From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41897) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VnsnA-00069R-6u for qemu-devel@nongnu.org; Tue, 03 Dec 2013 11:25:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vnsn3-0006pH-OY for qemu-devel@nongnu.org; Tue, 03 Dec 2013 11:25:44 -0500 Date: Tue, 3 Dec 2013 18:29:04 +0200 From: "Michael S. Tsirkin" Message-ID: <1386087086-3691-17-git-send-email-mst@redhat.com> References: <1386087086-3691-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1386087086-3691-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PATCH 16/23] virtio: validate num_sg when mapping List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Anthony Liguori , Michael Roth 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 --- hw/virtio/virtio.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index b3c38f7..edc2ce7 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -427,6 +427,12 @@ 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: %d > %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