added `ImmutableSandboxedEnvironment`.
--HG--
branch : trunk
diff --git a/jinja2/sandbox.py b/jinja2/sandbox.py
index 714a0e1..c558c73 100644
--- a/jinja2/sandbox.py
+++ b/jinja2/sandbox.py
@@ -12,6 +12,10 @@
:copyright: Copyright 2008 by Armin Ronacher.
:license: BSD.
"""
+import operator
+from UserDict import UserDict, DictMixin
+from UserList import UserList
+from sets import Set, ImmutableSet
from types import FunctionType, MethodType, TracebackType, CodeType, \
FrameType, GeneratorType
from jinja2.runtime import Undefined
@@ -29,6 +33,20 @@
#: unsafe method attributes. function attributes are unsafe for methods too
UNSAFE_METHOD_ATTRIBUTES = set(['im_class', 'im_func', 'im_self'])
+SET_TYPES = (ImmutableSet, Set, set)
+MODIFYING_SET_ATTRIBUTES = set([
+ 'add', 'clear', 'difference_update', 'discard', 'pop', 'remove',
+ 'symmetric_difference_update', 'update'
+])
+
+DICT_TYPES = (UserDict, DictMixin, dict)
+MODIFYING_DICT_ATTRIBUTES = set(['clear', 'pop', 'popitem', 'setdefault',
+ 'update'])
+
+LIST_TYPES = (UserList, list)
+MODIFYING_LIST_ATTRIBUTES = set(['append', 'reverse', 'insert', 'sort',
+ 'extend', 'remove'])
+
def safe_range(*args):
"""A range that can't generate ranges with a length of more than
@@ -81,6 +99,35 @@
return attr.startswith('__')
+def modifies_builtin_mutable(obj, attr):
+ """This function checks if an attribute on a builtin mutable object
+ (list, dict or set) would modify it if called. It also supports
+ the "user"-versions of the objects (`sets.Set`, `UserDict.*` etc.)
+
+ >>> modifies_builtin_mutable({}, "clear")
+ True
+ >>> modifies_builtin_mutable({}, "keys")
+ False
+ >>> modifies_builtin_mutable([], "append")
+ True
+ >>> modifies_builtin_mutable([], "index")
+ False
+
+ If called with an unsupported object (such as unicode) `False` is
+ returned.
+
+ >>> modifies_builtin_mutable("foo", "upper")
+ False
+ """
+ if isinstance(obj, LIST_TYPES):
+ return attr in MODIFYING_LIST_ATTRIBUTES
+ elif isinstance(obj, DICT_TYPES):
+ return attr in MODIFYING_DICT_ATTRIBUTES
+ elif isinstance(obj, SET_TYPES):
+ return attr in MODIFYING_SET_ATTRIBUTES
+ return False
+
+
class SandboxedEnvironment(Environment):
"""The sandboxed environment. It works like the regular environment but
tells the compiler to generate sandboxed code. Additionally subclasses of
@@ -150,3 +197,15 @@
if not __self.is_safe_callable(__obj):
raise SecurityError('%r is not safely callable' % (__obj,))
return __obj(*args, **kwargs)
+
+
+class ImmutableSandboxedEnvironment(SandboxedEnvironment):
+ """Works exactly like the regular `SandboxedEnvironment` but does not
+ permit modifications on the builtin mutable objects `list`, `set`, and
+ `dict` by using the :func:`modifies_builtin_mutable` function.
+ """
+
+ def is_safe_attribute(self, obj, attr, value):
+ if not SandboxedEnvironment.is_safe_attribute(self, obj, attr, value):
+ return False
+ return not modifies_builtin_mutable(obj, attr)