[PATCH v2 2/8] vsock/virtio: Validate length in packet header before skb_put()
From: Will Deacon <will@kernel.org>
Date: 2025-07-01 16:45:21
Also in:
lkml, stable, virtualization
Subsystem:
networking [general], the rest, virtio and vhost vsock driver, virtio core, vm sockets (af_vsock) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Stefan Hajnoczi, Stefano Garzarella, "Michael S. Tsirkin", Jason Wang
When receiving a vsock packet in the guest, only the virtqueue buffer
size is validated prior to virtio_vsock_skb_rx_put(). Unfortunately,
virtio_vsock_skb_rx_put() uses the length from the packet header as the
length argument to skb_put(), potentially resulting in SKB overflow if
the host has gone wonky.
Validate the length as advertised by the packet header before calling
virtio_vsock_skb_rx_put().
Cc: <redacted>
Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
Signed-off-by: Will Deacon <will@kernel.org>
---
net/vmw_vsock/virtio_transport.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index f0e48e6911fc..bd2c6aaa1a93 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c@@ -624,8 +624,9 @@ static void virtio_transport_rx_work(struct work_struct *work) do { virtqueue_disable_cb(vq); for (;;) { + unsigned int len, payload_len; + struct virtio_vsock_hdr *hdr; struct sk_buff *skb; - unsigned int len; if (!virtio_transport_more_replies(vsock)) { /* Stop rx until the device processes already
@@ -642,12 +643,19 @@ static void virtio_transport_rx_work(struct work_struct *work) vsock->rx_buf_nr--; /* Drop short/long packets */ - if (unlikely(len < sizeof(struct virtio_vsock_hdr) || + if (unlikely(len < sizeof(*hdr) || len > virtio_vsock_skb_len(skb))) { kfree_skb(skb); continue; } + hdr = virtio_vsock_hdr(skb); + payload_len = le32_to_cpu(hdr->len); + if (payload_len > len - sizeof(*hdr)) { + kfree_skb(skb); + continue; + } + virtio_vsock_skb_rx_put(skb); virtio_transport_deliver_tap_pkt(skb); virtio_transport_recv_pkt(&virtio_transport, skb);
--
2.50.0.727.gbf7dc18ff4-goog