[libvirt] [PATCH] qemu: don't share kerberos caches between domains

[Eric Blake]

https://bugzilla.redhat.com/show_bug.cgi?id=718377
complains that there were some SELinux AVCs when using vnc console
over Kerberos.  The root problem was that Kerberos tries to set up
a cache file, and if we don't tell it where, then all domains use
the same cache file, which violates sVirt protections.  Setting the
environment variable unconditionally should be safe, even for setups
where Kerboros won't actually create a cache file.

* src/qemu/qemu_process.c (qemuProcessStart): Set KRB5CACHEDIR for
each domain.
---
 src/qemu/qemu_process.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 55d00e3..986e8ee 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -1,7 +1,7 @@
 /*
  * qemu_process.h: QEMU process management
  *
- * Copyright (C) 2006-2012 Red Hat, Inc.
+ * Copyright (C) 2006-2013 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -3857,6 +3857,8 @@ int qemuProcessStart(virConnectPtr conn,
     virCommandSetPidFile(cmd, priv->pidfile);
     virCommandDaemonize(cmd);
     virCommandRequireHandshake(cmd);
+    virCommandAddEnvFormat(cmd, "KRB5CACHEDIR=%s/%s.krb",
+                           driver->cacheDir, vm->def->name);

     ret = virCommandRun(cmd, NULL);

-- 
1.8.1