From cc61050e8f26697463142d99864b562e8470b41d Mon Sep 17 00:00:00 2001 From: Ben Darnell Date: Thu, 8 May 2025 13:29:43 -0400 Subject: [PATCH] httputil: Raise errors instead of logging in multipart/form-data parsing We used to continue after logging an error, which allowed repeated errors to spam the logs. The error raised here will still be logged, but only once per request, consistent with other error handling in Tornado. Upstream: https://github.com/tornadoweb/tornado/commit/b39b892bf78fe8fea01dd45199aa88307e7162f3 CVE: CVE-2025-47287 Signed-off-by: Titouan Christophe --- tornado/httputil.py | 30 +++++++++++------------------- tornado/test/httpserver_test.py | 4 ++-- tornado/test/httputil_test.py | 13 ++++++++----- tornado/web.py | 17 +++++++++++++---- 4 files changed, 34 insertions(+), 30 deletions(-) diff --git a/tornado/httputil.py b/tornado/httputil.py index 7044aca02..ef460985e 100644 --- a/tornado/httputil.py +++ b/tornado/httputil.py @@ -34,7 +34,6 @@ from urllib.parse import urlencode, urlparse, urlunparse, parse_qsl from tornado.escape import native_str, parse_qs_bytes, utf8 -from tornado.log import gen_log from tornado.util import ObjectDict, unicode_type @@ -884,25 +883,22 @@ def parse_body_arguments( """ if content_type.startswith("application/x-www-form-urlencoded"): if headers and "Content-Encoding" in headers: - gen_log.warning( - "Unsupported Content-Encoding: %s", headers["Content-Encoding"] + raise HTTPInputError( + "Unsupported Content-Encoding: %s" % headers["Content-Encoding"] ) - return try: # real charset decoding will happen in RequestHandler.decode_argument() uri_arguments = parse_qs_bytes(body, keep_blank_values=True) except Exception as e: - gen_log.warning("Invalid x-www-form-urlencoded body: %s", e) - uri_arguments = {} + raise HTTPInputError("Invalid x-www-form-urlencoded body: %s" % e) from e for name, values in uri_arguments.items(): if values: arguments.setdefault(name, []).extend(values) elif content_type.startswith("multipart/form-data"): if headers and "Content-Encoding" in headers: - gen_log.warning( - "Unsupported Content-Encoding: %s", headers["Content-Encoding"] + raise HTTPInputError( + "Unsupported Content-Encoding: %s" % headers["Content-Encoding"] ) - return try: fields = content_type.split(";") for field in fields: @@ -911,9 +907,9 @@ def parse_body_arguments( parse_multipart_form_data(utf8(v), body, arguments, files) break else: - raise ValueError("multipart boundary not found") + raise HTTPInputError("multipart boundary not found") except Exception as e: - gen_log.warning("Invalid multipart/form-data: %s", e) + raise HTTPInputError("Invalid multipart/form-data: %s" % e) from e def parse_multipart_form_data( @@ -942,26 +938,22 @@ def parse_multipart_form_data( boundary = boundary[1:-1] final_boundary_index = data.rfind(b"--" + boundary + b"--") if final_boundary_index == -1: - gen_log.warning("Invalid multipart/form-data: no final boundary") - return + raise HTTPInputError("Invalid multipart/form-data: no final boundary found") parts = data[:final_boundary_index].split(b"--" + boundary + b"\r\n") for part in parts: if not part: continue eoh = part.find(b"\r\n\r\n") if eoh == -1: - gen_log.warning("multipart/form-data missing headers") - continue + raise HTTPInputError("multipart/form-data missing headers") headers = HTTPHeaders.parse(part[:eoh].decode("utf-8")) disp_header = headers.get("Content-Disposition", "") disposition, disp_params = _parse_header(disp_header) if disposition != "form-data" or not part.endswith(b"\r\n"): - gen_log.warning("Invalid multipart/form-data") - continue + raise HTTPInputError("Invalid multipart/form-data") value = part[eoh + 4 : -2] if not disp_params.get("name"): - gen_log.warning("multipart/form-data value missing name") - continue + raise HTTPInputError("multipart/form-data missing name") name = disp_params["name"] if disp_params.get("filename"): ctype = headers.get("Content-Type", "application/unknown") diff --git a/tornado/test/httpserver_test.py b/tornado/test/httpserver_test.py index 570cb64ca..f197cfef8 100644 --- a/tornado/test/httpserver_test.py +++ b/tornado/test/httpserver_test.py @@ -1148,9 +1148,9 @@ def test_gzip_unsupported(self): # Gzip support is opt-in; without it the server fails to parse # the body (but parsing form bodies is currently just a log message, # not a fatal error). - with ExpectLog(gen_log, "Unsupported Content-Encoding"): + with ExpectLog(gen_log, ".*Unsupported Content-Encoding"): response = self.post_gzip("foo=bar") - self.assertEqual(json_decode(response.body), {}) + self.assertEqual(response.code, 400) class StreamingChunkSizeTest(AsyncHTTPTestCase): diff --git a/tornado/test/httputil_test.py b/tornado/test/httputil_test.py index 30fbec4d7..7a09beaa3 100644 --- a/tornado/test/httputil_test.py +++ b/tornado/test/httputil_test.py @@ -12,7 +12,6 @@ ) from tornado.escape import utf8, native_str from tornado.log import gen_log -from tornado.testing import ExpectLog from tornado.test.util import ignore_deprecation import copy @@ -195,7 +194,9 @@ def test_missing_headers(self): b"\n", b"\r\n" ) args, files = form_data_args() - with ExpectLog(gen_log, "multipart/form-data missing headers"): + with self.assertRaises( + HTTPInputError, msg="multipart/form-data missing headers" + ): parse_multipart_form_data(b"1234", data, args, files) self.assertEqual(files, {}) @@ -209,7 +210,7 @@ def test_invalid_content_disposition(self): b"\n", b"\r\n" ) args, files = form_data_args() - with ExpectLog(gen_log, "Invalid multipart/form-data"): + with self.assertRaises(HTTPInputError, msg="Invalid multipart/form-data"): parse_multipart_form_data(b"1234", data, args, files) self.assertEqual(files, {}) @@ -222,7 +223,7 @@ def test_line_does_not_end_with_correct_line_break(self): b"\n", b"\r\n" ) args, files = form_data_args() - with ExpectLog(gen_log, "Invalid multipart/form-data"): + with self.assertRaises(HTTPInputError, msg="Invalid multipart/form-data"): parse_multipart_form_data(b"1234", data, args, files) self.assertEqual(files, {}) @@ -236,7 +237,9 @@ def test_content_disposition_header_without_name_parameter(self): b"\n", b"\r\n" ) args, files = form_data_args() - with ExpectLog(gen_log, "multipart/form-data value missing name"): + with self.assertRaises( + HTTPInputError, msg="multipart/form-data value missing name" + ): parse_multipart_form_data(b"1234", data, args, files) self.assertEqual(files, {}) diff --git a/tornado/web.py b/tornado/web.py index 0303f547e..2f702d648 100644 --- a/tornado/web.py +++ b/tornado/web.py @@ -1801,6 +1801,14 @@ async def _execute( try: if self.request.method not in self.SUPPORTED_METHODS: raise HTTPError(405) + + # If we're not in stream_request_body mode, this is the place where we parse the body. + if not _has_stream_request_body(self.__class__): + try: + self.request._parse_body() + except httputil.HTTPInputError as e: + raise HTTPError(400, "Invalid body: %s" % e) from e + self.path_args = [self.decode_argument(arg) for arg in args] self.path_kwargs = dict( (k, self.decode_argument(v, name=k)) for (k, v) in kwargs.items() @@ -1992,7 +2000,7 @@ def _has_stream_request_body(cls: Type[RequestHandler]) -> bool: def removeslash( - method: Callable[..., Optional[Awaitable[None]]] + method: Callable[..., Optional[Awaitable[None]]], ) -> Callable[..., Optional[Awaitable[None]]]: """Use this decorator to remove trailing slashes from the request path. @@ -2021,7 +2029,7 @@ def wrapper( # type: ignore def addslash( - method: Callable[..., Optional[Awaitable[None]]] + method: Callable[..., Optional[Awaitable[None]]], ) -> Callable[..., Optional[Awaitable[None]]]: """Use this decorator to add a missing trailing slash to the request path. @@ -2445,8 +2453,9 @@ def finish(self) -> None: if self.stream_request_body: future_set_result_unless_cancelled(self.request._body_future, None) else: + # Note that the body gets parsed in RequestHandler._execute so it can be in + # the right exception handler scope. self.request.body = b"".join(self.chunks) - self.request._parse_body() self.execute() def on_connection_close(self) -> None: @@ -3332,7 +3341,7 @@ def transform_chunk(self, chunk: bytes, finishing: bool) -> bytes: def authenticated( - method: Callable[..., Optional[Awaitable[None]]] + method: Callable[..., Optional[Awaitable[None]]], ) -> Callable[..., Optional[Awaitable[None]]]: """Decorate methods with this to require that the user be logged in.