https://github.com/python/cpython/commit/cef0a90d8f3a94aa534593f39b4abf98165675b9 commit: cef0a90d8f3a94aa534593f39b4abf98165675b9 branch: main author: Melissa0x1f992 <[email protected]> committer: encukou <[email protected]> date: 2024-12-10T13:13:11+01:00 summary:
gh-126937: ctypes: fix TypeError when a field's size is >65535 bytes (GH-126938) Co-authored-by: Peter Bierma <[email protected]> Co-authored-by: Terry Jan Reedy <[email protected]> Co-authored-by: Petr Viktorin <[email protected]> files: A Misc/NEWS.d/next/Core_and_Builtins/2024-11-17-21-35-55.gh-issue-126937.qluVM0.rst M Lib/test/test_ctypes/test_struct_fields.py M Modules/_ctypes/cfield.c M Modules/_ctypes/stgdict.c diff --git a/Lib/test/test_ctypes/test_struct_fields.py b/Lib/test/test_ctypes/test_struct_fields.py index b5e165f3bae929..1b3e64efd410b8 100644 --- a/Lib/test/test_ctypes/test_struct_fields.py +++ b/Lib/test/test_ctypes/test_struct_fields.py @@ -1,4 +1,5 @@ import unittest +import sys from ctypes import Structure, Union, sizeof, c_char, c_int from ._support import (CField, Py_TPFLAGS_DISALLOW_INSTANTIATION, Py_TPFLAGS_IMMUTABLETYPE) @@ -75,6 +76,28 @@ def __init_subclass__(cls, **kwargs): 'ctypes state is not initialized'): class Subclass(BrokenStructure): ... + def test_max_field_size_gh126937(self): + # Classes for big structs should be created successfully. + # (But they most likely can't be instantiated.) + # Here we test the exact limit: the number of *bits* must fit + # in Py_ssize_t. + + class X(self.cls): + _fields_ = [('char', c_char),] + max_field_size = sys.maxsize // 8 + + class Y(self.cls): + _fields_ = [('largeField', X * max_field_size)] + class Z(self.cls): + _fields_ = [('largeField', c_char * max_field_size)] + + with self.assertRaises(ValueError): + class TooBig(self.cls): + _fields_ = [('largeField', X * (max_field_size + 1))] + with self.assertRaises(ValueError): + class TooBig(self.cls): + _fields_ = [('largeField', c_char * (max_field_size + 1))] + # __set__ and __get__ should raise a TypeError in case their self # argument is not a ctype instance. def test___set__(self): diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-11-17-21-35-55.gh-issue-126937.qluVM0.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-11-17-21-35-55.gh-issue-126937.qluVM0.rst new file mode 100644 index 00000000000000..8d7da0d4107021 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2024-11-17-21-35-55.gh-issue-126937.qluVM0.rst @@ -0,0 +1,3 @@ +Fix :exc:`TypeError` when a :class:`ctypes.Structure` has a field size +that doesn't fit into an unsigned 16-bit integer. +Instead, the maximum number of *bits* is :data:`sys.maxsize`. diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c index 3220852c8398e0..2b9e8a1a10d6f5 100644 --- a/Modules/_ctypes/cfield.c +++ b/Modules/_ctypes/cfield.c @@ -110,10 +110,16 @@ PyCField_new_impl(PyTypeObject *type, PyObject *name, PyObject *proto, goto error; } - Py_ssize_t bit_size = NUM_BITS(size); - if (bit_size) { + if (bit_size_obj != Py_None) { +#ifdef Py_DEBUG + Py_ssize_t bit_size = NUM_BITS(size); assert(bit_size > 0); assert(bit_size <= info->size * 8); + // Currently, the bit size is specified redundantly + // in NUM_BITS(size) and bit_size_obj. + // Verify that they match. + assert(PyLong_AsSsize_t(bit_size_obj) == bit_size); +#endif switch(info->ffi_type_pointer.type) { case FFI_TYPE_UINT8: case FFI_TYPE_UINT16: diff --git a/Modules/_ctypes/stgdict.c b/Modules/_ctypes/stgdict.c index 5dbbe0b3285d58..5ca5b62427600d 100644 --- a/Modules/_ctypes/stgdict.c +++ b/Modules/_ctypes/stgdict.c @@ -292,7 +292,7 @@ PyCStructUnionType_update_stginfo(PyObject *type, PyObject *fields, int isStruct if (!tmp) { goto error; } - Py_ssize_t total_align = PyLong_AsInt(tmp); + Py_ssize_t total_align = PyLong_AsSsize_t(tmp); Py_DECREF(tmp); if (total_align < 0) { if (!PyErr_Occurred()) { @@ -306,7 +306,7 @@ PyCStructUnionType_update_stginfo(PyObject *type, PyObject *fields, int isStruct if (!tmp) { goto error; } - Py_ssize_t total_size = PyLong_AsInt(tmp); + Py_ssize_t total_size = PyLong_AsSsize_t(tmp); Py_DECREF(tmp); if (total_size < 0) { if (!PyErr_Occurred()) { _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-checkins.python.org/ Member address: [email protected]
