From ee0d896b3c3ba2dbf5a7a2598a2d8dbe242a0aa7 Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Mon, 23 Apr 2018 11:33:43 +0200 Subject: [PATCH 06/11] vhost: handle virtually non-contiguous buffers in Tx This patch enables the handling of buffers non-contiguous in process virtual address space in the dequeue path. When virtio-net header doesn't fit in a single chunck, it is copied into a local variablei before being processed. For packet content, the copy length is limited to the chunck size, next chuncks VAs being fetched afterward. This issue has been assigned CVE-2018-1059. Signed-off-by: Maxime Coquelin --- lib/librte_vhost/virtio_net.c | 117 ++++++++++++++++++++++++++++++++++-------- 1 file changed, 95 insertions(+), 22 deletions(-) diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c index 13252e6..47717a1 100644 --- a/lib/librte_vhost/virtio_net.c +++ b/lib/librte_vhost/virtio_net.c @@ -996,10 +996,11 @@ { struct vring_desc *desc; - uint64_t desc_addr; + uint64_t desc_addr, desc_gaddr; uint32_t desc_avail, desc_offset; uint32_t mbuf_avail, mbuf_offset; uint32_t cpy_len; - uint64_t dlen; + uint64_t desc_chunck_len; struct rte_mbuf *cur = m, *prev = m; + struct virtio_net_hdr tmp_hdr; struct virtio_net_hdr *hdr = NULL; /* A counter to avoid desc dead loop chain */ @@ -1016,10 +1017,11 @@ } - dlen = desc->len; + desc_chunck_len = desc->len; + desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, - vq, desc->addr, - &dlen, + vq, desc_gaddr, + &desc_chunck_len, VHOST_ACCESS_RO); - if (unlikely(!desc_addr || dlen != desc->len)) { + if (unlikely(!desc_addr)) { error = -1; goto out; @@ -1027,6 +1029,38 @@ if (virtio_net_with_host_offload(dev)) { - hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr); - rte_prefetch0(hdr); + if (unlikely(desc_chunck_len < sizeof(struct virtio_net_hdr))) { + uint64_t len = desc_chunck_len; + uint64_t remain = sizeof(struct virtio_net_hdr); + uint64_t src = desc_addr; + uint64_t dst = (uint64_t)(uintptr_t)&tmp_hdr; + uint64_t guest_addr = desc_gaddr; + + /* + * No luck, the virtio-net header doesn't fit + * in a contiguous virtual area. + */ + while (remain) { + len = remain; + src = vhost_iova_to_vva(dev, vq, + guest_addr, &len, + VHOST_ACCESS_RO); + if (unlikely(!src || !len)) { + error = -1; + goto out; + } + + rte_memcpy((void *)(uintptr_t)dst, + (void *)(uintptr_t)src, len); + + guest_addr += len; + remain -= len; + dst += len; + } + + hdr = &tmp_hdr; + } else { + hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr); + rte_prefetch0(hdr); + } } @@ -1044,10 +1078,11 @@ } - dlen = desc->len; + desc_chunck_len = desc->len; + desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, - vq, desc->addr, - &dlen, + vq, desc_gaddr, + &desc_chunck_len, VHOST_ACCESS_RO); - if (unlikely(!desc_addr || dlen != desc->len)) { + if (unlikely(!desc_addr)) { error = -1; goto out; @@ -1059,10 +1094,28 @@ } else { desc_avail = desc->len - dev->vhost_hlen; - desc_offset = dev->vhost_hlen; + + if (unlikely(desc_chunck_len < dev->vhost_hlen)) { + desc_chunck_len = desc_avail; + desc_gaddr += dev->vhost_hlen; + desc_addr = vhost_iova_to_vva(dev, + vq, desc_gaddr, + &desc_chunck_len, + VHOST_ACCESS_RO); + if (unlikely(!desc_addr)) { + error = -1; + goto out; + } + + desc_offset = 0; + } else { + desc_offset = dev->vhost_hlen; + desc_chunck_len -= dev->vhost_hlen; + } } rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset)); - PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0); + PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), + desc_chunck_len, 0); mbuf_offset = 0; @@ -1071,5 +1124,5 @@ uint64_t hpa; - cpy_len = RTE_MIN(desc_avail, mbuf_avail); + cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail); /* @@ -1079,5 +1132,5 @@ */ if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev, - desc->addr + desc_offset, cpy_len)))) { + desc_gaddr + desc_offset, cpy_len)))) { cur->data_len = cpy_len; cur->data_off = 0; @@ -1094,5 +1147,6 @@ if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size || - (hdr && cur == m))) { + (hdr && cur == m) || + desc->len != desc_chunck_len)) { rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *, mbuf_offset), @@ -1115,4 +1169,5 @@ mbuf_offset += cpy_len; desc_avail -= cpy_len; + desc_chunck_len -= cpy_len; desc_offset += cpy_len; @@ -1133,9 +1188,11 @@ } - dlen = desc->len; + desc_chunck_len = desc->len; + desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, - vq, desc->addr, - &dlen, VHOST_ACCESS_RO); - if (unlikely(!desc_addr || dlen != desc->len)) { + vq, desc_gaddr, + &desc_chunck_len, + VHOST_ACCESS_RO); + if (unlikely(!desc_addr)) { error = -1; goto out; @@ -1147,5 +1204,21 @@ desc_avail = desc->len; - PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0); + PRINT_PACKET(dev, (uintptr_t)desc_addr, + desc_chunck_len, 0); + } else if (unlikely(desc_chunck_len == 0)) { + desc_chunck_len = desc_avail; + desc_gaddr += desc_offset; + desc_addr = vhost_iova_to_vva(dev, vq, + desc_gaddr, + &desc_chunck_len, + VHOST_ACCESS_RO); + if (unlikely(!desc_addr)) { + error = -1; + goto out; + } + desc_offset = 0; + + PRINT_PACKET(dev, (uintptr_t)desc_addr, + desc_chunck_len, 0); } -- 1.8.3.1