Merge pull request #47 from geoadmin/bug-BGDIINF_SB-2442-fix-origin-c…

…heck

BGDIINF_SB-2442: Fixed origin check - #patch

app/__init__.py

@@ -23,6 +23,10 @@
 app.config.from_object(settings)
 
 
+def is_domain_allowed(domain):
+    return re.match(ALLOWED_DOMAINS_PATTERN, domain) is not None
+
+
 # NOTE it is better to have this method registered first (before validate_origin) otherwise
 # the route might not be logged if another method reject the request.
 @app.before_request
@@ -34,12 +38,35 @@ def log_route():
 # Reject request from non allowed origins
 @app.before_request
 def validate_origin():
-    if 'Origin' not in request.headers:
-        logger.error('Origin header is not set')
-        abort(403, 'Not allowed')
-    if not re.match(ALLOWED_DOMAINS_PATTERN, request.headers['Origin']):
-        logger.error('Origin=%s is not allowed', request.headers['Origin'])
-        abort(403, 'Not allowed')
+    # The Origin header is automatically set by the browser and cannot be changed by the javascript
+    # application. Unfortunately this header is only set if the request comes from another origin.
+    # Sec-Fetch-Site header is set to `same-origin` by most of the browsers except by Safari!
+    # The best protection would be to use the Sec-Fetch-Site and Origin header, however this is
+    # not supported by Safari. Therefore we added a fallback to the Referer header for Safari.
+    sec_fetch_site = request.headers.get('Sec-Fetch-Site', None)
+    origin = request.headers.get('Origin', None)
+    referrer = request.headers.get('Referer', None)
+
+    if origin is not None:
+        if is_domain_allowed(origin):
+            return
+        logger.error('Origin=%s does not match %s', origin, ALLOWED_DOMAINS_PATTERN)
+        abort(403, 'Permission denied')
+
+    if sec_fetch_site is not None:
+        if sec_fetch_site in ['same-origin', 'same-site']:
+            return
+        logger.error('Sec-Fetch-Site=%s is not allowed', sec_fetch_site)
+        abort(403, 'Permission denied')
+
+    if referrer is not None:
+        if is_domain_allowed(referrer):
+            return
+        logger.error('Referer=%s does not match %s', referrer, ALLOWED_DOMAINS_PATTERN)
+        abort(403, 'Permission denied')
+
+    logger.error('Referer and/or Origin and/or Sec-Fetch-Site headers not set')
+    abort(403, 'Permission denied')
 
 
 # Add CORS Headers to all request
@@ -64,10 +91,9 @@ def log_response(response):
         request.path,
         response.status,
         extra={
-            'response':
-                {
-                    "status_code": response.status_code, "headers": dict(response.headers.items())
-                },
+            'response': {
+                "status_code": response.status_code, "headers": dict(response.headers.items())
+            },
             "duration": time.time() - g.get('request_started', time.time())
         }
     )

app/settings.py

@@ -24,6 +24,7 @@
     raise RuntimeError("Environment variable $ALLOWED_DOMAINS was not set")
 
 ALLOWED_DOMAINS = ALLOWED_DOMAINS_STRING.split(',')
+ALLOWED_DOMAINS_PATTERN = f"({'|'.join(ALLOWED_DOMAINS)})"
 
 # Proxy settings
 FORWARED_ALLOW_IPS = os.getenv('FORWARED_ALLOW_IPS', '*')
@@ -32,4 +33,4 @@
 if WSGI_WORKERS <= 0:
     from multiprocessing import cpu_count
     WSGI_WORKERS = (cpu_count() * 2) + 1
-WSGI_TIMEOUT = int(os.getenv('WSGI_TIMEOUT', '3'))
+WSGI_TIMEOUT = int(os.getenv('WSGI_TIMEOUT', '3'))

app/version.py

@@ -10,17 +10,16 @@
 # the tag is directly related to the commit or has an additional
 # suffix 'v[0-9]+\.[0-9]+\.[0-9]+-beta.[0-9]-[0-9]+-gHASH' denoting
 # the 'distance' to the latest tag
-with subprocess.Popen(
-    ["git", "describe", "--tags"], stdout=subprocess.PIPE, stderr=subprocess.PIPE
-) as proc:
+with subprocess.Popen(["git", "describe", "--tags"], stdout=subprocess.PIPE,
+                      stderr=subprocess.PIPE) as proc:
     stdout, stderr = proc.communicate()
 GIT_VERSION = stdout.decode('utf-8').strip()
 if GIT_VERSION == '':
     # If theres no git tag found in the history we simply use the short
     # version of the latest git commit hash
-    with subprocess.Popen(
-        ["git", "rev-parse", "--short", "HEAD"], stdout=subprocess.PIPE, stderr=subprocess.PIPE
-    ) as proc:
+    with subprocess.Popen(["git", "rev-parse", "--short", "HEAD"],
+                          stdout=subprocess.PIPE,
+                          stderr=subprocess.PIPE) as proc:
         stdout, stderr = proc.communicate()
     APP_VERSION = f"v_{stdout.decode('utf-8').strip()}"
 else:

tests/unit_tests/test_route.py

@@ -1,6 +1,8 @@
 import logging
 import unittest
 
+from nose2.tools import params
+
 from flask import url_for
 
 from app import app
@@ -16,13 +18,7 @@ def setUp(self):
         self.context.push()
         self.app = app.test_client()
         self.app.testing = True
-        self.origin_headers = {
-            "allowed": {
-                "Origin": "some_random_domain"
-            }, "bad": {
-                "Origin": "big-bad-wolf.com"
-            }
-        }
+        self.origin_headers = {"allowed": {"Origin": "some_random_domain"}}
 
     def test_checker(self):
         response = self.app.get(url_for('checker'), headers=self.origin_headers["allowed"])
@@ -35,3 +31,43 @@ def test_checker_non_allowed_origin(self):
         self.assertEqual(response.status_code, 403)
         self.assertEqual(response.content_type, "application/json")
         self.assertEqual(response.json["error"]["message"], "Not allowed")
+
+    @params(
+        None,
+        {'Origin': 'www.example'},
+        {
+            'Origin': 'www.example', 'Sec-Fetch-Site': 'cross-site'
+        },
+        {
+            'Origin': 'www.example', 'Sec-Fetch-Site': 'same-site'
+        },
+        {
+            'Origin': 'www.example', 'Sec-Fetch-Site': 'same-origin'
+        },
+        {'Referer': 'http://www.example'},
+    )
+    def test_feedback_non_allowed_origin(self, headers):
+        response = self.app.get(url_for('checker'), headers=headers)
+        self.assertEqual(response.status_code, 403)
+        self.assertEqual(response.content_type, "application/json")
+        self.assertEqual(response.json["error"]["message"], "Not allowed")
+
+
+    @params(
+        {'Origin': 'map.geo.admin.ch'},
+        {
+            'Origin': 'map.geo.admin.ch', 'Sec-Fetch-Site': 'same-site'
+        },
+        {
+            'Origin': 'public.geo.admin.ch', 'Sec-Fetch-Site': 'same-origin'
+        },
+        {
+            'Origin': 'http://localhost', 'Sec-Fetch-Site': 'cross-site'
+        },
+        {'Sec-Fetch-Site': 'same-origin'},
+        {'Referer': 'https://map.geo.admin.ch'},
+    )
+    def test_feedback_allowed_origin(self, headers):
+        response = self.app.get(url_for('checker'), headers=headers)
+        self.assertEqual(response.status_code, 200)
+        self.assertCors(response, check_origin=False)