From 44593865b7c5f55bf587f297c72d682c671eea2b Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Fri, 4 Jun 2021 13:53:47 +0800 Subject: [PATCH] virtio_ring: secure handling of mapping errors We should not depend on the DMA address, length and flag of descriptor table since they could be wrote with arbitrary value by the device. So this patch switches to use the stored one in desc_extra. Note that the indirect descriptors are fine since they are read-only streaming mappings. Signed-off-by: Jason Wang Link: https://lore.kernel.org/r/20210604055350.58753-5-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin --- drivers/virtio/virtio_ring.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index f2f4a3b..00e5411 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1219,13 +1219,16 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, unmap_release: err_idx = i; i = head; + curr = vq->free_head; vq->packed.avail_used_flags = avail_used_flags; for (n = 0; n < total_sg; n++) { if (i == err_idx) break; - vring_unmap_desc_packed(vq, &desc[i]); + vring_unmap_state_packed(vq, + &vq->packed.desc_extra[curr]); + curr = vq->packed.desc_extra[curr].next; i++; if (i >= vq->packed.vring.num) i = 0; -- 2.7.4