fix possible double free in TextIOWrapper.__init__ (closes #22849)

benjaminp · benjaminp · commit 6c14f231005a · 2014-11-12T10:19:46.000-05:00
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
@@ -2784,6 +2784,21 @@ def test_create_at_shutdown_with_encoding(self):
         self.assertFalse(err)
         self.assertEqual("ok", out.decode().strip())
 
+    def test_issue22849(self):
+        class F(object):
+            def readable(self): return True
+            def writable(self): return True
+            def seekable(self): return True
+
+        for i in range(10):
+            try:
+                self.TextIOWrapper(F(), encoding='utf-8')
+            except Exception:
+                pass
+
+        F.tell = lambda x: 0
+        t = self.TextIOWrapper(F(), encoding='utf-8')
+
 
 class CTextIOWrapperTest(TextIOWrapperTest):
     io = io
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -36,6 +36,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #22849: Fix possible double free in the io.TextIOWrapper constructor.
+
 - Issue #12728: Different Unicode characters having the same uppercase but
   different lowercase are now matched in case-insensitive regular expressions.
 
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
@@ -1061,7 +1061,7 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
     }
 
     /* Finished sorting out the codec details */
-    Py_DECREF(codec_info);
+    Py_CLEAR(codec_info);
 
     self->buffer = buffer;
     Py_INCREF(buffer);

Original file line number	Diff line number	Diff line change
`@@ -1061,7 +1061,7 @@ textiowrapper_init(textio self, PyObject args, PyObject *kwds)`
`1061`	`1061`	`}`
`1062`	`1062`
`1063`	`1063`	`/* Finished sorting out the codec details */`
`1064`		`- Py_DECREF(codec_info);`
	`1064`	`+ Py_CLEAR(codec_info);`
`1065`	`1065`
`1066`	`1066`	`self->buffer = buffer;`
`1067`	`1067`	`Py_INCREF(buffer);`