[Security] Bump waitress from 0.8.10 to 1.4.0

[dependabot-preview]

Bumps waitress from 0.8.10 to 1.4.0. This update includes security fixes.

Vulnerabilities fixed

Sourced from The GitHub Security Advisory Database.

Critical severity vulnerability that affects waitress

Impact

Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally.

So a request with:

Content-Length: 10
Content-Length: 10

would get transformed to:

Content-Length: 10, 10

Which would Waitress would then internally set to Content-Lenght: 0.

Waitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.

... (truncated)

Affected versions: < 1.3.1

Sourced from The GitHub Security Advisory Database.

Critical severity vulnerability that affects waitress

Impact

Waitress implemented a "MAY" part of the RFC7230 (https://tools.ietf.org/html/rfc7230#section-3.5) which states:

  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.

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.

Example:

Content-Length: 100[CRLF]
X-Header: x[LF]Content-Length: 0[CRLF]

Would get treated by Waitress as if it were:

</tr></table> ... (truncated)
Affected versions: <= 1.3.1

Sourced from The GitHub Security Advisory Database.

Critical severity vulnerability that affects waitress

Impact

Waitress would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead.

According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked.

Requests sent with:

Transfer-Encoding: gzip, chunked

Would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message.

This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.

Patches

This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.

... (truncated)

Affected versions: <= 1.3.1

Release notes

Sourced from waitress's releases.

v1.4.0

No release notes provided.

v1.3.1

No release notes provided.

v1.3.0

No release notes provided.

v1.3.0b0

No release notes provided.

v1.2.1

No release notes provided.

v1.2.0

No release notes provided.

v1.1.0

https://pypi.org/project/waitress/1.1.0/

v1.0.2

No release notes provided.

v1.0.1

No release notes provided.

v1.0.0

No release notes provided.

v1.0a2

No release notes provided.

v1.0a1

No release notes provided.

v0.9.0

No release notes provided.

v0.9.0b1

No release notes provided.

0.9.0b0

No release notes provided.

0.8.11b0

No release notes provided.

Changelog

Sourced from waitress's changelog.

1.4.0 (2019-12-20)

Bugfixes

- 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.

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 Pylons/waitress#273

Security Fixes

• Waitress implemented a "MAY" part of the RFC7230 (https://tools.ietf.org/html/rfc7230#section-3.5) which states:

  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.
  

  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.

  For more information I can highly recommend the blog post by ZeddYu Lu https://blog.zeddyu.info/2019/12/08/HTTP-Smuggling-en/

• 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.

• 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.

  That means that if the following header is sent:

  Transfer-Encoding: gzip, chunked

... (truncated)

Commits

• f11093a Merge pull request from GHSA-g2xc-35jw-c63p
• e586be8 Version 1.4.0
• d1f283b Update CHANGES.txt and HISTORY.txt as appropriate
• 60f92b8 Allow end of chunk parser to be resumeable
• 8ecd8dc Improve validation of Transfer-Encoding
• 575994c Upon receiving invalid Content-Length bail
• 804e313 Disallow BWS in header field-names
• fb08ecf Properly enforce max_request_header_size
• 8eba394 Remove support for non CRLF line endings
• 7ff1e6b Make sure all errors have a code/reason
• Additional commits viewable in compare view

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Superseded by #55.