[1.6.x] Dropped fix_IE_for_vary/attach.

This is a security fix. Disclosure following shortly.

django/core/handlers/base.py

@@ -23,8 +23,6 @@ class BaseHandler(object):
     response_fixes = [
         http.fix_location_header,
         http.conditional_content_removal,
-        http.fix_IE_for_attach,
-        http.fix_IE_for_vary,
     ]
 
     def __init__(self):

django/http/__init__.py

@@ -6,5 +6,4 @@ from django.http.response import (HttpResponse, StreamingHttpResponse,
     HttpResponseRedirect, HttpResponseNotModified, HttpResponseBadRequest,
     HttpResponseForbidden, HttpResponseNotFound, HttpResponseNotAllowed,
     HttpResponseGone, HttpResponseServerError, Http404, BadHeaderError)
-from django.http.utils import (fix_location_header, conditional_content_removal,
-    fix_IE_for_attach, fix_IE_for_vary)
+from django.http.utils import fix_location_header, conditional_content_removal

django/http/utils.py

@@ -39,58 +39,3 @@ def conditional_content_removal(request, response):
         else:
             response.content = b''
     return response
-
-
-def fix_IE_for_attach(request, response):
-    """
-    This function will prevent Django from serving a Content-Disposition header
-    while expecting the browser to cache it (only when the browser is IE). This
-    leads to IE not allowing the client to download.
-    """
-    useragent = request.META.get('HTTP_USER_AGENT', '').upper()
-    if 'MSIE' not in useragent and 'CHROMEFRAME' not in useragent:
-        return response
-
-    offending_headers = ('no-cache', 'no-store')
-    if response.has_header('Content-Disposition'):
-        try:
-            del response['Pragma']
-        except KeyError:
-            pass
-        if response.has_header('Cache-Control'):
-            cache_control_values = [value.strip() for value in
-                    response['Cache-Control'].split(',')
-                    if value.strip().lower() not in offending_headers]
-
-            if not len(cache_control_values):
-                del response['Cache-Control']
-            else:
-                response['Cache-Control'] = ', '.join(cache_control_values)
-
-    return response
-
-
-def fix_IE_for_vary(request, response):
-    """
-    This function will fix the bug reported at
-    http://support.microsoft.com/kb/824847/en-us?spid=8722&sid=global
-    by clearing the Vary header whenever the mime-type is not safe
-    enough for Internet Explorer to handle.  Poor thing.
-    """
-    useragent = request.META.get('HTTP_USER_AGENT', '').upper()
-    if 'MSIE' not in useragent and 'CHROMEFRAME' not in useragent:
-        return response
-
-    # These mime-types that are decreed "Vary-safe" for IE:
-    safe_mime_types = ('text/html', 'text/plain', 'text/sgml')
-
-    # The first part of the Content-Type field will be the MIME type,
-    # everything after ';', such as character-set, can be ignored.
-    mime_type = response.get('Content-Type', '').partition(';')[0]
-    if mime_type not in safe_mime_types:
-        try:
-            del response['Vary']
-        except KeyError:
-            pass
-
-    return response

tests/utils_tests/test_http.py

@@ -67,50 +67,6 @@ class TestUtilsHttp(unittest.TestCase):
         ]
         self.assertTrue(result in acceptable_results)
 
-    def test_fix_IE_for_vary(self):
-        """
-        Regression for #16632.
-
-        `fix_IE_for_vary` shouldn't crash when there's no Content-Type header.
-        """
-
-        # functions to generate responses
-        def response_with_unsafe_content_type():
-            r = HttpResponse(content_type="text/unsafe")
-            r['Vary'] = 'Cookie'
-            return r
-
-        def no_content_response_with_unsafe_content_type():
-            # 'Content-Type' always defaulted, so delete it
-            r = response_with_unsafe_content_type()
-            del r['Content-Type']
-            return r
-
-        # request with & without IE user agent
-        rf = RequestFactory()
-        request = rf.get('/')
-        ie_request = rf.get('/', HTTP_USER_AGENT='MSIE')
-
-        # not IE, unsafe_content_type
-        response = response_with_unsafe_content_type()
-        utils.fix_IE_for_vary(request, response)
-        self.assertTrue('Vary' in response)
-
-        # IE, unsafe_content_type
-        response = response_with_unsafe_content_type()
-        utils.fix_IE_for_vary(ie_request, response)
-        self.assertFalse('Vary' in response)
-
-        # not IE, no_content
-        response = no_content_response_with_unsafe_content_type()
-        utils.fix_IE_for_vary(request, response)
-        self.assertTrue('Vary' in response)
-
-        # IE, no_content
-        response = no_content_response_with_unsafe_content_type()
-        utils.fix_IE_for_vary(ie_request, response)
-        self.assertFalse('Vary' in response)
-
     def test_base36(self):
         # reciprocity works
         for n in [0, 1, 1000, 1000000]: