python311/CVE-2023-6597-TempDir-cleaning-symlink.patch

---
 Lib/tempfile.py                                                        |   16 +
 Lib/test/test_tempfile.py                                              |  113 ++++++++++
 Misc/NEWS.d/next/Library/2022-12-01-16-57-44.gh-issue-91133.LKMVCV.rst |    2 
 3 files changed, 131 insertions(+)

--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -286,6 +286,22 @@ def _resetperms(path):
         _dont_follow_symlinks(chflags, path, 0)
     _dont_follow_symlinks(_os.chmod, path, 0o700)
 
+def _dont_follow_symlinks(func, path, *args):
+    # Pass follow_symlinks=False, unless not supported on this platform.
+    if func in _os.supports_follow_symlinks:
+        func(path, *args, follow_symlinks=False)
+    elif _os.name == 'nt' or not _os.path.islink(path):
+        func(path, *args)
+
+def _resetperms(path):
+    try:
+        chflags = _os.chflags
+    except AttributeError:
+        pass
+    else:
+        _dont_follow_symlinks(chflags, path, 0)
+    _dont_follow_symlinks(_os.chmod, path, 0o700)
+
 
 # User visible interfaces.
 
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -1673,6 +1673,103 @@ class TestTemporaryDirectory(BaseTestCas
                 new_flags = os.stat(dir1).st_flags
                 self.assertEqual(new_flags, old_flags)
 
+    @os_helper.skip_unless_symlink
+    def test_cleanup_with_symlink_modes(self):
+        # cleanup() should not follow symlinks when fixing mode bits (#91133)
+        with self.do_create(recurse=0) as d2:
+            file1 = os.path.join(d2, 'file1')
+            open(file1, 'wb').close()
+            dir1 = os.path.join(d2, 'dir1')
+            os.mkdir(dir1)
+            for mode in range(8):
+                mode <<= 6
+                with self.subTest(mode=format(mode, '03o')):
+                    def test(target, target_is_directory):
+                        d1 = self.do_create(recurse=0)
+                        symlink = os.path.join(d1.name, 'symlink')
+                        os.symlink(target, symlink,
+                                target_is_directory=target_is_directory)
+                        try:
+                            os.chmod(symlink, mode, follow_symlinks=False)
+                        except NotImplementedError:
+                            pass
+                        try:
+                            os.chmod(symlink, mode)
+                        except FileNotFoundError:
+                            pass
+                        os.chmod(d1.name, mode)
+                        d1.cleanup()
+                        self.assertFalse(os.path.exists(d1.name))
+
+                    with self.subTest('nonexisting file'):
+                        test('nonexisting', target_is_directory=False)
+                    with self.subTest('nonexisting dir'):
+                        test('nonexisting', target_is_directory=True)
+
+                    with self.subTest('existing file'):
+                        os.chmod(file1, mode)
+                        old_mode = os.stat(file1).st_mode
+                        test(file1, target_is_directory=False)
+                        new_mode = os.stat(file1).st_mode
+                        self.assertEqual(new_mode, old_mode,
+                                         '%03o != %03o' % (new_mode, old_mode))
+
+                    with self.subTest('existing dir'):
+                        os.chmod(dir1, mode)
+                        old_mode = os.stat(dir1).st_mode
+                        test(dir1, target_is_directory=True)
+                        new_mode = os.stat(dir1).st_mode
+                        self.assertEqual(new_mode, old_mode,
+                                         '%03o != %03o' % (new_mode, old_mode))
+
+    @unittest.skipUnless(hasattr(os, 'chflags'), 'requires os.chflags')
+    @os_helper.skip_unless_symlink
+    def test_cleanup_with_symlink_flags(self):
+        # cleanup() should not follow symlinks when fixing flags (#91133)
+        flags = stat.UF_IMMUTABLE | stat.UF_NOUNLINK
+        self.check_flags(flags)
+
+        with self.do_create(recurse=0) as d2:
+            file1 = os.path.join(d2, 'file1')
+            open(file1, 'wb').close()
+            dir1 = os.path.join(d2, 'dir1')
+            os.mkdir(dir1)
+            def test(target, target_is_directory):
+                d1 = self.do_create(recurse=0)
+                symlink = os.path.join(d1.name, 'symlink')
+                os.symlink(target, symlink,
+                           target_is_directory=target_is_directory)
+                try:
+                    os.chflags(symlink, flags, follow_symlinks=False)
+                except NotImplementedError:
+                    pass
+                try:
+                    os.chflags(symlink, flags)
+                except FileNotFoundError:
+                    pass
+                os.chflags(d1.name, flags)
+                d1.cleanup()
+                self.assertFalse(os.path.exists(d1.name))
+
+            with self.subTest('nonexisting file'):
+                test('nonexisting', target_is_directory=False)
+            with self.subTest('nonexisting dir'):
+                test('nonexisting', target_is_directory=True)
+
+            with self.subTest('existing file'):
+                os.chflags(file1, flags)
+                old_flags = os.stat(file1).st_flags
+                test(file1, target_is_directory=False)
+                new_flags = os.stat(file1).st_flags
+                self.assertEqual(new_flags, old_flags)
+
+            with self.subTest('existing dir'):
+                os.chflags(dir1, flags)
+                old_flags = os.stat(dir1).st_flags
+                test(dir1, target_is_directory=True)
+                new_flags = os.stat(dir1).st_flags
+                self.assertEqual(new_flags, old_flags)
+
     @support.cpython_only
     def test_del_on_collection(self):
         # A TemporaryDirectory is deleted when garbage collected
@@ -1847,6 +1944,22 @@ class TestTemporaryDirectory(BaseTestCas
 
     def check_flags(self, flags):
         # skip the test if these flags are not supported (ex: FreeBSD 13)
+        filename = os_helper.TESTFN
+        try:
+            open(filename, "w").close()
+            try:
+                os.chflags(filename, flags)
+            except OSError as exc:
+                # "OSError: [Errno 45] Operation not supported"
+                self.skipTest(f"chflags() doesn't support flags "
+                              f"{flags:#b}: {exc}")
+            else:
+                os.chflags(filename, 0)
+        finally:
+            os_helper.unlink(filename)
+
+    def check_flags(self, flags):
+        # skip the test if these flags are not supported (ex: FreeBSD 13)
         filename = os_helper.TESTFN
         try:
             open(filename, "w").close()
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-12-01-16-57-44.gh-issue-91133.LKMVCV.rst
@@ -0,0 +1,2 @@
+Fix a bug in :class:`tempfile.TemporaryDirectory` cleanup, which now no longer
+dereferences symlinks when working around file system permission errors.