From 471344db88cc3e7adf7664aa34d54ce0cacc3419 Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Fri, 10 Dec 2010 17:29:49 +0530 Subject: [PATCH] virtio-serial: Don't copy over guest buffer to host When the guest writes something to a host, we copied over the entire buffer first into the host and then processed it. Do away with that, it could result in a malicious guest causing a DoS on the host. Reported-by: Paul Brook Signed-off-by: Amit Shah --- hw/virtio-serial-bus.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c index e8c2a168ec..6726f72b6f 100644 --- a/hw/virtio-serial-bus.c +++ b/hw/virtio-serial-bus.c @@ -132,16 +132,17 @@ static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq, assert(virtio_queue_ready(vq)); while (!port->throttled && virtqueue_pop(vq, &elem)) { - uint8_t *buf; - size_t ret, buf_size; + unsigned int i; - buf_size = iov_size(elem.out_sg, elem.out_num); - buf = qemu_malloc(buf_size); - ret = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, buf_size); + for (i = 0; i < elem.out_num; i++) { + size_t buf_size; - port->info->have_data(port, buf, ret); - qemu_free(buf); + buf_size = elem.out_sg[i].iov_len; + port->info->have_data(port, + elem.out_sg[i].iov_base, + buf_size); + } virtqueue_push(vq, &elem, 0); } virtio_notify(vdev, vq); -- GitLab