From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54281) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f5Xzt-00063b-17 for qemu-devel@nongnu.org; Mon, 09 Apr 2018 10:42:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f5Xzr-000860-Tc for qemu-devel@nongnu.org; Mon, 09 Apr 2018 10:42:17 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49082 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f5Xzr-00085l-Oh for qemu-devel@nongnu.org; Mon, 09 Apr 2018 10:42:15 -0400 Date: Mon, 9 Apr 2018 17:42:09 +0300 From: "Michael S. Tsirkin" Message-ID: <1523284856-251254-6-git-send-email-mst@redhat.com> References: <1523284856-251254-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1523284856-251254-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 5/5] virtio-serial: fix heap-over-flow List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , linzhecheng , Stefan Hajnoczi , Amit Shah , Paolo Bonzini From: linzhecheng Check device having the feature of VIRTIO_CONSOLE_F_EMERG_WRITE before get config->emerg_wr. It is neccessary because sizeof(virtio_console_config) is 8 byte if VirtIOSerial doesn't have the feature of VIRTIO_CONSOLE_F_EMERG_WRITE(see virtio_serial_device_realize), read/write emerg_wr will lead to heap-over-flow. Signed-off-by: linzhecheng Reviewed-by: Stefan Hajnoczi Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/char/virtio-serial-bus.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index 9470bd7..d2dd8ab 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -580,13 +580,16 @@ static void set_config(VirtIODevice *vdev, const uint8_t *config_data) VirtIOSerial *vser = VIRTIO_SERIAL(vdev); struct virtio_console_config *config = (struct virtio_console_config *)config_data; - uint8_t emerg_wr_lo = le32_to_cpu(config->emerg_wr); VirtIOSerialPort *port = find_first_connected_console(vser); VirtIOSerialPortClass *vsc; + uint8_t emerg_wr_lo; - if (!config->emerg_wr) { + if (!virtio_has_feature(vser->host_features, + VIRTIO_CONSOLE_F_EMERG_WRITE) || !config->emerg_wr) { return; } + + emerg_wr_lo = le32_to_cpu(config->emerg_wr); /* Make sure we don't misdetect an emergency write when the guest * does a short config write after an emergency write. */ config->emerg_wr = 0; -- MST