diff options
| -rw-r--r-- | django/core/files/storage.py | 9 | ||||
| -rw-r--r-- | docs/releases/2.2.26.txt | 9 | ||||
| -rw-r--r-- | tests/file_storage/test_generate_filename.py | 19 | ||||
| -rw-r--r-- | tests/file_storage/tests.py | 6 |
4 files changed, 36 insertions, 7 deletions
diff --git a/django/core/files/storage.py b/django/core/files/storage.py index 89faa626e6..ea5bbc82d0 100644 --- a/django/core/files/storage.py +++ b/django/core/files/storage.py @@ -51,7 +51,10 @@ class Storage: content = File(content, name) name = self.get_available_name(name, max_length=max_length) - return self._save(name, content) + name = self._save(name, content) + # Ensure that the name returned from the storage system is still valid. + validate_file_name(name, allow_relative_path=True) + return name # These methods are part of the public API, with default implementations. @@ -67,6 +70,7 @@ class Storage: Return a filename that's free on the target storage system and available for new content to be written to. """ + name = str(name).replace('\\', '/') dir_name, file_name = os.path.split(name) if '..' in pathlib.PurePath(dir_name).parts: raise SuspiciousFileOperation("Detected path traversal attempt in '%s'" % dir_name) @@ -101,6 +105,7 @@ class Storage: Validate the filename by calling get_valid_name() and return a filename to be passed to the save() method. """ + filename = str(filename).replace('\\', '/') # `filename` may include a path as returned by FileField.upload_to. dirname, filename = os.path.split(filename) if '..' in pathlib.PurePath(dirname).parts: @@ -296,6 +301,8 @@ class FileSystemStorage(Storage): if self.file_permissions_mode is not None: os.chmod(full_path, self.file_permissions_mode) + # Ensure the saved path is always relative to the storage root. + name = os.path.relpath(full_path, self.location) # Store filenames with forward slashes, even on Windows. return name.replace('\\', '/') diff --git a/docs/releases/2.2.26.txt b/docs/releases/2.2.26.txt index 2ed9b32119..7fbdc02089 100644 --- a/docs/releases/2.2.26.txt +++ b/docs/releases/2.2.26.txt @@ -36,3 +36,12 @@ As a reminder, all untrusted user input should be validated before use. This issue has severity "low" according to the :ref:`Django security policy <security-disclosure>`. + +CVE-2021-45452: Potential directory-traversal via ``Storage.save()`` +==================================================================== + +``Storage.save()`` allowed directory-traversal if directly passed suitably +crafted file names. + +This issue has severity "low" according to the :ref:`Django security policy +<security-disclosure>`. diff --git a/tests/file_storage/test_generate_filename.py b/tests/file_storage/test_generate_filename.py index cb64650920..fd8da6debf 100644 --- a/tests/file_storage/test_generate_filename.py +++ b/tests/file_storage/test_generate_filename.py @@ -53,13 +53,20 @@ class GenerateFilenameStorageTests(SimpleTestCase): s.generate_filename(file_name) def test_storage_dangerous_paths_dir_name(self): - file_name = '/tmp/../path' + candidates = [ + ('tmp/../path', 'tmp/..'), + ('tmp\\..\\path', 'tmp/..'), + ('/tmp/../path', '/tmp/..'), + ('\\tmp\\..\\path', '/tmp/..'), + ] s = FileSystemStorage() - msg = "Detected path traversal attempt in '/tmp/..'" - with self.assertRaisesMessage(SuspiciousFileOperation, msg): - s.get_available_name(file_name) - with self.assertRaisesMessage(SuspiciousFileOperation, msg): - s.generate_filename(file_name) + for file_name, path in candidates: + msg = "Detected path traversal attempt in '%s'" % path + with self.subTest(file_name=file_name): + with self.assertRaisesMessage(SuspiciousFileOperation, msg): + s.get_available_name(file_name) + with self.assertRaisesMessage(SuspiciousFileOperation, msg): + s.generate_filename(file_name) def test_filefield_dangerous_filename(self): candidates = [ diff --git a/tests/file_storage/tests.py b/tests/file_storage/tests.py index 0e692644b7..4c6f6920ed 100644 --- a/tests/file_storage/tests.py +++ b/tests/file_storage/tests.py @@ -291,6 +291,12 @@ class FileStorageTests(SimpleTestCase): self.storage.delete('path/to/test.file') + def test_file_save_abs_path(self): + test_name = 'path/to/test.file' + f = ContentFile('file saved with path') + f_name = self.storage.save(os.path.join(self.temp_dir, test_name), f) + self.assertEqual(f_name, test_name) + def test_save_doesnt_close(self): with TemporaryUploadedFile('test', 'text/plain', 1, 'utf8') as file: file.write(b'1') |