Code review of the new buffer protocol. Mostly add questions that should

be answered with the comments removed.

There are many places that require checks when doing arithmetic for memory
sizes when allocating memory.  Otherwise, overflow is possible with
a subsequent crash.

Fix SF #1777057 which was a result of not initializing the new BufferError
properly.  Had to update the test for exceptions for BufferError too.

9 files changed, 29 insertions, 20 deletions

diff --git a/Include/bytesobject.h b/Include/bytesobject.h
index 12ecf64d0c..729af398f0 100644
--- a/Include/bytesobject.h
+++ b/Include/bytesobject.h
@@ -21,6 +21,7 @@ extern "C" {
 /* Object layout */
 typedef struct {
     PyObject_VAR_HEAD
+    /* XXX(nnorwitz): should ob_exports be Py_ssize_t? */
     int ob_exports; /* how many buffer exports */
     Py_ssize_t ob_alloc; /* How many bytes allocated */
     char *ob_bytes;
diff --git a/Include/object.h b/Include/object.h
index d936bcaa80..dfabefdd83 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -147,7 +147,7 @@ typedef struct bufferinfo {
         Py_ssize_t len;
         Py_ssize_t itemsize;  
         int readonly;
-        int ndim; 
+        int ndim; /* XXX(nnorwitz): should be Py_ssize_t??? */
         char *format;
         Py_ssize_t *shape;
         Py_ssize_t *strides;
diff --git a/Lib/test/exception_hierarchy.txt b/Lib/test/exception_hierarchy.txt
index 079ce2963c..3714a4115a 100644
--- a/Lib/test/exception_hierarchy.txt
+++ b/Lib/test/exception_hierarchy.txt
@@ -10,6 +10,7 @@ BaseException
       |    +-- ZeroDivisionError
       +-- AssertionError
       +-- AttributeError
+      +-- BufferError
       +-- EnvironmentError
       |    +-- IOError
       |    +-- OSError
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 656fc09173..0e8673f164 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -42,10 +42,8 @@ static PyTypeObject Arraytype;
 
 #ifdef Py_UNICODE_WIDE
 #define PyArr_UNI 'w'
-/*static const char *PyArr_UNISTR = "w"; */
 #else
 #define PyArr_UNI 'u'
-/*static const char *PyArr_UNISTR = "u"; */
 #endif
 
 #define array_Check(op) PyObject_TypeCheck(op, &Arraytype)
@@ -1773,6 +1771,8 @@ array_buffer_getbuf(arrayobject *self, PyBuffer *view, int flags)
         view->internal = NULL;
         if ((flags & PyBUF_FORMAT) == PyBUF_FORMAT) {
                 view->internal = malloc(3);
+		/* XXX(nnorwitz): need to check for malloc failure.
+			Should probably use PyObject_Malloc. */
                 view->format = view->internal;
                 view->format[0] = (char)(self->ob_descr->typecode);
                 view->format[1] = '\0';
diff --git a/Objects/abstract.c b/Objects/abstract.c
index a48d5dc992..4e250614e4 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -471,6 +471,7 @@ PyBuffer_ToContiguous(void *buf, PyBuffer *view, Py_ssize_t len, char fort)
 
         /* Otherwise a more elaborate scheme is needed */
         
+	/* XXX(nnorwitz): need to check for overflow! */
         indices = (Py_ssize_t *)PyMem_Malloc(sizeof(Py_ssize_t)*(view->ndim));
         if (indices == NULL) {
                 PyErr_NoMemory();
@@ -521,6 +522,7 @@ PyBuffer_FromContiguous(PyBuffer *view, void *buf, Py_ssize_t len, char fort)
 
         /* Otherwise a more elaborate scheme is needed */
         
+	/* XXX(nnorwitz): need to check for overflow! */
         indices = (Py_ssize_t *)PyMem_Malloc(sizeof(Py_ssize_t)*(view->ndim));
         if (indices == NULL) {
                 PyErr_NoMemory();
@@ -594,6 +596,7 @@ int PyObject_CopyData(PyObject *dest, PyObject *src)
 
         /* Otherwise a more elaborate copy scheme is needed */
         
+	/* XXX(nnorwitz): need to check for overflow! */
         indices = (Py_ssize_t *)PyMem_Malloc(sizeof(Py_ssize_t)*view_src.ndim);
         if (indices == NULL) {
                 PyErr_NoMemory();
@@ -606,6 +609,7 @@ int PyObject_CopyData(PyObject *dest, PyObject *src)
         }        
         elements = 1;
         for (k=0; k<view_src.ndim; k++) {
+		/* XXX(nnorwitz): can this overflow? */
                 elements *= view_src.shape[k];
         }
         while (elements--) {
diff --git a/Objects/bufferobject.c b/Objects/bufferobject.c
index a8bbd151c8..ccd49805ce 100644
--- a/Objects/bufferobject.c
+++ b/Objects/bufferobject.c
@@ -64,7 +64,7 @@ buffer_releasebuf(PyBufferObject *self, PyBuffer *view)
                         (*bp->bf_releasebuffer)(self->b_base, view);
                 }
         }
-        return;
+	/* XXX(nnorwitz): do we need to release view here?  it leaks. */
 }
 
 static PyObject *
@@ -401,6 +401,7 @@ buffer_concat(PyBufferObject *self, PyObject *other)
                 return NULL;
         }
 
+	/* XXX(nnorwitz): need to check for overflow! */
  	ob = PyBytes_FromStringAndSize(NULL, view.len+view2.len);
 	if ( ob == NULL ) {
                 PyObject_ReleaseBuffer((PyObject *)self, &view);
@@ -427,6 +428,7 @@ buffer_repeat(PyBufferObject *self, Py_ssize_t count)
 		count = 0;
 	if (!get_buf(self, &view, PyBUF_SIMPLE))
 		return NULL;
+	/* XXX(nnorwitz): need to check for overflow! */
 	ob = PyBytes_FromStringAndSize(NULL, view.len * count);
 	if ( ob == NULL )
 		return NULL;
@@ -474,6 +476,7 @@ buffer_slice(PyBufferObject *self, Py_ssize_t left, Py_ssize_t right)
 		right = view.len;
 	if ( right < left )
 		right = left;
+	/* XXX(nnorwitz): is it possible to access unitialized memory? */
 	ob = PyBytes_FromStringAndSize((char *)view.buf + left,
                                        right - left);
         PyObject_ReleaseBuffer((PyObject *)self, &view);
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 5a03beb234..0ada1e7209 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -507,6 +507,7 @@ bytes_setslice(PyBytesObject *self, Py_ssize_t lo, Py_ssize_t hi,
             memmove(self->ob_bytes + lo + needed, self->ob_bytes + hi,
                     Py_Size(self) - hi);
         }
+	/* XXX(nnorwitz): need to verify this can't overflow! */
         if (PyBytes_Resize((PyObject *)self,
                            Py_Size(self) + needed - avail) < 0) {
                 res = -1;
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 710495f610..7afaac04f3 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -1694,6 +1694,7 @@ _PyExc_Init(void)
     PRE_INIT(ZeroDivisionError)
     PRE_INIT(SystemError)
     PRE_INIT(ReferenceError)
+    PRE_INIT(BufferError)
     PRE_INIT(MemoryError)
     PRE_INIT(Warning)
     PRE_INIT(UserWarning)
@@ -1753,6 +1754,7 @@ _PyExc_Init(void)
     POST_INIT(ZeroDivisionError)
     POST_INIT(SystemError)
     POST_INIT(ReferenceError)
+    POST_INIT(BufferError)
     POST_INIT(MemoryError)
     POST_INIT(Warning)
     POST_INIT(UserWarning)
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index efcb7aeb19..27fb9695e9 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -26,6 +26,7 @@ Create a new memoryview object which references the given object.");
 PyObject *
 PyMemoryView_FromMemory(PyBuffer *info)
 {
+	/* XXX(nnorwitz): need to implement something here? */
         return NULL;
 }
 
@@ -59,7 +60,7 @@ static PyObject *
 memory_new(PyTypeObject *subtype, PyObject *args, PyObject *kwds)
 {
         PyObject *obj;
-        if (!PyArg_ParseTuple(args, "O", &obj)) return NULL;
+        if (!PyArg_UnpackTuple(args, "memoryview", 1, 1, &obj)) return NULL;
 
         return PyMemoryView_FromObject(obj);        
 }
@@ -136,6 +137,7 @@ _indirect_copy_nd(char *dest, PyBuffer *view, char fort)
         void (*func)(int, Py_ssize_t *, Py_ssize_t *);
         
         
+        /* XXX(nnorwitz): need to check for overflow! */
         indices = (Py_ssize_t *)PyMem_Malloc(sizeof(Py_ssize_t)*view->ndim);
         if (indices == NULL) {
                 PyErr_NoMemory();
@@ -260,6 +262,7 @@ PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char fort)
                 /* return a shadowed memory-view object */
                 view->buf = dest;
                 mem->base = PyTuple_Pack(2, obj, bytes);
+		/* XXX(nnorwitz): need to verify alloc was successful. */
                 Py_DECREF(bytes);
         }
         else {
@@ -373,17 +376,15 @@ static PyGetSetDef memory_getsetlist[] ={
 
 
 static PyObject *
-memory_tobytes(PyMemoryViewObject *mem, PyObject *args)
+memory_tobytes(PyMemoryViewObject *mem, PyObject *noargs)
 {
-        if (!PyArg_ParseTuple(args, "")) return NULL;
         /* Create new Bytes object for data */
         return PyBytes_FromObject((PyObject *)mem);
 }
 
 static PyObject *
-memory_tolist(PyMemoryViewObject *mem, PyObject *args)
+memory_tolist(PyMemoryViewObject *mem, PyObject *noargs)
 {
-        if (!PyArg_ParseTuple(args, "")) return NULL;        
         Py_INCREF(Py_NotImplemented);
         return Py_NotImplemented;
 }
@@ -391,8 +392,8 @@ memory_tolist(PyMemoryViewObject *mem, PyObject *args)
 
 
 static PyMethodDef memory_methods[] = {
-        {"tobytes", (PyCFunction)memory_tobytes, 1, NULL},
-        {"tolist", (PyCFunction)memory_tolist, 1, NULL},
+        {"tobytes", (PyCFunction)memory_tobytes, METH_NOARGS, NULL},
+        {"tolist", (PyCFunction)memory_tolist, METH_NOARGS, NULL},
         {NULL,          NULL}           /* sentinel */
 };
 
@@ -400,7 +401,6 @@ static PyMethodDef memory_methods[] = {
 static void
 memory_dealloc(PyMemoryViewObject *self)
 {
-
         if (PyTuple_Check(self->base)) {
                 /* Special case when first element is generic object
                    with buffer interface and the second element is a
@@ -423,21 +423,18 @@ memory_dealloc(PyMemoryViewObject *self)
         else {
                 PyObject_ReleaseBuffer(self->base, &(self->view));
         }
-        Py_DECREF(self->base);
+        Py_CLEAR(self->base);
         PyObject_DEL(self);
 }
 
 static PyObject *
 memory_repr(PyMemoryViewObject *self)
 {
-
-	if ( self->base == NULL )
-		return PyUnicode_FromFormat("<memory at %p>",
-					   self);
+	/* XXX(nnorwitz): the code should be different or remove condition. */
+	if (self->base == NULL)
+		return PyUnicode_FromFormat("<memory at %p>", self);
 	else
-		return PyUnicode_FromFormat(
-			"<memory at %p>",
-			self);
+		return PyUnicode_FromFormat("<memory at %p>", self);
 }