From 29b9f5efd78ae0f9cc02dd169b6e80d2c404bade Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Fri, 25 Sep 2015 13:21:29 +0800 Subject: [PATCH] virtio: introduce virtqueue_discard() This patch introduces virtqueue_discard() to discard a descriptor and unmap the sgs. This will be used by the patch that will discard descriptor when packet is truncated. Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Upstream-Status: Backport git.qemu.org/?p=qemu.git;a=commit;h=29b9f5efd78ae0f9cc02dd169b6e80d2c404bade CVE: CVE-2015-7295 patch #2 [Yocto # 9013] Signed-off-by: Armin Kuster --- hw/virtio/virtio.c | 7 +++++++ include/hw/virtio/virtio.h | 2 ++ 2 files changed, 9 insertions(+) Index: qemu-2.4.0/hw/virtio/virtio.c =================================================================== --- qemu-2.4.0.orig/hw/virtio/virtio.c +++ qemu-2.4.0/hw/virtio/virtio.c @@ -266,6 +266,13 @@ static void virtqueue_unmap_sg(VirtQueue 0, elem->out_sg[i].iov_len); } +void virtqueue_discard(VirtQueue *vq, const VirtQueueElement *elem, + unsigned int len) +{ + vq->last_avail_idx--; + virtqueue_unmap_sg(vq, elem, len); +} + void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx) { Index: qemu-2.4.0/include/hw/virtio/virtio.h =================================================================== --- qemu-2.4.0.orig/include/hw/virtio/virtio.h +++ qemu-2.4.0/include/hw/virtio/virtio.h @@ -146,6 +146,8 @@ void virtio_del_queue(VirtIODevice *vdev void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len); void virtqueue_flush(VirtQueue *vq, unsigned int count); +void virtqueue_discard(VirtQueue *vq, const VirtQueueElement *elem, + unsigned int len); void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx);