Version Bump

Co-authored-by: Adam Hopkins <adam@amhopkins.com>
Co-authored-by: Zhiwei Liang <zhi.wei.liang@outlook.com>

codecov.yml

@@ -0,0 +1,28 @@
+coverage:
+  status:
+    patch:
+      default:
+        target: auto
+        threshold: 0.75
+        informational: true
+    project:
+      default:
+        target: auto
+        threshold: 0.5
+  precision: 3
+codecov:
+  require_ci_to_pass: false
+ignore:
+  - "sanic/__main__.py"
+  - "sanic/compat.py"
+  - "sanic/reloader_helpers.py"
+  - "sanic/simple.py"
+  - "sanic/utils.py"
+  - "sanic/cli"
+  - ".github/"
+  - "changelogs/"
+  - "docker/"
+  - "docs/"
+  - "examples/"
+  - "scripts/"
+  - "tests/"

sanic/__version__.py

@@ -1 +1 @@
-__version__ = "21.12.1"
+__version__ = "21.12.2"

sanic/mixins/routes.py

@@ -4,8 +4,7 @@ from functools import partial, wraps
 from inspect import getsource, signature
 from mimetypes import guess_type
 from os import path
-from pathlib import PurePath
-from re import sub
+from pathlib import Path, PurePath
 from textwrap import dedent
 from time import gmtime, strftime
 from typing import Any, Callable, Iterable, List, Optional, Set, Tuple, Union
@@ -17,12 +16,7 @@ from sanic.base.meta import SanicMeta
 from sanic.compat import stat_async
 from sanic.constants import DEFAULT_HTTP_CONTENT_TYPE, HTTP_METHODS
 from sanic.errorpages import RESPONSE_MAPPING
-from sanic.exceptions import (
-    ContentRangeError,
-    FileNotFound,
-    HeaderNotFound,
-    InvalidUsage,
-)
+from sanic.exceptions import ContentRangeError, FileNotFound, HeaderNotFound
 from sanic.handlers import ContentRangeHandler
 from sanic.log import deprecation, error_logger
 from sanic.models.futures import FutureRoute, FutureStatic
@@ -775,32 +769,40 @@ class RouteMixin(metaclass=SanicMeta):
         content_type=None,
         __file_uri__=None,
     ):
-        # Using this to determine if the URL is trying to break out of the path
-        # served.  os.path.realpath seems to be very slow
-        if __file_uri__ and "../" in __file_uri__:
-            raise InvalidUsage("Invalid URL")
         # Merge served directory and requested file if provided
-        # Strip all / that in the beginning of the URL to help prevent python
-        # from herping a derp and treating the uri as an absolute path
-        root_path = file_path = file_or_directory
-        if __file_uri__:
-            file_path = path.join(
-                file_or_directory, sub("^[/]*", "", __file_uri__)
-            )
+        file_path_raw = Path(unquote(file_or_directory))
+        root_path = file_path = file_path_raw.resolve()
+        not_found = FileNotFound(
+            "File not found",
+            path=file_or_directory,
+            relative_url=__file_uri__,
+        )
 
-        # URL decode the path sent by the browser otherwise we won't be able to
-        # match filenames which got encoded (filenames with spaces etc)
-        file_path = path.abspath(unquote(file_path))
-        if not file_path.startswith(path.abspath(unquote(root_path))):
-            error_logger.exception(
-                f"File not found: path={file_or_directory}, "
-                f"relative_url={__file_uri__}"
-            )
-            raise FileNotFound(
-                "File not found",
-                path=file_or_directory,
-                relative_url=__file_uri__,
-            )
+        if __file_uri__:
+            # Strip all / that in the beginning of the URL to help prevent
+            # python from herping a derp and treating the uri as an
+            # absolute path
+            unquoted_file_uri = unquote(__file_uri__).lstrip("/")
+            file_path_raw = Path(file_or_directory, unquoted_file_uri)
+            file_path = file_path_raw.resolve()
+            if (
+                file_path < root_path and not file_path_raw.is_symlink()
+            ) or ".." in file_path_raw.parts:
+                error_logger.exception(
+                    f"File not found: path={file_or_directory}, "
+                    f"relative_url={__file_uri__}"
+                )
+                raise not_found
+
+        try:
+            file_path.relative_to(root_path)
+        except ValueError:
+            if not file_path_raw.is_symlink():
+                error_logger.exception(
+                    f"File not found: path={file_or_directory}, "
+                    f"relative_url={__file_uri__}"
+                )
+                raise not_found
         try:
             headers = {}
             # Check if the client has been sent this file before
@@ -868,11 +870,7 @@ class RouteMixin(metaclass=SanicMeta):
         except ContentRangeError:
             raise
         except FileNotFoundError:
-            raise FileNotFound(
-                "File not found",
-                path=file_or_directory,
-                relative_url=__file_uri__,
-            )
+            raise not_found
         except Exception:
             error_logger.exception(
                 f"Exception in static request handler: "

tests/test_static.py

@@ -1,6 +1,7 @@
 import inspect
 import logging
 import os
+import sys
 
 from collections import Counter
 from pathlib import Path
@@ -8,7 +9,7 @@ from time import gmtime, strftime
 
 import pytest
 
-from sanic import text
+from sanic import Sanic, text
 from sanic.exceptions import FileNotFound
 
 
@@ -21,6 +22,22 @@ def static_file_directory():
     return static_directory
 
 
+@pytest.fixture(scope="module")
+def double_dotted_directory_file(static_file_directory: str):
+    """Generate double dotted directory and its files"""
+    if sys.platform == "win32":
+        raise Exception("Windows doesn't support double dotted directories")
+
+    file_path = Path(static_file_directory) / "dotted.." / "dot.txt"
+    double_dotted_dir = file_path.parent
+    Path.mkdir(double_dotted_dir, exist_ok=True)
+    with open(file_path, "w") as f:
+        f.write("DOT\n")
+    yield file_path
+    Path.unlink(file_path)
+    Path.rmdir(double_dotted_dir)
+
+
 def get_file_path(static_file_directory, file_name):
     return os.path.join(static_file_directory, file_name)
 
@@ -578,3 +595,43 @@ def test_resource_type_dir(app, static_file_directory):
 def test_resource_type_unknown(app, static_file_directory, caplog):
     with pytest.raises(ValueError):
         app.static("/static", static_file_directory, resource_type="unknown")
+
+
+@pytest.mark.skipif(
+    sys.platform == "win32",
+    reason="Windows does not support double dotted directories",
+)
+def test_dotted_dir_ok(
+    app: Sanic, static_file_directory: str, double_dotted_directory_file: Path
+):
+    app.static("/foo", static_file_directory)
+    dot_relative_path = str(
+        double_dotted_directory_file.relative_to(static_file_directory)
+    )
+    _, response = app.test_client.get("/foo/" + dot_relative_path)
+    assert response.status == 200
+    assert response.body == b"DOT\n"
+
+
+def test_breakout(app: Sanic, static_file_directory: str):
+    app.static("/foo", static_file_directory)
+
+    _, response = app.test_client.get("/foo/..%2Ffake/server.py")
+    assert response.status == 404
+
+    _, response = app.test_client.get("/foo/..%2Fstatic/test.file")
+    assert response.status == 404
+
+
+@pytest.mark.skipif(
+    sys.platform != "win32", reason="Block backslash on Windows only"
+)
+def test_double_backslash_prohibited_on_win32(
+    app: Sanic, static_file_directory: str
+):
+    app.static("/foo", static_file_directory)
+
+    _, response = app.test_client.get("/foo/static/..\\static/test.file")
+    assert response.status == 404
+    _, response = app.test_client.get("/foo/static\\../static/test.file")
+    assert response.status == 404