Implement generic OIDC-based authentication by lheckemann · Pull Request #1298 · NixOS/hydra

lheckemann · 2023-08-20T17:47:47Z

No description provided.

Co-Authored-By: Maximilian Bosch <maximilian@mbosch.me>

dasJ

We actually have a patch for our idam that is less generic than yours (which is why it's not upstreamed). The comments probably reflect that ;)
I do like your approach which using proper libraries a lot! Also, how testable is this?

dasJ · 2023-08-21T06:43:15Z

src/lib/Hydra/Controller/User.pm

+
+    my $after = "/" . $c->req->params->{after};
+
+    $c->res->cookies->{'after_oidc'} = {


I saw this in GitHub as well and I really don't know why we would do this. We already have a session so why not do:

$c->session->{oidc_after} = $after;

You already do this for the state (which is what GitHub is not doing right now afaik 👀)

Yes, this is just taken directly from the other auth methods. We did discuss that it should also probably be a single session variable regardless of the auth method. I'd prefer to fix this later though.

dasJ · 2023-08-21T06:44:08Z

src/lib/Hydra/Controller/User.pm

+    $c->session->{oidc_state} = $state;
+    my $redirect_url = $oidc_client->uri_to_redirect(
+        redirect_uri => $c->uri_for('/oidc-login'),
+        scope        => q{openid},


Would be nice to have this configurable

I'm not sure that's desirable: we care about the name, email and sub fields which are standard in openid, and I would very much like to avoid going further than that and requiring mapping logic.

dasJ · 2023-08-21T06:44:49Z

src/lib/Hydra/Controller/User.pm


    # Be paranoid about the email address format, since we do use it
    # in URLs.
    die "Illegal email address.\n" unless $email =~ /^[a-zA-Z0-9\.\-\_]+@[a-zA-Z0-9\.\-\_]+$/;


Unrelated: this is the absolute worst because it excludes plus-emails

dasJ · 2023-08-21T06:46:36Z

src/lib/Hydra/Controller/User.pm

+    error($c, "Email address must be verified.", 401) unless $claims->{email_verified};
+
+    doEmailLogin($self, $c, "oidc", $claims->{email}, $claims->{name} // undef, sprintf("oidc:$claims->{sub}"));
+


I think it'd be nice to have some role mapping as well because otherwise everyone has no permissions. We use:

+ my $role_mapping = $c->config->{oidc}->{role_mapping} or (); + # Give out roles + $c->user->userroles->delete; + push(@{$user_data->{groups}}, ("default")); + foreach my $group (@{$user_data->{groups}}) { + if (defined($role_mapping->{$group})) { + my $roles = $role_mapping->{$group}; + if (ref($roles) eq 'ARRAY') { + for my $mapped_role (@{$roles}) { + $c->user->userroles->create({ role => $mapped_role }); + } + } else { + $c->user->userroles->create({ role => $roles }); + } + } + }

We discussed this at length (this was what took longest by far), and came to the conclusion that this is a real can of worms, because OIDC is about authentication and identity but not authorisation. For now, our recommended approach is to manage permissions manually.

dasJ · 2023-08-21T06:47:46Z

src/lib/Hydra/Controller/User.pm

+sub oidc_login :Path('/oidc-login') Args(0) {
+    my ($self, $c) = @_;
+
+    error($c, "Logging in via OIDC is not enabled.", 404) unless $c->config->{enable_oidc_login};


Why not scope these? Something like $c>config->{oidc}->{enable}? Or even better $c->config->{oidc}->{client_id} which can be undef or defined and enable/disable oidc auth that way

dasJ · 2023-08-21T06:48:48Z

src/lib/Hydra/Controller/User.pm

+
+    doEmailLogin($self, $c, "oidc", $claims->{email}, $claims->{name} // undef, sprintf("oidc:$claims->{sub}"));
+
+    $c->res->redirect($c->uri_for($c->res->cookies->{'after_oidc'}));


Same issue as with the GitHub auth: Doesn't work. If you use the cookie (and not the session which I recommended in another comment), you need $c->req->cookies, not res

Ergh, you're right. I think it did work for some reason though.

dasJ · 2023-08-21T06:49:18Z

src/root/topbar.tt

        <div class="dropdown-divider"></div>
      [% END %]
+      [% IF c.config.enable_oidc_login %]
+        <a class="dropdown-item" href="/oidc-redirect?after=[% c.req.path %]">Sign in with OIDC</a>


Would also be nice to be able to change the name of the provider so it can be consistent in an organization.

arianvp · 2023-09-04T10:21:47Z

src/lib/Hydra/Controller/User.pm

+    $c->session->{access_token} = $token_response->access_token;
+    $c->session->{expires_at} = time() + $token_response->expires_in;
+    $c->session->{refresh_token} = $token_response->refresh_token;
+


We really ought to check the id_token and its signature here and make sure that the id_token is bound to the audience (client_id).. And then save the sub and compare it to the sub received in userinfo.

Otherwise we are vulnerable against token substitution attacks as the access token is not audience-bound.

NOTE: Due to the possibility of token substitution attacks, the UserInfo Response is not guaranteed to be about the End-User identified by the sub (subject) element of the ID Token. The sub Claim in the UserInfo Response MUST be verified to exactly match the sub Claim in the ID Token; if they do not match, the UserInfo Response values MUST NOT be used.

https://openid.net/specs/openid-connect-basic-1_0.html#UserInfo

We're not reusing the access_token long-term but still. we should use the id_token as the source of truth about the user identity. Not the userinfo response. the userinfo endpoint is there to augment the id_token given that you know and verified the sub. Not as a replacement for the id_token

ners · 2025-08-17T13:54:34Z

I would like to host Hydra in an environment where not having custom SSO is a blocker, so I am quite keen on this change. What can we do to push it through? @lheckemann if you're not working on this anymore, can I take it over?

I've rebased against master here: https://github.com/ners/hydra/tree/oidc

lheckemann · 2025-08-18T10:06:12Z

It's on my "one day" pile; if you have a bit more time pressure on it, you're very welcome to take over :)

stepbrobd · 2025-09-01T09:32:31Z

i tried using @ners's rebased patch but couldn't get role mapping to work (with kanidm)... not quite sure if its my configuration issue or the support isn't there yet?

also, kanidm is complaining about PKCE:

No PKCE code challenge was provided with client in enforced PKCE mode. | event_tag_id: 12 | o2rs.name: "hydra"

so i had to set allowInsecureClientDisablePkce = true in oauth client configuration. since i really don't know much about security side of oidc, i'm not sure if this is a big risk or not

stepbrobd · 2025-09-07T15:04:44Z

apparently i don't know how oidc role mapping work :-0
@ners resolved this for me at nixcon (nice)

example with kanidm:

services.hydra.extraConfig = ''
        enable_hydra_login = 0
        enable_oidc_login = 1
        oidc_client_id = "hydra"
        oidc_scope = "openid email profile groups"
        oidc_auth_uri = "https://kanidm.example.com/ui/oauth2"
        oidc_token_uri = "https://kanidm.example.com/oauth2/token"
        oidc_userinfo_uri = "https://kanidm.example.com/oauth2/openid/hydra/userinfo"
        include ${config.sops.secrets.hydra.path} # oidc_client_secret = ...

        <oidc_role_mapping>
          <my hydra admin role>@<kanidm tenant domain> = admin
          <my hydra admin role>@<kanidm tenant domain> = bump-to-front
          <my hydra user role>@<kanidm tenant domain> = cancel-build
          <my hydra user role>@<kanidm tenant domain> = eval-jobset
          <my hydra user role>@<kanidm tenant domain> = create-projects
          <my hydra user role>@<kanidm tenant domain> = restart-jobs
        </oidc_role_mapping>
'';

the only drawback of the current implementation is that we are missing PKCE support, otherwise patch lgtm (i can add docs if needed)

maybe this is the wrong place to approve pr since i'm testing against https://github.com/ners/hydra/tree/oidc, but i'll do it anyways

KJTsanaktsidis · 2026-01-31T07:37:17Z

I had a bit of a go at this in #1568 this weekend as well, building on this work (which was indispensable for working out how this all works - thank you!)

lheckemann and others added 2 commits August 20, 2023 19:46

Implement generic OIDC-based authentication

5c3f1b9

Co-Authored-By: Maximilian Bosch <maximilian@mbosch.me>

Set convenient variables for db access in shellHook

9a92fef

dasJ requested changes Aug 21, 2023

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arianvp reviewed Sep 4, 2023

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stepbrobd approved these changes Sep 7, 2025

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dasJ added the www hydra-www component label Jan 30, 2026

KJTsanaktsidis mentioned this pull request Jan 31, 2026

Another attempt at an OIDC integration #1568

Open

lheckemann closed this Feb 3, 2026


		my $after = "/" . $c->req->params->{after};

		$c->res->cookies->{'after_oidc'} = {

		error($c, "Email address must be verified.", 401) unless $claims->{email_verified};

		doEmailLogin($self, $c, "oidc", $claims->{email}, $claims->{name} // undef, sprintf("oidc:$claims->{sub}"));


		doEmailLogin($self, $c, "oidc", $claims->{email}, $claims->{name} // undef, sprintf("oidc:$claims->{sub}"));

		$c->res->redirect($c->uri_for($c->res->cookies->{'after_oidc'}));

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lheckemann commented Aug 18, 2025

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