This file is indexed.

/usr/lib/python3/dist-packages/jinja2/sandbox.py is in python3-jinja2 2.7.2-2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
# -*- coding: utf-8 -*-
"""
    jinja2.sandbox
    ~~~~~~~~~~~~~~

    Adds a sandbox layer to Jinja as it was the default behavior in the old
    Jinja 1 releases.  This sandbox is slightly different from Jinja 1 as the
    default behavior is easier to use.

    The behavior can be changed by subclassing the environment.

    :copyright: (c) 2010 by the Jinja Team.
    :license: BSD.
"""
import operator
from jinja2.environment import Environment
from jinja2.exceptions import SecurityError
from jinja2._compat import string_types, function_type, method_type, \
     traceback_type, code_type, frame_type, generator_type, PY2


#: maximum number of items a range may produce
MAX_RANGE = 100000

#: attributes of function objects that are considered unsafe.
UNSAFE_FUNCTION_ATTRIBUTES = set(['func_closure', 'func_code', 'func_dict',
                                  'func_defaults', 'func_globals'])

#: unsafe method attributes.  function attributes are unsafe for methods too
UNSAFE_METHOD_ATTRIBUTES = set(['im_class', 'im_func', 'im_self'])

#: unsafe generator attirbutes.
UNSAFE_GENERATOR_ATTRIBUTES = set(['gi_frame', 'gi_code'])

# On versions > python 2 the special attributes on functions are gone,
# but they remain on methods and generators for whatever reason.
if not PY2:
    UNSAFE_FUNCTION_ATTRIBUTES = set()

import warnings

# make sure we don't warn in python 2.6 about stuff we don't care about
warnings.filterwarnings('ignore', 'the sets module', DeprecationWarning,
                        module='jinja2.sandbox')

from collections import deque

_mutable_set_types = (set,)
_mutable_mapping_types = (dict,)
_mutable_sequence_types = (list,)


# on python 2.x we can register the user collection types
try:
    from UserDict import UserDict, DictMixin
    from UserList import UserList
    _mutable_mapping_types += (UserDict, DictMixin)
    _mutable_set_types += (UserList,)
except ImportError:
    pass

# if sets is still available, register the mutable set from there as well
try:
    from sets import Set
    _mutable_set_types += (Set,)
except ImportError:
    pass

#: register Python 2.6 abstract base classes
try:
    from collections import MutableSet, MutableMapping, MutableSequence
    _mutable_set_types += (MutableSet,)
    _mutable_mapping_types += (MutableMapping,)
    _mutable_sequence_types += (MutableSequence,)
except ImportError:
    pass

_mutable_spec = (
    (_mutable_set_types, frozenset([
        'add', 'clear', 'difference_update', 'discard', 'pop', 'remove',
        'symmetric_difference_update', 'update'
    ])),
    (_mutable_mapping_types, frozenset([
        'clear', 'pop', 'popitem', 'setdefault', 'update'
    ])),
    (_mutable_sequence_types, frozenset([
        'append', 'reverse', 'insert', 'sort', 'extend', 'remove'
    ])),
    (deque, frozenset([
        'append', 'appendleft', 'clear', 'extend', 'extendleft', 'pop',
        'popleft', 'remove', 'rotate'
    ]))
)


def safe_range(*args):
    """A range that can't generate ranges with a length of more than
    MAX_RANGE items.
    """
    rng = range(*args)
    if len(rng) > MAX_RANGE:
        raise OverflowError('range too big, maximum size for range is %d' %
                            MAX_RANGE)
    return rng


def unsafe(f):
    """Marks a function or method as unsafe.

    ::

        @unsafe
        def delete(self):
            pass
    """
    f.unsafe_callable = True
    return f


def is_internal_attribute(obj, attr):
    """Test if the attribute given is an internal python attribute.  For
    example this function returns `True` for the `func_code` attribute of
    python objects.  This is useful if the environment method
    :meth:`~SandboxedEnvironment.is_safe_attribute` is overridden.

    >>> from jinja2.sandbox import is_internal_attribute
    >>> is_internal_attribute(lambda: None, "func_code")
    True
    >>> is_internal_attribute((lambda x:x).func_code, 'co_code')
    True
    >>> is_internal_attribute(str, "upper")
    False
    """
    if isinstance(obj, function_type):
        if attr in UNSAFE_FUNCTION_ATTRIBUTES:
            return True
    elif isinstance(obj, method_type):
        if attr in UNSAFE_FUNCTION_ATTRIBUTES or \
           attr in UNSAFE_METHOD_ATTRIBUTES:
            return True
    elif isinstance(obj, type):
        if attr == 'mro':
            return True
    elif isinstance(obj, (code_type, traceback_type, frame_type)):
        return True
    elif isinstance(obj, generator_type):
        if attr in UNSAFE_GENERATOR_ATTRIBUTES:
            return True
    return attr.startswith('__')


def modifies_known_mutable(obj, attr):
    """This function checks if an attribute on a builtin mutable object
    (list, dict, set or deque) would modify it if called.  It also supports
    the "user"-versions of the objects (`sets.Set`, `UserDict.*` etc.) and
    with Python 2.6 onwards the abstract base classes `MutableSet`,
    `MutableMapping`, and `MutableSequence`.

    >>> modifies_known_mutable({}, "clear")
    True
    >>> modifies_known_mutable({}, "keys")
    False
    >>> modifies_known_mutable([], "append")
    True
    >>> modifies_known_mutable([], "index")
    False

    If called with an unsupported object (such as unicode) `False` is
    returned.

    >>> modifies_known_mutable("foo", "upper")
    False
    """
    for typespec, unsafe in _mutable_spec:
        if isinstance(obj, typespec):
            return attr in unsafe
    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
    this environment may override the methods that tell the runtime what
    attributes or functions are safe to access.

    If the template tries to access insecure code a :exc:`SecurityError` is
    raised.  However also other exceptions may occour during the rendering so
    the caller has to ensure that all exceptions are catched.
    """
    sandboxed = True

    #: default callback table for the binary operators.  A copy of this is
    #: available on each instance of a sandboxed environment as
    #: :attr:`binop_table`
    default_binop_table = {
        '+':        operator.add,
        '-':        operator.sub,
        '*':        operator.mul,
        '/':        operator.truediv,
        '//':       operator.floordiv,
        '**':       operator.pow,
        '%':        operator.mod
    }

    #: default callback table for the unary operators.  A copy of this is
    #: available on each instance of a sandboxed environment as
    #: :attr:`unop_table`
    default_unop_table = {
        '+':        operator.pos,
        '-':        operator.neg
    }

    #: a set of binary operators that should be intercepted.  Each operator
    #: that is added to this set (empty by default) is delegated to the
    #: :meth:`call_binop` method that will perform the operator.  The default
    #: operator callback is specified by :attr:`binop_table`.
    #:
    #: The following binary operators are interceptable:
    #: ``//``, ``%``, ``+``, ``*``, ``-``, ``/``, and ``**``
    #:
    #: The default operation form the operator table corresponds to the
    #: builtin function.  Intercepted calls are always slower than the native
    #: operator call, so make sure only to intercept the ones you are
    #: interested in.
    #:
    #: .. versionadded:: 2.6
    intercepted_binops = frozenset()

    #: a set of unary operators that should be intercepted.  Each operator
    #: that is added to this set (empty by default) is delegated to the
    #: :meth:`call_unop` method that will perform the operator.  The default
    #: operator callback is specified by :attr:`unop_table`.
    #:
    #: The following unary operators are interceptable: ``+``, ``-``
    #:
    #: The default operation form the operator table corresponds to the
    #: builtin function.  Intercepted calls are always slower than the native
    #: operator call, so make sure only to intercept the ones you are
    #: interested in.
    #:
    #: .. versionadded:: 2.6
    intercepted_unops = frozenset()

    def intercept_unop(self, operator):
        """Called during template compilation with the name of a unary
        operator to check if it should be intercepted at runtime.  If this
        method returns `True`, :meth:`call_unop` is excuted for this unary
        operator.  The default implementation of :meth:`call_unop` will use
        the :attr:`unop_table` dictionary to perform the operator with the
        same logic as the builtin one.

        The following unary operators are interceptable: ``+`` and ``-``

        Intercepted calls are always slower than the native operator call,
        so make sure only to intercept the ones you are interested in.

        .. versionadded:: 2.6
        """
        return False


    def __init__(self, *args, **kwargs):
        Environment.__init__(self, *args, **kwargs)
        self.globals['range'] = safe_range
        self.binop_table = self.default_binop_table.copy()
        self.unop_table = self.default_unop_table.copy()

    def is_safe_attribute(self, obj, attr, value):
        """The sandboxed environment will call this method to check if the
        attribute of an object is safe to access.  Per default all attributes
        starting with an underscore are considered private as well as the
        special attributes of internal python objects as returned by the
        :func:`is_internal_attribute` function.
        """
        return not (attr.startswith('_') or is_internal_attribute(obj, attr))

    def is_safe_callable(self, obj):
        """Check if an object is safely callable.  Per default a function is
        considered safe unless the `unsafe_callable` attribute exists and is
        True.  Override this method to alter the behavior, but this won't
        affect the `unsafe` decorator from this module.
        """
        return not (getattr(obj, 'unsafe_callable', False) or
                    getattr(obj, 'alters_data', False))

    def call_binop(self, context, operator, left, right):
        """For intercepted binary operator calls (:meth:`intercepted_binops`)
        this function is executed instead of the builtin operator.  This can
        be used to fine tune the behavior of certain operators.

        .. versionadded:: 2.6
        """
        return self.binop_table[operator](left, right)

    def call_unop(self, context, operator, arg):
        """For intercepted unary operator calls (:meth:`intercepted_unops`)
        this function is executed instead of the builtin operator.  This can
        be used to fine tune the behavior of certain operators.

        .. versionadded:: 2.6
        """
        return self.unop_table[operator](arg)

    def getitem(self, obj, argument):
        """Subscribe an object from sandboxed code."""
        try:
            return obj[argument]
        except (TypeError, LookupError):
            if isinstance(argument, string_types):
                try:
                    attr = str(argument)
                except Exception:
                    pass
                else:
                    try:
                        value = getattr(obj, attr)
                    except AttributeError:
                        pass
                    else:
                        if self.is_safe_attribute(obj, argument, value):
                            return value
                        return self.unsafe_undefined(obj, argument)
        return self.undefined(obj=obj, name=argument)

    def getattr(self, obj, attribute):
        """Subscribe an object from sandboxed code and prefer the
        attribute.  The attribute passed *must* be a bytestring.
        """
        try:
            value = getattr(obj, attribute)
        except AttributeError:
            try:
                return obj[attribute]
            except (TypeError, LookupError):
                pass
        else:
            if self.is_safe_attribute(obj, attribute, value):
                return value
            return self.unsafe_undefined(obj, attribute)
        return self.undefined(obj=obj, name=attribute)

    def unsafe_undefined(self, obj, attribute):
        """Return an undefined object for unsafe attributes."""
        return self.undefined('access to attribute %r of %r '
                              'object is unsafe.' % (
            attribute,
            obj.__class__.__name__
        ), name=attribute, obj=obj, exc=SecurityError)

    def call(__self, __context, __obj, *args, **kwargs):
        """Call an object from sandboxed code."""
        # the double prefixes are to avoid double keyword argument
        # errors when proxying the call.
        if not __self.is_safe_callable(__obj):
            raise SecurityError('%r is not safely callable' % (__obj,))
        return __context.call(__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_known_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_known_mutable(obj, attr)