Issue #7019: Unmarshalling of bad long data could produce unnormalized
PyLongs. Raise ValueError instead.
diff --git a/Lib/test/test_marshal.py b/Lib/test/test_marshal.py
index 0cd46a2..7669182 100644
--- a/Lib/test/test_marshal.py
+++ b/Lib/test/test_marshal.py
@@ -262,6 +262,11 @@
testString = 'abc' * size
marshal.dumps(testString)
+ def test_invalid_longs(self):
+ # Issue #7019: marshal.loads shouldn't produce unnormalized PyLongs
+ invalid_string = 'l\x02\x00\x00\x00\x00\x00\x00\x00'
+ self.assertRaises(ValueError, marshal.loads, invalid_string)
+
def test_main():
test_support.run_unittest(IntTestCase,
diff --git a/Misc/NEWS b/Misc/NEWS
index cb24b3f..9cd6638 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
Core and Builtins
-----------------
+- Issue #7019: Raise ValueError when unmarshalling bad long data, instead
+ of producing internally inconsistent Python longs.
+
- Issue #6990: Fix threading.local subclasses leaving old state around
after a reference cycle GC which could be recycled by new locals.
diff --git a/Python/marshal.c b/Python/marshal.c
index 8f8ac36..1ef41b0 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -556,7 +556,7 @@
r_PyLong(RFILE *p)
{
PyLongObject *ob;
- int size, i, j, md;
+ int size, i, j, md, shorts_in_top_digit;
long n;
digit d;
@@ -569,7 +569,8 @@
return NULL;
}
- size = 1 + (ABS(n)-1) / PyLong_MARSHAL_RATIO;
+ size = 1 + (ABS(n) - 1) / PyLong_MARSHAL_RATIO;
+ shorts_in_top_digit = 1 + (ABS(n) - 1) % PyLong_MARSHAL_RATIO;
ob = _PyLong_New(size);
if (ob == NULL)
return NULL;
@@ -586,12 +587,21 @@
ob->ob_digit[i] = d;
}
d = 0;
- for (j=0; j < (ABS(n)-1)%PyLong_MARSHAL_RATIO + 1; j++) {
+ for (j=0; j < shorts_in_top_digit; j++) {
md = r_short(p);
if (md < 0 || md > PyLong_MARSHAL_BASE)
goto bad_digit;
+ /* topmost marshal digit should be nonzero */
+ if (md == 0 && j == shorts_in_top_digit - 1) {
+ Py_DECREF(ob);
+ PyErr_SetString(PyExc_ValueError,
+ "bad marshal data (unnormalized long data)");
+ return NULL;
+ }
d += (digit)md << j*PyLong_MARSHAL_SHIFT;
}
+ /* top digit should be nonzero, else the resulting PyLong won't be
+ normalized */
ob->ob_digit[size-1] = d;
return (PyObject *)ob;
bad_digit: