Add django header writes

Author: joefarebrother

python/ql/lib/semmle/python/frameworks/Django.qll

@@ -2239,6 +2239,37 @@ module PrivateDjango {
 
           override DataFlow::Node getValueArg() { result = value }
         }
+
+        class DjangoResponseHeaderSubscriptWrite extends Http::Server::ResponseHeaderWrite::Range {
+          DataFlow::Node index;
+          DataFlow::Node value;
+
+          DjangoResponseHeaderSubscriptWrite() {
+            exists(SubscriptNode subscript, DataFlow::AttrRead headerLookup |
+              // To give `this` a value, we need to choose between either LHS or RHS,
+              // and just go with the LHS
+              this.asCfgNode() = subscript
+            |
+              headerLookup
+                  .accesses(DjangoImpl::DjangoHttp::Response::HttpResponse::instance(), "headers") and
+              exists(DataFlow::Node subscriptObj |
+                subscriptObj.asCfgNode() = subscript.getObject()
+              |
+                headerLookup.flowsTo(subscriptObj)
+              ) and
+              value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+              index.asCfgNode() = subscript.getIndex()
+            )
+          }
+
+          override DataFlow::Node getNameArg() { result = index }
+
+          override DataFlow::Node getValueArg() { result = value }
+
+          override predicate nameAllowsNewline() { none() }
+
+          override predicate valueAllowsNewline() { none() }
+        }
       }
     }
 

python/ql/test/library-tests/frameworks/django-v2-v3/response_test.py

@@ -72,7 +72,7 @@ def redirect_through_normal_response_new_headers_attr(request):
 
     resp = HttpResponse() # $ HttpResponse mimetype=text/html
     resp.status_code = 302
-    resp.headers['Location'] = next # $ MISSING: redirectLocation=next
+    resp.headers['Location'] = next # $ headerWriteName='Location' headerWriteValue=next MISSING: redirectLocation=next
     resp.content = private # $ MISSING: responseBody=private
     return resp
 
@@ -130,7 +130,7 @@ def setting_cookie(request):
     resp = HttpResponse() # $ HttpResponse mimetype=text/html
     resp.set_cookie("key", "value") # $ CookieWrite CookieName="key" CookieValue="value"
     resp.set_cookie(key="key", value="value") # $ CookieWrite CookieName="key" CookieValue="value"
-    resp.headers["Set-Cookie"] = "key2=value2" # $ MISSING: CookieWrite CookieRawHeader="key2=value2"
+    resp.headers["Set-Cookie"] = "key2=value2" # $ headerWriteName="Set-Cookie" headerWriteValue="key2=value2" CookieWrite CookieRawHeader="key2=value2"
     resp.cookies["key3"] = "value3" # $ CookieWrite CookieName="key3" CookieValue="value3"
     resp.delete_cookie("key4") # $ CookieWrite CookieName="key4"
     resp.delete_cookie(key="key4") # $ CookieWrite CookieName="key4"