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

[Mathew Hodson]

** Changed in: openssl (Ubuntu)
   Importance: Undecided => Medium

** Changed in: openssl (Ubuntu Bionic)
   Importance: Undecided => Medium

** Changed in: openssl (Ubuntu)
       Status: New => Fix Released

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https://bugs.launchpad.net/bugs/1940141

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

  [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. As a non-empty reply is incorrect behavior

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