Python: Model BaseHTTPRequestHandler.rfile as file-like object

Author: RasmusWL

python/ql/src/semmle/python/frameworks/Stdlib.qll

@@ -1031,6 +1031,13 @@ private module StdlibPrivate {
       }
     }
 
+    /** A file-like object that originates from a `BaseHTTPRequestHandler` instance. */
+    private class BaseHTTPRequestHandlerFileLikeObjectInstances extends Stdlib::FileLikeObject::InstanceSource {
+      BaseHTTPRequestHandlerFileLikeObjectInstances() {
+        this.(DataFlow::AttrRead).accesses(instance(), "rfile")
+      }
+    }
+
     /**
      * The entry-point for handling a request with a `BaseHTTPRequestHandler` subclass.
      *

python/ql/test/library-tests/frameworks/stdlib/http_server.py

@@ -68,7 +68,7 @@ def taint_sources(self):
             bytes(self.headers), # $ tainted
 
             self.rfile, # $ tainted
-            self.rfile.read(), # $ MISSING: tainted
+            self.rfile.read(), # $ tainted
         )
 
         form = cgi.FieldStorage(