From 065334d1ee5b7210e1a0a93c37238c86858f2af7 Mon Sep 17 00:00:00 2001
From: David Lord <davidism@gmail.com>
Date: Wed, 5 Mar 2025 10:08:48 -0800
Subject: [PATCH] attr filter uses env.getattr
---
 Jinja2-3.0.3/CHANGES.rst            |  3 +++
 Jinja2-3.0.3/src/jinja2/filters.py  | 38 ++++++++++++-----------------
 Jinja2-3.0.3/tests/test_security.py | 11 +++++++++
 3 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/Jinja2-3.0.3/CHANGES.rst b/Jinja2-3.0.3/CHANGES.rst
index 55d8a96..9170467 100644
--- a/Jinja2-3.0.3/CHANGES.rst
+++ b/Jinja2-3.0.3/CHANGES.rst
@@ -1,5 +1,8 @@
 .. currentmodule:: jinja2
 
+-   The ``|attr`` filter does not bypass the environment's attribute lookup,
+    allowing the sandbox to apply its checks. :ghsa:`cpwx-vrp4-4pq7`
+
 -   Escape template name before formatting it into error messages, to avoid
     issues with names that contain f-string syntax.
     :issue:`1792`, :ghsa:`gmj6-6f8f-6699`
diff --git a/Jinja2-3.0.3/src/jinja2/filters.py b/Jinja2-3.0.3/src/jinja2/filters.py
index f3d4fca..0449901 100644
--- a/Jinja2-3.0.3/src/jinja2/filters.py
+++ b/Jinja2-3.0.3/src/jinja2/filters.py
@@ -6,6 +6,7 @@ import typing
 import typing as t
 import warnings
 from collections import abc
+from inspect import getattr_static
 from itertools import chain
 from itertools import groupby
 
@@ -1382,32 +1383,25 @@ def do_reverse(value: t.Union[str, t.Iterable[V]]) -> t.Union[str, t.Iterable[V]
 def do_attr(
     environment: "Environment", obj: t.Any, name: str
 ) -> t.Union[Undefined, t.Any]:
-    """Get an attribute of an object.  ``foo|attr("bar")`` works like
-    ``foo.bar`` just that always an attribute is returned and items are not
-    looked up.
+    """Get an attribute of an object. ``foo|attr("bar")`` works like
+    ``foo.bar``, but returns undefined instead of falling back to ``foo["bar"]``
+    if the attribute doesn't exist.
 
     See :ref:`Notes on subscriptions <notes-on-subscriptions>` for more details.
     """
+    # Environment.getattr will fall back to obj[name] if obj.name doesn't exist.
+    # But we want to call env.getattr to get behavior such as sandboxing.
+    # Determine if the attr exists first, so we know the fallback won't trigger.
     try:
-        name = str(name)
-    except UnicodeError:
-        pass
-    else:
-        try:
-            value = getattr(obj, name)
-        except AttributeError:
-            pass
-        else:
-            if environment.sandboxed:
-                environment = t.cast("SandboxedEnvironment", environment)
-
-                if not environment.is_safe_attribute(obj, name, value):
-                    return environment.unsafe_undefined(obj, name)
-
-            return value
-
-    return environment.undefined(obj=obj, name=name)
-
+        # This avoids executing properties/descriptors, but misses __getattr__
+        # and __getattribute__ dynamic attrs.
+        getattr_static(obj, name)
+    except AttributeError:
+        # This finds dynamic attrs, and we know it's not a descriptor at this point.
+        if not hasattr(obj, name):
+            return environment.undefined(obj=obj, name=name)
+
+    return environment.getattr(obj, name)
 
 @typing.overload
 def sync_do_map(
diff --git a/Jinja2-3.0.3/tests/test_security.py b/Jinja2-3.0.3/tests/test_security.py
index 9c8bad6..323c6b5 100644
--- a/Jinja2-3.0.3/tests/test_security.py
+++ b/Jinja2-3.0.3/tests/test_security.py
@@ -189,3 +189,14 @@ class TestStringFormatMap:
 
         with pytest.raises(SecurityError):
             t.render()
+
+
+    def test_attr_filter(self) -> None:
+        env = SandboxedEnvironment()
+        t = env.from_string(
+            """{{ "{0.__call__.__builtins__[__import__]}"
+                  | attr("format")(not_here) }}"""
+        )
+
+        with pytest.raises(SecurityError):
+            t.render()
-- 
2.46.0