From f60ab5337f968e2f10c639ab59db7afb0fe4f7c3 Mon Sep 17 00:00:00 2001
From: Jan Beulich <jbeulich@suse.com>
Date: Wed, 30 Sep 2020 09:10:01 +0200
Subject: [PATCH] evtchn: refuse EVTCHNOP_status for Xen-bound event channels

Callers have no business knowing the state of the Xen end of an event
channel.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Paul Durrant <Paul@xen.org>
---
 xen/common/event_channel.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index d2ee83bbbf..49cb318b81 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -933,6 +933,11 @@ int evtchn_status(evtchn_status_t *status)
     }
 
     chn = evtchn_from_port(d, port);
+    if ( consumer_is_xen(chn) )
+    {
+        rc = -EACCES;
+        goto out;
+    }
 
     rc = xsm_evtchn_status(XSM_TARGET, d, chn);
     if ( rc )
-- 
2.30.2