Prevent expandtabs() on string and unicode objects from causing a segfault when

a large width is passed on 32-bit platforms.  Found by Google.

It would be good for people to review this especially carefully and verify
I don't have an off by one error and there is no other way to cause overflow.

1 files changed, 11 insertions, 0 deletions

diff --git a/Lib/test/test_str.py b/Lib/test/test_str.py
index 45942a6..1853517 100644
--- a/Lib/test/test_str.py
+++ b/Lib/test/test_str.py
@@ -1,4 +1,6 @@
+
 import unittest
+import sys
 from test import test_support, string_tests
 
 
@@ -82,6 +84,15 @@ class StrTest(
         self.assertEqual(str(Foo9("foo")), "string")
         self.assertEqual(unicode(Foo9("foo")), u"not unicode")
 
+    def test_expandtabs_overflows_gracefully(self):
+        # This test only affects 32-bit platforms because expandtabs can only take
+        # an int as the max value, not a 64-bit C long.  If expandtabs is changed
+        # to take a 64-bit long, this test should apply to all platforms.
+        if sys.maxint > (1 << 32):
+            return
+        self.assertRaises(OverflowError, 't\tt\t'.expandtabs, sys.maxint)
+
+
 def test_main():
     test_support.run_unittest(StrTest)