The hdr->csum_start does two successive reads from user space to read a
variable length data structure. The result overflow if the data structure
changes between the two reads.
To fix this, we can prevent double fetch issue by copying virtio_hdr to
the temporary variable.
Fixes: 4dc4e33ffa10 ("net/virtio: fix Rx checksum calculation")
Cc: sta...@dpdk.org
Signed-off-by: Yunjian Wang <wangyunj...@huawei.com>
---
v2: update code styles suggested by David Marchand
---
lib/vhost/virtio_net.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 69901ab3b5..2676447906 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -2896,8 +2896,8 @@ desc_to_mbuf(struct virtio_net *dev, struct
vhost_virtqueue *vq,
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;
+ bool has_vnet_hdr = false;
+ struct virtio_net_hdr hdr;
uint16_t vec_idx;
struct vhost_async *async = vq->async;
struct async_inflight_info *pkts_info;
@@ -2913,11 +2913,11 @@ desc_to_mbuf(struct virtio_net *dev, struct
vhost_virtqueue *vq,
* No luck, the virtio-net header doesn't fit
* in a contiguous virtual area.
*/
- copy_vnet_hdr_from_desc(&tmp_hdr, buf_vec);
- hdr = &tmp_hdr;
+ copy_vnet_hdr_from_desc(&hdr, buf_vec);
} else {
- hdr = (struct virtio_net_hdr
*)((uintptr_t)buf_vec[0].buf_addr);
+ hdr = *(struct virtio_net_hdr
*)((uintptr_t)buf_vec[0].buf_addr);
}
+ has_vnet_hdr = true;
}
for (vec_idx = 0; vec_idx < nr_vec; vec_idx++) {
@@ -2953,7 +2953,7 @@ desc_to_mbuf(struct virtio_net *dev, struct
vhost_virtqueue *vq,
if (async_fill_seg(dev, vq, cur, mbuf_offset,
buf_iova + buf_offset, cpy_len,
false) < 0)
goto error;
- } else if (likely(hdr && cur == m)) {
+ } else if (likely(has_vnet_hdr && cur == m)) {
rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
mbuf_offset),
(void *)((uintptr_t)(buf_addr + buf_offset)),
cpy_len);
@@ -3013,10 +3013,10 @@ desc_to_mbuf(struct virtio_net *dev, struct
vhost_virtqueue *vq,
if (is_async) {
async_iter_finalize(async);
- if (hdr)
- pkts_info[slot_idx].nethdr = *hdr;
- } else if (hdr) {
- vhost_dequeue_offload(dev, hdr, m, legacy_ol_flags);
+ if (has_vnet_hdr)
+ pkts_info[slot_idx].nethdr = hdr;
+ } else if (has_vnet_hdr) {
+ vhost_dequeue_offload(dev, &hdr, m, legacy_ol_flags);
}
return 0;
@@ -3363,7 +3363,6 @@ virtio_dev_tx_batch_packed(struct virtio_net *dev,
{
uint16_t avail_idx = vq->last_avail_idx;
uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
- struct virtio_net_hdr *hdr;
uintptr_t desc_addrs[PACKED_BATCH_SIZE];
uint16_t ids[PACKED_BATCH_SIZE];
uint16_t i;
@@ -3381,9 +3380,11 @@ virtio_dev_tx_batch_packed(struct virtio_net *dev,
pkts[i]->pkt_len);
if (virtio_net_with_host_offload(dev)) {
+ struct virtio_net_hdr hdr;
+
vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
- hdr = (struct virtio_net_hdr *)(desc_addrs[i]);
- vhost_dequeue_offload(dev, hdr, pkts[i],
legacy_ol_flags);
+ hdr = *(struct virtio_net_hdr *)(desc_addrs[i]);
+ vhost_dequeue_offload(dev, &hdr, pkts[i],
legacy_ol_flags);
}
}
--
2.33.0
