Guillermo Gastonandkfox1111
4f8ac5af06
The SPIRE OIDC Discovery Provider binary supports a top-level
`jwt_issuer` configuration key. When set, the provider returns that
exact string as the `issuer` field in the OIDC discovery document
(`.well-known/openid-configuration`) regardless of how the request was
routed. When unset, it derives `issuer` from the inbound HTTP Host
header. This chart did not render that key into the OIDC provider
config, leaving the discovery document Host-derived even when the
operator had a fixed issuer in mind.
Why this matters
OpenID Connect Discovery requires the discovery doc's `issuer` to be
byte-equal to the JWT `iss` claim. Conformant verifiers reject the chain
when the two differ. Production OIDC consumers routinely reach the
discovery endpoint at a URL different from the canonical issuer:
- a load balancer, ingress, or NodePort exposes the provider on an
IP or host different from the canonical issuer name;
- TLS terminates at a hostname different from the one advertised to
clients;
- the discovery URL is fetched by an internal service (e.g. the API
server in a private cluster) over a different DNS view than
external clients use;
- a pinned issuer URL is contractually required and must survive
infrastructure changes that move the actual service endpoint.
In all of these the JWT's `iss` claim is a logical, stable URL; the
discovery doc must report that same value, or downstream verifiers
reject the tokens.
Current chart behavior
The chart already has `global.spire.jwtIssuer` (and a subchart-local
`jwtIssuer`), resolved by the `spire-lib.jwt-issuer` helper to
`global.spire.jwtIssuer` -> subchart-local `jwtIssuer` ->
`https://oidc-discovery.<trustDomain>`. The spire-server subchart writes
that helper's result unconditionally as `jwt_issuer:` into the server's
config -- this controls the `iss` claim of every JWT-SVID the server
mints. In the OIDC subchart, however, the same helper was only used for
two things:
1. as the strict-mode assertion gate (fails the render when the
resolved value is the `example.org` default);
2. as the default source for `config.jwtDomain` (the Host
allow-list).
It was never written into the rendered OIDC provider configuration file.
The asymmetry means the chart shipped a structurally invalid OIDC setup
by default: the spire-server signs JWTs with `iss = <resolved issuer>`,
while the OIDC discovery endpoint advertises whatever Host header was
used to reach it. The only way to correct that today is to patch the
rendered ConfigMap out of band (`kubectl patch`, a CMP, a kustomize
post-renderer), which defeats the purpose of the chart.
Backward compatibility and behavior changes
Operators who set `global.spire.jwtIssuer` will see one additional
`jwt_issuer:` line in the rendered OIDC ConfigMap. The discovery doc's
`issuer` will start returning that pinned value instead of being
Host-derived, bringing the chain into spec compliance; this is a fix for
any spec-compliant verifier that previously rejected tokens. Operators
who only set the OIDC subchart-local `jwtIssuer` see the same fix
applied via the helper's fallback chain. Operators with nothing set will
see the new line default to `https://oidc-discovery.<trustDomain>`,
matching what the spire-server config already emits today.
Signed-off-by: Guillermo Gaston <[email protected]>
Co-authored-by: kfox1111 <[email protected]>
Note
Things to consider:
- We do not support running out of the git main branch. This is where development happens. Please use released versions via the published repo or git tags.
- All the helm charts in this repo are beta. We encourage you to try them out and contribute. The API may change as we move towards a production ready release.
SPIFFE Helm Charts
A suite of Helm Charts for standardized installations of SPIRE components in Kubernetes environments.
How to install or upgrade
You most likely want to do an integrated setup based on the spire chart. See the Instructions.
Contributing
Before contributing ensure to check our CONTRIBUTING guidelines.
LICENSE
This project is licensed under Apache License, Version 2.0.
Reporting a Vulnerability
Vulnerabilities can be reported by sending an email to [email protected]. A confirmation email will be sent to acknowledge the report within 72 hours. A second acknowledgement will be sent within 7 days when the vulnerability has been positively or negatively confirmed.