From b471cac8b5467cb3258ff0bd751ee1e0db5bd6d4 Mon Sep 17 00:00:00 2001
From: Steffen Klemer <steffen.klemer@gwdg.de>
Date: Sun, 14 Jul 2024 13:48:51 +0200
Subject: [PATCH] Client: Support enforcement of Message-Authenticator usage

Partialy solves #200 and CVE-2024-3596 (Blast-RADIUS)
---
 pyrad/client.py       | 10 ++++++++--
 pyrad/client_async.py | 10 ++++++++--
 pyrad/packet.py       |  9 ++++++++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/pyrad/client.py b/pyrad/client.py
index 6964963..0b8b5c7 100644
--- a/pyrad/client.py
+++ b/pyrad/client.py
@@ -34,7 +34,7 @@ class Client(host.Host):
     :type timeout: float
     """
     def __init__(self, server, authport=1812, acctport=1813,
-            coaport=3799, secret=six.b(''), dict=None, retries=3, timeout=5):
+            coaport=3799, secret=six.b(''), dict=None, retries=3, timeout=5, enforce_ma=False):
 
         """Constructor.
 
@@ -50,6 +50,8 @@ def __init__(self, server, authport=1812, acctport=1813,
         :type    secret: string
         :param     dict: RADIUS dictionary
         :type      dict: pyrad.dictionary.Dictionary
+        :param enforce_ma: Enforce usage and check of Message-Authenticator
+        :type  enforce_ma: boolean
         """
         host.Host.__init__(self, authport, acctport, coaport, dict)
 
@@ -58,6 +60,7 @@ def __init__(self, server, authport=1812, acctport=1813,
         self._socket = None
         self.retries = retries
         self.timeout = timeout
+        self.enforce_ma = enforce_ma
         self._poll = select.poll()
 
     def bind(self, addr):
@@ -100,6 +103,9 @@ def CreateAuthPacket(self, **args):
         :return: a new empty packet instance
         :rtype:  pyrad.packet.AuthPacket
         """
+        if self.enforce_ma:
+            return host.Host.CreateAuthPacket(self, secret=self.secret,
+                                              message_authenticator=True, **args)
         return host.Host.CreateAuthPacket(self, secret=self.secret, **args)
 
     def CreateAcctPacket(self, **args):
@@ -163,7 +169,7 @@ def _SendPacket(self, pkt, port):
 
                 try:
                     reply = pkt.CreateReply(packet=rawreply)
-                    if pkt.VerifyReply(reply, rawreply):
+                    if pkt.VerifyReply(reply, rawreply, enforce_ma=self.enforce_ma):
                         return reply
                 except packet.PacketError:
                     pass
diff --git a/pyrad/client_async.py b/pyrad/client_async.py
index e9d5df3..7a9d344 100644
--- a/pyrad/client_async.py
+++ b/pyrad/client_async.py
@@ -128,7 +128,7 @@ def datagram_received(self, data, addr):
                 reply.dict = packet.dict
                 reply.secret = packet.secret
 
-                if packet.VerifyReply(reply, data):
+                if packet.VerifyReply(reply, data, enforce_ma=self.client.enforce_ma):
                     req['future'].set_result(reply)
                     # Remove request for map
                     del self.pending_requests[reply.id]
@@ -177,7 +177,7 @@ class ClientAsync:
     def __init__(self, server, auth_port=1812, acct_port=1813,
                  coa_port=3799, secret=six.b(''), dict=None,
                  loop=None, retries=3, timeout=30,
-                 logger_name='pyrad'):
+                 logger_name='pyrad', enforce_ma=False):
 
         """Constructor.
 
@@ -216,6 +216,7 @@ def __init__(self, server, auth_port=1812, acct_port=1813,
 
         self.protocol_coa = None
         self.coa_port = coa_port
+        self.enforce_ma = enforce_ma
 
     async def initialize_transports(self, enable_acct=False,
                                     enable_auth=False, enable_coa=False,
@@ -325,6 +326,11 @@ def CreateAuthPacket(self, **args):
         """
         if not self.protocol_auth:
             raise Exception('Transport not initialized')
+        if self.enforce_ma:
+            return AuthPacket(dict=self.dict,
+                                id=self.protocol_auth.create_id(),
+                                secret=self.secret,
+                                message_authenticator=True, **args)
 
         return AuthPacket(dict=self.dict,
                           id=self.protocol_auth.create_id(),
diff --git a/pyrad/packet.py b/pyrad/packet.py
index 821c02d..99f8819 100644
--- a/pyrad/packet.py
+++ b/pyrad/packet.py
@@ -422,7 +422,7 @@ def ReplyPacket(self):
 
         return header + authenticator + attr
 
-    def VerifyReply(self, reply, rawreply=None):
+    def VerifyReply(self, reply, rawreply=None, enforce_ma=False):
         if reply.id != self.id:
             return False
 
@@ -443,6 +443,13 @@ def VerifyReply(self, reply, rawreply=None):
 
         if hash != rawreply[4:20]:
             return False
+
+        if enforce_ma:
+            if self.message_authenticator is None:
+                return False
+            if not self.verify_message_authenticator():
+                return False
+
         return True
 
     def _PktEncodeAttribute(self, key, value):