Add more configuration options for OIDC auth (#344)

* Make user claim configurable and add labels * Add `scopes` option to OIDC * Update OIDC template with `scope` from config * Return labels from token
cesanta · Mar 1, 2023 · 3a7249e · 3a7249e
1 parent 1e44729
commit 3a7249e
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Showing 4 changed files with 72 additions and 23 deletions.
diff --git a/auth_server/authn/data/oidc_auth.tmpl b/auth_server/authn/data/oidc_auth.tmpl
@@ -9,7 +9,7 @@
 <body>
   <div id="panel">
     <p>
-      <a id="login-with-oidc" href="{{.AuthEndpoint}}?response_type=code&scope=openid%20email&client_id={{.ClientId}}&redirect_uri={{.RedirectURI}}">
+      <a id="login-with-oidc" href="{{.AuthEndpoint}}?response_type=code&scope={{.Scope}}&client_id={{.ClientId}}&redirect_uri={{.RedirectURI}}">
         Login with OIDC Provider
       </a>
     </p>

diff --git a/auth_server/authn/oidc_auth.go b/auth_server/authn/oidc_auth.go
@@ -21,13 +21,14 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"golang.org/x/oauth2"
 	"html/template"
 	"io/ioutil"
 	"net/http"
 	"strings"
 	"time"
 
+	"golang.org/x/oauth2"
+
 	"github.com/coreos/go-oidc/v3/oidc"
 
 	"github.com/cesanta/glog"
@@ -52,6 +53,14 @@ type OIDCAuthConfig struct {
 	HTTPTimeout int `yaml:"http_timeout,omitempty"`
 	// the URL of the docker registry. Used to generate a full docker login command after authentication
 	RegistryURL string `yaml:"registry_url,omitempty"`
+	// --- optional ---
+	// String claim to use for the username
+	UserClaim string `yaml:"user_claim,omitempty"`
+	// --- optional ---
+	// []string to add as labels.
+	LabelsClaims []string `yaml:"labels_claims,omitempty"`
+	// --- optional ---
+	Scopes []string `yaml:"scopes,omitempty"`
 }
 
 // OIDCRefreshTokenResponse is sent by OIDC provider in response to the grant_type=refresh_token request.
@@ -66,14 +75,6 @@ type OIDCRefreshTokenResponse struct {
 	ErrorDescription string `json:"error_description,omitempty"`
 }
 
-// ProfileResponse is sent by the /userinfo endpoint or contained in the ID token.
-// We use it to validate access token and (re)verify the email address associated with it.
-type OIDCProfileResponse struct {
-	Email         string `json:"email,omitempty"`
-	VerifiedEmail bool   `json:"verified_email,omitempty"`
-	// There are more fields, but we only need email.
-}
-
 // The specific OIDC authenticator
 type OIDCAuth struct {
 	config     *OIDCAuthConfig
@@ -109,7 +110,7 @@ func NewOIDCAuth(c *OIDCAuthConfig) (*OIDCAuth, error) {
 		ClientSecret: c.ClientSecret,
 		Endpoint:     prov.Endpoint(),
 		RedirectURL:  c.RedirectURL,
-		Scopes:       []string{oidc.ScopeOpenID, "email"},
+		Scopes:       c.Scopes,
 	}
 	return &OIDCAuth{
 		config:     c,
@@ -144,11 +145,12 @@ Executes tmpl for the OIDC login page.
 */
 func (ga *OIDCAuth) doOIDCAuthPage(rw http.ResponseWriter) {
 	if err := ga.tmpl.Execute(rw, struct {
-		AuthEndpoint, RedirectURI, ClientId string
+		AuthEndpoint, RedirectURI, ClientId, Scope string
 	}{
 		AuthEndpoint: ga.provider.Endpoint().AuthURL,
 		RedirectURI:  ga.oauth.RedirectURL,
 		ClientId:     ga.oauth.ClientID,
+		Scope:        strings.Join(ga.config.Scopes, " "),
 	}); err != nil {
 		http.Error(rw, fmt.Sprintf("Template error: %s", err), http.StatusInternalServerError)
 	}
@@ -191,32 +193,47 @@ func (ga *OIDCAuth) doOIDCAuthCreateToken(rw http.ResponseWriter, code string) {
 		http.Error(rw, fmt.Sprintf("Failed to verify ID token: %s", err), http.StatusInternalServerError)
 		return
 	}
-	var prof OIDCProfileResponse
-	if err := idTok.Claims(&prof); err != nil {
-		http.Error(rw, fmt.Sprintf("Failed to get mail information from ID token: %s", err), http.StatusInternalServerError)
+	var claims map[string]interface{}
+	if err := idTok.Claims(&claims); err != nil {
+		http.Error(rw, fmt.Sprintf("Failed to get claims from ID token: %s", err), http.StatusInternalServerError)
 		return
 	}
-	if prof.Email == "" {
-		http.Error(rw, fmt.Sprintf("No mail information given in ID token"), http.StatusInternalServerError)
+	username, _ := claims[ga.config.UserClaim].(string)
+	if username == "" {
+		http.Error(rw, fmt.Sprintf("No %q claim in ID token", ga.config.UserClaim), http.StatusInternalServerError)
 		return
 	}
 
-	glog.V(2).Infof("New OIDC auth token for %s (Current time: %s, expiration time: %s)", prof.Email, time.Now().String(), tok.Expiry.String())
+	glog.V(2).Infof("New OIDC auth token for %s (Current time: %s, expiration time: %s)", username, time.Now().String(), tok.Expiry.String())
 
 	dbVal := &TokenDBValue{
 		TokenType:    tok.TokenType,
 		AccessToken:  tok.AccessToken,
 		RefreshToken: tok.RefreshToken,
 		ValidUntil:   tok.Expiry.Add(time.Duration(-30) * time.Second),
+		Labels:       ga.getLabels(claims),
 	}
-	dp, err := ga.db.StoreToken(prof.Email, dbVal, true)
+	dp, err := ga.db.StoreToken(username, dbVal, true)
 	if err != nil {
 		glog.Errorf("Failed to record server token: %s", err)
 		http.Error(rw, "Failed to record server token: %s", http.StatusInternalServerError)
 		return
 	}
 
-	ga.doOIDCAuthResultPage(rw, prof.Email, dp)
+	ga.doOIDCAuthResultPage(rw, username, dp)
+}
+
+func (ga *OIDCAuth) getLabels(claims map[string]interface{}) api.Labels {
+	labels := make(api.Labels, len(ga.config.LabelsClaims))
+	for _, claim := range ga.config.LabelsClaims {
+		values, _ := claims[claim].([]interface{})
+		for _, v := range values {
+			if str, _ := v.(string); str != "" {
+				labels[claim] = append(labels[claim], str)
+			}
+		}
+	}
+	return labels
 }
 
 /*
@@ -294,8 +311,15 @@ func (ga *OIDCAuth) validateServerToken(user string) (*TokenDBValue, error) {
 		glog.Warningf("Token for %q failed validation: %s", user, err)
 		return nil, fmt.Errorf("server token invalid: %s", err)
 	}
-	if tokUser.Email != user {
-		glog.Errorf("token for wrong user: expected %s, found %s", user, tokUser.Email)
+
+	var claims map[string]interface{}
+	if err := tokUser.Claims(&claims); err != nil {
+		glog.Errorf("error retrieving claims: %v", err)
+		return nil, fmt.Errorf("error retrieving claims: %w", err)
+	}
+	claimUsername, _ := claims[ga.config.UserClaim].(string)
+	if claimUsername != user {
+		glog.Errorf("token for wrong user: expected %s, found %s", user, claimUsername)
 		return nil, fmt.Errorf("found token for wrong user")
 	}
 	texp := v.ValidUntil.Sub(time.Now())
@@ -335,7 +359,15 @@ func (ga *OIDCAuth) Authenticate(user string, password api.PasswordString) (bool
 	} else if err != nil {
 		return false, nil, err
 	}
-	return true, nil, nil
+
+	v, err := ga.db.GetValue(user)
+	if err != nil || v == nil {
+		if err == nil {
+			err = errors.New("no db value, please sign out and sign in again")
+		}
+		return false, nil, err
+	}
+	return true, v.Labels, err
 }
 
 func (ga *OIDCAuth) Stop() {

diff --git a/auth_server/server/config.go b/auth_server/server/config.go
@@ -240,6 +240,12 @@ func validate(c *Config) error {
 		if oidc.HTTPTimeout <= 0 {
 			oidc.HTTPTimeout = 10
 		}
+		if oidc.UserClaim == "" {
+			oidc.UserClaim = "email"
+		}
+		if oidc.Scopes == nil {
+			oidc.Scopes = []string{"openid", "email"}
+		}
 	}
 	if glab := c.GitlabAuth; glab != nil {
 		if glab.ClientSecretFile != "" {

diff --git a/examples/reference.yml b/examples/reference.yml
@@ -187,6 +187,17 @@ oidc_auth:
   http_timeout: 10
   # the url of the registry where you want to login. Is used to present the full docker login command.
   registry_url: "url_of_my_beautiful_docker_registry"
+  # The claim to use for the username.
+  # Default: email
+  user_claim: email
+  # String array claims that will be used as labels.
+  label_claims:
+    - groups
+  # Default: [openid, email]
+  scopes:
+    - openid
+    - email
+
 
 # Gitlab authentication.
 # ==! NB: DO NOT ENTER YOUR Gitlab PASSWORD AT "docker login". IT WILL NOT WORK.