From fc8d6f4b73c995b6de2e2b1058140192cf1f7e72 Mon Sep 17 00:00:00 2001 From: Antoine Pitrou Date: Sun, 17 Jan 2010 12:38:54 +0000 Subject: 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. ........ --- Include/bytearrayobject.h | 6 +++++- Lib/test/test_bytes.py | 8 ++++++++ Misc/NEWS | 5 +++++ Objects/bytearrayobject.c | 17 +++-------------- 4 files changed, 21 insertions(+), 15 deletions(-) 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(char *) PyByteArray_AsString(PyObject *); 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 @@ class ByteArrayTest(BaseBytesTest): 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 @@ What's New in Python 3.2 Alpha 1? 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 @@ bytearray_getbuffer(PyByteArrayObject *obj, Py_buffer *view, int flags) 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 @@ PyByteArray_FromStringAndSize(const char *bytes, Py_ssize_t size) 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 @@ bytearray_dealloc(PyByteArrayObject *self) #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 -- cgit v0.12