Fixing serious memory allocation bug in sbus_message_handler.

dbus_message_append_args() adds a reference to memory that is not
copied to the outgoing message until dbus_connection_send() is
called. Since we compile our reply messages in functions and then
return the reply, we need a mechanism for deleting allocated
memory after invoking dbus_connection_send. I have changed the
arguments to sbus_msg_handler_fn so that it takes a talloc ctx
containing the sbus_message_handler_ctx and a pointer to a reply
object. We can now allocate memory as a child of the reply context
and free it after calling dbus_connection_send.

1 files changed, 3 insertions, 6 deletions

diff --git a/server/monitor/monitor.c b/server/monitor/monitor.c
index 166cf3cdd..45191a680 100644
--- a/server/monitor/monitor.c
+++ b/server/monitor/monitor.c
@@ -88,22 +88,19 @@ static void set_global_checker(struct mt_ctx *ctx);
 /* dbus_get_monitor_version
  * Return the monitor version over D-BUS */
 static int dbus_get_monitor_version(DBusMessage *message,
-                                    void *data,
-                                    DBusMessage **r)
+                                    struct sbus_message_ctx *reply)
 {
     const char *version = MONITOR_VERSION;
-    DBusMessage *reply;
     dbus_bool_t ret;
 
-    reply = dbus_message_new_method_return(message);
-    ret = dbus_message_append_args(reply, DBUS_TYPE_STRING,
+    reply->reply_message = dbus_message_new_method_return(message);
+    ret = dbus_message_append_args(reply->reply_message, DBUS_TYPE_STRING,
                                    &version, DBUS_TYPE_INVALID);
 
     if (!ret) {
         return EIO;
     }
 
-    *r = reply;
     return EOK;
 }