diff --git a/Objects/intobject.c b/Objects/intobject.c
index b420c12..0b746de 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -557,6 +557,17 @@
 	}
 }
 
+/* Integer overflow checking for unary negation: on a 2's-complement
+ * box, -x overflows iff x is the most negative long.  In this case we
+ * get -x == x.  However, -x is undefined (by C) if x /is/ the most
+ * negative long (it's a signed overflow case), and some compilers care.
+ * So we cast x to unsigned long first.  However, then other compilers
+ * warn about applying unary minus to an unsigned operand.  Hence the
+ * weird "0-".
+ */
+#define UNARY_NEG_WOULD_OVERFLOW(x)	\
+	((x) < 0 && (unsigned long)(x) == 0-(unsigned long)(x))
+
 /* Return type of i_divmod */
 enum divmod_result {
 	DIVMOD_OK,		/* Correct result */
@@ -576,7 +587,7 @@
 		return DIVMOD_ERROR;
 	}
 	/* (-sys.maxint-1)/-1 is the only overflow case. */
-	if (y == -1 && x < 0 && x == -x)
+	if (y == -1 && UNARY_NEG_WOULD_OVERFLOW(x))
 		return DIVMOD_OVERFLOW;
 	xdivy = x / y;
 	xmody = x - xdivy * y;
@@ -744,10 +755,10 @@
 static PyObject *
 int_neg(PyIntObject *v)
 {
-	register long a, x;
+	register long a;
 	a = v->ob_ival;
-	x = -a;
-	if (a < 0 && x < 0) {
+        /* check for overflow */
+	if (UNARY_NEG_WOULD_OVERFLOW(a)) {
 		PyObject *o = PyLong_FromLong(a);
 		if (o != NULL) {
 			PyObject *result = PyNumber_Negative(o);
@@ -756,7 +767,7 @@
 		}
 		return NULL;
 	}
-	return PyInt_FromLong(x);
+	return PyInt_FromLong(-a);
 }
 
 static PyObject *
@@ -955,8 +966,25 @@
 		return PyInt_FromLong(0L);
 	if (base == -909)
 		return PyNumber_Int(x);
-	if (PyString_Check(x))
-		return PyInt_FromString(PyString_AS_STRING(x), NULL, base);
+	if (PyString_Check(x)) {
+		/* Since PyInt_FromString doesn't have a length parameter,
+		 * check here for possible NULs in the string. */
+		char *string = PyString_AS_STRING(x);
+		if (strlen(string) != PyString_Size(x)) {
+			/* create a repr() of the input string,
+			 * just like PyInt_FromString does */
+			PyObject *srepr;
+			srepr = PyObject_Repr(x);
+			if (srepr == NULL)
+				return NULL;
+			PyErr_Format(PyExc_ValueError,
+			     "invalid literal for int() with base %d: %s",
+			     base, PyString_AS_STRING(srepr));
+			Py_DECREF(srepr);
+			return NULL;
+		}
+		return PyInt_FromString(string, NULL, base);
+	}
 #ifdef Py_USING_UNICODE
 	if (PyUnicode_Check(x))
 		return PyInt_FromUnicode(PyUnicode_AS_UNICODE(x),