[Zope3-checkins] SVN: Zope3/trunk/src/zope/app/pagetemplate/ - add tests for trusted and untrusted path:modules/... expressions

[Fred L. Drake, Jr.]

Log message for revision 26657:
  - add tests for trusted and untrusted path:modules/... expressions
  - make them actually work as advertised
    (untrusted module import can raise KeyError instead of NotFoundErr or
    some flavor of Forbidden; seems less than right)
  - add docstrings
  


Changed:
  U   Zope3/trunk/src/zope/app/pagetemplate/engine.py
  A   Zope3/trunk/src/zope/app/pagetemplate/tests/trusted.py


-=-
Modified: Zope3/trunk/src/zope/app/pagetemplate/engine.py
===================================================================
--- Zope3/trunk/src/zope/app/pagetemplate/engine.py	2004-07-21 16:01:38 UTC (rev 26656)
+++ Zope3/trunk/src/zope/app/pagetemplate/engine.py	2004-07-21 16:02:21 UTC (rev 26657)
@@ -19,12 +19,15 @@
 """
 import sys
 
+from zope.interface import implements
+
 from zope.tales.expressions import PathExpr, StringExpr, NotExpr, DeferExpr
 from zope.tales.expressions import SimpleModuleImporter
 from zope.tales.pythonexpr import PythonExpr
 from zope.tales.tales import ExpressionEngine, Context
 
 from zope.component.exceptions import ComponentLookupError
+from zope.exceptions import NotFoundError
 from zope.proxy import removeAllProxies
 from zope.security.proxy import ProxyFactory
 from zope.security.builtins import RestrictedBuiltins
@@ -33,7 +36,7 @@
 from zope.app import zapi
 from zope.app.i18n import ZopeMessageIDFactory as _
 from zope.app.traversing.adapters import Traverser
-from zope.app.traversing.interfaces import IPathAdapter
+from zope.app.traversing.interfaces import IPathAdapter, ITraversable
 
 class InlineCodeError(Exception):
     pass
@@ -59,6 +62,7 @@
         return eval(self._code, vars)
 
 class ZopeContextBase(Context):
+    """Base class for both trusted and untrusted evaluation contexts."""
 
     def evaluateText(self, expr):
         text = self.evaluate(expr)
@@ -110,6 +114,7 @@
 
 
 class ZopeContext(ZopeContextBase):
+    """Evaluation context for untrusted programs."""
 
     def setContext(self, name, value):
         # Hook to allow subclasses to do things like adding security proxies
@@ -117,7 +122,7 @@
 
 
 class TrustedZopeContext(ZopeContextBase):
-    pass
+    """Evaluation context for trusted programs."""
 
 
 class AdapterNamespaces(object):
@@ -170,7 +175,38 @@
         return namespace
 
 class ZopeEngine(ExpressionEngine):
+    """Untrusted expression engine.
 
+    This engine does not allow modules to be imported; only modules
+    already available may be accessed::
+
+      >>> modname = 'zope.app.pagetemplate.tests.trusted'
+      >>> engine = _Engine()
+      >>> context = engine.getContext(engine.getBaseNames())
+
+      >>> modname in sys.modules
+      False
+      >>> context.evaluate('modules/' + modname)
+      Traceback (most recent call last):
+        ...
+      KeyError: 'zope.app.pagetemplate.tests.trusted'
+
+    (The use of KeyError is an unfortunate implementation detail; I
+    think this should be a NotFoundError.)
+
+    Modules which have already been imported by trusted code are
+    available, wrapped in security proxies::
+
+      >>> m = context.evaluate('modules/sys')
+      >>> m.__name__
+      'sys'
+      >>> m._getframe
+      Traceback (most recent call last):
+        ...
+      ForbiddenAttribute: ('_getframe', <module 'sys' (built-in)>)
+
+    """
+
     _create_context = ZopeContext
 
     def __init__(self):
@@ -198,10 +234,49 @@
 
 
 class TrustedZopeEngine(ZopeEngine):
+    """Trusted expression engine.
 
+    This engine allows modules to be imported::
+
+      >>> modname = 'zope.app.pagetemplate.tests.trusted'
+      >>> engine = _TrustedEngine()
+      >>> context = engine.getContext(engine.getBaseNames())
+
+      >>> modname in sys.modules
+      False
+      >>> m = context.evaluate('modules/' + modname)
+      >>> m.__name__ == modname
+      True
+      >>> modname in sys.modules
+      True
+
+    Since this is trusted code, we can look at whatever is in the
+    module, not just __name__ or what's declared in a security
+    assertion::
+
+      >>> m.x
+      42
+
+    Clean up after ourselves::
+
+      >>> del sys.modules[modname]
+
+    """
+
     _create_context = TrustedZopeContext
 
 
+class TraversableModuleImporter(SimpleModuleImporter):
+
+    implements(ITraversable)
+
+    def traverse(self, name, further_path):
+        try:
+            return self[name]
+        except KeyError:
+            raise NotFoundError(name)
+
+
 def _Engine(engine=None):
     if engine is None:
         engine = ZopeEngine()
@@ -221,7 +296,7 @@
         engine = TrustedZopeEngine()
     engine = _create_base_engine(engine)
     engine.registerType('python', PythonExpr)
-    engine.registerBaseName('modules', SimpleModuleImporter())
+    engine.registerBaseName('modules', TraversableModuleImporter())
     return engine
 
 def _create_base_engine(engine):

Added: Zope3/trunk/src/zope/app/pagetemplate/tests/trusted.py
===================================================================
--- Zope3/trunk/src/zope/app/pagetemplate/tests/trusted.py	2004-07-21 16:01:38 UTC (rev 26656)
+++ Zope3/trunk/src/zope/app/pagetemplate/tests/trusted.py	2004-07-21 16:02:21 UTC (rev 26657)
@@ -0,0 +1,22 @@
+##############################################################################
+#
+# Copyright (c) 2004 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Sample of a module imported by a trusted module.
+
+This module won't be imported by an untrusted template using a
+path:modules/... expression.
+
+$Id$
+"""
+
+x = 42


Property changes on: Zope3/trunk/src/zope/app/pagetemplate/tests/trusted.py
___________________________________________________________________
Name: svn:mime-type
   + text/x-python
Name: svn:eol-style
   + native