Release 0.7.2

CHANGES.md

@@ -1,5 +1,21 @@
 # Microdot change log
 
+**Release 0.7.2** - 2021-09-28
+
+- Document a security risk in the send_file function ([commit](https://github.com/miguelgrinberg/microdot/commit/d29ed6aaa1f2080fcf471bf6ae0f480f95ff1716)) (thanks **Ky Tran**!)
+- Validate redirect URLs ([commit](https://github.com/miguelgrinberg/microdot/commit/8e5fb92ff1ccd50972b0c1cb5a6c3bd5eb54d86b)) (thanks **Ky Tran**!)
+- Return a 400 error when request object could not be created ([commit](https://github.com/miguelgrinberg/microdot/commit/06015934b834622d39f52b3e13d16bfee9dc8e5a))
+
+**Release 0.7.1** - 2021-09-27
+
+- Breaking change: Limit the size of each request line to 2KB. A different maximum can be set in `Request.max_readline`. ([commit](https://github.com/miguelgrinberg/microdot/commit/de9c991a9ab836d57d5c08bf4282f99f073b502a)) (thanks **Ky Tran**!)
+
+**Release 0.7.0** - 2021-09-27
+
+- Breaking change: Limit the size of the request body to 16KB. A different maximum can be set in `Request.max_content_length`. ([commit](https://github.com/miguelgrinberg/microdot/commit/5003a5b3d948a7cf365857b419bebf6e388593a1))
+- Add documentation for `request.client_addr` [#27](https://github.com/miguelgrinberg/microdot/issues/27) ([commit](https://github.com/miguelgrinberg/microdot/commit/833fecb105ce456b95f1d2a6ea96dceca1075814)) (thanks **Mark Blakeney**!)
+- Added documentation for reason argument in the Response object ([commit](https://github.com/miguelgrinberg/microdot/commit/d527bdb7c32ab918a1ecf6956cf3a9f544504354))
+
 **Release 0.6.0** - 2021-08-11
 
 - Better handling of content types in form and json methods [#24](https://github.com/miguelgrinberg/microdot/issues/24) ([commit](https://github.com/miguelgrinberg/microdot/commit/da32f23e35f871470a40638e7000e84b0ff6d17f))

SECURITY.md

@@ -0,0 +1,9 @@
+# Security Policy
+
+## Reporting a Vulnerability
+
+If you think you've found a vulnerability on this project, please send me (Miguel Grinberg) an email at miguel.grinberg@gmail.com with a description of the problem. I will personally review the issue and respond to you with next steps.
+
+If the issue is highly sensitive, you are welcome to encrypt your message. Here is my [PGP key](https://keyserver.ubuntu.com/pks/lookup?search=miguel.grinberg%40gmail.com&fingerprint=on&op=index).
+
+Please do not disclose vulnerabilities publicly before discussing how to proceed with me.

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = microdot
-version = 0.6.0
+version = 0.7.2
 author = Miguel Grinberg
 author_email = miguel.grinberg@gmail.com
 description = The impossibly small web framework for MicroPython

src/microdot.py

@@ -172,6 +172,7 @@ class Request():
     """An HTTP request class.
 
     :var app: The application instance to which this request belongs.
+    :var client_addr: The address of the client, as a tuple (host, port).
     :var method: The HTTP method of the request.
     :var path: The path portion of the URL.
     :var query_string: The query string portion of the URL.
@@ -188,6 +189,24 @@ class Request():
     :var g: A general purpose container for applications to store data during
             the life of the request.
     """
+    #: Specify the maximum payload size that is accepted. Requests with larger
+    #: payloads will be rejected with a 413 status code. Applications can
+    #: change this maximum as necessary.
+    #:
+    #: Example::
+    #:
+    #:    Request.max_content_length = 1 * 1024 * 1024  # 1MB requests allowed
+    max_content_length = 16 * 1024
+
+    #: Specify the maximum length allowed for a line in the request. Requests
+    #: with longer lines will not be correctly interpreted. Applications can
+    #: change this maximum as necessary.
+    #:
+    #: Example::
+    #:
+    #:    Request.max_readline = 16 * 1024  # 16KB lines allowed
+    max_readline = 2 * 1024
+
     class G:
         pass
 
@@ -234,7 +253,7 @@ class Request():
         This method returns a newly created ``Request`` object.
         """
         # request line
-        line = client_stream.readline().strip().decode()
+        line = Request._safe_readline(client_stream).strip().decode()
         if not line:
             return None
         method, url, http_version = line.split()
@@ -244,7 +263,7 @@ class Request():
         headers = {}
         content_length = 0
         while True:
-            line = client_stream.readline().strip().decode()
+            line = Request._safe_readline(client_stream).strip().decode()
             if line == '':
                 break
             header, value = line.split(':', 1)
@@ -254,7 +273,8 @@ class Request():
                 content_length = int(value)
 
         # body
-        body = client_stream.read(content_length) if content_length else b''
+        body = client_stream.read(content_length) if content_length and \
+            content_length <= Request.max_content_length else b''
 
         return Request(app, client_addr, method, url, http_version, headers,
                        body)
@@ -287,6 +307,13 @@ class Request():
             self._form = self._parse_urlencoded(self.body.decode())
         return self._form
 
+    @staticmethod
+    def _safe_readline(stream):
+        line = stream.readline(Request.max_readline + 1)
+        if len(line) > Request.max_readline:
+            raise ValueError('line too long')
+        return line
+
 
 class Response():
     """An HTTP response class.
@@ -296,6 +323,9 @@ class Response():
     :param status_code: The numeric HTTP status code of the response. The
                         default is 200.
     :param headers: A dictionary of headers to include in the response.
+    :param reason: A custom reason phrase to add after the status code. The
+                   default is "OK" for responses with a 200 status code and
+                   "N/A" for any other status codes.
     """
     types_map = {
         'css': 'text/css',
@@ -400,6 +430,8 @@ class Response():
         :param status_code: The 3xx status code to use for the redirect. The
                             default is 302.
         """
+        if '\x0d' in location or '\x0a' in location:
+            raise ValueError('invalid redirect URL')
         return cls(status_code=status_code, headers={'Location': location})
 
     @classmethod
@@ -412,6 +444,10 @@ class Response():
         :param content_type: The ``Content-Type`` header to use in the
                              response. If omitted, it is generated
                              automatically from the file extension.
+
+        Security note: The filename is assumed to be trusted. Never pass
+        filenames provided by the user before validating and sanitizing them
+        first.
         """
         if content_type is None:
             ext = filename.split('.')[-1]
@@ -764,46 +800,58 @@ class Microdot():
         else:
             stream = sock
 
-        req = Request.create(self, stream, addr)
+        req = None
+        try:
+            req = Request.create(self, stream, addr)
+        except Exception as exc:  # pragma: no cover
+            print_exception(exc)
         if req:
-            f = self.find_route(req)
-            try:
-                res = None
-                if f:
-                    for handler in self.before_request_handlers:
-                        res = handler(req)
-                        if res:
-                            break
-                    if res is None:
-                        res = f(req, **req.url_args)
-                    if isinstance(res, tuple):
-                        res = Response(*res)
-                    elif not isinstance(res, Response):
-                        res = Response(res)
-                    for handler in self.after_request_handlers:
-                        res = handler(req, res) or res
-                elif 404 in self.error_handlers:
-                    res = self.error_handlers[404](req)
+            if req.content_length > req.max_content_length:
+                if 413 in self.error_handlers:
+                    res = self.error_handlers[413](req)
                 else:
-                    res = 'Not found', 404
-            except Exception as exc:
-                print_exception(exc)
-                res = None
-                if exc.__class__ in self.error_handlers:
-                    try:
-                        res = self.error_handlers[exc.__class__](req, exc)
-                    except Exception as exc2:  # pragma: no cover
-                        print_exception(exc2)
-                if res is None:
-                    if 500 in self.error_handlers:
-                        res = self.error_handlers[500](req)
+                    res = 'Payload too large', 413
+            else:
+                f = self.find_route(req)
+                try:
+                    res = None
+                    if f:
+                        for handler in self.before_request_handlers:
+                            res = handler(req)
+                            if res:
+                                break
+                        if res is None:
+                            res = f(req, **req.url_args)
+                        if isinstance(res, tuple):
+                            res = Response(*res)
+                        elif not isinstance(res, Response):
+                            res = Response(res)
+                        for handler in self.after_request_handlers:
+                            res = handler(req, res) or res
+                    elif 404 in self.error_handlers:
+                        res = self.error_handlers[404](req)
                     else:
-                        res = 'Internal server error', 500
-            if isinstance(res, tuple):
-                res = Response(*res)
-            elif not isinstance(res, Response):
-                res = Response(res)
-            res.write(stream)
+                        res = 'Not found', 404
+                except Exception as exc:
+                    print_exception(exc)
+                    res = None
+                    if exc.__class__ in self.error_handlers:
+                        try:
+                            res = self.error_handlers[exc.__class__](req, exc)
+                        except Exception as exc2:  # pragma: no cover
+                            print_exception(exc2)
+                    if res is None:
+                        if 500 in self.error_handlers:
+                            res = self.error_handlers[500](req)
+                        else:
+                            res = 'Internal server error', 500
+        else:
+            res = 'Bad request', 400
+        if isinstance(res, tuple):
+            res = Response(*res)
+        elif not isinstance(res, Response):
+            res = Response(res)
+        res.write(stream)
         stream.close()
         if stream != sock:  # pragma: no cover
             sock.close()

src/microdot_asyncio.py

@@ -34,7 +34,7 @@ class Request(BaseRequest):
         object.
         """
         # request line
-        line = (await client_stream.readline()).strip().decode()
+        line = (await Request._safe_readline(client_stream)).strip().decode()
         if not line:  # pragma: no cover
             return None
         method, url, http_version = line.split()
@@ -44,7 +44,8 @@ class Request(BaseRequest):
         headers = {}
         content_length = 0
         while True:
-            line = (await client_stream.readline()).strip().decode()
+            line = (await Request._safe_readline(
+                client_stream)).strip().decode()
             if line == '':
                 break
             header, value = line.split(':', 1)
@@ -54,12 +55,19 @@ class Request(BaseRequest):
                 content_length = int(value)
 
         # body
-        body = await client_stream.read(content_length) \
-            if content_length else b''
+        body = await client_stream.read(content_length) if content_length and \
+            content_length <= Request.max_content_length else b''
 
         return Request(app, client_addr, method, url, http_version, headers,
                        body)
 
+    @staticmethod
+    async def _safe_readline(stream):
+        line = (await stream.readline())
+        if len(line) > Request.max_readline:
+            raise ValueError('line too long')
+        return line
+
 
 class Response(BaseResponse):
     """An HTTP response class.
@@ -69,6 +77,9 @@ class Response(BaseResponse):
     :param status_code: The numeric HTTP status code of the response. The
                         default is 200.
     :param headers: A dictionary of headers to include in the response.
+    :param reason: A custom reason phrase to add after the status code. The
+                   default is "OK" for responses with a 200 status code and
+                   "N/A" for any other status codes.
     """
     async def write(self, stream):
         self.complete()
@@ -207,52 +218,65 @@ class Microdot(BaseMicrodot):
         self.server.close()
 
     async def dispatch_request(self, reader, writer):
-        req = await Request.create(self, reader,
-                                   writer.get_extra_info('peername'))
+        req = None
+        try:
+            req = await Request.create(self, reader,
+                                       writer.get_extra_info('peername'))
+        except Exception as exc:  # pragma: no cover
+            print_exception(exc)
         if req:
-            f = self.find_route(req)
-            try:
-                res = None
-                if f:
-                    for handler in self.before_request_handlers:
-                        res = await self._invoke_handler(handler, req)
-                        if res:
-                            break
-                    if res is None:
-                        res = await self._invoke_handler(
-                            f, req, **req.url_args)
-                    if isinstance(res, tuple):
-                        res = Response(*res)
-                    elif not isinstance(res, Response):
-                        res = Response(res)
-                    for handler in self.after_request_handlers:
-                        res = await self._invoke_handler(
-                            handler, req, res) or res
-                elif 404 in self.error_handlers:
+            if req.content_length > req.max_content_length:
+                if 413 in self.error_handlers:
                     res = await self._invoke_handler(
-                        self.error_handlers[404], req)
+                        self.error_handlers[413], req)
                 else:
-                    res = 'Not found', 404
-            except Exception as exc:
-                print_exception(exc)
-                res = None
-                if exc.__class__ in self.error_handlers:
-                    try:
+                    res = 'Payload too large', 413
+            else:
+                f = self.find_route(req)
+                try:
+                    res = None
+                    if f:
+                        for handler in self.before_request_handlers:
+                            res = await self._invoke_handler(handler, req)
+                            if res:
+                                break
+                        if res is None:
+                            res = await self._invoke_handler(
+                                f, req, **req.url_args)
+                        if isinstance(res, tuple):
+                            res = Response(*res)
+                        elif not isinstance(res, Response):
+                            res = Response(res)
+                        for handler in self.after_request_handlers:
+                            res = await self._invoke_handler(
+                                handler, req, res) or res
+                    elif 404 in self.error_handlers:
                         res = await self._invoke_handler(
-                            self.error_handlers[exc.__class__], req, exc)
-                    except Exception as exc2:  # pragma: no cover
-                        print_exception(exc2)
-                if res is None:
-                    if 500 in self.error_handlers:
-                        res = await self._invoke_handler(
-                            self.error_handlers[500], req)
+                            self.error_handlers[404], req)
                     else:
-                        res = 'Internal server error', 500
-            if isinstance(res, tuple):
-                res = Response(*res)
-            elif not isinstance(res, Response):
-                res = Response(res)
-            await res.write(writer)
+                        res = 'Not found', 404
+                except Exception as exc:
+                    print_exception(exc)
+                    res = None
+                    if exc.__class__ in self.error_handlers:
+                        try:
+                            res = await self._invoke_handler(
+                                self.error_handlers[exc.__class__], req, exc)
+                        except Exception as exc2:  # pragma: no cover
+                            print_exception(exc2)
+                    if res is None:
+                        if 500 in self.error_handlers:
+                            res = await self._invoke_handler(
+                                self.error_handlers[500], req)
+                        else:
+                            res = 'Internal server error', 500
+        else:
+            res = 'Bad request', 400
+        if isinstance(res, tuple):
+            res = Response(*res)
+        elif not isinstance(res, Response):
+            res = Response(res)
+        await res.write(writer)
         await writer.aclose()
         if self.debug and req:  # pragma: no cover
             print('{method} {path} {status_code}'.format(

tests/microdot/test_microdot.py

@@ -73,7 +73,10 @@ class TestMicrodot(unittest.TestCase):
         mock_socket._requests.append(fd)
         self._add_shutdown(app)
         app.run()
-        assert fd.response == b''
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 400 N/A\r\n'))
+        self.assertIn(b'Content-Length: 11\r\n', fd.response)
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\nBad request'))
 
     def test_method_decorators(self):
         app = Microdot()
@@ -192,6 +195,42 @@ class TestMicrodot(unittest.TestCase):
         self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
         self.assertTrue(fd.response.endswith(b'\r\n\r\n404'))
 
+    def test_413(self):
+        app = Microdot()
+
+        @app.route('/')
+        def index(req):
+            return 'foo'
+
+        mock_socket.clear_requests()
+        fd = mock_socket.add_request('GET', '/foo', body='x' * 17000)
+        self._add_shutdown(app)
+        app.run()
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 413 N/A\r\n'))
+        self.assertIn(b'Content-Length: 17\r\n', fd.response)
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\nPayload too large'))
+
+    def test_413_handler(self):
+        app = Microdot()
+
+        @app.route('/')
+        def index(req):
+            return 'foo'
+
+        @app.errorhandler(413)
+        def handle_413(req):
+            return '413', 400
+
+        mock_socket.clear_requests()
+        fd = mock_socket.add_request('GET', '/foo', body='x' * 17000)
+        self._add_shutdown(app)
+        app.run()
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 400 N/A\r\n'))
+        self.assertIn(b'Content-Length: 3\r\n', fd.response)
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\n413'))
+
     def test_500(self):
         app = Microdot()
 

tests/microdot/test_request.py

@@ -78,3 +78,27 @@ class TestRequest(unittest.TestCase):
             body='foo=bar&abc=def&x=%2f%%')
         req = Request.create('app', fd, 'addr')
         self.assertIsNone(req.form)
+
+    def test_large_line(self):
+        saved_max_readline = Request.max_readline
+        Request.max_readline = 16
+
+        fd = get_request_fd('GET', '/foo', headers={
+            'Content-Type': 'application/x-www-form-urlencoded'},
+            body='foo=bar&abc=def&x=y')
+        with self.assertRaises(ValueError):
+            Request.create('app', fd, 'addr')
+
+        Request.max_readline = saved_max_readline
+
+    def test_large_payload(self):
+        saved_max_content_length = Request.max_content_length
+        Request.max_content_length = 16
+
+        fd = get_request_fd('GET', '/foo', headers={
+            'Content-Type': 'application/x-www-form-urlencoded'},
+            body='foo=bar&abc=def&x=y')
+        req = Request.create('app', fd, 'addr')
+        self.assertEqual(req.body, b'')
+
+        Request.max_content_length = saved_max_content_length

tests/microdot_asyncio/test_microdot_asyncio.py

@@ -84,7 +84,10 @@ class TestMicrodotAsync(unittest.TestCase):
         mock_socket._requests.append(fd)
         self._add_shutdown(app)
         app.run()
-        assert fd.response == b''
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 400 N/A\r\n'))
+        self.assertIn(b'Content-Length: 11\r\n', fd.response)
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\nBad request'))
 
     def test_before_after_request(self):
         app = Microdot()
@@ -170,6 +173,42 @@ class TestMicrodotAsync(unittest.TestCase):
         self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
         self.assertTrue(fd.response.endswith(b'\r\n\r\n404'))
 
+    def test_413(self):
+        app = Microdot()
+
+        @app.route('/')
+        def index(req):
+            return 'foo'
+
+        mock_socket.clear_requests()
+        fd = mock_socket.add_request('GET', '/foo', body='x' * 17000)
+        self._add_shutdown(app)
+        app.run()
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 413 N/A\r\n'))
+        self.assertIn(b'Content-Length: 17\r\n', fd.response)
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\nPayload too large'))
+
+    def test_413_handler(self):
+        app = Microdot()
+
+        @app.route('/')
+        def index(req):
+            return 'foo'
+
+        @app.errorhandler(413)
+        async def handle_413(req):
+            return '413', 400
+
+        mock_socket.clear_requests()
+        fd = mock_socket.add_request('GET', '/foo', body='x' * 17000)
+        self._add_shutdown(app)
+        app.run()
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 400 N/A\r\n'))
+        self.assertIn(b'Content-Length: 3\r\n', fd.response)
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\n413'))
+
     def test_500(self):
         app = Microdot()
 

tests/microdot_asyncio/test_request_asyncio.py

@@ -88,3 +88,27 @@ class TestRequestAsync(unittest.TestCase):
             body='foo=bar&abc=def&x=%2f%%')
         req = _run(Request.create('app', fd, 'addr'))
         self.assertIsNone(req.form)
+
+    def test_large_line(self):
+        saved_max_readline = Request.max_readline
+        Request.max_readline = 16
+
+        fd = get_async_request_fd('GET', '/foo', headers={
+            'Content-Type': 'application/x-www-form-urlencoded'},
+            body='foo=bar&abc=def&x=y')
+        with self.assertRaises(ValueError):
+            _run(Request.create('app', fd, 'addr'))
+
+        Request.max_readline = saved_max_readline
+
+    def test_large_payload(self):
+        saved_max_content_length = Request.max_content_length
+        Request.max_content_length = 16
+
+        fd = get_async_request_fd('GET', '/foo', headers={
+            'Content-Type': 'application/x-www-form-urlencoded'},
+            body='foo=bar&abc=def&x=y')
+        req = _run(Request.create('app', fd, 'addr'))
+        self.assertEqual(req.body, b'')
+
+        Request.max_content_length = saved_max_content_length