bpo-37188: Fix a divide-by-zero in arrays of size-0 objects (GH-13881) (#13882)

miss-islington · Stefan Krah · commit 8f0bbbdcae73 · 2019-06-07T10:34:14.000+02:00
diff --git a/Lib/ctypes/test/test_arrays.py b/Lib/ctypes/test/test_arrays.py
@@ -194,6 +194,21 @@ class T(Array):
                 _type_ = c_int
                 _length_ = 1.87
 
+    def test_empty_element_struct(self):
+        class EmptyStruct(Structure):
+            _fields_ = []
+
+        obj = (EmptyStruct * 2)()  # bpo37188: Floating point exception
+        assert sizeof(obj) == 0
+
+    def test_empty_element_array(self):
+        class EmptyArray(Array):
+            _type_ = c_int
+            _length_ = 0
+
+        obj = (EmptyArray * 2)()  # bpo37188: Floating point exception
+        assert sizeof(obj) == 0
+
     def test_bpo36504_signed_int_overflow(self):
         # The overflow check in PyCArrayType_new() could cause signed integer
         # overflow.
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
@@ -1466,7 +1466,7 @@ PyCArrayType_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     }
 
     itemsize = itemdict->size;
-    if (length > PY_SSIZE_T_MAX / itemsize) {
+    if (itemsize != 0 && length > PY_SSIZE_T_MAX / itemsize) {
         PyErr_SetString(PyExc_OverflowError,
                         "array too large");
         goto error;

Original file line number	Diff line number	Diff line change
`@@ -1466,7 +1466,7 @@ PyCArrayType_new(PyTypeObject type, PyObject args, PyObject *kwds)`
`1466`	`1466`	`}`
`1467`	`1467`
`1468`	`1468`	`itemsize = itemdict->size;`
`1469`		`- if (length > PY_SSIZE_T_MAX / itemsize) {`
	`1469`	`+ if (itemsize != 0 && length > PY_SSIZE_T_MAX / itemsize) {`
`1470`	`1470`	`PyErr_SetString(PyExc_OverflowError,`
`1471`	`1471`	`"array too large");`
`1472`	`1472`	`goto error;`