Fix perms for virConnectDomainXML{To,From}Native (CVE-2013-4401)

The virConnectDomainXMLToNative API should require 'connect:write'
not 'connect:read', since it will trigger execution of the QEMU
binaries listed in the XML.

Also make virConnectDomainXMLFromNative API require a full
read-write connection and 'connect:write' permission. Although the
current impl doesn't trigger execution of QEMU, we should not
rely on that impl detail from an API permissioning POV.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/libvirt.c

@@ -4611,6 +4611,10 @@ char *virConnectDomainXMLFromNative(virConnectPtr conn,
         virDispatchError(NULL);
         return NULL;
     }
+    if (conn->flags & VIR_CONNECT_RO) {
+        virLibDomainError(VIR_ERR_OPERATION_DENIED, __FUNCTION__);
+        goto error;
+    }
 
     virCheckNonNullArgGoto(nativeFormat, error);
     virCheckNonNullArgGoto(nativeConfig, error);

src/remote/remote_protocol.x

@@ -3826,13 +3826,13 @@ enum remote_procedure {
 
     /**
      * @generate: both
-     * @acl: connect:read
+     * @acl: connect:write
      */
     REMOTE_PROC_CONNECT_DOMAIN_XML_FROM_NATIVE = 135,
 
     /**
      * @generate: both
-     * @acl: connect:read
+     * @acl: connect:write
      */
     REMOTE_PROC_CONNECT_DOMAIN_XML_TO_NATIVE = 136,