From ca303fea3ce554afc1255ec71524ba981a8db71b Mon Sep 17 00:00:00 2001
From: David Baker <dave@matrix.org>
Date: Fri, 21 Apr 2017 17:41:02 +0100
Subject: [PATCH] Add support for rejecting sms reqs to countries

Reject requests to send SMS to countries based on rules in the
config file

https://github.com/vector-im/riot-web/issues/3542
---
 sydent/http/servlets/msisdnservlet.py |  8 +++++++-
 sydent/validators/__init__.py         |  6 +++++-
 sydent/validators/msisdnvalidator.py  | 19 ++++++++++++++++++-
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/sydent/http/servlets/msisdnservlet.py b/sydent/http/servlets/msisdnservlet.py
index 750aaed4..64087ffb 100644
--- a/sydent/http/servlets/msisdnservlet.py
+++ b/sydent/http/servlets/msisdnservlet.py
@@ -19,7 +19,9 @@
 from twisted.web.resource import Resource
 import phonenumbers
 
-from sydent.validators import IncorrectClientSecretException, SessionExpiredException
+from sydent.validators import (
+    IncorrectClientSecretException, SessionExpiredException, DestinationRejectedException
+)
 
 from sydent.http.servlets import get_args, jsonwrap, send_cors
 
@@ -70,6 +72,10 @@ def render_POST(self, request):
             sid = self.sydent.validators.msisdn.requestToken(
                 phone_number_object, clientSecret, sendAttempt, None
             )
+        except DestinationRejectedException:
+            logger.error("Destination rejected for number: %s", msisdn);
+            request.setResponseCode(400)
+            resp = {'errcode': 'M_DESTINATION_REJECTED', 'error': 'Phone numbers in this country are not currently supported'}
         except Exception as e:
             logger.error("Exception sending SMS: %r", e);
             request.setResponseCode(500)
diff --git a/sydent/validators/__init__.py b/sydent/validators/__init__.py
index 13e14599..821f1b84 100644
--- a/sydent/validators/__init__.py
+++ b/sydent/validators/__init__.py
@@ -44,4 +44,8 @@ class InvalidSessionIdException(Exception):
 
 
 class SessionNotValidatedException(Exception):
-    pass
\ No newline at end of file
+    pass
+
+
+class DestinationRejectedException(Exception):
+    pass
diff --git a/sydent/validators/msisdnvalidator.py b/sydent/validators/msisdnvalidator.py
index dcd7d296..d0d0825f 100644
--- a/sydent/validators/msisdnvalidator.py
+++ b/sydent/validators/msisdnvalidator.py
@@ -23,6 +23,8 @@
 from sydent.validators import ValidationSession, common
 from sydent.sms.openmarket import OpenMarketSMS
 
+from sydent.validators import DestinationRejectedException
+
 from sydent.util import time_msec
 
 logger = logging.getLogger(__name__)
@@ -33,8 +35,9 @@ def __init__(self, sydent):
         self.sydent = sydent
         self.omSms = OpenMarketSMS(sydent)
 
-        # cache originators from config file
+        # cache originators & sms rules from config file
         self.originators = {}
+        self.smsRules = {}
         for opt in self.sydent.cfg.options('sms'):
             if opt.startswith('originators.'):
                 country = opt.split('.')[1]
@@ -52,8 +55,22 @@ def __init__(self, sydent):
                         "type": parts[0],
                         "text": parts[1],
                     })
+            elif opt.startswith('smsrule.'):
+                country = opt.split('.')[1]
+                action = self.sydent.cfg.get('sms', opt)
+
+                if action not in ['allow', 'reject']:
+                    raise Exception("Invalid SMS rule action: %s, expecting 'allow' or 'deny'" % action)
+
+                self.smsRules[country] = action
+
 
     def requestToken(self, phoneNumber, clientSecret, sendAttempt, nextLink):
+        if str(phoneNumber.country_code) in self.smsRules:
+            action = self.smsRules[str(phoneNumber.country_code)]
+            if action == 'reject':
+                raise DestinationRejectedException()
+
         valSessionStore = ThreePidValSessionStore(self.sydent)
 
         msisdn = phonenumbers.format_number(