Security audit of the Python 3.15 changes

CHANGES.rst

@@ -4,6 +4,19 @@ Changes
 8.5 (unreleased)
 ----------------
 
+- Officially support Python 3.15 after performing a security audit of its
+  changes:
+
+  - Disallow lazy import statements (PEP 810) as they bypass a guarded
+    ``__import__``.
+
+  - Disallow unpacking in comprehensions (PEP 798) as it bypasses the
+    ``_getiter_`` guard.
+
+- Add the attributes of asynchronous generator objects (``ag_await``,
+  ``ag_frame``, ``ag_code``) to the restricted names in
+  ``INSPECT_ATTRIBUTES`` as they were missing there.
+
 - Fix the combined coverage report: the ``coverage`` tox environment now
   combines the coverage data of all supported Python versions instead of
   measuring a single one, and enforces 100 % coverage. The broken

docs/conf.py

@@ -117,6 +117,7 @@
     'python312': ('https://docs.python.org/3.12', None),
     'python313': ('https://docs.python.org/3.13', None),
     'python314': ('https://docs.python.org/3.14', None),
+    'python315': ('https://docs.python.org/3.15', None),
 }
 
 # Options for sphinx.ext.todo:

docs/contributing/ast/python3_15.ast

@@ -0,0 +1,196 @@
+-- Python 3.15 AST
+-- ASDL's 4 builtin types are:
+-- identifier, int, string, constant
+
+module Python version "3.15"
+{
+    mod = Module(stmt* body, type_ignore* type_ignores)
+        | Interactive(stmt* body)
+        | Expression(expr body)
+        | FunctionType(expr* argtypes, expr returns)
+
+    stmt = FunctionDef(identifier name,
+                       arguments args,
+                       stmt* body,
+                       expr* decorator_list,
+                       expr? returns,
+                       string? type_comment,
+                       type_param* type_params)
+         | AsyncFunctionDef(identifier name,
+                            arguments args,
+                            stmt* body,
+                            expr* decorator_list,
+                            expr? returns,
+                            string? type_comment,
+                            type_param* type_params)
+
+         | ClassDef(identifier name,
+                    expr* bases,
+                    keyword* keywords,
+                    stmt* body,
+                    expr* decorator_list,
+                    type_param* type_params)
+         | Return(expr? value)
+
+         | Delete(expr* targets)
+         | Assign(expr* targets, expr value, string? type_comment)
+         | TypeAlias(expr name, type_param* type_params, expr value)
+         | AugAssign(expr target, operator op, expr value)
+         -- 'simple' indicates that we annotate simple name without parens
+         | AnnAssign(expr target, expr annotation, expr? value, int simple)
+
+         -- use 'orelse' because else is a keyword in target languages
+         | For(expr target, expr iter, stmt* body, stmt* orelse, string? type_comment)
+         | AsyncFor(expr target, expr iter, stmt* body, stmt* orelse, string? type_comment)
+         | While(expr test, stmt* body, stmt* orelse)
+         | If(expr test, stmt* body, stmt* orelse)
+         | With(withitem* items, stmt* body, string? type_comment)
+         | AsyncWith(withitem* items, stmt* body, string? type_comment)
+
+         | Match(expr subject, match_case* cases)
+
+         | Raise(expr? exc, expr? cause)
+         | Try(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
+         | TryStar(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
+         | Assert(expr test, expr? msg)
+
+         | Import(alias* names, int? is_lazy)
+         | ImportFrom(identifier? module, alias* names, int? level, int? is_lazy)
+
+         | Global(identifier* names)
+         | Nonlocal(identifier* names)
+         | Expr(expr value)
+         | Pass
+         | Break
+         | Continue
+
+         -- col_offset is the byte offset in the utf8 string the parser uses
+         attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
+
+         -- BoolOp() can use left & right?
+    expr = BoolOp(boolop op, expr* values)
+         | NamedExpr(expr target, expr value)
+         | BinOp(expr left, operator op, expr right)
+         | UnaryOp(unaryop op, expr operand)
+         | Lambda(arguments args, expr body)
+         | IfExp(expr test, expr body, expr orelse)
+         | Dict(expr?* keys, expr* values)
+         | Set(expr* elts)
+         | ListComp(expr elt, comprehension* generators)
+         | SetComp(expr elt, comprehension* generators)
+         | DictComp(expr key, expr? value, comprehension* generators)
+         | GeneratorExp(expr elt, comprehension* generators)
+         -- the grammar constrains where yield expressions can occur
+         | Await(expr value)
+         | Yield(expr? value)
+         | YieldFrom(expr value)
+         -- need sequences for compare to distinguish between
+         -- x < 4 < 3 and (x < 4) < 3
+         | Compare(expr left, cmpop* ops, expr* comparators)
+         | Call(expr func, expr* args, keyword* keywords)
+         | FormattedValue(expr value, int conversion, expr? format_spec)
+         | Interpolation(expr value, constant str, int conversion, expr? format_spec)
+         | JoinedStr(expr* values)
+         | TemplateStr(expr* values)
+         | Constant(constant value, string? kind)
+
+         -- the following expression can appear in assignment context
+         | Attribute(expr value, identifier attr, expr_context ctx)
+         | Subscript(expr value, expr slice, expr_context ctx)
+         | Starred(expr value, expr_context ctx)
+         | Name(identifier id, expr_context ctx)
+         | List(expr* elts, expr_context ctx)
+         | Tuple(expr* elts, expr_context ctx)
+
+         -- can appear only in Subscript
+         | Slice(expr? lower, expr? upper, expr? step)
+
+          -- col_offset is the byte offset in the utf8 string the parser uses
+          attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
+
+    expr_context = Load
+                 | Store
+                 | Del
+
+    boolop = And
+           | Or
+
+    operator = Add
+             | Sub
+             | Mult
+             | MatMult
+             | Div
+             | Mod
+             | Pow
+             | LShift
+             | RShift
+             | BitOr
+             | BitXor
+             | BitAnd
+             | FloorDiv
+
+    unaryop = Invert
+            | Not
+            | UAdd
+            | USub
+
+    cmpop = Eq
+          | NotEq
+          | Lt
+          | LtE
+          | Gt
+          | GtE
+          | Is
+          | IsNot
+          | In
+          | NotIn
+
+    comprehension = (expr target, expr iter, expr* ifs, int is_async)
+
+    excepthandler = ExceptHandler(expr? type, identifier? name, stmt* body)
+                    attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
+
+    arguments = (arg* posonlyargs,
+                 arg* args,
+                 arg? vararg,
+                 arg* kwonlyargs,
+                 expr* kw_defaults,
+                 arg? kwarg,
+                 expr* defaults)
+
+    arg = (identifier arg, expr? annotation, string? type_comment)
+          attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
+
+    -- keyword arguments supplied to call (NULL identifier for **kwargs)
+    keyword = (identifier? arg, expr value)
+              attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
+
+    -- import name with optional 'as' alias.
+    alias = (identifier name, identifier? asname)
+            attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
+
+    withitem = (expr context_expr, expr? optional_vars)
+
+    match_case = (pattern pattern, expr? guard, stmt* body)
+
+    pattern = MatchValue(expr value)
+            | MatchSingleton(constant value)
+            | MatchSequence(pattern* patterns)
+            | MatchMapping(expr* keys, pattern* patterns, identifier? rest)
+            | MatchClass(expr cls, pattern* patterns, identifier* kwd_attrs, pattern* kwd_patterns)
+
+            | MatchStar(identifier? name)
+            -- The optional "rest" MatchMapping parameter handles capturing extra mapping keys
+
+            | MatchAs(pattern? pattern, identifier? name)
+            | MatchOr(pattern* patterns)
+
+             attributes (int lineno, int col_offset, int end_lineno, int end_col_offset)
+
+    type_ignore = TypeIgnore(int lineno, string tag)
+
+    type_param = TypeVar(identifier name, expr? bound, expr? default_value)
+               | ParamSpec(identifier name, expr? default_value)
+               | TypeVarTuple(identifier name, expr? default_value)
+               attributes (int lineno, int col_offset, int end_lineno, int end_col_offset)
+}

docs/contributing/changes_from314to315.rst

@@ -0,0 +1,48 @@
+Changes from Python 3.14 to Python 3.15
+---------------------------------------
+
+.. literalinclude:: ast/python3_15.ast
+   :diff: ast/python3_14.ast
+
+Security audit of the Python 3.15 changes
++++++++++++++++++++++++++++++++++++++++++
+
+Lazy imports (:pep:`810`)
+    ``lazy import`` statements do not introduce a new AST node.
+    They only add a new field ``is_lazy`` to the existing ``Import`` and
+    ``ImportFrom`` nodes, so the default-deny mechanism of
+    ``RestrictingNodeTransformer.generic_visit`` does **not** apply to them.
+    At run time a lazy import is resolved through the new ``__lazy_import__``
+    builtin instead of ``__import__``, thus bypassing a guarded
+    ``__import__``.
+    Therefore lazy imports are explicitly not allowed.
+    Assigning ``__lazy_modules__`` was already blocked by the rule denying
+    names which start with an underscore.
+
+Unpacking in comprehensions (:pep:`798`)
+    ``[*x for x in seq]``, ``{*x for x in seq}``, ``(*x for x in seq)`` and
+    ``{**x for x in seq}`` reuse the existing ``Starred`` node (resp. a
+    ``DictComp`` node without a value), so they compiled silently.
+    The unpacked value is iterated by the bytecode without calling the
+    ``_getiter_`` guard — unlike the equivalent nested comprehension
+    ``[y for x in seq for y in x]``.
+    Therefore unpacking in comprehensions is explicitly not allowed.
+
+Unary ``+`` in ``match`` literal patterns
+    No action needed as the ``match`` statement is not allowed in
+    RestrictedPython.
+
+New builtins ``frozendict`` (:pep:`814`) and ``sentinel`` (:pep:`661`)
+    No action needed as ``safe_builtins`` is an allow list, so the new
+    builtins are not available in restricted code.
+
+New ``inspect`` attributes ``gi_state``, ``cr_state`` and ``ag_state``
+    They only reveal the state of a (async) generator resp. coroutine as a
+    string, so they are treated like the other harmless attributes
+    (e. g. ``gi_running``) and remain accessible.
+    Reviewing ``INSPECT_ATTRIBUTES`` also revealed that the attributes of
+    asynchronous generator objects (``ag_await``, ``ag_frame``, ``ag_code``)
+    were missing from the list; they are now blocked.
+
+Removed ``ast`` classes (``ast.Num``, ``ast.Str``, ``ast.Bytes``, ``ast.NameConstant``, ``ast.Ellipsis``)
+    No action needed as they are no longer used by RestrictedPython.

docs/contributing/index.rst

@@ -67,7 +67,7 @@ To do so:
 * Add a corresponding changelog entry.
 * Additionally modify ``.meta.toml`` and run the ``meta/config`` script (for details see: https://github.com/mgedmin/check-python-versions) to update the following files:
 
-  * ``/setup.py`` - Check that the new Python version classifier has been added ``"Programming Language :: Python :: <version>",``, and that the ``python_requires`` section has been updated correctly.
+  * ``/pyproject.toml`` - Check that the new Python version classifier has been added ``"Programming Language :: Python :: <version>",``, and that the ``requires-python`` value has been updated correctly.
   * ``/tox.ini`` - Check that a ``testenv`` entry is added to the general ``envlist`` statement.
   * ``/.github/workflows/tests.yml`` - Check that a corresponding Python version entry has been added to the matrix definition.
   * ``/docs/conf.py`` - Add the Python version to the ``intersphinx_mapping`` list.
@@ -103,6 +103,7 @@ A (modified style) Copy of all Abstract Grammar Definitions for the Python versi
    changes_from311to312
    changes_from312to313
    changes_from313to314
+   changes_from314to315
 
 .. _understand:
 
@@ -235,6 +236,7 @@ Technical Backgrounds - Links to External Documentation
 
   * AST Grammar of Python (`Status of Python Versions`_)
 
+    * `Python 3.15 AST`_ (EOL 2031-10)
     * `Python 3.14 AST`_ (EOL 2030-10)
     * `Python 3.13 AST`_ (EOL 2029-10)
     * `Python 3.12 AST`_ (EOL 2028-10)
@@ -257,6 +259,8 @@ Todos
 
 .. _`What's new in Python`: https://docs.python.org/3/whatsnew/
 
+.. _`What's new in Python 3.15`: https://docs.python.org/3.15/whatsnew/3.15.html
+
 .. _`What's new in Python 3.14`: https://docs.python.org/3.14/whatsnew/3.14.html
 
 .. _`What's new in Python 3.13`: https://docs.python.org/3.13/whatsnew/3.13.html
@@ -281,6 +285,8 @@ Todos
 
 .. _`Python 3 AST`: https://docs.python.org/3/library/ast.html#abstract-grammar
 
+.. _`Python 3.15 AST`: https://docs.python.org/3.15/library/ast.html#abstract-grammar
+
 .. _`Python 3.14 AST`: https://docs.python.org/3.14/library/ast.html#abstract-grammar
 
 .. _`Python 3.13 AST`: https://docs.python.org/3.13/library/ast.html#abstract-grammar

docs/index.rst

@@ -15,7 +15,7 @@ RestrictedPython is not a sandbox system or a secured environment, but it helps
 Supported Python versions
 =========================
 
-RestrictedPython supports CPython 3.10 up to 3.14.
+RestrictedPython supports CPython 3.10 up to 3.15.
 It does _not_ support PyPy or other alternative Python implementations.
 
 Contents

pyproject.toml

@@ -22,6 +22,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     "Programming Language :: Python :: Implementation :: CPython",
     "Topic :: Security",
     "Typing :: Typed",

src/RestrictedPython/_compat.py

@@ -7,5 +7,6 @@
 IS_PY312_OR_GREATER = _version.major == 3 and _version.minor >= 12
 IS_PY313_OR_GREATER = _version.major == 3 and _version.minor >= 13
 IS_PY314_OR_GREATER = _version.major == 3 and _version.minor >= 14
+IS_PY315_OR_GREATER = _version.major == 3 and _version.minor >= 15
 
 IS_CPYTHON = platform.python_implementation() == 'CPython'