If the socket has been de-assigned or assigned to another transport,
we must discard any packets received because they are not expected
and would cause issues when we access vsk->transport.
A possible scenario is described by Hyunwoo Kim in the attached link,
where after a first connect() interrupted by a signal, and a second
connect() failed, we can find `vsk->transport` at NULL, leading to a
NULL pointer dereference.
Fixes: c0cfa2d8a788 ("vsock: add multi-transports support")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Hyunwoo Kim <v4bel@xxxxxxxxx>
Reported-by: Wongi Lee <qwerty@xxxxxxxxx>
Closes: https://lore.kernel.org/netdev/Z2LvdTTQR7dBmPb5@v4bel-B760M-AORUS-ELITE-AX/
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
net/vmw_vsock/virtio_transport_common.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 9acc13ab3f82..51a494b69be8 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1628,8 +1628,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
lock_sock(sk);
- /* Check if sk has been closed before lock_sock */
- if (sock_flag(sk, SOCK_DONE)) {
+ /* Check if sk has been closed or assigned to another transport before
+ * lock_sock (note: listener sockets are not assigned to any transport)
+ */
+ if (sock_flag(sk, SOCK_DONE) ||
+ (sk->sk_state != TCP_LISTEN && vsk->transport != &t->transport)) {
(void)virtio_transport_reset_no_sock(t, skb);
release_sock(sk);
sock_put(sk);
--
2.47.1
