170 lines
6.0 KiB
Diff
170 lines
6.0 KiB
Diff
From 91a972f5808973cd441f4dc06873b2f8378f30c7 Mon Sep 17 00:00:00 2001
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From: Lydxn <hlyndon20@gmail.com>
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Date: Mon, 23 Sep 2024 15:09:10 -0700
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Subject: [PATCH] sandbox indirect calls to str.format
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---
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src/jinja2/sandbox.py | 81 ++++++++++++++++++++++--------------------
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tests/test_security.py | 17 +++++++++
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2 files changed, 60 insertions(+), 38 deletions(-)
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Index: jinja2-3.1.4/src/jinja2/sandbox.py
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===================================================================
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--- jinja2-3.1.4.orig/src/jinja2/sandbox.py
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+++ jinja2-3.1.4/src/jinja2/sandbox.py
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@@ -7,6 +7,7 @@ import types
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import typing as t
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from collections import abc
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from collections import deque
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+from functools import update_wrapper
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from string import Formatter
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from _string import formatter_field_name_split # type: ignore
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@@ -81,20 +82,6 @@ _mutable_spec: t.Tuple[t.Tuple[t.Type[t.
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)
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-def inspect_format_method(callable: t.Callable[..., t.Any]) -> t.Optional[str]:
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- if not isinstance(
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- callable, (types.MethodType, types.BuiltinMethodType)
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- ) or callable.__name__ not in ("format", "format_map"):
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- return None
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-
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- obj = callable.__self__
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-
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- if isinstance(obj, str):
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- return obj
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-
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- return None
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-
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-
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def safe_range(*args: int) -> range:
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"""A range that can't generate ranges with a length of more than
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MAX_RANGE items.
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@@ -314,6 +301,9 @@ class SandboxedEnvironment(Environment):
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except AttributeError:
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pass
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else:
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+ fmt = self.wrap_str_format(value)
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+ if fmt is not None:
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+ return fmt
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if self.is_safe_attribute(obj, argument, value):
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return value
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return self.unsafe_undefined(obj, argument)
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@@ -331,6 +321,9 @@ class SandboxedEnvironment(Environment):
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except (TypeError, LookupError):
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pass
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else:
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+ fmt = self.wrap_str_format(value)
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+ if fmt is not None:
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+ return fmt
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if self.is_safe_attribute(obj, attribute, value):
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return value
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return self.unsafe_undefined(obj, attribute)
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@@ -346,34 +339,49 @@ class SandboxedEnvironment(Environment):
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exc=SecurityError,
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)
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- def format_string(
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- self,
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- s: str,
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- args: t.Tuple[t.Any, ...],
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- kwargs: t.Dict[str, t.Any],
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- format_func: t.Optional[t.Callable[..., t.Any]] = None,
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- ) -> str:
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- """If a format call is detected, then this is routed through this
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- method so that our safety sandbox can be used for it.
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+ def wrap_str_format(self, value: t.Any) -> t.Optional[t.Callable[..., str]]:
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+ """If the given value is a ``str.format`` or ``str.format_map`` method,
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+ return a new function than handles sandboxing. This is done at access
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+ rather than in :meth:`call`, so that calls made without ``call`` are
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+ also sandboxed.
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"""
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+ if not isinstance(
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+ value, (types.MethodType, types.BuiltinMethodType)
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+ ) or value.__name__ not in ("format", "format_map"):
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+ return None
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+
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+ f_self: t.Any = value.__self__
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+
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+ if not isinstance(f_self, str):
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+ return None
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+
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+ str_type: t.Type[str] = type(f_self)
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+ is_format_map = value.__name__ == "format_map"
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formatter: SandboxedFormatter
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- if isinstance(s, Markup):
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- formatter = SandboxedEscapeFormatter(self, escape=s.escape)
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+
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+ if isinstance(f_self, Markup):
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+ formatter = SandboxedEscapeFormatter(self, escape=f_self.escape)
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else:
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formatter = SandboxedFormatter(self)
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- if format_func is not None and format_func.__name__ == "format_map":
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- if len(args) != 1 or kwargs:
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- raise TypeError(
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- "format_map() takes exactly one argument"
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- f" {len(args) + (kwargs is not None)} given"
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- )
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+ vformat = formatter.vformat
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+
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+ def wrapper(*args: t.Any, **kwargs: t.Any) -> str:
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+ if is_format_map:
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+ if kwargs:
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+ raise TypeError("format_map() takes no keyword arguments")
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+
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+ if len(args) != 1:
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+ raise TypeError(
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+ f"format_map() takes exactly one argument ({len(args)} given)"
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+ )
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+
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+ kwargs = args[0]
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+ args = ()
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- kwargs = args[0]
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- args = ()
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+ return str_type(vformat(f_self, args, kwargs))
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- rv = formatter.vformat(s, args, kwargs)
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- return type(s)(rv)
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+ return update_wrapper(wrapper, value)
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def call(
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__self, # noqa: B902
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@@ -383,9 +391,6 @@ class SandboxedEnvironment(Environment):
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**kwargs: t.Any,
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) -> t.Any:
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"""Call an object from sandboxed code."""
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- fmt = inspect_format_method(__obj)
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- if fmt is not None:
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- return __self.format_string(fmt, args, kwargs, __obj)
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# the double prefixes are to avoid double keyword argument
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# errors when proxying the call.
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Index: jinja2-3.1.4/tests/test_security.py
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===================================================================
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--- jinja2-3.1.4.orig/tests/test_security.py
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+++ jinja2-3.1.4/tests/test_security.py
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@@ -171,3 +171,20 @@ class TestStringFormatMap:
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'{{ ("a{x.foo}b{y}"|safe).format_map({"x":{"foo": 42}, "y":"<foo>"}) }}'
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)
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assert t.render() == "a42b<foo>"
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+
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+ def test_indirect_call(self):
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+ def run(value, arg):
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+ return value.run(arg)
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+
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+ env = SandboxedEnvironment()
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+ env.filters["run"] = run
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+ t = env.from_string(
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+ """{% set
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+ ns = namespace(run="{0.__call__.__builtins__[__import__]}".format)
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+ %}
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+ {{ ns | run(not_here) }}
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+ """
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+ )
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+
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+ with pytest.raises(SecurityError):
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+ t.render()
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