From 2f5732e9648fcddc8759a8fd25c0b41a38352be6 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Fri, 27 Jun 2014 20:02:48 +0100 Subject: [PATCH] Allow mismatched virtio config-len Commit 'virtio: validate config_len on load' restricted config_len loaded from the wire to match the config_len that the device had. Unfortunately, there are cases where this isn't true, the one we found it on was the wce addition in virtio-blk. Allow mismatched config-lengths: *) If the version on the wire is shorter then fine *) If the version on the wire is longer, load what we have space for and skip the rest. (This is mst@redhat.com's rework of what I originally posted) Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index a3082d569d..c1d538c5f3 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -926,12 +926,18 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f) return -1; } config_len = qemu_get_be32(f); - if (config_len != vdev->config_len) { - error_report("Unexpected config length 0x%x. Expected 0x%zx", - config_len, vdev->config_len); - return -1; + + /* + * There are cases where the incoming config can be bigger or smaller + * than what we have; so load what we have space for, and skip + * any excess that's in the stream. + */ + qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len)); + + while (config_len > vdev->config_len) { + qemu_get_byte(f); + config_len--; } - qemu_get_buffer(f, vdev->config, vdev->config_len); num = qemu_get_be32(f);