From ebd02c060abddfa1a5cf971c05c8ebc65b70bbd6 Mon Sep 17 00:00:00 2001 From: Ilya Maximets Date: Fri, 15 Jul 2016 14:15:05 +0300 Subject: [PATCH] vhost: check ring descriptor address In current implementation vhost will crash with segmentation fault if malicious or buggy virtio application breaks addresses of descriptors. Before commit 0823c1cb0a73 ("vhost: workaround stale vring base") this crash was reproducible even with normal DPDK application that tries to change number of virtqueues dynamically inside VM. Fix that by checking addresses of descriptors before using. Signed-off-by: Ilya Maximets Acked-by: Yuanhan Liu --- lib/librte_vhost/vhost_rxtx.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c index a9b04df370..bc00518ad2 100644 --- a/lib/librte_vhost/vhost_rxtx.c +++ b/lib/librte_vhost/vhost_rxtx.c @@ -147,10 +147,15 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq, struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0}; desc = &vq->desc[desc_idx]; - if (unlikely(desc->len < dev->vhost_hlen)) + desc_addr = gpa_to_vva(dev, desc->addr); + /* + * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid + * performance issue with some versions of gcc (4.8.4 and 5.3.0) which + * otherwise stores offset on the stack instead of in a register. + */ + if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr) return -1; - desc_addr = gpa_to_vva(dev, desc->addr); rte_prefetch0((void *)(uintptr_t)desc_addr); virtio_enqueue_offload(m, &virtio_hdr.hdr); @@ -182,7 +187,10 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq, return -1; desc = &vq->desc[desc->next]; - desc_addr = gpa_to_vva(dev, desc->addr); + desc_addr = gpa_to_vva(dev, desc->addr); + if (unlikely(!desc_addr)) + return -1; + desc_offset = 0; desc_avail = desc->len; } @@ -387,10 +395,10 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq, LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n", dev->vid, cur_idx, end_idx); - if (buf_vec[vec_idx].buf_len < dev->vhost_hlen) + desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr); + if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr) return 0; - desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr); rte_prefetch0((void *)(uintptr_t)desc_addr); virtio_hdr.num_buffers = end_idx - start_idx; @@ -425,6 +433,8 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq, vec_idx++; desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr); + if (unlikely(!desc_addr)) + return 0; /* Prefetch buffer address. */ rte_prefetch0((void *)(uintptr_t)desc_addr); @@ -688,6 +698,9 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, return -1; desc_addr = gpa_to_vva(dev, desc->addr); + if (unlikely(!desc_addr)) + return -1; + hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr); rte_prefetch0(hdr); @@ -701,6 +714,9 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, desc = &vq->desc[desc->next]; desc_addr = gpa_to_vva(dev, desc->addr); + if (unlikely(!desc_addr)) + return -1; + rte_prefetch0((void *)(uintptr_t)desc_addr); desc_offset = 0; @@ -737,6 +753,9 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, desc = &vq->desc[desc->next]; desc_addr = gpa_to_vva(dev, desc->addr); + if (unlikely(!desc_addr)) + return -1; + rte_prefetch0((void *)(uintptr_t)desc_addr); desc_offset = 0; -- 2.20.1