From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=46546 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PR2yz-0005FA-1I for qemu-devel@nongnu.org; Fri, 10 Dec 2010 08:25:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PR2yv-0000kO-FK for qemu-devel@nongnu.org; Fri, 10 Dec 2010 08:25:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56086) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PR2yv-0000k1-8O for qemu-devel@nongnu.org; Fri, 10 Dec 2010 08:25:53 -0500 From: Amit Shah Date: Fri, 10 Dec 2010 18:55:17 +0530 Message-Id: <60d0ef242fa5d7e014a8c56f2bcc6d0cd7b6e56e.1291987020.git.amit.shah@redhat.com> In-Reply-To: References: In-Reply-To: References: Subject: [Qemu-devel] [PATCH 4/5] virtio-serial: Don't copy over guest buffer to host List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu list Cc: Amit Shah , Paul Brook 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 | 20 ++++++++++++-------- 1 files changed, 12 insertions(+), 8 deletions(-) diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c index ecf0056..3bbd915 100644 --- a/hw/virtio-serial-bus.c +++ b/hw/virtio-serial-bus.c @@ -125,17 +125,21 @@ static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq, return; } while (virtqueue_pop(vq, &elem)) { - uint8_t *buf; - size_t ret, buf_size; + unsigned int i; - if (!discard) { - 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); + if (discard) { + goto next; + } + 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); } + next: virtqueue_push(vq, &elem, 0); } virtio_notify(vdev, vq); -- 1.7.3.2