:08:19PM +0800, Xie Yongji wrote: > > > Current virtio device drivers may trust the used length returned > > > in virtqueue_get_buf()/virtqueue_get_buf_ctx(). But the used length > > > might come from an untrusted device when VDUSE[1] is enabled. To > > > protect this case, this series tries to add validation for the > > > used length. > > > > > > Since many legacy devices will also set the used length incorrectly, > > > we did not add the validation unconditionally. Instead, we will do > > > the validation only when the device driver needs the used length. > > > A NULL len passed to virtqueue_get_buf()/virtqueue_get_buf_ctx() > > > will mean the used length is not needed by the device driver. > > > > Can we be more specific? Which drivers have problems when used len > > is incorrect? Maybe there's an easier way like validating the length > > in the driver ... > > > > It's ok to me. But this means all future new drivers need to remember > to do the validation. > > Now only virtio-net and virtio-console drivers have this problem. I > can send some patches to fix it. > > Thanks, > Yongji I'd say let's just document the requirement for now. -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
