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HTTP Request Smuggling Fixes
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1.3.1 (2019-08-27) | ||
1.4.0 (2019-12-20) | ||
------------------ | ||
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Bugfixes | ||
~~~~~~~~ | ||
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- Waitress won't accidentally throw away part of the path if it starts with a | ||
double slash (``GET //testing/whatever HTTP/1.0``). WSGI applications will | ||
now receive a ``PATH_INFO`` in the environment that contains | ||
``//testing/whatever`` as required. See | ||
https://github.com/Pylons/waitress/issues/260 and | ||
https://github.com/Pylons/waitress/pull/261 | ||
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1.3.0 (2019-04-22) | ||
------------------ | ||
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Deprecations | ||
~~~~~~~~~~~~ | ||
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- The ``send_bytes`` adjustment now defaults to ``1`` and is deprecated | ||
pending removal in a future release. | ||
and https://github.com/Pylons/waitress/pull/246 | ||
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Features | ||
~~~~~~~~ | ||
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- Add a new ``outbuf_high_watermark`` adjustment which is used to apply | ||
backpressure on the ``app_iter`` to avoid letting it spin faster than data | ||
can be written to the socket. This stabilizes responses that iterate quickly | ||
with a lot of data. | ||
See https://github.com/Pylons/waitress/pull/242 | ||
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- Stop early and close the ``app_iter`` when attempting to write to a closed | ||
socket due to a client disconnect. This should notify a long-lived streaming | ||
response when a client hangs up. | ||
See https://github.com/Pylons/waitress/pull/238 | ||
and https://github.com/Pylons/waitress/pull/240 | ||
and https://github.com/Pylons/waitress/pull/241 | ||
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- Adjust the flush to output ``SO_SNDBUF`` bytes instead of whatever was | ||
set in the ``send_bytes`` adjustment. ``send_bytes`` now only controls how | ||
much waitress will buffer internally before flushing to the kernel, whereas | ||
previously it used to also throttle how much data was sent to the kernel. | ||
This change enables a streaming ``app_iter`` containing small chunks to | ||
still be flushed efficiently. | ||
See https://github.com/Pylons/waitress/pull/246 | ||
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Bugfixes | ||
~~~~~~~~ | ||
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- Upon receiving a request that does not include HTTP/1.0 or HTTP/1.1 we will | ||
no longer set the version to the string value "None". See | ||
https://github.com/Pylons/waitress/pull/252 and | ||
https://github.com/Pylons/waitress/issues/110 | ||
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- When a client closes a socket unexpectedly there was potential for memory | ||
leaks in which data was written to the buffers after they were closed, | ||
causing them to reopen. | ||
See https://github.com/Pylons/waitress/pull/239 | ||
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- Fix the queue depth warnings to only show when all threads are busy. | ||
See https://github.com/Pylons/waitress/pull/243 | ||
and https://github.com/Pylons/waitress/pull/247 | ||
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- Trigger the ``app_iter`` to close as part of shutdown. This will only be | ||
noticeable for users of the internal server api. In more typical operations | ||
the server will die before benefiting from these changes. | ||
See https://github.com/Pylons/waitress/pull/245 | ||
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- Fix a bug in which a streaming ``app_iter`` may never cleanup data that has | ||
already been sent. This would cause buffers in waitress to grow without | ||
bounds. These buffers now properly rotate and release their data. | ||
See https://github.com/Pylons/waitress/pull/242 | ||
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- Fix a bug in which non-seekable subclasses of ``io.IOBase`` would trigger | ||
an exception when passed to the ``wsgi.file_wrapper`` callback. | ||
See https://github.com/Pylons/waitress/pull/249 | ||
- Waitress used to slam the door shut on HTTP pipelined requests without | ||
setting the ``Connection: close`` header as appropriate in the response. This | ||
is of course not very friendly. Waitress now explicitly sets the header when | ||
responding with an internally generated error such as 400 Bad Request or 500 | ||
Internal Server Error to notify the remote client that it will be closing the | ||
connection after the response is sent. | ||
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- Waitress no longer allows any spaces to exist between the header field-name | ||
and the colon. While waitress did not strip the space and thereby was not | ||
vulnerable to any potential header field-name confusion, it should have sent | ||
back a 400 Bad Request. See https://github.com/Pylons/waitress/issues/273 | ||
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Security Fixes | ||
~~~~~~~~~~~~~~ | ||
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- Waitress implemented a "MAY" part of the RFC7230 | ||
(https://tools.ietf.org/html/rfc7230#section-3.5) which states: | ||
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Although the line terminator for the start-line and header fields is | ||
the sequence CRLF, a recipient MAY recognize a single LF as a line | ||
terminator and ignore any preceding CR. | ||
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Unfortunately if a front-end server does not parse header fields with an LF | ||
the same way as it does those with a CRLF it can lead to the front-end and | ||
the back-end server parsing the same HTTP message in two different ways. This | ||
can lead to a potential for HTTP request smuggling/splitting whereby Waitress | ||
may see two requests while the front-end server only sees a single HTTP | ||
message. | ||
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For more information I can highly recommend the blog post by ZeddYu Lu | ||
https://blog.zeddyu.info/2019/12/08/HTTP-Smuggling-en/ | ||
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- Waitress used to treat LF the same as CRLF in ``Transfer-Encoding: chunked`` | ||
requests, while the maintainer doesn't believe this could lead to a security | ||
issue, this is no longer supported and all chunks are now validated to be | ||
properly framed with CRLF as required by RFC7230. | ||
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- Waitress now validates that the ``Transfer-Encoding`` header contains only | ||
transfer codes that it is able to decode. At the moment that includes the | ||
only valid header value being ``chunked``. | ||
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That means that if the following header is sent: | ||
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``Transfer-Encoding: gzip, chunked`` | ||
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Waitress will send back a 501 Not Implemented with an error message stating | ||
as such, as while Waitress supports ``chunked`` encoding it does not support | ||
``gzip`` and it is unable to pass that to the underlying WSGI environment | ||
correctly. | ||
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Waitress DOES NOT implement support for ``Transfer-Encoding: identity`` | ||
eventhough ``identity`` was valid in RFC2616, it was removed in RFC7230. | ||
Please update your clients to remove the ``Transfer-Encoding`` header if the | ||
only transfer coding is ``identity`` or update your client to use | ||
``Transfer-Encoding: chunked`` instead of ``Transfer-Encoding: identity, | ||
chunked``. | ||
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- While validating the ``Transfer-Encoding`` header, Waitress now properly | ||
handles line-folded ``Transfer-Encoding`` headers or those that contain | ||
multiple comma seperated values. This closes a potential issue where a | ||
front-end server may treat the request as being a chunked request (and thus | ||
ignoring the Content-Length) and Waitress using the Content-Length as it was | ||
looking for the single value ``chunked`` and did not support comma seperated | ||
values. | ||
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- Waitress used to explicitly set the Content-Length header to 0 if it was | ||
unable to parse it as an integer (for example if the Content-Length header | ||
was sent twice (and thus folded together), or was invalid) thereby allowing | ||
for a potential request to be split and treated as two requests by HTTP | ||
pipelining support in Waitress. If Waitress is now unable to parse the | ||
Content-Length header, a 400 Bad Request is sent back to the client. |
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setup( | ||
name="waitress", | ||
version="1.3.1", | ||
version="1.4.0", | ||
author="Zope Foundation and Contributors", | ||
author_email="[email protected]", | ||
maintainer="Pylons Project", | ||
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