diff --git a/root/usr/local/bin/manage_cred.py b/root/usr/local/bin/manage_cred.py
index 0e2938d..0ce9ca2 100755
--- a/root/usr/local/bin/manage_cred.py
+++ b/root/usr/local/bin/manage_cred.py
@@ -1,130 +1,133 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 """
 manage_cred : receives user credentials during pam auth.
 It keeps it until MANAGE_CRED_TIMEOUT.
 Other applications (extensions) can ask it to do operations that need credentials.
 
-Extensions have to configure themselves with an /usr/local/lib/manage_cred/app.py
-They have to implement :
+The folder /usr/local/lib/manage_cred/ is the place where extensions have to be
+installed. It has to be root:root 0x700.
+
+Each extension file /usr/local/lib/manage_cred/*.py has to be root:root 0x600.
+It has to implement :
 + FLAG_FILE : the file that flags it's epfl_roaming that sent USR1 signal to manage_cred
 + run(username, password) method that does the job
 """
 
 import os
 import sys
 import time
 import stat
 import signal
 import importlib
 
 MANAGE_CRED_TIMEOUT = 20  # sec
 EXT_FOLDER = "/usr/local/lib/manage_cred"
 
 VAR_RUN = "/var/run/manage_cred"
 PID_FILE = "/var/run/manage_cred/manage_cred_{username}.pid"
 
 class PID():
     def __init__(self):
         self.pid_file = PID_FILE.format(username=USERNAME)
 
     def __enter__(self):
         with open(self.pid_file, "w") as f:
             f.write("%s\n" % os.getpid())
 
     def __exit__(self, typ, val, tb):
         os.unlink(self.pid_file)
 
 
 def fork_and_wait():
     def signal_USR1_handler(signum, frame):
         an_ext_was_run = False
         for ext in extensions:
             if os.path.exists(extensions[ext].FLAG_FILE):
                 an_ext_was_run = True
                 print "Running extension %s." % ext
                 extensions[ext].run(USERNAME, PASSWORD)
                 try:
                     os.unlink(extensions[ext].FLAG_FILE)
                 except:
                     pass
                 print "done."
         if not an_ext_was_run:
             print "got USR1 signal, but no extension were run."
 
     def signal_KILL_handler(signum, frame):
         print "got TERM signal, gonna exit."
         sys.exit(0)
 
     if os.fork() != 0:
         return
 
     with PID():
         extensions = {}
 
         # SIGUSR1 and SIGTERM handling
         signal.signal(signal.SIGUSR1, signal_USR1_handler)
         signal.signal(signal.SIGTERM, signal_KILL_handler)
 
         # Check that Extension folder has correct rights : root:root 0x700
         ext_folder_stat = os.stat(EXT_FOLDER)
         if (ext_folder_stat.st_uid != 0 or
             ext_folder_stat.st_gid != 0 or
             ext_folder_stat.st_mode & (stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO) != stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR):
             print "Error, extensions folder %s doesn't have correct rights : root:root 0x700.\nAborting." % EXT_FOLDER
             sys.exit(1)
 
         sys.path.insert(0, EXT_FOLDER)
         for f in os.listdir(EXT_FOLDER):
             if f == "__init__.py" or not f.endswith(".py"):
                 continue
 
             # check extension has correct rights : root:root 0x600
             ext_path = os.path.join(EXT_FOLDER, f)
             ext_stat = os.stat(ext_path)
             if (ext_stat.st_uid != 0 or
                 ext_stat.st_gid != 0 or
                 ext_stat.st_mode & (stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO) != stat.S_IRUSR | stat.S_IWUSR):
                 print "Error, extensions %s doesn't have correct rights : root:root 0x600.\nSkipping." % ext_path
                 continue
 
             try:
                 ext_name = f[:-3]
                 mod = importlib.import_module(ext_name)
                 if ("FLAG_FILE" in dir(mod) and "run" in dir(mod) and
                     type(mod.FLAG_FILE) == str and callable(mod.run)):
                     extensions[ext_name] = mod
                 else:
                     print "Error, %s doesn't implement required variables and functions; Skipping." % ext_name
             except Exception, e:
                 print "Error, could not import %s; Skipping." % ext_name
                 print e
 
 
         for i in range(MANAGE_CRED_TIMEOUT):
             time.sleep(1)
         print "Finished to wait for %i seconds; exiting." % MANAGE_CRED_TIMEOUT
 
 
 if __name__ == "__main__":
     USERNAME = os.environ["PAM_USER"]
     SERVICE = os.environ["PAM_SERVICE"]
     TYPE = os.environ["PAM_TYPE"]
 
     print "USERNAME %s" % USERNAME
     print "SERVICE %s" % SERVICE
     print "TYPE %s" % TYPE
 
     if TYPE != "auth":
         sys.exit(0)
 
     PASSWORD = sys.stdin.readline().rstrip(chr(0))
 
     try:
         os.makedirs(VAR_RUN)
     except OSError:
         pass
 
     fork_and_wait()
     sys.exit(0)