netdev - Re: [PATCH v4 2/9] vsock/virtio: Validate length in packet header before skb

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <y6taqbyskzr4k7tetixgkhdo2z2dgrionsor3jriuo4bxlqdfc@fjnq7tig4bik>
Date: Thu, 17 Jul 2025 11:39:12 +0200
From: Stefano Garzarella <sgarzare@...hat.com>
To: Will Deacon <will@...nel.org>
Cc: linux-kernel@...r.kernel.org, Keir Fraser <keirf@...gle.com>, 
	Steven Moreland <smoreland@...gle.com>, Frederick Mayle <fmayle@...gle.com>, 
	Stefan Hajnoczi <stefanha@...hat.com>, "Michael S. Tsirkin" <mst@...hat.com>, 
	Jason Wang <jasowang@...hat.com>, Eugenio Pérez <eperezma@...hat.com>, 
	netdev@...r.kernel.org, virtualization@...ts.linux.dev, stable@...r.kernel.org
Subject: Re: [PATCH v4 2/9] vsock/virtio: Validate length in packet header
 before skb_put()

On Thu, Jul 17, 2025 at 10:01:09AM +0100, Will Deacon wrote:
>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: <stable@...r.kernel.org>
>Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
>Signed-off-by: Will Deacon <will@...nel.org>
>---
> net/vmw_vsock/virtio_transport.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@...hat.com>

>
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index f0e48e6911fc..eb08a393413d 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 (unlikely(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
>