[feature] overhaul the oidc system (#961)

* [feature] overhaul the oidc system

this allows for more flexible username handling and prevents account
takeover using old email addresses

* [feature] add migration path for old OIDC users

* [feature] nicer error reporting for users

* [docs] document the new OIDC flow

* [fix] return early on oidc error

* [docs]: add comments on the finalization logic

1 files changed, 12 insertions, 4 deletions

diff --git a/internal/oidc/claims.go b/internal/oidc/claims.go
index 4ff337cfb..6f0e58ca9 100644
--- a/internal/oidc/claims.go
+++ b/internal/oidc/claims.go
@@ -18,10 +18,18 @@
 
 package oidc
 
+import "encoding/gob"
+
 // Claims represents claims as found in an id_token returned from an OIDC flow.
 type Claims struct {
-	Email         string   `json:"email"`
-	EmailVerified bool     `json:"email_verified"`
-	Groups        []string `json:"groups"`
-	Name          string   `json:"name"`
+	Sub               string   `json:"sub"`
+	Email             string   `json:"email"`
+	EmailVerified     bool     `json:"email_verified"`
+	Groups            []string `json:"groups"`
+	Name              string   `json:"name"`
+	PreferredUsername string   `json:"preferred_username"`
+}
+
+func init() {
+	gob.Register(&Claims{})
 }