xenserver: Remove cacert when user reconfigures the controller

If a user moves from one controller to another, we did not remove the
cacert.  This prevents the switch from connecting to the new controller.
To ease confusion, we now delete the cacert when the user changes or
removes the controller in xsconsole.

Note: This commit has a minor security issue, since we do not remove
trust for the old certificate until the switch is restarted.  In
general, users should only be connected to trusted servers, so the
impact should be low.  Fixes this would require larger changes to the
vconn-ssl code, which we don't want to do so late in the release cycle.

Bug #1457

3 files changed, 32 insertions, 2 deletions

diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index 0236f14cb..0d9e49b30 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -27,6 +27,7 @@
 #include <strings.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
+#include <sys/types.h>
 #include <unistd.h>
 #include "bitmap.h"
 #include "cfg.h"
@@ -323,6 +324,7 @@ bridge_configure_ssl(void)
     static char *private_key_file;
     static char *certificate_file;
     static char *cacert_file;
+    struct stat s;
 
     if (config_string_change("ssl.private-key", &private_key_file)) {
         vconn_ssl_set_private_key_file(private_key_file);
@@ -332,7 +334,13 @@ bridge_configure_ssl(void)
         vconn_ssl_set_certificate_file(certificate_file);
     }
 
-    if (config_string_change("ssl.ca-cert", &cacert_file)) {
+    /* We assume that even if the filename hasn't changed, if the CA cert 
+     * file has been removed, that we want to move back into
+     * boot-strapping mode.  This opens a small security hole, because
+     * the old certificate will still be trusted until vSwitch is
+     * restarted.  We may want to address this in vconn's SSL library. */
+    if (config_string_change("ssl.ca-cert", &cacert_file)
+            || (stat(cacert_file, &s) && errno == ENOENT)) {
         vconn_ssl_set_ca_cert_file(cacert_file,
                                    cfg_get_bool(0, "ssl.bootstrap-ca-cert"));
     }
diff --git a/vswitchd/mgmt.c b/vswitchd/mgmt.c
index ce9d9f334..45c358024 100644
--- a/vswitchd/mgmt.c
+++ b/vswitchd/mgmt.c
@@ -19,6 +19,9 @@
 #include <assert.h>
 #include <errno.h>
 #include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/types.h>
 
 #include "bridge.h"
 #include "cfg.h"
@@ -101,6 +104,7 @@ mgmt_configure_ssl(void)
     static char *private_key_file;
     static char *certificate_file;
     static char *cacert_file;
+    struct stat s;
 
     /* XXX SSL should be configurable separate from the bridges.
      * XXX should be possible to de-configure SSL. */
@@ -112,7 +116,13 @@ mgmt_configure_ssl(void)
         vconn_ssl_set_certificate_file(certificate_file);
     }
 
-    if (config_string_change("ssl.ca-cert", &cacert_file)) {
+    /* We assume that even if the filename hasn't changed, if the CA cert 
+     * file has been removed, that we want to move back into
+     * boot-strapping mode.  This opens a small security hole, because
+     * the old certificate will still be trusted until vSwitch is
+     * restarted.  We may want to address this in vconn's SSL library. */
+    if (config_string_change("ssl.ca-cert", &cacert_file) 
+            || (stat(cacert_file, &s) && errno == ENOENT)) {
         vconn_ssl_set_ca_cert_file(cacert_file,
                 cfg_get_bool(0, "ssl.bootstrap-ca-cert"));
     }
diff --git a/xenserver/etc_xapi.d_plugins_vswitch-cfg-update b/xenserver/etc_xapi.d_plugins_vswitch-cfg-update
index ef4ce782e..ce407ad1b 100755
--- a/xenserver/etc_xapi.d_plugins_vswitch-cfg-update
+++ b/xenserver/etc_xapi.d_plugins_vswitch-cfg-update
@@ -27,10 +27,20 @@ logging.basicConfig(filename="/var/log/vswitch-cfg-update.log", level=logging.DE
 
 import XenAPIPlugin
 import XenAPI
+import os
 import subprocess
 
 cfg_mod="/root/vswitch/bin/ovs-cfg-mod"
 vswitchd_cfg_filename="/etc/ovs-vswitchd.conf"
+cacert_filename="/etc/ovs-vswitchd.cacert"
+
+# Delete the CA certificate, so that we go back to boot-strapping mode
+def delete_cacert():
+    try:
+        os.remove(cacert_filename)
+    except OSError:
+        # Ignore error if file doesn't exist
+        pass
 
 def update(session, args):
     pools = session.xenapi.pool.get_all()
@@ -49,6 +59,7 @@ def update(session, args):
     currentController = vswitchCurrentController()
     if controller == "" and currentController != "":
         log.debug("Removing controller configuration.")
+        delete_cacert()
         removeControllerCfg()
         return "Successfully removed controller config"
     elif controller != currentController:
@@ -56,6 +67,7 @@ def update(session, args):
             log.debug("Setting controller to: %s" % (controller))
         else:
             log.debug("Changing controller from %s to %s" % (currentController, controller))
+        delete_cacert()
         setControllerCfg(controller)
         return "Successfully set controller to " + controller
     else: