* [PATCH 6.18 318/325] vsock/virtio: fix potential unbounded skb queue
[not found] <20260616145057.827196531@linuxfoundation.org>
@ 2026-06-16 15:01 ` Greg Kroah-Hartman
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From: Greg Kroah-Hartman @ 2026-06-16 15:01 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Eric Dumazet, Arseniy Krasnov,
Stefan Hajnoczi, Stefano Garzarella, Michael S. Tsirkin,
Jason Wang, Xuan Zhuo, Eugenio Pérez, virtualization,
Jakub Kicinski
6.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
commit 059b7dbd20a6f0c539a45ddff1573cb8946685b5 upstream.
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 <edumazet@google.com>
Cc: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Stefano Garzarella <sgarzare@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: virtualization@lists.linux.dev
Link: https://patch.msgid.link/20260430122653.554058-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/vmw_vsock/virtio_transport_common.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -425,7 +425,9 @@ static int virtio_transport_send_pkt_inf
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;
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