From 059b7dbd20a6f0c539a45ddff1573cb8946685b5 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 30 Apr 2026 12:26:52 +0000 Subject: [PATCH] vsock/virtio: fix potential unbounded skb queue MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit virtio_transport_inc_rx_pkt() checks vvs->rx_bytes + len > vvs->buf_alloc. virtio_transport_recv_enqueue() skips coalescing for packets with VIRTIO_VSOCK_SEQ_EOM. If fed with packets with len == 0 and VIRTIO_VSOCK_SEQ_EOM, a very large number of packets can be queued because vvs->rx_bytes stays at 0. Fix this by estimating the skb metadata size: (Number of skbs in the queue) * SKB_TRUESIZE(0) Fixes: 077706165717 ("virtio/vsock: don't use skbuff state to account credit") Signed-off-by: Eric Dumazet Cc: Arseniy Krasnov Cc: Stefan Hajnoczi Cc: Stefano Garzarella Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Xuan Zhuo Cc: "Eugenio Pérez" Cc: virtualization@lists.linux.dev Link: https://patch.msgid.link/20260430122653.554058-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/vmw_vsock/virtio_transport_common.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 416d533f493d..9b8014516f4f 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -447,7 +447,9 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs, u32 len) { - if (vvs->buf_used + len > vvs->buf_alloc) + u64 skb_overhead = (skb_queue_len(&vvs->rx_queue) + 1) * SKB_TRUESIZE(0); + + if (skb_overhead + vvs->buf_used + len > vvs->buf_alloc) return false; vvs->rx_bytes += len;