Enable V2 authentication for Me2Me host.

remoting/tools/me2me_virtual_host.py

Index: remoting/tools/me2me_virtual_host.py
diff --git a/remoting/tools/me2me_virtual_host.py b/remoting/tools/me2me_virtual_host.py
index 5a742c25da26397a5800d298e900c5a862478431..9dc450e30b2c85242c0103cb04566781e21f46e3 100755
--- a/remoting/tools/me2me_virtual_host.py
+++ b/remoting/tools/me2me_virtual_host.py
@@ -10,8 +10,10 @@
 # process, running under an ordinary (non-root) user account.
 
 import atexit
+import base64
 import getpass
 import hashlib
+import hmac
 import json
 import logging
 import optparse
@@ -115,13 +117,13 @@ class Host:
   Callers should instantiate a Host object (passing in a filename where the
   config will be kept), then should call either of the methods:
 
-  * create_config(auth): Create a new Host configuration and register it with
-  the Directory Service (the "auth" parameter is used to authenticate with the
-  Service).
+  * register(auth): Create a new Host configuration and register it
+  with the Directory Service (the "auth" parameter is used to
+  authenticate with the Service).
   * load_config(): Load a config from disk, with details of an existing Host
   registration.
 
-  After calling create_config() (or making any config changes) the method
+  After calling register() (or making any config changes) the method
   save_config() should be called to save the details to disk.
   """
 
@@ -130,11 +132,13 @@ class Host:
 
   def __init__(self, config_file):
     self.config_file = config_file
-
-  def create_config(self, auth):
     self.host_id = str(uuid.uuid1())
-    logging.info("HostId: " + self.host_id)
     self.host_name = socket.gethostname()
+    self.host_secret_hash = None
+    self.private_key = None
+
+  def register(self, auth):
+    logging.info("HostId: " + self.host_id)
     logging.info("HostName: " + self.host_name)
 
     logging.info("Generating RSA key pair...")
@@ -168,22 +172,36 @@ class Host:
       sys.exit(1)
     logging.info("Done")
 
+  def ask_pin(self):
+    pin = getpass.getpass("Host PIN (can be empty): ")

[Wez, 2012/01/23 23:53:49]

nit: Verify that the PIN is either empty or at least 4 characters long?

[Sergey Ulanov, 2012/01/24 06:32:22]

Done.

+    self.host_secret_hash = "hmac;" + base64.b64encode(
+        hmac.new(str(self.host_id), pin, hashlib.sha256).digest())

[Wez, 2012/01/23 23:53:49]

nit: It will make changes to inform the client of whether a PIN is required
easier of you store nothing when the user doesn't enter a PIN, and have the host
understand that.  That would also let the host be backward-compatible with
existing dogfooder's configs.

[Sergey Ulanov, 2012/01/24 06:32:22]

Done.

+
+  def ask_pin_if_unknown(self):
+    if not self.host_secret_hash:
+      self.ask_pin()
+      return True
+    return False
+
   def load_config(self):
     try:
       settings_file = open(self.config_file, 'r')
       data = json.load(settings_file)
       settings_file.close()
-      self.host_id = data["host_id"]
-      self.host_name = data["host_name"]
-      self.private_key = data["private_key"]
     except:
+      logging.info("Failed to load: " + self.config_file)
       return False
+    self.host_id = data["host_id"]
+    self.host_name = data["host_name"]
+    self.host_secret_hash = data.get("host_secret_hash")
+    self.private_key = data["private_key"]
     return True
 
   def save_config(self):
     data = {
         "host_id": self.host_id,
         "host_name": self.host_name,
+        "host_secret_hash": self.host_secret_hash,
         "private_key": self.private_key,
     }
     old_umask = os.umask(0066)
@@ -503,7 +521,11 @@ def main():
   host = Host(os.path.join(CONFIG_DIR, "host#%s.json" % host_hash))
 
   if not host.load_config():
-    host.create_config(auth)
+    host.ask_pin()
+    host.register(auth)
+    host.save_config()
+
+  if host.ask_pin_if_unknown():
     host.save_config()
 
   global g_pidfile