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[3.11] gh-106905: Use separate structs to track recursion depth in each PyAST_mod2obj call. (GH-113035) (GH-113472) (GH-113476)

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(cherry picked from commit 48c49739f5)
(cherry picked from commit d58a5f453f)

Co-authored-by: Yilei Yang <yileiyang@google.com>
Co-authored-by: Gregory P. Smith [Google LLC] <greg@krypto.org>
This commit is contained in:
Serhiy Storchaka 2023-12-25 22:40:33 +02:00 • committed by GitHub
parent 1cc594d571
commit 4b358d754c
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GPG key ID: 4AEE18F83AFDEB23
4 changed files with 397 additions and 310 deletions
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4
Include/internal/pycore_ast_state.h generated
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@ -12,8 +12,8 @@ extern "C" {
struct ast_state {
int initialized;
int recursion_depth;
int recursion_limit;
int unused_recursion_depth;
int unused_recursion_limit;
PyObject *AST_type;
PyObject *Add_singleton;
PyObject *Add_type;

7
Misc/NEWS.d/next/Core and Builtins/2023-12-13-11-45-53.gh-issue-106905.5dslTN.rst Normal file
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@ -0,0 +1,7 @@
Use per AST-parser state rather than global state to track recursion depth
within the AST parser to prevent potential race condition due to
simultaneous parsing.
The issue primarily showed up in 3.11 by multithreaded users of
:func:`ast.parse`. In 3.12 a change to when garbage collection can be
triggered prevented the race condition from occurring.

58
Parser/asdl_c.py
View file

@ -724,7 +724,7 @@ def emit_sequence_constructor(self, name, type):
class PyTypesDeclareVisitor(PickleVisitor):
def visitProduct(self, prod, name):
self.emit("static PyObject* ast2obj_%s(struct ast_state *state, void*);" % name, 0)
self.emit("static PyObject* ast2obj_%s(struct ast_state *state, struct validator *vstate, void*);" % name, 0)
if prod.attributes:
self.emit("static const char * const %s_attributes[] = {" % name, 0)
for a in prod.attributes:
@ -745,7 +745,7 @@ def visitSum(self, sum, name):
ptype = "void*"
if is_simple(sum):
ptype = get_c_type(name)
self.emit("static PyObject* ast2obj_%s(struct ast_state *state, %s);" % (name, ptype), 0)
self.emit("static PyObject* ast2obj_%s(struct ast_state *state, struct validator *vstate, %s);" % (name, ptype), 0)
for t in sum.types:
self.visitConstructor(t, name)
@ -977,7 +977,8 @@ def visitModule(self, mod):
/* Conversion AST -> Python */
static PyObject* ast2obj_list(struct ast_state *state, asdl_seq *seq, PyObject* (*func)(struct ast_state *state, void*))
static PyObject* ast2obj_list(struct ast_state *state, struct validator *vstate, asdl_seq *seq,
PyObject* (*func)(struct ast_state *state, struct validator *vstate, void*))
{
Py_ssize_t i, n = asdl_seq_LEN(seq);
PyObject *result = PyList_New(n);
@ -985,7 +986,7 @@ def visitModule(self, mod):
if (!result)
return NULL;
for (i = 0; i < n; i++) {
value = func(state, asdl_seq_GET_UNTYPED(seq, i));
value = func(state, vstate, asdl_seq_GET_UNTYPED(seq, i));
if (!value) {
Py_DECREF(result);
return NULL;
@ -995,7 +996,7 @@ def visitModule(self, mod):
return result;
}
static PyObject* ast2obj_object(struct ast_state *Py_UNUSED(state), void *o)
static PyObject* ast2obj_object(struct ast_state *Py_UNUSED(state), struct validator *Py_UNUSED(vstate), void *o)
{
if (!o)
o = Py_None;
@ -1006,7 +1007,7 @@ def visitModule(self, mod):
#define ast2obj_identifier ast2obj_object
#define ast2obj_string ast2obj_object
static PyObject* ast2obj_int(struct ast_state *Py_UNUSED(state), long b)
static PyObject* ast2obj_int(struct ast_state *Py_UNUSED(state), struct validator *Py_UNUSED(vstate), long b)
{
return PyLong_FromLong(b);
}
@ -1114,8 +1115,6 @@ def visitModule(self, mod):
for dfn in mod.dfns:
self.visit(dfn)
self.file.write(textwrap.dedent('''
state->recursion_depth = 0;
state->recursion_limit = 0;
state->initialized = 1;
return 1;
}
@ -1255,7 +1254,7 @@ class ObjVisitor(PickleVisitor):
def func_begin(self, name):
ctype = get_c_type(name)
self.emit("PyObject*", 0)
self.emit("ast2obj_%s(struct ast_state *state, void* _o)" % (name), 0)
self.emit("ast2obj_%s(struct ast_state *state, struct validator *vstate, void* _o)" % (name), 0)
self.emit("{", 0)
self.emit("%s o = (%s)_o;" % (ctype, ctype), 1)
self.emit("PyObject *result = NULL, *value = NULL;", 1)
@ -1263,16 +1262,17 @@ def func_begin(self, name):
self.emit('if (!o) {', 1)
self.emit("Py_RETURN_NONE;", 2)
self.emit("}", 1)
self.emit("if (++state->recursion_depth > state->recursion_limit) {", 1)
self.emit("if (++vstate->recursion_depth > vstate->recursion_limit) {", 1)
self.emit("PyErr_SetString(PyExc_RecursionError,", 2)
self.emit('"maximum recursion depth exceeded during ast construction");', 3)
self.emit("return 0;", 2)
self.emit("}", 1)
def func_end(self):
self.emit("state->recursion_depth--;", 1)
self.emit("vstate->recursion_depth--;", 1)
self.emit("return result;", 1)
self.emit("failed:", 0)
self.emit("vstate->recursion_depth--;", 1)
self.emit("Py_XDECREF(value);", 1)
self.emit("Py_XDECREF(result);", 1)
self.emit("return NULL;", 1)
@ -1290,7 +1290,7 @@ def visitSum(self, sum, name):
self.visitConstructor(t, i + 1, name)
self.emit("}", 1)
for a in sum.attributes:
self.emit("value = ast2obj_%s(state, o->%s);" % (a.type, a.name), 1)
self.emit("value = ast2obj_%s(state, vstate, o->%s);" % (a.type, a.name), 1)
self.emit("if (!value) goto failed;", 1)
self.emit('if (PyObject_SetAttr(result, state->%s, value) < 0)' % a.name, 1)
self.emit('goto failed;', 2)
@ -1298,7 +1298,7 @@ def visitSum(self, sum, name):
self.func_end()
def simpleSum(self, sum, name):
self.emit("PyObject* ast2obj_%s(struct ast_state *state, %s_ty o)" % (name, name), 0)
self.emit("PyObject* ast2obj_%s(struct ast_state *state, struct validator *vstate, %s_ty o)" % (name, name), 0)
self.emit("{", 0)
self.emit("switch(o) {", 1)
for t in sum.types:
@ -1317,7 +1317,7 @@ def visitProduct(self, prod, name):
for field in prod.fields:
self.visitField(field, name, 1, True)
for a in prod.attributes:
self.emit("value = ast2obj_%s(state, o->%s);" % (a.type, a.name), 1)
self.emit("value = ast2obj_%s(state, vstate, o->%s);" % (a.type, a.name), 1)
self.emit("if (!value) goto failed;", 1)
self.emit("if (PyObject_SetAttr(result, state->%s, value) < 0)" % a.name, 1)
self.emit('goto failed;', 2)
@ -1358,7 +1358,7 @@ def set(self, field, value, depth):
self.emit("for(i = 0; i < n; i++)", depth+1)
# This cannot fail, so no need for error handling
self.emit(
"PyList_SET_ITEM(value, i, ast2obj_{0}(state, ({0}_ty)asdl_seq_GET({1}, i)));".format(
"PyList_SET_ITEM(value, i, ast2obj_{0}(state, vstate, ({0}_ty)asdl_seq_GET({1}, i)));".format(
field.type,
value
),
@ -1367,9 +1367,9 @@ def set(self, field, value, depth):
)
self.emit("}", depth)
else:
self.emit("value = ast2obj_list(state, (asdl_seq*)%s, ast2obj_%s);" % (value, field.type), depth)
self.emit("value = ast2obj_list(state, vstate, (asdl_seq*)%s, ast2obj_%s);" % (value, field.type), depth)
else:
self.emit("value = ast2obj_%s(state, %s);" % (field.type, value), depth, reflow=False)
self.emit("value = ast2obj_%s(state, vstate, %s);" % (field.type, value), depth, reflow=False)
class PartingShots(StaticVisitor):
@ -1388,23 +1388,24 @@ class PartingShots(StaticVisitor):
int COMPILER_STACK_FRAME_SCALE = 3;
PyThreadState *tstate = _PyThreadState_GET();
if (!tstate) {
return 0;
return NULL;
}
state->recursion_limit = (recursion_limit < INT_MAX / COMPILER_STACK_FRAME_SCALE) ?
struct validator vstate;
vstate.recursion_limit = (recursion_limit < INT_MAX / COMPILER_STACK_FRAME_SCALE) ?
recursion_limit * COMPILER_STACK_FRAME_SCALE : recursion_limit;
int recursion_depth = tstate->recursion_limit - tstate->recursion_remaining;
starting_recursion_depth = (recursion_depth < INT_MAX / COMPILER_STACK_FRAME_SCALE) ?
recursion_depth * COMPILER_STACK_FRAME_SCALE : recursion_depth;
state->recursion_depth = starting_recursion_depth;
vstate.recursion_depth = starting_recursion_depth;
PyObject *result = ast2obj_mod(state, t);
PyObject *result = ast2obj_mod(state, &vstate, t);
/* Check that the recursion depth counting balanced correctly */
if (result && state->recursion_depth != starting_recursion_depth) {
if (result && vstate.recursion_depth != starting_recursion_depth) {
PyErr_Format(PyExc_SystemError,
"AST constructor recursion depth mismatch (before=%d, after=%d)",
starting_recursion_depth, state->recursion_depth);
return 0;
starting_recursion_depth, vstate.recursion_depth);
return NULL;
}
return result;
}
@ -1472,8 +1473,8 @@ def visit(self, object):
def generate_ast_state(module_state, f):
f.write('struct ast_state {\n')
f.write(' int initialized;\n')
f.write(' int recursion_depth;\n')
f.write(' int recursion_limit;\n')
f.write(' int unused_recursion_depth;\n')
f.write(' int unused_recursion_limit;\n')
for s in module_state:
f.write(' PyObject *' + s + ';\n')
f.write('};')
@ -1537,6 +1538,11 @@ def generate_module_def(mod, metadata, f, internal_h):
#include "structmember.h"
#include <stddef.h>
struct validator {
int recursion_depth; /* current recursion depth */
int recursion_limit; /* recursion limit */
};
// Forward declaration
static int init_types(struct ast_state *state);

638
Python/Python-ast.c generated
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