bpo-16576: Add checks for bitfields passed by value to functions. (GH-17097) (GH-17223)
(cherry picked from commit 106271568c58cfebae58f0c52b640dbe716ba2ce)
diff --git a/Lib/ctypes/test/test_structures.py b/Lib/ctypes/test/test_structures.py
index 8541674..19c4430 100644
--- a/Lib/ctypes/test/test_structures.py
+++ b/Lib/ctypes/test/test_structures.py
@@ -651,6 +651,87 @@
self.assertEqual(test5.nested.an_int, 0)
self.assertEqual(test5.another_int, 0)
+ #@unittest.skipIf('s390' in MACHINE, 'Test causes segfault on S390')
+ def test_bitfield_by_value(self):
+ # See bpo-16576
+
+ # These should mirror the structures in Modules/_ctypes/_ctypes_test.c
+
+ class Test6(Structure):
+ _fields_ = [
+ ('A', c_int, 1),
+ ('B', c_int, 2),
+ ('C', c_int, 3),
+ ('D', c_int, 2),
+ ]
+
+ test6 = Test6()
+ # As these are signed int fields, all are logically -1 due to sign
+ # extension.
+ test6.A = 1
+ test6.B = 3
+ test6.C = 7
+ test6.D = 3
+ dll = CDLL(_ctypes_test.__file__)
+ with self.assertRaises(TypeError) as ctx:
+ func = dll._testfunc_bitfield_by_value1
+ func.restype = c_long
+ func.argtypes = (Test6,)
+ result = func(test6)
+ self.assertEqual(ctx.exception.args[0], 'item 1 in _argtypes_ passes '
+ 'a struct/union with a bitfield by value, which is '
+ 'unsupported.')
+ # passing by reference should be OK
+ func = dll._testfunc_bitfield_by_reference1
+ func.restype = c_long
+ func.argtypes = (POINTER(Test6),)
+ result = func(byref(test6))
+ self.assertEqual(result, -4)
+ self.assertEqual(test6.A, 0)
+ self.assertEqual(test6.B, 0)
+ self.assertEqual(test6.C, 0)
+ self.assertEqual(test6.D, 0)
+
+ class Test7(Structure):
+ _fields_ = [
+ ('A', c_uint, 1),
+ ('B', c_uint, 2),
+ ('C', c_uint, 3),
+ ('D', c_uint, 2),
+ ]
+ test7 = Test7()
+ test7.A = 1
+ test7.B = 3
+ test7.C = 7
+ test7.D = 3
+ func = dll._testfunc_bitfield_by_reference2
+ func.restype = c_long
+ func.argtypes = (POINTER(Test7),)
+ result = func(byref(test7))
+ self.assertEqual(result, 14)
+ self.assertEqual(test7.A, 0)
+ self.assertEqual(test7.B, 0)
+ self.assertEqual(test7.C, 0)
+ self.assertEqual(test7.D, 0)
+
+ # for a union with bitfields, the union check happens first
+ class Test8(Union):
+ _fields_ = [
+ ('A', c_int, 1),
+ ('B', c_int, 2),
+ ('C', c_int, 3),
+ ('D', c_int, 2),
+ ]
+
+ test8 = Test8()
+ with self.assertRaises(TypeError) as ctx:
+ func = dll._testfunc_bitfield_by_value2
+ func.restype = c_long
+ func.argtypes = (Test8,)
+ result = func(test8)
+ self.assertEqual(ctx.exception.args[0], 'item 1 in _argtypes_ passes '
+ 'a union by value, which is unsupported.')
+
class PointerMemberTestCase(unittest.TestCase):
def test(self):
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index a2fddda..13f9f21 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -2400,11 +2400,18 @@
}
return NULL;
}
- /*
if (stgdict->flags & TYPEFLAG_HASBITFIELD) {
- printf("found stgdict with bitfield\n");
+ Py_DECREF(converters);
+ Py_DECREF(ob);
+ if (!PyErr_Occurred()) {
+ PyErr_Format(PyExc_TypeError,
+ "item %zd in _argtypes_ passes a struct/"
+ "union with a bitfield by value, which is "
+ "unsupported.",
+ i + 1);
+ }
+ return NULL;
}
- */
}
if (_PyObject_LookupAttrId(tp, &PyId_from_param, &cnv) <= 0) {
diff --git a/Modules/_ctypes/_ctypes_test.c b/Modules/_ctypes/_ctypes_test.c
index 223be85..3392208 100644
--- a/Modules/_ctypes/_ctypes_test.c
+++ b/Modules/_ctypes/_ctypes_test.c
@@ -198,6 +198,56 @@
return result;
}
+typedef struct {
+ signed int A: 1, B:2, C:3, D:2;
+} Test6;
+
+EXPORT(long)
+_testfunc_bitfield_by_value1(Test6 in) {
+ long result = in.A + in.B + in.C + in.D;
+
+ /* As the struct is passed by value, changes to it shouldn't be
+ * reflected in the caller.
+ */
+ memset(&in, 0, sizeof(in));
+ return result;
+}
+
+EXPORT(long)
+_testfunc_bitfield_by_reference1(Test6 *in) {
+ long result = in->A + in->B + in->C + in->D;
+
+ memset(in, 0, sizeof(Test6));
+ return result;
+}
+
+typedef struct {
+ unsigned int A: 1, B:2, C:3, D:2;
+} Test7;
+
+EXPORT(long)
+_testfunc_bitfield_by_reference2(Test7 *in) {
+ long result = in->A + in->B + in->C + in->D;
+
+ memset(in, 0, sizeof(Test7));
+ return result;
+}
+
+typedef union {
+ signed int A: 1, B:2, C:3, D:2;
+} Test8;
+
+EXPORT(long)
+_testfunc_bitfield_by_value2(Test8 in) {
+ long result = in.A + in.B + in.C + in.D;
+
+ /* As the struct is passed by value, changes to it shouldn't be
+ * reflected in the caller.
+ */
+ memset(&in, 0, sizeof(in));
+ return result;
+}
+
EXPORT(void)testfunc_array(int values[4])
{
printf("testfunc_array %d %d %d %d\n",