[Python-checkins] [3.7] bpo-16575: Add checks for unions passed by value to functions. (GH-16799) (GH-17017)
Vinay Sajip
webhook-mailer at python.org
Thu Oct 31 10:15:19 EDT 2019
https://github.com/python/cpython/commit/0118d109d54bf75c99a8b0fa9aeae1a478ac4b7e
commit: 0118d109d54bf75c99a8b0fa9aeae1a478ac4b7e
branch: 3.7
author: Vinay Sajip <vinay_sajip at yahoo.co.uk>
committer: GitHub <noreply at github.com>
date: 2019-10-31T14:15:04Z
summary:
[3.7] bpo-16575: Add checks for unions passed by value to functions. (GH-16799) (GH-17017)
(cherry picked from commit 79d4ed102a5069c6cebaed2627cb1645637f0429)
files:
M Lib/ctypes/test/test_structures.py
M Modules/_ctypes/_ctypes.c
M Modules/_ctypes/_ctypes_test.c
M Modules/_ctypes/ctypes.h
M Modules/_ctypes/stgdict.c
diff --git a/Lib/ctypes/test/test_structures.py b/Lib/ctypes/test/test_structures.py
index d8d6c657928bf..8e2897ad51230 100644
--- a/Lib/ctypes/test/test_structures.py
+++ b/Lib/ctypes/test/test_structures.py
@@ -532,6 +532,86 @@ class U(Union):
self.assertEqual(f2, [0x4567, 0x0123, 0xcdef, 0x89ab,
0x3210, 0x7654, 0xba98, 0xfedc])
+ def test_union_by_value(self):
+ # See bpo-16575
+
+ # These should mirror the structures in Modules/_ctypes/_ctypes_test.c
+
+ class Nested1(Structure):
+ _fields_ = [
+ ('an_int', c_int),
+ ('another_int', c_int),
+ ]
+
+ class Test4(Union):
+ _fields_ = [
+ ('a_long', c_long),
+ ('a_struct', Nested1),
+ ]
+
+ class Nested2(Structure):
+ _fields_ = [
+ ('an_int', c_int),
+ ('a_union', Test4),
+ ]
+
+ class Test5(Structure):
+ _fields_ = [
+ ('an_int', c_int),
+ ('nested', Nested2),
+ ('another_int', c_int),
+ ]
+
+ test4 = Test4()
+ dll = CDLL(_ctypes_test.__file__)
+ with self.assertRaises(TypeError) as ctx:
+ func = dll._testfunc_union_by_value1
+ func.restype = c_long
+ func.argtypes = (Test4,)
+ result = func(test4)
+ self.assertEqual(ctx.exception.args[0], 'item 1 in _argtypes_ passes '
+ 'a union by value, which is unsupported.')
+ test5 = Test5()
+ with self.assertRaises(TypeError) as ctx:
+ func = dll._testfunc_union_by_value2
+ func.restype = c_long
+ func.argtypes = (Test5,)
+ result = func(test5)
+ self.assertEqual(ctx.exception.args[0], 'item 1 in _argtypes_ passes '
+ 'a union by value, which is unsupported.')
+
+ # passing by reference should be OK
+ test4.a_long = 12345;
+ func = dll._testfunc_union_by_reference1
+ func.restype = c_long
+ func.argtypes = (POINTER(Test4),)
+ result = func(byref(test4))
+ self.assertEqual(result, 12345)
+ self.assertEqual(test4.a_long, 0)
+ self.assertEqual(test4.a_struct.an_int, 0)
+ self.assertEqual(test4.a_struct.another_int, 0)
+ test4.a_struct.an_int = 0x12340000
+ test4.a_struct.another_int = 0x5678
+ func = dll._testfunc_union_by_reference2
+ func.restype = c_long
+ func.argtypes = (POINTER(Test4),)
+ result = func(byref(test4))
+ self.assertEqual(result, 0x12345678)
+ self.assertEqual(test4.a_long, 0)
+ self.assertEqual(test4.a_struct.an_int, 0)
+ self.assertEqual(test4.a_struct.another_int, 0)
+ test5.an_int = 0x12000000
+ test5.nested.an_int = 0x345600
+ test5.another_int = 0x78
+ func = dll._testfunc_union_by_reference3
+ func.restype = c_long
+ func.argtypes = (POINTER(Test5),)
+ result = func(byref(test5))
+ self.assertEqual(result, 0x12345678)
+ self.assertEqual(test5.an_int, 0)
+ self.assertEqual(test5.nested.an_int, 0)
+ self.assertEqual(test5.another_int, 0)
+
class PointerMemberTestCase(unittest.TestCase):
def test(self):
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index f186e5082afbf..d2ce1b074348d 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -446,6 +446,9 @@ StructUnionType_new(PyTypeObject *type, PyObject *args, PyObject *kwds, int isSt
Py_DECREF(result);
return NULL;
}
+ if (!isStruct) {
+ dict->flags |= TYPEFLAG_HASUNION;
+ }
/* replace the class dict by our updated stgdict, which holds info
about storage requirements of the instances */
if (-1 == PyDict_Update((PyObject *)dict, result->tp_dict)) {
@@ -2276,6 +2279,26 @@ converters_from_argtypes(PyObject *ob)
PyObject *cnv = PyObject_GetAttrString(tp, "from_param");
if (!cnv)
goto argtypes_error_1;
+ StgDictObject *stgdict = PyType_stgdict(tp);
+
+ if (stgdict != NULL) {
+ if (stgdict->flags & TYPEFLAG_HASUNION) {
+ Py_DECREF(converters);
+ Py_DECREF(ob);
+ if (!PyErr_Occurred()) {
+ PyErr_Format(PyExc_TypeError,
+ "item %zd in _argtypes_ passes a union by "
+ "value, which is unsupported.",
+ i + 1);
+ }
+ return NULL;
+ }
+ /*
+ if (stgdict->flags & TYPEFLAG_HASBITFIELD) {
+ printf("found stgdict with bitfield\n");
+ }
+ */
+ }
PyTuple_SET_ITEM(converters, i, cnv);
}
Py_DECREF(ob);
diff --git a/Modules/_ctypes/_ctypes_test.c b/Modules/_ctypes/_ctypes_test.c
index f59abcc451591..e06a045545578 100644
--- a/Modules/_ctypes/_ctypes_test.c
+++ b/Modules/_ctypes/_ctypes_test.c
@@ -135,6 +135,69 @@ _testfunc_array_in_struct2a(Test3B in)
return result;
}
+typedef union {
+ long a_long;
+ struct {
+ int an_int;
+ int another_int;
+ } a_struct;
+} Test4;
+
+typedef struct {
+ int an_int;
+ struct {
+ int an_int;
+ Test4 a_union;
+ } nested;
+ int another_int;
+} Test5;
+
+EXPORT(long)
+_testfunc_union_by_value1(Test4 in) {
+ long result = in.a_long + in.a_struct.an_int + in.a_struct.another_int;
+
+ /* As the union/struct are passed by value, changes to them shouldn't be
+ * reflected in the caller.
+ */
+ memset(&in, 0, sizeof(in));
+ return result;
+}
+
+EXPORT(long)
+_testfunc_union_by_value2(Test5 in) {
+ long result = in.an_int + in.nested.an_int;
+
+ /* As the union/struct are passed by value, changes to them shouldn't be
+ * reflected in the caller.
+ */
+ memset(&in, 0, sizeof(in));
+ return result;
+}
+
+EXPORT(long)
+_testfunc_union_by_reference1(Test4 *in) {
+ long result = in->a_long;
+
+ memset(in, 0, sizeof(Test4));
+ return result;
+}
+
+EXPORT(long)
+_testfunc_union_by_reference2(Test4 *in) {
+ long result = in->a_struct.an_int + in->a_struct.another_int;
+
+ memset(in, 0, sizeof(Test4));
+ return result;
+}
+
+EXPORT(long)
+_testfunc_union_by_reference3(Test5 *in) {
+ long result = in->an_int + in->nested.an_int + in->another_int;
+
+ memset(in, 0, sizeof(Test5));
+ return result;
+}
+
EXPORT(void)testfunc_array(int values[4])
{
printf("testfunc_array %d %d %d %d\n",
diff --git a/Modules/_ctypes/ctypes.h b/Modules/_ctypes/ctypes.h
index 5d3b9663385f5..e58f85233cb71 100644
--- a/Modules/_ctypes/ctypes.h
+++ b/Modules/_ctypes/ctypes.h
@@ -288,6 +288,8 @@ PyObject *_ctypes_callproc(PPROC pProc,
#define TYPEFLAG_ISPOINTER 0x100
#define TYPEFLAG_HASPOINTER 0x200
+#define TYPEFLAG_HASUNION 0x400
+#define TYPEFLAG_HASBITFIELD 0x800
#define DICTFLAG_FINAL 0x1000
diff --git a/Modules/_ctypes/stgdict.c b/Modules/_ctypes/stgdict.c
index af12d314ab98f..231c3feb8f335 100644
--- a/Modules/_ctypes/stgdict.c
+++ b/Modules/_ctypes/stgdict.c
@@ -407,6 +407,13 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
PyMem_Free(stgdict->ffi_type_pointer.elements);
basedict = PyType_stgdict((PyObject *)((PyTypeObject *)type)->tp_base);
+ if (basedict) {
+ stgdict->flags |= (basedict->flags &
+ (TYPEFLAG_HASUNION | TYPEFLAG_HASBITFIELD));
+ }
+ if (!isStruct) {
+ stgdict->flags |= TYPEFLAG_HASUNION;
+ }
if (basedict && !use_broken_old_ctypes_semantics) {
size = offset = basedict->size;
align = basedict->align;
@@ -482,8 +489,10 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
stgdict->ffi_type_pointer.elements[ffi_ofs + i] = &dict->ffi_type_pointer;
if (dict->flags & (TYPEFLAG_ISPOINTER | TYPEFLAG_HASPOINTER))
stgdict->flags |= TYPEFLAG_HASPOINTER;
+ stgdict->flags |= dict->flags & (TYPEFLAG_HASUNION | TYPEFLAG_HASBITFIELD);
dict->flags |= DICTFLAG_FINAL; /* mark field type final */
if (PyTuple_Size(pair) == 3) { /* bits specified */
+ stgdict->flags |= TYPEFLAG_HASBITFIELD;
switch(dict->ffi_type_pointer.type) {
case FFI_TYPE_UINT8:
case FFI_TYPE_UINT16:
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