From e12d415556994d0901c317f6338ed2961185465f Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: References: From: Maxime Coquelin Date: Thu, 16 Jun 2022 14:25:07 +0200 Subject: [PATCH 2/2] vhost: fix header spanned across more than two descriptors [ upstream commit dc1516e260a0df272b218392faf6db3cbf45e717 ] This patch aims at supporting the unlikely case where a Virtio-net header is spanned across more than two descriptors. CVE-2022-2132 Fixes: fd68b4739d2c ("vhost: use buffer vectors in dequeue path") Signed-off-by: Maxime Coquelin Acked-by: Chenbo Xia Reviewed-by: David Marchand --- lib/vhost/virtio_net.c | 41 +++++++++++++---------------------------- 1 file changed, 13 insertions(+), 28 deletions(-) diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index 991a7a2bd4..bf4d75b4bd 100644 --- a/lib/vhost/virtio_net.c +++ b/lib/vhost/virtio_net.c @@ -2322,25 +2322,22 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, uint32_t buf_avail, buf_offset; uint64_t buf_addr, buf_len; uint32_t mbuf_avail, mbuf_offset; + uint32_t hdr_remain = dev->vhost_hlen; uint32_t cpy_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 */ - uint16_t vec_idx = 0; + uint16_t vec_idx; struct batch_copy_elem *batch_copy = vq->batch_copy_elems; int error = 0; - buf_addr = buf_vec[vec_idx].buf_addr; - buf_len = buf_vec[vec_idx].buf_len; - /* * The caller has checked the descriptors chain is larger than the * header size. */ if (virtio_net_with_host_offload(dev)) { - if (unlikely(buf_len < sizeof(struct virtio_net_hdr))) { + if (unlikely(buf_vec[0].buf_len < sizeof(struct virtio_net_hdr))) { /* * No luck, the virtio-net header doesn't fit * in a contiguous virtual area. @@ -2348,34 +2345,22 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, copy_vnet_hdr_from_desc(&tmp_hdr, buf_vec); hdr = &tmp_hdr; } else { - hdr = (struct virtio_net_hdr *)((uintptr_t)buf_addr); + hdr = (struct virtio_net_hdr *)((uintptr_t)buf_vec[0].buf_addr); } } - /* - * A virtio driver normally uses at least 2 desc buffers - * for Tx: the first for storing the header, and others - * for storing the data. - */ - if (unlikely(buf_len < dev->vhost_hlen)) { - buf_offset = dev->vhost_hlen - buf_len; - vec_idx++; - buf_addr = buf_vec[vec_idx].buf_addr; - buf_len = buf_vec[vec_idx].buf_len; - buf_avail = buf_len - buf_offset; - } else if (buf_len == dev->vhost_hlen) { - if (unlikely(++vec_idx >= nr_vec)) - goto out; - buf_addr = buf_vec[vec_idx].buf_addr; - buf_len = buf_vec[vec_idx].buf_len; + for (vec_idx = 0; vec_idx < nr_vec; vec_idx++) { + if (buf_vec[vec_idx].buf_len > hdr_remain) + break; - buf_offset = 0; - buf_avail = buf_len; - } else { - buf_offset = dev->vhost_hlen; - buf_avail = buf_vec[vec_idx].buf_len - dev->vhost_hlen; + hdr_remain -= buf_vec[vec_idx].buf_len; } + buf_addr = buf_vec[vec_idx].buf_addr; + buf_len = buf_vec[vec_idx].buf_len; + buf_offset = hdr_remain; + buf_avail = buf_vec[vec_idx].buf_len - hdr_remain; + PRINT_PACKET(dev, (uintptr_t)(buf_addr + buf_offset), (uint32_t)buf_avail, 0); -- 2.37.3