Userinfo endpoint discards JWT claims

[mohammadlashkari]

Hi,
In the userinfo.go implementation, when validating JWT access tokens, the getTokenIDAndSubject() function successfully verifies the token and extracts all claims, but then only returns the JWTID and Subject, discarding the rest:

func getTokenIDAndSubject(ctx context.Context, userinfoProvider UserinfoProvider, accessToken string) (string, string, bool) {
    // ...
    accessTokenClaims, err := VerifyAccessToken[*oidc.AccessTokenClaims](ctx, accessToken, userinfoProvider.AccessTokenVerifier(ctx))
    if err != nil {
        return "", "", false
    }
    // All claims available here, but only JWTID and Subject are returned
    return accessTokenClaims.JWTID, accessTokenClaims.Subject, true
}

Then in the Userinfo() function, an empty oidc.UserInfo object is created and passed to the storage implementation:

func Userinfo(w http.ResponseWriter, r *http.Request, userinfoProvider UserinfoProvider) {
    // ...
    tokenID, subject, ok := getTokenIDAndSubject(r.Context(), userinfoProvider, accessToken)
    // ...
    info := new(oidc.UserInfo)  // Empty UserInfo with no claims
    err = userinfoProvider.Storage().SetUserinfoFromToken(r.Context(), info, tokenID, subject, r.Header.Get("origin"))
    // ...
}

This design makes it very difficult to implement Storage.SetUserinfoFromToken() for stateless JWT access tokens (tokens not stored in a database). The implementation has no access to:

• Scopes (needed to determine which claims to return)
• Client ID (needed for user data lookup and authorization)
• Custom claims embedded in the JWT

Instead of getTokenIDAndSubject(), use getTokenIDAndClaims() that preserves the verified claims and pre-populates the UserInfo object then it works well.

If this approach is incorrect, could you please explain the intended flow for implementing SetUserinfoFromToken() with stateless JWT tokens?