bpo-25455: Fixed crashes in repr of recursive buffered file-like objects. (#514)

3 files changed, 45 insertions, 8 deletions

diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 6c88bbb..59e9beb 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1415,8 +1415,18 @@ buffered_repr(buffered *self)
         res = PyUnicode_FromFormat("<%s>", Py_TYPE(self)->tp_name);
     }
     else {
-        res = PyUnicode_FromFormat("<%s name=%R>",
-                                   Py_TYPE(self)->tp_name, nameobj);
+        int status = Py_ReprEnter((PyObject *)self);
+        res = NULL;
+        if (status == 0) {
+            res = PyUnicode_FromFormat("<%s name=%R>",
+                                       Py_TYPE(self)->tp_name, nameobj);
+            Py_ReprLeave((PyObject *)self);
+        }
+        else if (status > 0) {
+            PyErr_Format(PyExc_RuntimeError,
+                         "reentrant call inside %s.__repr__",
+                         Py_TYPE(self)->tp_name);
+        }
         Py_DECREF(nameobj);
     }
     return res;
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index b99506f..6000508 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -1082,9 +1082,19 @@ fileio_repr(fileio *self)
             self->fd, mode_string(self), self->closefd ? "True" : "False");
     }
     else {
-        res = PyUnicode_FromFormat(
-            "<_io.FileIO name=%R mode='%s' closefd=%s>",
-            nameobj, mode_string(self), self->closefd ? "True" : "False");
+        int status = Py_ReprEnter((PyObject *)self);
+        res = NULL;
+        if (status == 0) {
+            res = PyUnicode_FromFormat(
+                "<_io.FileIO name=%R mode='%s' closefd=%s>",
+                nameobj, mode_string(self), self->closefd ? "True" : "False");
+            Py_ReprLeave((PyObject *)self);
+        }
+        else if (status > 0) {
+            PyErr_Format(PyExc_RuntimeError,
+                         "reentrant call inside %s.__repr__",
+                         Py_TYPE(self)->tp_name);
+        }
         Py_DECREF(nameobj);
     }
     return res;
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 4133bf3..fce662a 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -2483,6 +2483,7 @@ static PyObject *
 textiowrapper_repr(textio *self)
 {
     PyObject *nameobj, *modeobj, *res, *s;
+    int status;
 
     CHECK_INITIALIZED(self);
 
@@ -2490,6 +2491,15 @@ textiowrapper_repr(textio *self)
     if (res == NULL)
         return NULL;
 
+    status = Py_ReprEnter((PyObject *)self);
+    if (status != 0) {
+        if (status > 0) {
+            PyErr_Format(PyExc_RuntimeError,
+                         "reentrant call inside %s.__repr__",
+                         Py_TYPE(self)->tp_name);
+        }
+        goto error;
+    }
     nameobj = _PyObject_GetAttrId((PyObject *) self, &PyId_name);
     if (nameobj == NULL) {
         if (PyErr_ExceptionMatches(PyExc_Exception))
@@ -2504,7 +2514,7 @@ textiowrapper_repr(textio *self)
             goto error;
         PyUnicode_AppendAndDel(&res, s);
         if (res == NULL)
-            return NULL;
+            goto error;
     }
     modeobj = _PyObject_GetAttrId((PyObject *) self, &PyId_mode);
     if (modeobj == NULL) {
@@ -2520,14 +2530,21 @@ textiowrapper_repr(textio *self)
             goto error;
         PyUnicode_AppendAndDel(&res, s);
         if (res == NULL)
-            return NULL;
+            goto error;
     }
     s = PyUnicode_FromFormat("%U encoding=%R>",
                              res, self->encoding);
     Py_DECREF(res);
+    if (status == 0) {
+        Py_ReprLeave((PyObject *)self);
+    }
     return s;
-error:
+
+  error:
     Py_XDECREF(res);
+    if (status == 0) {
+        Py_ReprLeave((PyObject *)self);
+    }
     return NULL;
 }