[Python-checkins] cpython (merge 3.5 -> default): Issue #27570: Merge null pointer fixes from 3.5

Wed Sep 7 19:42:48 EDT 2016

https://hg.python.org/cpython/rev/2d0fb659372c
changeset: 103259:2d0fb659372c
parent: 103255:9f2467e13c98
parent: 103256:e231dcad3a9b
user: Martin Panter <vadmium+py at gmail.com>
date: Wed Sep 07 23:31:39 2016 +0000
summary:
 Issue #27570: Merge null pointer fixes from 3.5
files:
 Lib/test/test_array.py | 14 ++++++++++++--
 Misc/NEWS | 3 +++
 Modules/_ctypes/_ctypes.c | 6 ++++--
 Modules/_ctypes/stgdict.c | 8 +++++---
 Modules/arraymodule.c | 24 ++++++++++++++++--------
 5 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -36,14 +36,24 @@
 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
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -96,6 +96,9 @@
 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
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -1375,8 +1375,10 @@
 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
--- 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
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -740,8 +740,10 @@
 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;
 }
 
@@ -799,9 +801,13 @@
 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
 }
@@ -821,7 +827,7 @@
 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;
@@ -942,8 +948,10 @@
 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
-- 
Repository URL: https://hg.python.org/cpython
