mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-04 08:59:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 11

gh-95185: Check recursion depth in the AST constructor (#95186)

Browse source 
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
This commit is contained in:
Pablo Galindo Salgado 2022-07-24 15:58:52 +01:00 • committed by GitHub
parent 3c94d3395e
commit 0047447294
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
5 changed files with 168 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

37
Parser/asdl_c.py
View file

@ -1112,6 +1112,8 @@ static int add_ast_fields(struct ast_state *state)
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;
}
@ -1259,8 +1261,14 @@ class ObjVisitor(PickleVisitor):
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("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("return result;", 1)
self.emit("failed:", 0)
self.emit("Py_XDECREF(value);", 1)
@ -1371,7 +1379,32 @@ PyObject* PyAST_mod2obj(mod_ty t)
if (state == NULL) {
return NULL;
}
return ast2obj_mod(state, t);
int recursion_limit = Py_GetRecursionLimit();
int starting_recursion_depth;
/* Be careful here to prevent overflow. */
int COMPILER_STACK_FRAME_SCALE = 3;
PyThreadState *tstate = _PyThreadState_GET();
if (!tstate) {
return 0;
}
state->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;
PyObject *result = ast2obj_mod(state, t);
/* Check that the recursion depth counting balanced correctly */
if (result && state->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;
}
return result;
}
/* mode is 0 for "exec", 1 for "eval" and 2 for "single" input */
@ -1437,6 +1470,8 @@ class ChainOfVisitors:
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')
for s in module_state:
f.write(' PyObject *' + s + ';\n')
f.write('};')