[Bug 1940141] Re: OpenSSL servers can send a non-empty status_request in a CertificateRequest

[Bruce Elrick]

It's not needed for actual functionality of the backport but that
assumes that any future backports or fixes don't break this backport. By
adding the tests (and wrapping the one test that fails when the
backport-enabling environment variable is not set with the enabling of
that environmetn variable, we ensure that and future changes don't break
this change.

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Title:
  OpenSSL servers can send a non-empty status_request in a
  CertificateRequest

Status in openssl package in Ubuntu:
  Fix Released
Status in openssl source package in Bionic:
  New

Bug description:
  [Impact]

  openssl does not conform to RFC8446, Sec. 4.4.2.1., by sending a
  CertificateRequest message to the client with a non-empty
  status_request extension.

  This issue was fixed in openssl-1.1.1d and is included in Focal
  onward.

  Upstream issue is tracked at https://github.com/openssl/openssl/issues/9767
  Upstream patch review at https://github.com/openssl/openssl/pull/9780

  The issue leads to various client failures with TLS 1.3 as described
  in, e.g.

  https://github.com/golang/go/issues/35722
  https://github.com/golang/go/issues/34040

  [Test Plan]

  The issue can be reproduced by building with `enable-ssl-trace`
  and then running `s_server` like this:

  ```
  openssl s_server -key key.pem -cert cert.pem -status_file test/recipes/ocsp-response.der -Verify 5
  ```

  And running `s_client` like this:

  ```
  openssl s_client -status -trace -cert cert.pem -key key.pem
  ```

  The output shows a `status_request` extension in the
  `CertificateRequest` as follows:

  Received Record
  Header:
    Version = TLS 1.2 (0x303)
    Content Type = ApplicationData (23)
    Length = 1591
    Inner Content Type = Handshake (22)
      CertificateRequest, Length=1570
        request_context (len=0):
        extensions, length = 1567
          extension_type=status_request(5), length=1521
            0000 - 01 00 05 ed 30 82 05 e9-0a 01 00 a0 82 05 e2   ....0..........
            000f - 30 82 05 de 06 09 2b 06-01 05 05 07 30 01 01   0.....+.....0..
            001e - 04 82 05 cf 30 82 05 cb-30 82 01 1a a1 81 86   ....0...0......
            002d - 30 81 83 31 0b 30 09 06-03 55 04 06 13 02 47   0..1.0...U....G
  ...more lines omitted...

  If the `status_request` extension is present in a
  `CertificateRequest` then it must be empty according to RFC8446,
  Sec. 4.4.2.1.

  [Where problems could occur]

  The patch disables the `status_request` extension inside a
  `CertificateRequest`. Applications expecting the incorrect,
  non-empty reply for the `status_request` extension will break
  with this patch.

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