csmud: Implement HMAC signing of cookies

This is intended to prevent people with leaked copies of the source from being able to login to a production server. The key is constructed from a shared secret appended to the server version.

config/public_client.prc

@@ -33,6 +33,10 @@ default-model-extension .bam
 # Now that we've loaded the phase files, tell panda to trust the TTRCA
 ssl-certificates phase_3/etc/TTRCA.crt
 
+# This is the shared secret for CSMUD login
+# ##### NB! Update deployment/server.prc too! #####
+csmud-secret Yv1JrpTUdkX6M86h44Z9q4AUaQYdFnectDgl2I5HOQf8CBh7LUZWpzKB9FBD
+
 # DC files are NOT configured.
 # They're wrapped up into the code automatically.
 

config/toon.dc

@@ -3272,7 +3272,7 @@ struct PotentialToon {
 };
 
 dclass ClientServicesManager : DistributedObjectGlobal {
-  login(string cookie) clsend;
+  login(string cookie, string sig) clsend;
   acceptLogin();
 
   requestAvatars() clsend;

deployment/server.prc

@@ -6,6 +6,10 @@
 want-dev #f
 want-cheesy-expirations #t
 
+# Shared secret for CSMUD
+# ##### NB! Update config/public_client.prc too! #####
+csmud-secret Yv1JrpTUdkX6M86h44Z9q4AUaQYdFnectDgl2I5HOQf8CBh7LUZWpzKB9FBD
+
 # ODE isn't ready yet :(
 want-golf #f
 

toontown/uberdog/ClientServicesManager.py

@@ -4,6 +4,8 @@ from otp.distributed.PotentialAvatar import PotentialAvatar
 from otp.otpbase import OTPLocalizer, OTPGlobals
 from otp.margins.WhisperPopup import *
 from pandac.PandaModules import *
+import hashlib
+import hmac
 
 class ClientServicesManager(DistributedObjectGlobal):
     notify = directNotify.newCategory('ClientServicesManager')
@@ -16,8 +18,12 @@ class ClientServicesManager(DistributedObjectGlobal):
 
         cookie = self.cr.playToken or 'dev'
 
+        # Sign the login cookie
+        key = base.config.GetString('csmud-secret', 'streetlamps') + base.config.GetString('server-version', 'no_version_set')
+        sig = hmac.new(key, cookie, hashlib.sha256).hexdigest()
+
         self.notify.debug('Sending login cookie: ' + cookie)
-        self.sendUpdate('login', [cookie])
+        self.sendUpdate('login', [cookie, sig])
 
     def acceptLogin(self):
         messenger.send(self.doneEvent, [{'mode': 'success'}])

toontown/uberdog/ClientServicesManagerUD.py

@@ -896,7 +896,7 @@ class ClientServicesManagerUD(DistributedObjectGlobalUD):
             self.notify.warning('The CSMUD has been told to reject logins! All future logins will now be rejected.')
         self.loginsEnabled = enable
 
-    def login(self, cookie):
+    def login(self, cookie, sig):
         self.notify.debug('Received login cookie %r from %d' % (cookie, self.air.getMsgSender()))
 
         sender = self.air.getMsgSender()
@@ -914,6 +914,13 @@ class ClientServicesManagerUD(DistributedObjectGlobalUD):
             self.killConnection(sender, 'Client is already logged in.')
             return
 
+        # Test the signature
+        key = simbase.config.GetString('csmud-secret', 'streetlamps') + simbase.config.GetString('server-version', 'no_version_set')
+        computedSig = hmac.new(key, cookie, hashlib.sha256).hexdigest()
+        if not hmac.compare_digest(sig, computedSig):
+            self.killConnection(sender, 'Invalid cookie signature')
+            return
+
         if sender in self.connection2fsm:
             self.killConnectionFSM(sender)
             return