Thread (3 messages) 3 messages, 3 authors, 2021-11-23
STALE1771d

[PATCH] vsock/virtio: suppress used length validation

From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2021-11-22 09:32:11
Also in: kvm, lkml, netdev
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, Eugenio Pérez

It turns out that vhost vsock violates the virtio spec
by supplying the out buffer length in the used length
(should just be the in length).
As a result, attempts to validate the used length fail with:
vmw_vsock_virtio_transport virtio1: tx: used len 44 is larger than in buflen 0

Since vsock driver does not use the length fox tx and
validates the length before use for rx, it is safe to
suppress the validation in virtio core for this driver.

Reported-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: 939779f5152d ("virtio_ring: validate used buffer length")
Cc: "Jason Wang" <redacted>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 net/vmw_vsock/virtio_transport.c | 1 +
 1 file changed, 1 insertion(+)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 4f7c99dfd16c..3f82b2f1e6dd 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -731,6 +731,7 @@ static unsigned int features[] = {
 static struct virtio_driver virtio_vsock_driver = {
 	.feature_table = features,
 	.feature_table_size = ARRAY_SIZE(features),
+	.suppress_used_validation = true,
 	.driver.name = KBUILD_MODNAME,
 	.driver.owner = THIS_MODULE,
 	.id_table = id_table,
-- 
MST

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