netdev - [PATCH net v2 5/5] vsock: prevent null-ptr-deref in vsock_*[has_data|has

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Message-ID: <20250110083511.30419-6-sgarzare@redhat.com>
Date: Fri, 10 Jan 2025 09:35:11 +0100
From: Stefano Garzarella <sgarzare@...hat.com>
To: netdev@...r.kernel.org
Cc: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
	bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Luigi Leonardi <leonardi@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Wongi Lee <qwerty@...ori.io>,
	Stefano Garzarella <sgarzare@...hat.com>,
	Eugenio Pérez <eperezma@...hat.com>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Eric Dumazet <edumazet@...gle.com>,
	kvm@...r.kernel.org,
	Paolo Abeni <pabeni@...hat.com>,
	Stefan Hajnoczi <stefanha@...hat.com>,
	Jason Wang <jasowang@...hat.com>,
	Simon Horman <horms@...nel.org>,
	Hyunwoo Kim <v4bel@...ori.io>,
	Jakub Kicinski <kuba@...nel.org>,
	Michal Luczaj <mhal@...x.co>,
	virtualization@...ts.linux.dev,
	Bobby Eshleman <bobby.eshleman@...edance.com>,
	stable@...r.kernel.org
Subject: [PATCH net v2 5/5] vsock: prevent null-ptr-deref in vsock_*[has_data|has_space]

Recent reports have shown how we sometimes call vsock_*_has_data()
when a vsock socket has been de-assigned from a transport (see attached
links), but we shouldn't.

Previous commits should have solved the real problems, but we may have
more in the future, so to avoid null-ptr-deref, we can return 0
(no space, no data available) but with a warning.

This way the code should continue to run in a nearly consistent state
and have a warning that allows us to debug future problems.

Fixes: c0cfa2d8a788 ("vsock: add multi-transports support")
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/netdev/Z2K%2FI4nlHdfMRTZC@v4bel-B760M-AORUS-ELITE-AX/
Link: https://lore.kernel.org/netdev/5ca20d4c-1017-49c2-9516-f6f75fd331e9@rbox.co/
Link: https://lore.kernel.org/netdev/677f84a8.050a0220.25a300.01b3.GAE@google.com/
Co-developed-by: Hyunwoo Kim <v4bel@...ori.io>
Signed-off-by: Hyunwoo Kim <v4bel@...ori.io>
Co-developed-by: Wongi Lee <qwerty@...ori.io>
Signed-off-by: Wongi Lee <qwerty@...ori.io>
Signed-off-by: Stefano Garzarella <sgarzare@...hat.com>
---
 net/vmw_vsock/af_vsock.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 74d35a871644..fa9d1b49599b 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -879,6 +879,9 @@ EXPORT_SYMBOL_GPL(vsock_create_connected);
 
 s64 vsock_stream_has_data(struct vsock_sock *vsk)
 {
+	if (WARN_ON(!vsk->transport))
+		return 0;
+
 	return vsk->transport->stream_has_data(vsk);
 }
 EXPORT_SYMBOL_GPL(vsock_stream_has_data);
@@ -887,6 +890,9 @@ s64 vsock_connectible_has_data(struct vsock_sock *vsk)
 {
 	struct sock *sk = sk_vsock(vsk);
 
+	if (WARN_ON(!vsk->transport))
+		return 0;
+
 	if (sk->sk_type == SOCK_SEQPACKET)
 		return vsk->transport->seqpacket_has_data(vsk);
 	else
@@ -896,6 +902,9 @@ EXPORT_SYMBOL_GPL(vsock_connectible_has_data);
 
 s64 vsock_stream_has_space(struct vsock_sock *vsk)
 {
+	if (WARN_ON(!vsk->transport))
+		return 0;
+
 	return vsk->transport->stream_has_space(vsk);
 }
 EXPORT_SYMBOL_GPL(vsock_stream_has_space);
-- 
2.47.1