Merged revisions 77573 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r77573 | antoine.pitrou | 2010-01-17 13:26:20 +0100 (dim., 17 janv. 2010) | 6 lines
Issue #7561: Operations on empty bytearrays (such as `int(bytearray())`)
could crash in many places because of the PyByteArray_AS_STRING() macro
returning NULL. The macro now returns a statically allocated empty
string instead.
........
diff --git a/Include/bytearrayobject.h b/Include/bytearrayobject.h
index 265b4bb..8702e5a 100644
--- a/Include/bytearrayobject.h
+++ b/Include/bytearrayobject.h
@@ -44,9 +44,13 @@
PyAPI_FUNC(int) PyByteArray_Resize(PyObject *, Py_ssize_t);
/* Macros, trading safety for speed */
-#define PyByteArray_AS_STRING(self) (assert(PyByteArray_Check(self)),((PyByteArrayObject *)(self))->ob_bytes)
+#define PyByteArray_AS_STRING(self) \
+ (assert(PyByteArray_Check(self)), \
+ Py_SIZE(self) ? ((PyByteArrayObject *)(self))->ob_bytes : _PyByteArray_empty_string)
#define PyByteArray_GET_SIZE(self) (assert(PyByteArray_Check(self)),Py_SIZE(self))
+extern char _PyByteArray_empty_string[];
+
#ifdef __cplusplus
}
#endif
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index a4e5bd9..2813d96 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -817,6 +817,14 @@
self.assertRaises(BufferError, delslice)
self.assertEquals(b, orig)
+ def test_empty_bytearray(self):
+ # Issue #7561: operations on empty bytearrays could crash in many
+ # situations, due to a fragile implementation of the
+ # PyByteArray_AS_STRING() C macro.
+ self.assertRaises(ValueError, int, bytearray(b''))
+ self.assertRaises((ValueError, OSError), os.mkdir, bytearray(b''))
+
+
class AssortedBytesTest(unittest.TestCase):
#
# Test various combinations of bytes and bytearray
diff --git a/Misc/NEWS b/Misc/NEWS
index 1250509..1098613 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,11 @@
Core and Builtins
-----------------
+- Issue #7561: Operations on empty bytearrays (such as `int(bytearray())`)
+ could crash in many places because of the PyByteArray_AS_STRING() macro
+ returning NULL. The macro now returns a statically allocated empty
+ string instead.
+
- Issue #6690: Optimize the bytecode for expressions such as `x in {1, 2, 3}`,
where the right hand operand is a set of constants, by turning the set into
a frozenset and pre-building it as a constant. The comparison operation
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 823c800..7d52522 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -5,23 +5,16 @@
#include "structmember.h"
#include "bytes_methods.h"
-static PyByteArrayObject *nullbytes = NULL;
+char _PyByteArray_empty_string[] = "";
void
PyByteArray_Fini(void)
{
- Py_CLEAR(nullbytes);
}
int
PyByteArray_Init(void)
{
- nullbytes = PyObject_New(PyByteArrayObject, &PyByteArray_Type);
- if (nullbytes == NULL)
- return 0;
- nullbytes->ob_bytes = NULL;
- Py_SIZE(nullbytes) = nullbytes->ob_alloc = 0;
- nullbytes->ob_exports = 0;
return 1;
}
@@ -65,10 +58,7 @@
obj->ob_exports++;
return 0;
}
- if (obj->ob_bytes == NULL)
- ptr = "";
- else
- ptr = obj->ob_bytes;
+ ptr = (void *) PyByteArray_AS_STRING(obj);
ret = PyBuffer_FillInfo(view, (PyObject*)obj, ptr, Py_SIZE(obj), 0, flags);
if (ret >= 0) {
obj->ob_exports++;
@@ -152,7 +142,7 @@
Py_DECREF(new);
return PyErr_NoMemory();
}
- if (bytes != NULL)
+ if (bytes != NULL && size > 0)
memcpy(new->ob_bytes, bytes, size);
new->ob_bytes[size] = '\0'; /* Trailing null byte */
}
@@ -1038,7 +1028,6 @@
#define STRINGLIB_LEN PyByteArray_GET_SIZE
#define STRINGLIB_STR PyByteArray_AS_STRING
#define STRINGLIB_NEW PyByteArray_FromStringAndSize
-#define STRINGLIB_EMPTY nullbytes
#define STRINGLIB_ISSPACE Py_ISSPACE
#define STRINGLIB_ISLINEBREAK(x) ((x == '\n') || (x == '\r'))
#define STRINGLIB_CHECK_EXACT PyByteArray_CheckExact