From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47368) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WVkrQ-0005wO-La for qemu-devel@nongnu.org; Thu, 03 Apr 2014 12:51:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WVkrK-0005df-0c for qemu-devel@nongnu.org; Thu, 03 Apr 2014 12:51:28 -0400 Date: Thu, 3 Apr 2014 19:51:53 +0300 From: "Michael S. Tsirkin" Message-ID: <1396543778-22307-16-git-send-email-mst@redhat.com> References: <1396543778-22307-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1396543778-22307-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PATCH v5 15/24] virtio: validate num_sg when mapping List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , mdroth@linux.vnet.ibm.com, qemu-stable@nongnu.org, dgilbert@redhat.com, Anthony Liguori , Amit Shah CVE-2013-4535 CVE-2013-4536 Both virtio-block and virtio-serial read, VirtQueueElements are read in as buffers, and passed to virtqueue_map_sg(), where num_sg is taken from the wire and can force writes to indicies beyond VIRTQUEUE_MAX_SIZE. To fix, validate num_sg. Reported-by: Michael Roth Signed-off-by: Michael S. Tsirkin Cc: Amit Shah --- hw/virtio/virtio.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index bcbfbb2..3bad71e 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -430,6 +430,12 @@ void virtqueue_map_sg(struct iovec *sg, hwaddr *addr, unsigned int i; hwaddr len; + if (num_sg >= VIRTQUEUE_MAX_SIZE) { + error_report("virtio: map attempt out of bounds: %zd > %d", + num_sg, VIRTQUEUE_MAX_SIZE); + exit(1); + } + for (i = 0; i < num_sg; i++) { len = sg[i].iov_len; sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write); -- MST