[evolution] Avoid use-after-free in em_config_target_update_settings

[Milan Crha <mcrha src gnome org>]

commit a9cea92f5e356655013e20be8f1a94543c9ed72f
Author: Milan Crha <mcrha redhat com>
Date:   Thu Dec 15 14:45:57 2011 +0100

    Avoid use-after-free in em_config_target_update_settings

 mail/em-config.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/mail/em-config.c b/mail/em-config.c
index 1e02532..fbf27fa 100644
--- a/mail/em-config.c
+++ b/mail/em-config.c
@@ -207,6 +207,8 @@ em_config_target_update_settings (EConfig *ep,
                                   const gchar *transport_protocol,
                                   CamelSettings *transport_settings)
 {
+	gchar *tmp;
+
 	g_return_if_fail (ep != NULL);
 	g_return_if_fail (target != NULL);
 
@@ -228,8 +230,10 @@ em_config_target_update_settings (EConfig *ep,
 	if (target->transport_settings != NULL)
 		g_object_unref (target->transport_settings);
 
+	/* the pointers can be same, thus avoid use-after-free */
+	tmp = g_strdup (email_address);
 	g_free (target->email_address);
-	target->email_address = g_strdup (email_address);
+	target->email_address = tmp;
 
 	target->storage_protocol = storage_protocol;
 	target->storage_settings = storage_settings;