Fix crash in libvirtd when events are registered & ACLs active

When a client disconnects from libvirtd, all event callbacks
must be removed. This involves running the public API

  virConnectDomainEventDeregisterAny

This code does not run in normal API dispatch context, so no
identity was set. The result was that the access control drivers
denied the attempt to deregister callbacks. The callbacks thus
continued to trigger after the client was free'd causing fairly
predictable use of free memory & a crash.

This can be triggered by any client with readonly access when
the ACL drivers are active.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 8294aa0c1750dcb49d6345cd9bd97bf421580d8b)

diff --git a/daemon/remote.c b/daemon/remote.c
index 14fd0e54862c3cd191e1ca7dcb6081a0d005f9c0..3653a5f3045038901b38222cec2acf516ec39773 100644 (file)
--- a/daemon/remote.c
+++ b/daemon/remote.c
@@ -666,8 +666,11 @@ void remoteClientFreeFunc(void *data)
 
     /* Deregister event delivery callback */
     if (priv->conn) {
+        virIdentityPtr sysident = virIdentityGetSystem();
         size_t i;
 
+        virIdentitySetCurrent(sysident);
+
         for (i = 0; i < VIR_DOMAIN_EVENT_ID_LAST; i++) {
             if (priv->domainEventCallbackID[i] != -1) {
                 VIR_DEBUG("Deregistering to relay remote events %zu", i);
@@ -678,6 +681,9 @@ void remoteClientFreeFunc(void *data)
         }
 
         virConnectClose(priv->conn);
+
+        virIdentitySetCurrent(NULL);
+        virObjectUnref(sysident);
     }
 
     VIR_FREE(priv);