Issue #13546: Fixed an overflow issue that could crash the intepreter when

amauryfa · amauryfa · commit 4bf21e28dfb4 · 2011-12-07T21:46:48.000+01:00
calling sys.setrecursionlimit((1&lt;&lt;31)-1).

2.7 only.
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
@@ -224,6 +224,18 @@ def test_recursionlimit(self):
         self.assertEqual(sys.getrecursionlimit(), 10000)
         sys.setrecursionlimit(oldlimit)
 
+        self.assertRaises(OverflowError, sys.setrecursionlimit, 1 << 31)
+        try:
+            sys.setrecursionlimit((1 << 31) - 5)
+            try:
+                # issue13546: isinstance(e, ValueError) used to fail
+                # when the recursion limit is close to 1<<31
+                raise ValueError()
+            except ValueError, e:
+                pass
+        finally:
+            sys.setrecursionlimit(oldlimit)
+
     def test_getwindowsversion(self):
         # Raise SkipTest if sys doesn't have getwindowsversion attribute
         test.test_support.get_attribute(sys, "getwindowsversion")
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -9,6 +9,9 @@ What's New in Python 2.7.3?
 Core and Builtins
 -----------------
 
+- Issue #13546: Fixed an overflow issue that could crash the intepreter when
+  calling sys.setrecursionlimit((1<<31)-1).
+
 - Issue #13333: The UTF-7 decoder now accepts lone surrogates (the encoder
   already accepts them).
 
diff --git a/Python/errors.c b/Python/errors.c
@@ -111,9 +111,11 @@ PyErr_GivenExceptionMatches(PyObject *err, PyObject *exc)
         PyErr_Fetch(&exception, &value, &tb);
         /* Temporarily bump the recursion limit, so that in the most
            common case PyObject_IsSubclass will not raise a recursion
-           error we have to ignore anyway. */
+           error we have to ignore anyway.  Don't do it when the limit
+           is already insanely high, to avoid overflow */
         reclimit = Py_GetRecursionLimit();
-        Py_SetRecursionLimit(reclimit + 5);
+        if (reclimit < (1 << 30))
+            Py_SetRecursionLimit(reclimit + 5);
         res = PyObject_IsSubclass(err, exc);
         Py_SetRecursionLimit(reclimit);
         /* This function must not fail, so print the error here */
