[Python-checkins] cpython: Issue #27512: Don't segfault when os.fspath() calls an object whose

Fri Jul 15 13:41:56 EDT 2016

https://hg.python.org/cpython/rev/35bf83ff0828
changeset: 102356:35bf83ff0828
user: Brett Cannon <brett at python.org>
date: Fri Jul 15 10:41:49 2016 -0700
summary:
 Issue #27512: Don't segfault when os.fspath() calls an object whose
__fspath__() raises an exception.
Thanks to Xiang Zhang for the patch.
files:
 Lib/test/test_os.py | 24 +++++++++++++++++-------
 Misc/NEWS | 3 +++
 Modules/posixmodule.c | 4 ++++
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -3122,7 +3122,10 @@
 def __init__(self, path=''):
 self.path = path
 def __fspath__(self):
- return self.path
+ if isinstance(self.path, BaseException):
+ raise self.path
+ else:
+ return self.path
 
 def test_return_bytes(self):
 for b in b'hello', b'goodbye', b'some/path/and/file':
@@ -3145,18 +3148,25 @@
 self.assertTrue(issubclass(self.PathLike, os.PathLike))
 self.assertTrue(isinstance(self.PathLike(), os.PathLike))
 
- with self.assertRaises(TypeError):
- self.fspath(self.PathLike(42))
-
 def test_garbage_in_exception_out(self):
 vapor = type('blah', (), {})
 for o in int, type, os, vapor():
 self.assertRaises(TypeError, self.fspath, o)
 
 def test_argument_required(self):
- with self.assertRaises(TypeError):
- self.fspath()
-
+ self.assertRaises(TypeError, self.fspath)
+
+ def test_bad_pathlike(self):
+ # __fspath__ returns a value other than str or bytes.
+ self.assertRaises(TypeError, self.fspath, self.PathLike(42))
+ # __fspath__ attribute that is not callable.
+ c = type('foo', (), {})
+ c.__fspath__ = 1
+ self.assertRaises(TypeError, self.fspath, c())
+ # __fspath__ raises an exception.
+ c.__fspath__ = lambda self: self.__not_exist
+ self.assertRaises(ZeroDivisionError, self.fspath,
+ self.PathLike(ZeroDivisionError))
 
 # Only test if the C version is provided, otherwise TestPEP519 already tested
 # the pure Python implementation.
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -16,6 +16,9 @@
 Library
 -------
 
+- Issue 27512: Fix a segfault when os.fspath() called a an __fspath__() method
+ that raised an exception. Patch by Xiang Zhang.
+
 Tests
 -----
 
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -12319,6 +12319,10 @@
 
 path_repr = PyObject_CallFunctionObjArgs(func, NULL);
 Py_DECREF(func);
+ if (NULL == path_repr) {
+ return NULL;
+ }
+
 if (!(PyUnicode_Check(path_repr) || PyBytes_Check(path_repr))) {
 PyErr_Format(PyExc_TypeError,
 "expected %.200s.__fspath__() to return str or bytes, "
-- 
Repository URL: https://hg.python.org/cpython
