[Bug 1820279] Re: [FFe] [SRU] build mellon with --enable-diagnostics to ease up SSO debugging

Dmitrii Shcherbakov 1820279 at bugs.launchpad.net
Thu Jun 27 19:48:39 UTC 2019


Tested with stein-proposed:

 apt policy apt policy libapache2-mod-auth-mellon

apt:
  Installed: 1.6.11
  Candidate: 1.6.11
  Version table:
 *** 1.6.11 500
        500 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status

# grep MellonDiag /etc/apache2/mods-enabled/auth_mellon.conf
MellonDiagnosticsFile /var/log/apache2/mellon_diagnostics.log
MellonDiagnosticsEnable On


sudo tail -f /var/log/apache2/mellon_diagnostics.log
---------------------------------- New Request ---------------------------------
GET - /v3/OS-FEDERATION/identity_providers/samltestid/protocols/saml2/auth
log_id: (null)
server: scheme=(null) hostname=keystone.maas port=0
pid: 1668880, tid: 140134808790784
unparsed_uri: /v3/OS-FEDERATION/identity_providers/samltestid/protocols/saml2/auth
uri: /v3/OS-FEDERATION/identity_providers/samltestid/protocols/saml2/auth
path_info: (null)
filename: proxy:http://localhost:4980/v3/OS-FEDERATION/identity_providers/samltestid/protocols/saml2/auth
query args: (null)
Request Headers:
  Host: keystone.maas:5000
  User-Agent: openstacksdk/0.26.0 keystoneauth1/3.13.1 python-requests/2.18.4 CPython/3.6.7
  Accept-Encoding: gzip, deflate
  Accept: */*,application/vnd.paos+xml
  Connection: keep-alive
  PAOS: ver="urn:liberty:paos:2003-08";"urn:oasis:names:tc:SAML:2.0:profiles:SSO:ecp"
Mellon Directory Configuration for URL: /v3/OS-FEDERATION/identity_providers/samltestid/protocols/saml2/auth
# ...

** Tags removed: verification-needed verification-stein-needed
** Tags added: verification-done verification-stein-done

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https://bugs.launchpad.net/bugs/1820279

Title:
  [FFe] [SRU] build mellon with --enable-diagnostics to ease up SSO
  debugging

Status in Ubuntu Cloud Archive:
  Fix Committed
Status in Ubuntu Cloud Archive rocky series:
  Fix Committed
Status in Ubuntu Cloud Archive stein series:
  Fix Committed
Status in libapache2-mod-auth-mellon package in Ubuntu:
  Fix Released
Status in libapache2-mod-auth-mellon source package in Bionic:
  Won't Fix
Status in libapache2-mod-auth-mellon source package in Cosmic:
  Fix Committed
Status in libapache2-mod-auth-mellon source package in Disco:
  Fix Released

Bug description:
  FFE Section for disco
  ---------------------
  [Rationale]
  This change to mod_auth_mellon adds a very useful capability for enabling diagnostics output from the module:
  https://github.com/Uninett/mod_auth_mellon/commit/e8579f6387d9841ce619d836110050fb18117753

  It is available as of v0.14.0 (present in Cosmic):

  git --no-pager tag --contains=e8579f6387d9841ce619d836110050fb18117753
  v0.14.0
  v0.14.1

  This is generally useful for field engineering and operations teams
  and other users as SAML exchanges are difficult to debug.

  [Build Verification]
  https://paste.ubuntu.com/p/2kt3BsxJKn/

  [Installation]
  https://paste.ubuntu.com/p/VcfcgyPHqH/

  "MellonDiagnosticsEnable Off" is the default setting and it results in
  am_diag_open_log returning 1 which does NOT result in an error
  returned from am_diag_log_init. Also installed a package and verified
  that setting this to off explicitly or implicitly (default) does not
  result in errors on startup or page access.

  https://git.launchpad.net/ubuntu/+source/libapache2-mod-auth-
  mellon/tree/auth_mellon_diagnostics.c?h=ubuntu/disco&id=49c8ccfedca2db17d76348573e6daa862e104f6d#n311

  int am_diag_log_init(apr_pool_t *pc, apr_pool_t *p, apr_pool_t *pt, server_rec *s)
  {
      for ( ; s ; s = s->next) {
          if (!am_diag_open_log(s, p)) {
              return HTTP_INTERNAL_SERVER_ERROR;
          }
      }

  // ...
  static int am_diag_open_log(server_rec *s, apr_pool_t *p) {
  // ...
      if (!(diag_cfg->flags & AM_DIAG_FLAG_ENABLED)) {
          ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                       "mellon diagnostics disabled for %s", server_desc);
          return 1;
  // ...

  [Upgrades]
  No impact

  SRU section for cosmic and bionic
  ---------------------------------
  [Impact]
  See FFE Rationale above.

  [Test Case]
  To test

  Add the following to /etc/apache2/conf-available/mellon.conf

  MellonDiagnosticsFile /var/log/apache2/mellon_diagnostics.log
  MellonDiagnosticsEnable On

  a2enconf mellon
  systemctl reload apache2

  After browsing to a location that is mod_auth_mellon enabled (see the
  keystone-saml-mellon charm) logging from the mellon module including
  environment variables in the SAML messages will be found in
  /var/log/apache2/mellon_diagnostics.log.

  Regression testing can be done using the keystone-saml-mellon charm's functional tests. 
  https://github.com/openstack-charmers/charm-keystone-saml-mellon
  At the time of this writing the functional tests are not fully automated and still require some manual configuration:
  https://github.com/openstack-charmers/charm-keystone-saml-mellon/blob/master/src/README.md#configuration

  [Regression Potential]
  As mentioned above in the FFE section, "MellonDiagnosticsEnable Off" can be set in the apache configuration to disable diagnostics. This is also the default setting, so regression potential is certainly limited by this.

  In particular the cosmic regression potential is much lower than the
  bionic potential since there is much less involved.

  For bionic please see [Discussion] below.

  [Discussion]
  ** cosmic SRU **
  For the cosmic SRU this will be a fairly straight forward and trivial update to the package to run configure with "--enable-diagnostics". Cosmic is already at version 0.14.0 which has the diagnostics support.

  ** bionic SRU **
  For the bionic SRU, things are more complicated as bionic is at version 0.13.1 which does not include diagnostics support. What I'd like to do is to update the bionic package to 0.14.0. I know this is not business as usual but I think the regression potential is minimized by updating to 0.14.0 rather than risking any missed code when cherry-picking various patches.

  For some analysis regarding updating bionic to 0.14.0, I've analyzed
  the delta between 0.13.1 and 0.14.0 and I'm seeing mostly bug fixes
  and 2 new features (1 for diagnostics support, and 1 for
  MellonSignatureMethod support). Here's the full commit summary between
  0.13.1 and 0.14.0:

  /tmp/mod_auth_mellon$ git remote -v
  origin  https://github.com/UNINETT/mod_auth_mellon (fetch)
  origin  https://github.com/UNINETT/mod_auth_mellon (push)
  /tmp/mod_auth_mellon$ git log --no-merges --date-order --pretty=oneline --format=" - [%h] %s" v0.13.1..v0.14.0
   - [29d2872] Bump version to 0.14.0.
   - [21f78ab] Add release notes for version 0.14.0.
   - [262768a] NEWS: Add consistent whitespace between releases.
   - [7bb98cf] Fix config.h.in missing in .tar.gz.
   - [aee068f] Fix typos in the user guide
   - [8abbcf9] Update User Guide on error responses and ADFS issues
   - [9b17e5c] Add MellonSignatureMethod to control signature algorithm
   - [582f283] Log SAML status response information
   - [524d558] convert README to README.md
   - [0851045] Fix consistency, grammar, and usage in user guide
   - [70e8abc] Give clear error if building with diagnostics support on old Apache
   - [15fcbf7] Fix build error on Apache 2.2.
   - [fe8b978] Add example for dual auth support.
   - [f865919] Add clarification on using info vs auth
   - [5927b5c] Fix Mellon user guide typos
   - [86eb344] Fix conditional build of auth_mellon_diagnostics.c
   - [89a3c81] Add NameID discussion to User Guide
   - [93faba4] Update log msg for Invalid Destination and Invalid Audience to show both the expected and received values.
   - [de853e1] Add user_guide to distribution, use AC_DEFINE instead of CFLAGS
   - [8d49ab6] Replace ap_log_rerror with AM_LOG_RERROR
   - [e8579f6] Add diagnostic logging
   - [6d2ee84] Track file information
   - [ee97812] Add Mellon User Guide
   - [daa5d1e] If no IdP's are defined explicitly log that fact
   - [119cbdd] modify cache functions to take request_rec parameter instead of server_rec
   - [c291232] Make MellonUser case-insensitive.
   - [2c2e19d] Fix incorrect error check for many `lasso_*`-functions.
   - [5c5ed1d] Fix segmentation fault with POST field without a value.
   - [4c924d9] Fix some log message typos

  Of the commits above, those required for diagnostics support include:
   - [582f283] Log SAML status response information
   - [70e8abc] Give clear error if building with diagnostics support on old Apache
   - [86eb344] Fix conditional build of auth_mellon_diagnostics.c
   - [8d49ab6] Replace ap_log_rerror with AM_LOG_RERROR
   - [e8579f6] Add diagnostic logging
   - [6d2ee84] Track file information

  And the MellonSignatureMethod support is provided in a single commit:
   - [9b17e5c] Add MellonSignatureMethod to control signature algorithm

  MellonSignatureMethod is also controlled by a config option in the
  apache configuration.

  Following is the full commit message for 9b17e5c:
  https://github.com/Uninett/mod_auth_mellon/commit/9b17e5c1078a9be90de1e9d03079b34ca4056e96

  One upgrade consideration coming from this patch is that it changes
  the default sha algorithm used by Mellon from rsa-sha1 to rsa-sha256.
  And as the commit says, this was done because SHA1 is no longer
  considered safe, SHA256 is now the current recommendation. This would
  likely be a good update anyway.

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