Issue #27570: Avoid zero-length memcpy() calls with null source pointers
diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 482526e..2a21e74 100644
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -38,14 +38,24 @@
if have_long_long:
typecodes += 'qQ'
-class BadConstructorTest(unittest.TestCase):
+class MiscTest(unittest.TestCase):
- def test_constructor(self):
+ def test_bad_constructor(self):
self.assertRaises(TypeError, array.array)
self.assertRaises(TypeError, array.array, spam=42)
self.assertRaises(TypeError, array.array, 'xx')
self.assertRaises(ValueError, array.array, 'x')
+ def test_empty(self):
+ # Exercise code for handling zero-length arrays
+ a = array.array('B')
+ a[:] = a
+ self.assertEqual(len(a), 0)
+ self.assertEqual(len(a + a), 0)
+ self.assertEqual(len(a * 3), 0)
+ a += a
+ self.assertEqual(len(a), 0)
+
# Machine format codes.
#
diff --git a/Misc/NEWS b/Misc/NEWS
index 31bf815..83dc4f6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -67,6 +67,9 @@
Library
-------
+- Issue #27570: Avoid zero-length memcpy() etc calls with null source
+ pointers in the "ctypes" and "array" modules.
+
- Issue #22233: Break email header lines *only* on the RFC specified CR and LF
characters, not on arbitrary unicode line breaks. This also fixes a bug in
HTTP header parsing.
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index b20039f..7de9cee 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -1381,8 +1381,10 @@
goto error;
}
stgdict->shape[0] = length;
- memmove(&stgdict->shape[1], itemdict->shape,
- sizeof(Py_ssize_t) * (stgdict->ndim - 1));
+ if (stgdict->ndim > 1) {
+ memmove(&stgdict->shape[1], itemdict->shape,
+ sizeof(Py_ssize_t) * (stgdict->ndim - 1));
+ }
itemsize = itemdict->size;
if (length * itemsize < 0) {
diff --git a/Modules/_ctypes/stgdict.c b/Modules/_ctypes/stgdict.c
index 879afb8..6c0fda9 100644
--- a/Modules/_ctypes/stgdict.c
+++ b/Modules/_ctypes/stgdict.c
@@ -391,9 +391,11 @@
}
memset(stgdict->ffi_type_pointer.elements, 0,
sizeof(ffi_type *) * (basedict->length + len + 1));
- memcpy(stgdict->ffi_type_pointer.elements,
- basedict->ffi_type_pointer.elements,
- sizeof(ffi_type *) * (basedict->length));
+ if (basedict->length > 0) {
+ memcpy(stgdict->ffi_type_pointer.elements,
+ basedict->ffi_type_pointer.elements,
+ sizeof(ffi_type *) * (basedict->length));
+ }
ffi_ofs = basedict->length;
} else {
offset = 0;
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index b9f87ae..a4966b4 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -745,8 +745,10 @@
np = (arrayobject *) newarrayobject(&Arraytype, ihigh - ilow, a->ob_descr);
if (np == NULL)
return NULL;
- memcpy(np->ob_item, a->ob_item + ilow * a->ob_descr->itemsize,
- (ihigh-ilow) * a->ob_descr->itemsize);
+ if (ihigh > ilow) {
+ memcpy(np->ob_item, a->ob_item + ilow * a->ob_descr->itemsize,
+ (ihigh-ilow) * a->ob_descr->itemsize);
+ }
return (PyObject *)np;
}
@@ -804,9 +806,13 @@
if (np == NULL) {
return NULL;
}
- memcpy(np->ob_item, a->ob_item, Py_SIZE(a)*a->ob_descr->itemsize);
- memcpy(np->ob_item + Py_SIZE(a)*a->ob_descr->itemsize,
- b->ob_item, Py_SIZE(b)*b->ob_descr->itemsize);
+ if (Py_SIZE(a) > 0) {
+ memcpy(np->ob_item, a->ob_item, Py_SIZE(a)*a->ob_descr->itemsize);
+ }
+ if (Py_SIZE(b) > 0) {
+ memcpy(np->ob_item + Py_SIZE(a)*a->ob_descr->itemsize,
+ b->ob_item, Py_SIZE(b)*b->ob_descr->itemsize);
+ }
return (PyObject *)np;
#undef b
}
@@ -826,7 +832,7 @@
np = (arrayobject *) newarrayobject(&Arraytype, size, a->ob_descr);
if (np == NULL)
return NULL;
- if (n == 0)
+ if (size == 0)
return (PyObject *)np;
oldbytes = Py_SIZE(a) * a->ob_descr->itemsize;
newbytes = oldbytes * n;
@@ -985,8 +991,10 @@
size = oldsize + Py_SIZE(b);
if (array_resize(self, size) == -1)
return -1;
- memcpy(self->ob_item + oldsize * self->ob_descr->itemsize,
- b->ob_item, bbsize * b->ob_descr->itemsize);
+ if (bbsize > 0) {
+ memcpy(self->ob_item + oldsize * self->ob_descr->itemsize,
+ b->ob_item, bbsize * b->ob_descr->itemsize);
+ }
return 0;
#undef b