Add SAML2 auth #2511

This has two components, a regular Webwork Authen module and a Mojolicious plugin for SAML2. The plugin implements a SAML2 SP using the Net::SAML2 library. Net::SAML2 claims to be compatible with many SAML2 implementations, including Shibboleth. The intent for this plugin is to replace the old Shibboleth auth that depended on the shibd service which requires Apache's mod_shib. The WeBWorK::Authen::Saml2 authen module's main purpose is to call the Saml2 plugin helper sendLoginRequest() that properly sends the user to the IdP to authenticate. There is a bypass option that allows skipping the Saml2 authen in favour of the authen module after it. So you can, for example, put Basic_TheLastOption after it allow access to the internal username/password auth. It seems to be standard for Mojolicous plugins to be located in lib/Mojolicious/Plugin, so I've put the Saml2 plugin there. Additional detail and configuration instructions can be found in lib/Mojolicious/Plugin/Saml2/README.md The Saml2 plugin will only be loaded if the corresponding conf file exists. Copy conf/authen_saml2.dist.yml to conf/authen_saml2.yml to enable it. 3 settings in the conf are crucial, the idp.metadata_url must be set to the IdP's xml metadata endpoint and a unique sp.cert & sp.signing_key pair should be generated. The example cert and signing_key must not be used for prod under any circumstances. I initially put the config in conf/mojolicious.webwork.yml under a saml2 section but seeing as how other authen modules have their own conf files, I figure it was better to follow that convention. And as there seems to be more work around the yaml config, I've made the saml2 authen conf also a yaml file. The NotYAMLConfig plugin for reading yaml conf files gave me some trouble though, as I didn't want to step on the main conf and had to read the code to figure out how to use just the load conf file functionality. The Saml2 plugin will generate its own xml metadata that can be used by the IdP for configuration. This is available at the /saml2/metadata URL under the default config. Note that endpoints are configurable as I wanted to be able to change them to match shibd endpoints. The Saml2 plugin has its own set of controllers and a router for them. The AcsPostController is the most important one as it handles the SAMLResponse that sends the user back to Webwork from the IdP. The errors aren't the most friendly unfortunately, should probably add a proper 401 error template so users don't see the more scary stacktrace one. Note that unlike shibd, attribute maps are not supported. So you probably have to replace user friendly attribute names like "studentNumber" with URN style names like "urn:mace:dir:attribute-def:studentNumber". You can check your IdP's attribute map xml for the official URN names. Some discussion about alternatives that I tried before settling on the Mojolicious plugin approach: The Saml2 as a plugin idea started after trying out Mojolicious::Plugin::SAML. Mojolicious::Plugin::SAML didn't work out in the end due to two downsides. The major one being a lack of RelayState support. RelayState is the defacto standard way for SPs to store where the user wants to go after returning from a successful auth from the IdP. This is a necessary feature for Webwork as auth to each course is handled separately and we need to know exactly what course the user wants to get into. The minor issue is that it doesn't parse the SAMLResponse attributes for you and I really didn't want to have to muck with xml parsing. Apache mod_proxy using mod_shib and shibd was another possibility. This requires passing shib params through HTTP headers via the use of the ShibUseHeaders setting. Shibboleth documentation says the ShibUseHeaders option should be avoided as they're not confident in the protections against spoofed HTTP header attacks. Running Webwork under mod_perl again so we don't need to use mod_proxy. This resulted in hard to debug issues with a few sections of async code. While I was able to 'unasync' those sections to get the thing running, it feels unmaintainable in the long run, especially if Webwork increases usage of async features.

WEBWORK_ROOT_URL definition in Dockerfiles used two colons before the port when it's supposed to be only 1. Also deleted version line from docker-compose.dist.yml, as I get a warning message that `version` is obsolete.

Mojo::Base's -strict option removed where -signature is present as it makes strict redundant. Use Mojo::JSON's functions instead of JSON. When using WeBWorK::Debug, specify import of debug() function. Remove import of WeBWorK::Debug and Data::Dumper where they're not actually being used. Fix README.md to pass markdownlint inspection.

Reformatted to follow .editorconfig rules.

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Add SAML2 auth #2511

Add SAML2 auth #2511

Commits on Aug 30, 2024