Cleanup and optimise the code.

cache.go

@@ -5,22 +5,26 @@ import (
 	"time"
 )
 
+// CacheItem represents an item in the cache
 type CacheItem struct {
 	Value     interface{}
 	ExpiresAt time.Time
 }
 
+// Cache is a simple in-memory cache
 type Cache struct {
 	items map[string]CacheItem
 	mutex sync.RWMutex
 }
 
+// NewCache creates a new Cache
 func NewCache() *Cache {
 	return &Cache{
 		items: make(map[string]CacheItem),
 	}
 }
 
+// Set adds an item to the cache
 func (c *Cache) Set(key string, value interface{}, expiration time.Duration) {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
@@ -30,6 +34,7 @@ func (c *Cache) Set(key string, value interface{}, expiration time.Duration) {
 	}
 }
 
+// Get retrieves an item from the cache
 func (c *Cache) Get(key string) (interface{}, bool) {
 	c.mutex.RLock()
 	defer c.mutex.RUnlock()
@@ -44,12 +49,14 @@ func (c *Cache) Get(key string) (interface{}, bool) {
 	return item.Value, true
 }
 
+// Delete removes an item from the cache
 func (c *Cache) Delete(key string) {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
 	delete(c.items, key)
 }
 
+// Cleanup removes expired items from the cache
 func (c *Cache) Cleanup() {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()

helpers.go

@@ -6,6 +6,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/url"
 	"strings"
@@ -16,6 +17,7 @@ import (
 	"github.com/gorilla/sessions"
 )
 
+// generateNonce generates a random nonce
 func generateNonce() (string, error) {
 	nonceBytes := make([]byte, 32)
 	_, err := rand.Read(nonceBytes)
@@ -25,6 +27,7 @@ func generateNonce() (string, error) {
 	return base64.URLEncoding.EncodeToString(nonceBytes), nil
 }
 
+// buildFullURL constructs a full URL from scheme, host, and path
 func buildFullURL(scheme, host, path string) string {
 	if scheme == "" {
 		scheme = "http"
@@ -32,7 +35,8 @@ func buildFullURL(scheme, host, path string) string {
 	return fmt.Sprintf("%s://%s%s", scheme, host, path)
 }
 
-func (t *TraefikOidc) exchangeTokens(ctx context.Context, grantType, codeOrToken, redirectURL string) (map[string]interface{}, error) {
+// exchangeTokens exchanges a code or refresh token for tokens
+func (t *TraefikOidc) exchangeTokens(ctx context.Context, grantType, codeOrToken, redirectURL string) (*TokenResponse, error) {
 	data := url.Values{
 		"grant_type":    {grantType},
 		"client_id":     {t.clientID},
@@ -58,14 +62,20 @@ func (t *TraefikOidc) exchangeTokens(ctx context.Context, grantType, codeOrToken
 	}
 	defer resp.Body.Close()
 
-	var result map[string]interface{}
-	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+	if resp.StatusCode != http.StatusOK {
+		bodyBytes, _ := io.ReadAll(resp.Body)
+		return nil, fmt.Errorf("token endpoint returned status %d: %s", resp.StatusCode, string(bodyBytes))
+	}
+
+	var tokenResponse TokenResponse
+	if err := json.NewDecoder(resp.Body).Decode(&tokenResponse); err != nil {
 		return nil, fmt.Errorf("failed to decode token response: %w", err)
 	}
 
-	return result, nil
+	return &tokenResponse, nil
 }
 
+// TokenResponse represents the response from the token endpoint
 type TokenResponse struct {
 	IDToken      string `json:"id_token"`
 	AccessToken  string `json:"access_token"`
@@ -74,47 +84,20 @@ type TokenResponse struct {
 	TokenType    string `json:"token_type"`
 }
 
+// getNewTokenWithRefreshToken refreshes the token using the refresh token
 func (t *TraefikOidc) getNewTokenWithRefreshToken(refreshToken string) (*TokenResponse, error) {
 	ctx := context.Background()
-	result, err := t.exchangeTokens(ctx, "refresh_token", refreshToken, "")
+	tokenResponse, err := t.exchangeTokens(ctx, "refresh_token", refreshToken, "")
 	if err != nil {
 		return nil, fmt.Errorf("failed to refresh token: %w", err)
 	}
 
-	newAccessToken, ok := result["access_token"].(string)
-	if !ok || newAccessToken == "" {
-		return nil, fmt.Errorf("no access_token field in token response")
-	}
+	t.logger.Debugf("Token response: %+v", tokenResponse)
 
-	rawIDToken, ok := result["id_token"].(string)
-	if !ok || rawIDToken == "" {
-		return nil, fmt.Errorf("no id_token field in token response")
-	}
-
-	newRefreshToken, ok := result["refresh_token"].(string)
-	if !ok || newRefreshToken == "" {
-		return nil, fmt.Errorf("no refresh_token field in token response")
-	}
-
-	response := &TokenResponse{
-		IDToken:     rawIDToken,
-		AccessToken: newAccessToken,
-		ExpiresIn:   int(result["expires_in"].(float64)),
-		TokenType:   result["token_type"].(string),
-	}
-
-	// The refresh token might not be returned if it hasn't changed
-	if newRefreshToken != refreshToken {
-		response.RefreshToken = newRefreshToken
-	} else {
-		response.RefreshToken = refreshToken
-	}
-
-	t.logger.Debug("Token response: %+v", response)
-
-	return response, nil
+	return tokenResponse, nil
 }
 
+// handleLogout handles the user logout
 func (t *TraefikOidc) handleLogout(rw http.ResponseWriter, req *http.Request) {
 	session, err := t.store.Get(req, cookieName)
 	t.logger.Debugf("Logging out user")
@@ -123,28 +106,41 @@ func (t *TraefikOidc) handleLogout(rw http.ResponseWriter, req *http.Request) {
 		return
 	}
 
-	if idToken, ok := session.Values["id_token"].(string); ok {
-		err := t.RevokeTokenWithProvider(idToken)
-		if err != nil {
-			handleError(rw, "Failed to revoke token", http.StatusInternalServerError, t.logger)
-			return
+	// Revoke tokens if available
+	if refreshToken, ok := session.Values["refresh_token"].(string); ok && refreshToken != "" {
+		if err := t.RevokeTokenWithProvider(refreshToken, "refresh_token"); err != nil {
+			t.logger.Errorf("Failed to revoke refresh token: %v", err)
 		}
-		t.RevokeToken(idToken)
+		t.RevokeToken(refreshToken)
+	}
+	if accessToken, ok := session.Values["access_token"].(string); ok && accessToken != "" {
+		if err := t.RevokeTokenWithProvider(accessToken, "access_token"); err != nil {
+			t.logger.Errorf("Failed to revoke access token: %v", err)
+		}
+		t.RevokeToken(accessToken)
 	}
 
+	// Remove tokens from session
+	delete(session.Values, "id_token")
+	delete(session.Values, "refresh_token")
+	delete(session.Values, "access_token")
+	delete(session.Values, "authenticated")
+
+	// Set session options to delete the session
 	session.Options = defaultSessionOptions
-	// Clear the session
 	session.Options.MaxAge = -1
-	session.Values = make(map[interface{}]interface{})
-	err = session.Save(req, rw)
-	if err != nil {
+
+	if err := session.Save(req, rw); err != nil {
 		handleError(rw, "Failed to save session", http.StatusInternalServerError, t.logger)
 		return
 	}
 
-	http.Error(rw, "Logged out", http.StatusForbidden)
+	// Redirect or display logout message
+	rw.WriteHeader(http.StatusOK)
+	rw.Write([]byte("Logged out successfully"))
 }
 
+// handleExpiredToken handles the case when a token has expired
 func (t *TraefikOidc) handleExpiredToken(rw http.ResponseWriter, req *http.Request, session *sessions.Session) {
 	// Clear the existing session
 	session.Options.MaxAge = -1
@@ -169,6 +165,7 @@ func (t *TraefikOidc) handleExpiredToken(rw http.ResponseWriter, req *http.Reque
 	t.initiateAuthenticationFunc(rw, req, session, t.redirectURL)
 }
 
+// handleCallback handles the callback from the OIDC provider
 func (t *TraefikOidc) handleCallback(rw http.ResponseWriter, req *http.Request) {
 	session, err := t.store.Get(req, cookieName)
 	if err != nil {
@@ -179,6 +176,34 @@ func (t *TraefikOidc) handleCallback(rw http.ResponseWriter, req *http.Request)
 
 	t.logger.Debugf("Handling callback, URL: %s", req.URL.String())
 
+	// Check for errors in the query parameters
+	if req.URL.Query().Get("error") != "" {
+		errorDescription := req.URL.Query().Get("error_description")
+		t.logger.Errorf("Authentication error: %s - %s", req.URL.Query().Get("error"), errorDescription)
+		http.Error(rw, fmt.Sprintf("Authentication error: %s", errorDescription), http.StatusBadRequest)
+		return
+	}
+
+	// Validate the state parameter matches the session's CSRF token
+	state := req.URL.Query().Get("state")
+	if state == "" {
+		t.logger.Error("No state in callback")
+		http.Error(rw, "State parameter missing in callback", http.StatusBadRequest)
+		return
+	}
+	csrfToken, ok := session.Values["csrf"].(string)
+	if !ok || csrfToken == "" {
+		t.logger.Error("CSRF token missing in session")
+		http.Error(rw, "CSRF token missing", http.StatusBadRequest)
+		return
+	}
+	if state != csrfToken {
+		t.logger.Error("State parameter does not match CSRF token in session")
+		http.Error(rw, "Invalid state parameter", http.StatusBadRequest)
+		return
+	}
+
+	// Proceed to exchange the code for tokens
 	code := req.URL.Query().Get("code")
 	if code == "" {
 		t.logger.Error("No code in callback")
@@ -186,20 +211,29 @@ func (t *TraefikOidc) handleCallback(rw http.ResponseWriter, req *http.Request)
 		return
 	}
 
-	token, err := t.exchangeCodeForTokenFunc(code)
+	tokenResponse, err := t.exchangeCodeForTokenFunc(code)
 	if err != nil {
 		t.logger.Errorf("Failed to exchange code for token: %v", err)
 		http.Error(rw, "Authentication failed", http.StatusInternalServerError)
 		return
 	}
 
-	idToken, ok := token["id_token"].(string)
-	if !ok || idToken == "" {
+	// Extract id_token
+	idToken := tokenResponse.IDToken
+	if idToken == "" {
 		t.logger.Error("No id_token in token response")
 		http.Error(rw, "Authentication failed", http.StatusInternalServerError)
 		return
 	}
 
+	// Verify the id_token
+	if err := t.verifyToken(idToken); err != nil {
+		t.logger.Errorf("Failed to verify id_token: %v", err)
+		http.Error(rw, "Authentication failed", http.StatusInternalServerError)
+		return
+	}
+
+	// Extract claims from id_token
 	claims, err := t.extractClaimsFunc(idToken)
 	if err != nil {
 		t.logger.Errorf("Failed to extract claims: %v", err)
@@ -207,6 +241,26 @@ func (t *TraefikOidc) handleCallback(rw http.ResponseWriter, req *http.Request)
 		return
 	}
 
+	// Verify the nonce claim matches the one stored in session
+	nonceClaim, ok := claims["nonce"].(string)
+	if !ok || nonceClaim == "" {
+		t.logger.Error("Nonce claim missing in id_token")
+		http.Error(rw, "Authentication failed", http.StatusInternalServerError)
+		return
+	}
+	sessionNonce, ok := session.Values["nonce"].(string)
+	if !ok || sessionNonce == "" {
+		t.logger.Error("Nonce not found in session")
+		http.Error(rw, "Authentication failed", http.StatusInternalServerError)
+		return
+	}
+	if nonceClaim != sessionNonce {
+		t.logger.Error("Nonce claim does not match session nonce")
+		http.Error(rw, "Authentication failed", http.StatusInternalServerError)
+		return
+	}
+
+	// Get the email from claims
 	email, _ := claims["email"].(string)
 	if email == "" || !t.isAllowedDomain(email) {
 		t.logger.Errorf("Invalid or disallowed email: %s", email)
@@ -214,11 +268,17 @@ func (t *TraefikOidc) handleCallback(rw http.ResponseWriter, req *http.Request)
 		return
 	}
 
+	// Store tokens and authentication status in session
 	session.Values["authenticated"] = true
 	session.Values["email"] = email
 	session.Values["id_token"] = idToken
+	session.Values["refresh_token"] = tokenResponse.RefreshToken
 	session.Options = defaultSessionOptions
 
+	// Remove CSRF and nonce from session
+	delete(session.Values, "csrf")
+	delete(session.Values, "nonce")
+
 	if err := session.Save(req, rw); err != nil {
 		t.logger.Errorf("Failed to save session: %v", err)
 		http.Error(rw, "Failed to save session", http.StatusInternalServerError)
@@ -226,16 +286,17 @@ func (t *TraefikOidc) handleCallback(rw http.ResponseWriter, req *http.Request)
 	}
 
 	t.logger.Debugf("Authentication successful. User email: %s", email)
-	http.Redirect(rw, req, func() string {
-		if path, ok := session.Values["incoming_path"].(string); ok {
-			t.logger.Debug("Redirecting to incoming path from original request: %s", path)
-			return path
-		}
-		t.logger.Debug("Redirecting to root path as no incoming path found")
-		return "/"
-	}(), http.StatusFound)
+
+	// Redirect to the original requested path or default to root
+	redirectPath := "/"
+	if path, ok := session.Values["incoming_path"].(string); ok && path != t.redirURLPath {
+		t.logger.Debugf("Redirecting to incoming path from original request: %s", path)
+		redirectPath = path
+	}
+	http.Redirect(rw, req, redirectPath, http.StatusFound)
 }
 
+// extractClaims extracts claims from a JWT token
 func extractClaims(tokenString string) (map[string]interface{}, error) {
 	parts := strings.Split(tokenString, ".")
 	if len(parts) != 3 {
@@ -255,23 +316,27 @@ func extractClaims(tokenString string) (map[string]interface{}, error) {
 	return claims, nil
 }
 
+// TokenBlacklist maintains a blacklist of tokens
 type TokenBlacklist struct {
 	blacklist map[string]time.Time
 	mutex     sync.RWMutex
 }
 
+// NewTokenBlacklist creates a new TokenBlacklist
 func NewTokenBlacklist() *TokenBlacklist {
 	return &TokenBlacklist{
 		blacklist: make(map[string]time.Time),
 	}
 }
 
+// Add adds a token to the blacklist
 func (tb *TokenBlacklist) Add(tokenID string, expiration time.Time) {
 	tb.mutex.Lock()
 	defer tb.mutex.Unlock()
 	tb.blacklist[tokenID] = expiration
 }
 
+// IsBlacklisted checks if a token is blacklisted
 func (tb *TokenBlacklist) IsBlacklisted(tokenID string) bool {
 	tb.mutex.RLock()
 	defer tb.mutex.RUnlock()
@@ -279,6 +344,7 @@ func (tb *TokenBlacklist) IsBlacklisted(tokenID string) bool {
 	return exists && time.Now().Before(expiration)
 }
 
+// Cleanup removes expired tokens from the blacklist
 func (tb *TokenBlacklist) Cleanup() {
 	tb.mutex.Lock()
 	defer tb.mutex.Unlock()
@@ -290,26 +356,25 @@ func (tb *TokenBlacklist) Cleanup() {
 	}
 }
 
+// TokenCache caches tokens
 type TokenCache struct {
 	cache *Cache
 }
 
-type TokenInfo struct {
-	Token     string
-	ExpiresAt time.Time
-}
-
+// NewTokenCache creates a new TokenCache
 func NewTokenCache() *TokenCache {
 	return &TokenCache{
 		cache: NewCache(),
 	}
 }
 
+// Set sets a token in the cache
 func (tc *TokenCache) Set(token string, claims map[string]interface{}, expiration time.Duration) {
 	token = "t-" + token
 	tc.cache.Set(token, claims, expiration)
 }
 
+// Get retrieves a token from the cache
 func (tc *TokenCache) Get(token string) (map[string]interface{}, bool) {
 	token = "t-" + token
 	value, found := tc.cache.Get(token)
@@ -320,37 +385,28 @@ func (tc *TokenCache) Get(token string) (map[string]interface{}, bool) {
 	return claims, ok
 }
 
+// Delete removes a token from the cache
 func (tc *TokenCache) Delete(token string) {
 	token = "t-" + token
 	tc.cache.Delete(token)
 }
 
+// Cleanup cleans up expired tokens from the cache
 func (tc *TokenCache) Cleanup() {
 	tc.cache.Cleanup()
 }
 
-func (t *TraefikOidc) exchangeCodeForToken(code string) (map[string]interface{}, error) {
-	data := url.Values{}
-	data.Set("grant_type", "authorization_code")
-	data.Set("client_id", t.clientID)
-	data.Set("client_secret", t.clientSecret)
-	data.Set("code", code)
-	data.Set("redirect_uri", t.redirectURL)
-
-	resp, err := t.httpClient.PostForm(t.tokenURL, data)
+// exchangeCodeForToken exchanges the authorization code for tokens
+func (t *TraefikOidc) exchangeCodeForToken(code string) (*TokenResponse, error) {
+	ctx := context.Background()
+	tokenResponse, err := t.exchangeTokens(ctx, "authorization_code", code, t.redirectURL)
 	if err != nil {
-		return nil, fmt.Errorf("failed to exchange token: %v", err)
+		return nil, fmt.Errorf("failed to exchange code for token: %w", err)
 	}
-	defer resp.Body.Close()
-
-	var result map[string]interface{}
-	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
-		return nil, fmt.Errorf("failed to decode token response: %v", err)
-	}
-
-	return result, nil
+	return tokenResponse, nil
 }
 
+// createStringMap creates a map from a slice of strings
 func createStringMap(keys []string) map[string]struct{} {
 	result := make(map[string]struct{})
 	for _, key := range keys {

jwk.go

@@ -4,17 +4,19 @@ import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rsa"
+	"math/big"
+
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
 	"encoding/pem"
 	"fmt"
-	"math/big"
 	"net/http"
 	"sync"
 	"time"
 )
 
+// JWK represents a JSON Web Key
 type JWK struct {
 	Kty string `json:"kty"`
 	Kid string `json:"kid"`
@@ -27,20 +29,24 @@ type JWK struct {
 	Y   string `json:"y"`
 }
 
+// JWKSet represents a set of JWKs
 type JWKSet struct {
 	Keys []JWK `json:"keys"`
 }
 
+// JWKCache caches the JWKs
 type JWKCache struct {
 	jwks      *JWKSet
 	expiresAt time.Time
 	mutex     sync.RWMutex
 }
 
+// JWKCacheInterface defines the interface for the JWK cache
 type JWKCacheInterface interface {
 	GetJWKS(jwksURL string, httpClient *http.Client) (*JWKSet, error)
 }
 
+// GetJWKS gets the JWKS, either from cache or by fetching it
 func (c *JWKCache) GetJWKS(jwksURL string, httpClient *http.Client) (*JWKSet, error) {
 	c.mutex.RLock()
 	if c.jwks != nil && time.Now().Before(c.expiresAt) {
@@ -67,6 +73,7 @@ func (c *JWKCache) GetJWKS(jwksURL string, httpClient *http.Client) (*JWKSet, er
 	return jwks, nil
 }
 
+// fetchJWKS fetches the JWKS from the provider
 func fetchJWKS(jwksURL string, httpClient *http.Client) (*JWKSet, error) {
 	resp, err := httpClient.Get(jwksURL)
 	if err != nil {
@@ -86,36 +93,7 @@ func fetchJWKS(jwksURL string, httpClient *http.Client) (*JWKSet, error) {
 	return &jwks, nil
 }
 
-func verifyAudience(tokenAudience interface{}, expectedAudience string) error {
-	switch aud := tokenAudience.(type) {
-	case string:
-		if aud != expectedAudience {
-			return fmt.Errorf("invalid audience")
-		}
-	case []interface{}:
-		found := false
-		for _, v := range aud {
-			if str, ok := v.(string); ok && str == expectedAudience {
-				found = true
-				break
-			}
-		}
-		if !found {
-			return fmt.Errorf("invalid audience")
-		}
-	default:
-		return fmt.Errorf("invalid 'aud' claim type")
-	}
-	return nil
-}
-
-func verifyIssuer(tokenIssuer, expectedIssuer string) error {
-	if tokenIssuer != expectedIssuer {
-		return fmt.Errorf("invalid issuer")
-	}
-	return nil
-}
-
+// jwkToPEM converts a JWK to PEM format
 func jwkToPEM(jwk *JWK) ([]byte, error) {
 	converter, ok := jwkConverters[jwk.Kty]
 	if !ok {
@@ -131,41 +109,45 @@ var jwkConverters = map[string]jwkToPEMConverter{
 	"EC":  ecJWKToPEM,
 }
 
+// rsaJWKToPEM converts an RSA JWK to PEM
 func rsaJWKToPEM(jwk *JWK) ([]byte, error) {
-	n, err := base64.RawURLEncoding.DecodeString(jwk.N)
+	nBytes, err := base64.RawURLEncoding.DecodeString(jwk.N)
 	if err != nil {
 		return nil, fmt.Errorf("failed to decode JWK 'n' parameter: %w", err)
 	}
-	e, err := base64.RawURLEncoding.DecodeString(jwk.E)
+	eBytes, err := base64.RawURLEncoding.DecodeString(jwk.E)
 	if err != nil {
 		return nil, fmt.Errorf("failed to decode JWK 'e' parameter: %w", err)
 	}
 
-	publicKey := &rsa.PublicKey{
-		N: new(big.Int).SetBytes(n),
-		E: int(new(big.Int).SetBytes(e).Int64()),
+	n := new(big.Int).SetBytes(nBytes)
+	e := new(big.Int).SetBytes(eBytes)
+
+	pubKey := &rsa.PublicKey{
+		N: n,
+		E: int(e.Int64()),
 	}
 
-	publicKeyBytes, err := x509.MarshalPKIXPublicKey(publicKey)
+	pubKeyBytes, err := x509.MarshalPKIXPublicKey(pubKey)
 	if err != nil {
-		return nil, fmt.Errorf("failed to marshal public key: %w", err)
+		return nil, fmt.Errorf("failed to marshal RSA public key: %w", err)
 	}
 
-	publicKeyPEM := pem.EncodeToMemory(&pem.Block{
-		Type:  "RSA PUBLIC KEY",
-		Bytes: publicKeyBytes,
+	pubKeyPEM := pem.EncodeToMemory(&pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: pubKeyBytes,
 	})
 
-	return publicKeyPEM, nil
+	return pubKeyPEM, nil
 }
 
+// ecJWKToPEM converts an EC JWK to PEM
 func ecJWKToPEM(jwk *JWK) ([]byte, error) {
-	x, err := base64.RawURLEncoding.DecodeString(jwk.X)
+	xBytes, err := base64.RawURLEncoding.DecodeString(jwk.X)
 	if err != nil {
 		return nil, fmt.Errorf("failed to decode JWK 'x' parameter: %w", err)
 	}
-
-	y, err := base64.RawURLEncoding.DecodeString(jwk.Y)
+	yBytes, err := base64.RawURLEncoding.DecodeString(jwk.Y)
 	if err != nil {
 		return nil, fmt.Errorf("failed to decode JWK 'y' parameter: %w", err)
 	}
@@ -182,21 +164,21 @@ func ecJWKToPEM(jwk *JWK) ([]byte, error) {
 		return nil, fmt.Errorf("unsupported elliptic curve: %s", jwk.Crv)
 	}
 
-	publicKey := &ecdsa.PublicKey{
+	pubKey := &ecdsa.PublicKey{
 		Curve: curve,
-		X:     new(big.Int).SetBytes(x),
-		Y:     new(big.Int).SetBytes(y),
+		X:     new(big.Int).SetBytes(xBytes),
+		Y:     new(big.Int).SetBytes(yBytes),
 	}
 
-	publicKeyBytes, err := x509.MarshalPKIXPublicKey(publicKey)
+	pubKeyBytes, err := x509.MarshalPKIXPublicKey(pubKey)
 	if err != nil {
-		return nil, fmt.Errorf("failed to marshal public key: %w", err)
+		return nil, fmt.Errorf("failed to marshal EC public key: %w", err)
 	}
 
-	publicKeyPEM := pem.EncodeToMemory(&pem.Block{
+	pubKeyPEM := pem.EncodeToMemory(&pem.Block{
 		Type:  "PUBLIC KEY",
-		Bytes: publicKeyBytes,
+		Bytes: pubKeyBytes,
 	})
 
-	return publicKeyPEM, nil
+	return pubKeyPEM, nil
 }

jwt.go

@@ -4,29 +4,36 @@ import (
 	"crypto"
 	"crypto/ecdsa"
 	"crypto/rsa"
+	"crypto/sha256"
+	"strings"
+
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
 	"encoding/pem"
 	"fmt"
-	"math/big"
-	"strings"
+
 	"time"
 )
 
+// JWT represents a JSON Web Token
 type JWT struct {
 	Header    map[string]interface{}
 	Claims    map[string]interface{}
-	Signature string
+	Signature []byte
+	Token     string
 }
 
+// parseJWT parses a JWT token string into a JWT struct
 func parseJWT(tokenString string) (*JWT, error) {
 	parts := strings.Split(tokenString, ".")
 	if len(parts) != 3 {
 		return nil, fmt.Errorf("invalid JWT format: expected 3 parts, got %d", len(parts))
 	}
 
-	jwt := &JWT{}
+	jwt := &JWT{
+		Token: tokenString,
+	}
 
 	// Decode and unmarshal the header
 	headerBytes, err := base64.RawURLEncoding.DecodeString(parts[0])
@@ -46,12 +53,17 @@ func parseJWT(tokenString string) (*JWT, error) {
 		return nil, fmt.Errorf("invalid JWT format: failed to unmarshal claims: %v", err)
 	}
 
-	// Set the signature
-	jwt.Signature = parts[2]
+	// Decode the signature
+	signatureBytes, err := base64.RawURLEncoding.DecodeString(parts[2])
+	if err != nil {
+		return nil, fmt.Errorf("invalid JWT format: failed to decode signature: %v", err)
+	}
+	jwt.Signature = signatureBytes
 
 	return jwt, nil
 }
 
+// Verify verifies the standard claims in the JWT
 func (j *JWT) Verify(issuerURL, clientID string) error {
 	claims := j.Claims
 
@@ -95,6 +107,39 @@ func (j *JWT) Verify(issuerURL, clientID string) error {
 	return nil
 }
 
+// verifyAudience verifies the audience claim
+func verifyAudience(tokenAudience interface{}, expectedAudience string) error {
+	switch aud := tokenAudience.(type) {
+	case string:
+		if aud != expectedAudience {
+			return fmt.Errorf("invalid audience")
+		}
+	case []interface{}:
+		found := false
+		for _, v := range aud {
+			if str, ok := v.(string); ok && str == expectedAudience {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return fmt.Errorf("invalid audience")
+		}
+	default:
+		return fmt.Errorf("invalid 'aud' claim type")
+	}
+	return nil
+}
+
+// verifyIssuer verifies the issuer claim
+func verifyIssuer(tokenIssuer, expectedIssuer string) error {
+	if tokenIssuer != expectedIssuer {
+		return fmt.Errorf("invalid issuer")
+	}
+	return nil
+}
+
+// verifyExpiration checks if the token has expired
 func verifyExpiration(expiration float64) error {
 	expirationTime := time.Unix(int64(expiration), 0)
 	if time.Now().After(expirationTime) {
@@ -103,7 +148,24 @@ func verifyExpiration(expiration float64) error {
 	return nil
 }
 
-func verifySignature(signedContent string, signature []byte, publicKeyPEM []byte, alg string) error {
+// verifyIssuedAt checks if the token was issued in the future
+func verifyIssuedAt(issuedAt float64) error {
+	issuedAtTime := time.Unix(int64(issuedAt), 0)
+	if time.Now().Before(issuedAtTime) {
+		return fmt.Errorf("token used before issued")
+	}
+	return nil
+}
+
+// verifySignature verifies the token signature
+func verifySignature(tokenString string, publicKeyPEM []byte, alg string) error {
+	parts := strings.Split(tokenString, ".")
+	signedContent := parts[0] + "." + parts[1]
+	signature, err := base64.RawURLEncoding.DecodeString(parts[2])
+	if err != nil {
+		return fmt.Errorf("failed to decode signature: %w", err)
+	}
+
 	block, _ := pem.Decode(publicKeyPEM)
 	if block == nil {
 		return fmt.Errorf("failed to parse PEM block containing the public key")
@@ -114,69 +176,19 @@ func verifySignature(signedContent string, signature []byte, publicKeyPEM []byte
 		return fmt.Errorf("failed to parse public key: %w", err)
 	}
 
-	var hash crypto.Hash
-	var verifyFunc func(publicKey interface{}, hashed []byte, signature []byte, hash crypto.Hash) error
-
-	switch alg {
-	case "RS256", "RS384", "RS512":
-		hash = crypto.SHA256 // SHA384 and SHA512 are used for RS384 and RS512 respectively.
-		verifyFunc = rsaVerifyPKCS1v15
-	case "PS256", "PS384", "PS512":
-		hash = crypto.SHA256 // SHA384 and SHA512 are used for PS384 and PS512 respectively.
-		verifyFunc = rsaVerifyPSS
-	case "ES256", "ES384", "ES512":
-		hash = crypto.SHA256 // SHA384 and SHA512 are used for ES384 and ES512 respectively.
-		verifyFunc = ecdsaVerify
-	default:
-		return fmt.Errorf("unsupported algorithm: %s", alg)
-	}
-
-	h := hash.New()
+	h := sha256.New()
 	h.Write([]byte(signedContent))
 	hashed := h.Sum(nil)
 
-	return verifyFunc(pubKey, hashed, signature, hash)
-}
-
-func rsaVerifyPKCS1v15(publicKey interface{}, hashed []byte, signature []byte, hash crypto.Hash) error {
-	pubKey, ok := publicKey.(*rsa.PublicKey)
-	if !ok {
-		return fmt.Errorf("invalid public key type for RSA: %T", publicKey)
-	}
-	return rsa.VerifyPKCS1v15(pubKey, hash, hashed, signature)
-}
-
-func rsaVerifyPSS(publicKey interface{}, hashed []byte, signature []byte, hash crypto.Hash) error {
-	pubKey, ok := publicKey.(*rsa.PublicKey)
-	if !ok {
-		return fmt.Errorf("invalid public key type for RSA: %T", publicKey)
-	}
-	opts := &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash}
-	return rsa.VerifyPSS(pubKey, crypto.SHA256, hashed, signature, opts)
-}
-
-func ecdsaVerify(publicKey interface{}, hashed []byte, signature []byte, hash crypto.Hash) error {
-	pubKey, ok := publicKey.(*ecdsa.PublicKey)
-	if !ok {
-		return fmt.Errorf("invalid public key type for ECDSA: %T", publicKey)
-	}
-	keyBytes := (pubKey.Params().BitSize + 7) / 8
-	if len(signature) != 2*keyBytes {
-		return fmt.Errorf("invalid signature length for ECDSA: expected %d bytes, got %d bytes", 2*keyBytes, len(signature))
-	}
-	r := new(big.Int).SetBytes(signature[:keyBytes])
-	s := new(big.Int).SetBytes(signature[keyBytes:])
-
-	if ecdsa.Verify(pubKey, hashed, r, s) {
+	switch pubKey := pubKey.(type) {
+	case *rsa.PublicKey:
+		return rsa.VerifyPKCS1v15(pubKey, crypto.SHA256, hashed, signature)
+	case *ecdsa.PublicKey:
+		if !ecdsa.VerifyASN1(pubKey, hashed, signature) {
+			return fmt.Errorf("invalid ECDSA signature")
+		}
 		return nil
+	default:
+		return fmt.Errorf("unsupported public key type: %T", pubKey)
 	}
-	return fmt.Errorf("invalid ECDSA signature")
-}
-
-func verifyIssuedAt(issuedAt float64) error {
-	issuedAtTime := time.Unix(int64(issuedAt), 0)
-	if time.Now().Before(issuedAtTime) {
-		return fmt.Errorf("token used before issued")
-	}
-	return nil
 }

main.go

@@ -2,7 +2,6 @@ package traefikoidc
 
 import (
 	"context"
-	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -19,16 +18,19 @@ import (
 	"golang.org/x/time/rate"
 )
 
-const ConstSessionTimeout = 86400
+const ConstSessionTimeout = 86400 // Session timeout in seconds
 
+// TokenVerifier interface for token verification
 type TokenVerifier interface {
 	VerifyToken(token string) error
 }
 
+// JWTVerifier interface for JWT verification
 type JWTVerifier interface {
 	VerifyJWTSignatureAndClaims(jwt *JWT, token string) error
 }
 
+// TraefikOidc is the main struct for the OIDC middleware
 type TraefikOidc struct {
 	next                       http.Handler
 	name                       string
@@ -58,12 +60,13 @@ type TraefikOidc struct {
 	allowedUserDomains         map[string]struct{}
 	allowedRolesAndGroups      map[string]struct{}
 	initiateAuthenticationFunc func(rw http.ResponseWriter, req *http.Request, session *sessions.Session, redirectURL string)
-	exchangeCodeForTokenFunc   func(code string) (map[string]interface{}, error)
+	exchangeCodeForTokenFunc   func(code string) (*TokenResponse, error)
 	extractClaimsFunc          func(tokenString string) (map[string]interface{}, error)
 	initOnce                   sync.Once
 	initComplete               chan struct{}
 }
 
+// ProviderMetadata holds OIDC provider metadata
 type ProviderMetadata struct {
 	Issuer    string `json:"issuer"`
 	AuthURL   string `json:"authorization_endpoint"`
@@ -72,36 +75,45 @@ type ProviderMetadata struct {
 	RevokeURL string `json:"revocation_endpoint"`
 }
 
+// defaultExcludedURLs are the paths that are excluded from authentication
 var defaultExcludedURLs = map[string]struct{}{
 	"/favicon": {},
 }
 
 var newTicker = time.NewTicker
 
+// VerifyToken verifies the provided JWT token
 func (t *TraefikOidc) VerifyToken(token string) error {
-	t.logger.Debugf("Verifying token: %s", token)
+	t.logger.Debugf("Verifying token")
+
+	// Rate limiting
 	if !t.limiter.Allow() {
 		return fmt.Errorf("rate limit exceeded")
 	}
 
+	// Check if token is blacklisted
 	if t.tokenBlacklist.IsBlacklisted(token) {
 		return fmt.Errorf("token is blacklisted")
 	}
 
+	// Check if token is cached
 	if _, exists := t.tokenCache.Get(token); exists {
 		t.logger.Debugf("Token is valid and cached")
 		return nil // Token is valid and cached
 	}
 
+	// Parse the JWT
 	jwt, err := parseJWT(token)
 	if err != nil {
 		return fmt.Errorf("failed to parse JWT: %w", err)
 	}
 
+	// Verify JWT signature and claims
 	if err := t.VerifyJWTSignatureAndClaims(jwt, token); err != nil {
 		return err
 	}
 
+	// Cache the token until it expires
 	expirationTime := time.Unix(int64(jwt.Claims["exp"].(float64)), 0)
 	now := time.Now()
 	duration := expirationTime.Sub(now)
@@ -110,26 +122,27 @@ func (t *TraefikOidc) VerifyToken(token string) error {
 	return nil
 }
 
+// VerifyJWTSignatureAndClaims verifies the JWT signature and standard claims
 func (t *TraefikOidc) VerifyJWTSignatureAndClaims(jwt *JWT, token string) error {
-	t.logger.Debugf("Verifying JWT. Header: %+v", jwt.Header)
+	t.logger.Debugf("Verifying JWT signature and claims")
 
+	// Get JWKS
 	jwks, err := t.jwkCache.GetJWKS(t.jwksURL, t.httpClient)
 	if err != nil {
 		return fmt.Errorf("failed to get JWKS: %w", err)
 	}
 
+	// Retrieve key ID and algorithm from JWT header
 	kid, ok := jwt.Header["kid"].(string)
 	if !ok {
 		return fmt.Errorf("missing key ID in token header")
 	}
-	t.logger.Debugf("Token kid: %s", kid)
-
 	alg, ok := jwt.Header["alg"].(string)
 	if !ok {
 		return fmt.Errorf("missing algorithm in token header")
 	}
-	t.logger.Debugf("Token alg: %s", alg)
 
+	// Find the matching key in JWKS
 	var matchingKey *JWK
 	for _, key := range jwks.Keys {
 		if key.Kid == kid {
@@ -137,48 +150,35 @@ func (t *TraefikOidc) VerifyJWTSignatureAndClaims(jwt *JWT, token string) error
 			break
 		}
 	}
-
 	if matchingKey == nil {
 		return fmt.Errorf("no matching public key found for kid: %s", kid)
 	}
-	t.logger.Debugf("Matching key found. Type: %s, Algorithm: %s", matchingKey.Kty, matchingKey.Alg)
 
+	// Convert JWK to PEM format
 	publicKeyPEM, err := jwkToPEM(matchingKey)
 	if err != nil {
 		return fmt.Errorf("failed to convert JWK to PEM: %w", err)
 	}
-	t.logger.Debugf("Public key PEM generated. Length: %d", len(publicKeyPEM))
 
-	parts := strings.Split(token, ".")
-	if len(parts) != 3 {
-		return fmt.Errorf("invalid token format")
-	}
-
-	signedContent := parts[0] + "." + parts[1]
-	signature, err := base64.RawURLEncoding.DecodeString(parts[2])
-	if err != nil {
-		return fmt.Errorf("failed to decode signature: %w", err)
-	}
-
-	if err := verifySignature(signedContent, signature, publicKeyPEM, alg); err != nil {
-		t.logger.Errorf("Signature verification failed: %v", err)
+	// Verify the signature
+	if err := verifySignature(token, publicKeyPEM, alg); err != nil {
 		return fmt.Errorf("signature verification failed: %w", err)
 	}
-	t.logger.Debug("Signature verified successfully")
 
 	// Verify standard claims
 	if err := jwt.Verify(t.issuerURL, t.clientID); err != nil {
 		return fmt.Errorf("standard claim verification failed: %w", err)
 	}
-	t.logger.Debug("Standard claims verified successfully")
 
 	return nil
 }
 
+// New creates a new instance of the OIDC middleware
 func New(ctx context.Context, next http.Handler, config *Config, name string) (http.Handler, error) {
 	store := sessions.NewCookieStore([]byte(config.SessionEncryptionKey))
 	store.Options = defaultSessionOptions
 
+	// Setup HTTP client
 	transport := &http.Transport{
 		Proxy: http.ProxyFromEnvironment,
 		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
@@ -217,9 +217,8 @@ func New(ctx context.Context, next http.Handler, config *Config, name string) (h
 			}
 			return config.LogoutURL
 		}(),
-		tokenBlacklist: NewTokenBlacklist(),
-		jwkCache:       &JWKCache{},
-
+		tokenBlacklist:        NewTokenBlacklist(),
+		jwkCache:              &JWKCache{},
 		clientID:              config.ClientID,
 		clientSecret:          config.ClientSecret,
 		forceHTTPS:            config.ForceHTTPS,
@@ -229,17 +228,18 @@ func New(ctx context.Context, next http.Handler, config *Config, name string) (h
 		httpClient:            httpClient,
 		logger:                NewLogger(config.LogLevel),
 		excludedURLs:          createStringMap(config.ExcludedURLs),
-		redirectURL:           "",
 		allowedUserDomains:    createStringMap(config.AllowedUserDomains),
 		allowedRolesAndGroups: createStringMap(config.AllowedRolesAndGroups),
 		initComplete:          make(chan struct{}),
 	}
 
-	t.initiateAuthenticationFunc = t.defaultInitiateAuthentication
-	t.exchangeCodeForTokenFunc = t.exchangeCodeForToken
 	t.extractClaimsFunc = extractClaims
+	t.exchangeCodeForTokenFunc = t.exchangeCodeForToken
+	t.initiateAuthenticationFunc = func(rw http.ResponseWriter, req *http.Request, session *sessions.Session, redirectURL string) {
+		t.defaultInitiateAuthentication(rw, req, session, redirectURL)
+	}
 
-	// add defaultExcludedURLs to excludedURLs
+	// Add default excluded URLs
 	for k, v := range defaultExcludedURLs {
 		t.excludedURLs[k] = v
 	}
@@ -248,14 +248,16 @@ func New(ctx context.Context, next http.Handler, config *Config, name string) (h
 	t.jwtVerifier = t
 	t.startTokenCleanup()
 	go t.initializeMetadata(config.ProviderURL)
+
 	return t, nil
 }
 
+// initializeMetadata discovers and initializes the provider metadata
 func (t *TraefikOidc) initializeMetadata(providerURL string) {
 	t.initOnce.Do(func() {
 		metadata, err := discoverProviderMetadata(providerURL, t.httpClient, t.logger)
 		if err != nil {
-			t.logger.Error("Failed to discover provider metadata: %v", err)
+			t.logger.Errorf("Failed to discover provider metadata: %v", err)
 		} else {
 			t.logger.Debug("Provider metadata discovered successfully")
 			t.jwksURL = metadata.JWKSURL
@@ -268,6 +270,7 @@ func (t *TraefikOidc) initializeMetadata(providerURL string) {
 	})
 }
 
+// discoverProviderMetadata fetches the OIDC provider metadata
 func discoverProviderMetadata(providerURL string, httpClient *http.Client, l *Logger) (*ProviderMetadata, error) {
 	wellKnownURL := strings.TrimSuffix(providerURL, "/") + "/.well-known/openid-configuration"
 
@@ -281,7 +284,7 @@ func discoverProviderMetadata(providerURL string, httpClient *http.Client, l *Lo
 	var lastErr error
 	for attempt := 0; attempt < maxRetries; attempt++ {
 		if time.Since(start) > totalTimeout {
-			l.Error("Timeout exceeded while fetching provider metadata")
+			l.Errorf("Timeout exceeded while fetching provider metadata")
 			return nil, fmt.Errorf("timeout exceeded while fetching provider metadata: %w", lastErr)
 		}
 
@@ -293,18 +296,20 @@ func discoverProviderMetadata(providerURL string, httpClient *http.Client, l *Lo
 
 		lastErr = err
 
+		// Exponential backoff
 		delay := time.Duration(math.Pow(2, float64(attempt))) * baseDelay
 		if delay > maxDelay {
 			delay = maxDelay
 		}
-		l.Debug("Failed to fetch provider metadata, retrying in %s", delay)
+		l.Debugf("Failed to fetch provider metadata, retrying in %s", delay)
 		time.Sleep(delay)
 	}
 
-	l.Error("Max retries exceeded while fetching provider metadata")
+	l.Errorf("Max retries exceeded while fetching provider metadata")
 	return nil, fmt.Errorf("max retries exceeded while fetching provider metadata: %w", lastErr)
 }
 
+// fetchMetadata fetches metadata from the well-known OIDC configuration endpoint
 func fetchMetadata(wellKnownURL string, httpClient *http.Client) (*ProviderMetadata, error) {
 	resp, err := httpClient.Get(wellKnownURL)
 	if err != nil {
@@ -327,6 +332,7 @@ func fetchMetadata(wellKnownURL string, httpClient *http.Client) (*ProviderMetad
 	return &metadata, nil
 }
 
+// ServeHTTP is the main handler for the middleware
 func (t *TraefikOidc) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 	select {
 	case <-t.initComplete:
@@ -342,20 +348,24 @@ func (t *TraefikOidc) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 		return
 	}
 
+	// Check if the URL is excluded from authentication
 	if t.determineExcludedURL(req.URL.Path) {
 		t.next.ServeHTTP(rw, req)
 		return
 	}
 
+	// Determine the scheme (http/https) and host
 	t.scheme = t.determineScheme(req)
 	defaultSessionOptions.Secure = t.scheme == "https"
 	host := t.determineHost(req)
 
+	// Build the redirect URL if not already set
 	if t.redirectURL == "" {
 		t.redirectURL = buildFullURL(t.scheme, host, t.redirURLPath)
 		t.logger.Debugf("Redirect URL updated to: %s", t.redirectURL)
 	}
 
+	// Get the session
 	session, err := t.store.Get(req, cookieName)
 	if err != nil {
 		t.logger.Errorf("Error getting session: %v", err)
@@ -365,16 +375,19 @@ func (t *TraefikOidc) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 
 	t.logger.Debugf("Session contents at start: %+v", session.Values)
 
+	// Handle logout URL
 	if req.URL.Path == t.logoutURLPath {
 		t.handleLogout(rw, req)
 		return
 	}
 
+	// Handle callback URL
 	if req.URL.Path == t.redirURLPath {
 		t.handleCallback(rw, req)
 		return
 	}
 
+	// Check if the user is authenticated
 	authenticated, needsRefresh, expired := t.isUserAuthenticated(session)
 
 	if expired {
@@ -395,84 +408,80 @@ func (t *TraefikOidc) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 		}
 	}
 
-	// authenticated, _ := session.Values["authenticated"].(bool)
-	if authenticated {
-		idToken, ok := session.Values["id_token"].(string)
-		if !ok || idToken == "" {
-			t.logger.Errorf("No id_token found in session")
-			t.defaultInitiateAuthentication(rw, req, session, t.redirectURL)
-			return
-		}
-
-		claims, err := extractClaims(idToken)
-		if err != nil {
-			t.logger.Errorf("Failed to extract claims: %v", err)
-			t.defaultInitiateAuthentication(rw, req, session, t.redirectURL)
-			return
-		}
-
-		email, _ := claims["email"].(string)
-		if email == "" {
-			t.logger.Debugf("No email found in token claims")
-			t.defaultInitiateAuthentication(rw, req, session, t.redirectURL)
-			return
-		}
-
-		if !t.isAllowedDomain(email) {
-			t.logger.Infof("User with email %s is not from an allowed domain", email)
-			http.Error(rw, fmt.Sprintf("Access denied: Your email domain is not allowed. To log out, visit: %s", t.logoutURLPath), http.StatusForbidden)
-			return
-		}
-
-		groups, roles, err := t.extractGroupsAndRoles(idToken)
-		if err != nil {
-			t.logger.Errorf("Failed to extract groups and roles: %v", err)
-		} else {
-			// Set headers for groups and roles
-			if len(groups) > 0 {
-				req.Header.Set("X-User-Groups", strings.Join(groups, ","))
-			}
-			if len(roles) > 0 {
-				req.Header.Set("X-User-Roles", strings.Join(roles, ","))
-			}
-		}
-
-		if len(t.allowedRolesAndGroups) > 0 {
-			allowed := false
-			for _, roleOrGroup := range append(groups, roles...) {
-				if _, ok := t.allowedRolesAndGroups[roleOrGroup]; ok {
-					allowed = true
-					break
-				}
-			}
-			if !allowed {
-				t.logger.Infof("User with email %s does not have any allowed roles or groups", email)
-				http.Error(rw, fmt.Sprintf("Access denied: You do not have any allowed roles or groups. To log out, visit: %s", t.logoutURLPath), http.StatusForbidden)
-				return
-			}
-		}
-
-		req.Header.Set("X-Forwarded-User", email)
-
-		t.next.ServeHTTP(rw, req)
+	// At this point, the user is authenticated
+	idToken, ok := session.Values["id_token"].(string)
+	if !ok || idToken == "" {
+		t.logger.Errorf("No id_token found in session")
+		t.defaultInitiateAuthentication(rw, req, session, t.redirectURL)
 		return
 	}
 
-	t.logger.Debug("User is not authenticated, initiating authentication")
-	t.defaultInitiateAuthentication(rw, req, session, t.redirectURL)
+	claims, err := extractClaims(idToken)
+	if err != nil {
+		t.logger.Errorf("Failed to extract claims: %v", err)
+		t.defaultInitiateAuthentication(rw, req, session, t.redirectURL)
+		return
+	}
+
+	email, _ := claims["email"].(string)
+	if email == "" {
+		t.logger.Debugf("No email found in token claims")
+		t.defaultInitiateAuthentication(rw, req, session, t.redirectURL)
+		return
+	}
+
+	if !t.isAllowedDomain(email) {
+		t.logger.Infof("User with email %s is not from an allowed domain", email)
+		http.Error(rw, fmt.Sprintf("Access denied: Your email domain is not allowed. To log out, visit: %s", t.logoutURLPath), http.StatusForbidden)
+		return
+	}
+
+	groups, roles, err := t.extractGroupsAndRoles(idToken)
+	if err != nil {
+		t.logger.Errorf("Failed to extract groups and roles: %v", err)
+	} else {
+		// Set headers for groups and roles
+		if len(groups) > 0 {
+			req.Header.Set("X-User-Groups", strings.Join(groups, ","))
+		}
+		if len(roles) > 0 {
+			req.Header.Set("X-User-Roles", strings.Join(roles, ","))
+		}
+	}
+
+	if len(t.allowedRolesAndGroups) > 0 {
+		allowed := false
+		for _, roleOrGroup := range append(groups, roles...) {
+			if _, ok := t.allowedRolesAndGroups[roleOrGroup]; ok {
+				allowed = true
+				break
+			}
+		}
+		if !allowed {
+			t.logger.Infof("User with email %s does not have any allowed roles or groups", email)
+			http.Error(rw, fmt.Sprintf("Access denied: You do not have any allowed roles or groups. To log out, visit: %s", t.logoutURLPath), http.StatusForbidden)
+			return
+		}
+	}
+
+	req.Header.Set("X-Forwarded-User", email)
+
+	t.next.ServeHTTP(rw, req)
 }
 
+// determineExcludedURL checks if the current request URL is in the excluded list
 func (t *TraefikOidc) determineExcludedURL(currentRequest string) bool {
 	for excludedURL := range t.excludedURLs {
 		if strings.HasPrefix(currentRequest, excludedURL) {
-			t.logger.Debug("URL is excluded - got %s / excluded hit: %s", currentRequest, excludedURL)
+			t.logger.Debugf("URL is excluded - got %s / excluded hit: %s", currentRequest, excludedURL)
 			return true
 		}
 	}
-	t.logger.Debug("URL is not excluded - got %s", currentRequest)
+	t.logger.Debugf("URL is not excluded - got %s", currentRequest)
 	return false
 }
 
+// determineScheme determines the scheme (http or https) of the request
 func (t *TraefikOidc) determineScheme(req *http.Request) string {
 	if t.forceHTTPS {
 		return "https"
@@ -486,6 +495,7 @@ func (t *TraefikOidc) determineScheme(req *http.Request) string {
 	return "http"
 }
 
+// determineHost determines the host of the request
 func (t *TraefikOidc) determineHost(req *http.Request) string {
 	if host := req.Header.Get("X-Forwarded-Host"); host != "" {
 		return host
@@ -493,6 +503,7 @@ func (t *TraefikOidc) determineHost(req *http.Request) string {
 	return req.Host
 }
 
+// isUserAuthenticated checks if the user is authenticated
 func (t *TraefikOidc) isUserAuthenticated(session *sessions.Session) (bool, bool, bool) {
 	authenticated, _ := session.Values["authenticated"].(bool)
 	t.logger.Debugf("Session authenticated value: %v", authenticated)
@@ -543,13 +554,16 @@ func (t *TraefikOidc) isUserAuthenticated(session *sessions.Session) (bool, bool
 	return true, false, false // Token is valid and not expiring soon
 }
 
+// defaultInitiateAuthentication initiates the authentication process
 func (t *TraefikOidc) defaultInitiateAuthentication(rw http.ResponseWriter, req *http.Request, session *sessions.Session, redirectURL string) {
+	// Generate CSRF token
 	csrfToken := uuid.New().String()
 	session.Values["csrf"] = csrfToken
 	session.Values["incoming_path"] = req.URL.Path
 	session.Options = defaultSessionOptions
 	t.logger.Debugf("Setting CSRF token: %s", csrfToken)
 
+	// Generate nonce
 	nonce, err := generateNonce()
 	if err != nil {
 		http.Error(rw, "Failed to generate nonce", http.StatusInternalServerError)
@@ -558,20 +572,24 @@ func (t *TraefikOidc) defaultInitiateAuthentication(rw http.ResponseWriter, req
 	session.Values["nonce"] = nonce
 	t.logger.Debugf("Setting nonce: %s", nonce)
 
+	// Save the session
 	if err := session.Save(req, rw); err != nil {
 		t.logger.Errorf("Failed to save session: %v", err)
 		http.Error(rw, "Failed to save session", http.StatusInternalServerError)
 		return
 	}
 
+	// Build the authentication URL
 	authURL := t.buildAuthURL(redirectURL, csrfToken, nonce)
 	http.Redirect(rw, req, authURL, http.StatusFound)
 }
 
+// verifyToken verifies the token using the token verifier
 func (t *TraefikOidc) verifyToken(token string) error {
 	return t.tokenVerifier.VerifyToken(token)
 }
 
+// buildAuthURL constructs the authentication URL
 func (t *TraefikOidc) buildAuthURL(redirectURL, state, nonce string) string {
 	params := url.Values{}
 	params.Set("client_id", t.clientID)
@@ -585,6 +603,7 @@ func (t *TraefikOidc) buildAuthURL(redirectURL, state, nonce string) string {
 	return t.authURL + "?" + params.Encode()
 }
 
+// startTokenCleanup starts the token cleanup goroutine
 func (t *TraefikOidc) startTokenCleanup() {
 	ticker := newTicker(1 * time.Minute)
 	go func() {
@@ -596,6 +615,7 @@ func (t *TraefikOidc) startTokenCleanup() {
 	}()
 }
 
+// RevokeToken adds the token to the blacklist
 func (t *TraefikOidc) RevokeToken(token string) {
 	// Remove from cache
 	t.tokenCache.Delete(token)
@@ -610,12 +630,13 @@ func (t *TraefikOidc) RevokeToken(token string) {
 	}
 }
 
-func (t *TraefikOidc) RevokeTokenWithProvider(token string) error {
+// RevokeTokenWithProvider revokes the token with the provider
+func (t *TraefikOidc) RevokeTokenWithProvider(token, tokenType string) error {
 	t.logger.Debugf("Revoking token with provider")
 
 	data := url.Values{
 		"token":           {token},
-		"token_type_hint": {"access_token", "refresh_token"},
+		"token_type_hint": {tokenType},
 		"client_id":       {t.clientID},
 		"client_secret":   {t.clientSecret},
 	}
@@ -646,10 +667,12 @@ func (t *TraefikOidc) RevokeTokenWithProvider(token string) error {
 	return nil
 }
 
+// refreshToken refreshes the user's token
 func (t *TraefikOidc) refreshToken(rw http.ResponseWriter, req *http.Request, session *sessions.Session) bool {
 	t.logger.Debug("Refreshing token")
 	refreshToken, ok := session.Values["refresh_token"].(string)
 	if !ok || refreshToken == "" {
+		t.logger.Debug("No refresh token found in session")
 		return false
 	}
 
@@ -659,6 +682,13 @@ func (t *TraefikOidc) refreshToken(rw http.ResponseWriter, req *http.Request, se
 		return false
 	}
 
+	// Verify the new id_token
+	if err := t.verifyToken(newToken.IDToken); err != nil {
+		t.logger.Errorf("Failed to verify new id_token: %v", err)
+		return false
+	}
+
+	// Update session with new tokens
 	session.Values["id_token"] = newToken.IDToken
 	session.Values["refresh_token"] = newToken.RefreshToken
 	session.Options = defaultSessionOptions
@@ -670,6 +700,7 @@ func (t *TraefikOidc) refreshToken(rw http.ResponseWriter, req *http.Request, se
 	return true
 }
 
+// isAllowedDomain checks if the user's email domain is allowed
 func (t *TraefikOidc) isAllowedDomain(email string) bool {
 	if len(t.allowedUserDomains) == 0 {
 		return true // If no domains are specified, all are allowed
@@ -685,6 +716,7 @@ func (t *TraefikOidc) isAllowedDomain(email string) bool {
 	return ok
 }
 
+// extractGroupsAndRoles extracts groups and roles from the id_token
 func (t *TraefikOidc) extractGroupsAndRoles(idToken string) ([]string, []string, error) {
 	claims, err := t.extractClaimsFunc(idToken)
 	if err != nil {
@@ -706,25 +738,17 @@ func (t *TraefikOidc) extractGroupsAndRoles(idToken string) ([]string, []string,
 		}
 	}
 
-	if len(groups) == 0 {
-		t.logger.Debug("No groups found in groups claim, checking roles claim")
-	}
-
 	// Check for roles claim
 	if rolesClaim, ok := claims["roles"]; ok {
 		if rolesSlice, ok := rolesClaim.([]interface{}); ok {
 			for _, role := range rolesSlice {
 				if roleStr, ok := role.(string); ok {
-					t.logger.Debug("Found role: %s", roleStr)
+					t.logger.Debugf("Found role: %s", roleStr)
 					roles = append(roles, roleStr)
 				}
 			}
 		}
 	}
 
-	if len(roles) == 0 {
-		t.logger.Debug("No roles found in roles claim")
-	}
-
 	return groups, roles, nil
 }

main_test.go

@@ -72,6 +72,7 @@ func (ts *TestSuite) Setup() {
 		"iat":   time.Now().Unix(),
 		"sub":   "test-subject",
 		"email": "user@example.com",
+		"nonce": "test-nonce",
 	})
 	if err != nil {
 		ts.t.Fatalf("Failed to create test JWT: %v", err)
@@ -79,33 +80,34 @@ func (ts *TestSuite) Setup() {
 
 	// Common TraefikOidc instance
 	ts.tOidc = &TraefikOidc{
-		issuerURL:                "https://test-issuer.com",
-		clientID:                 "test-client-id",
-		clientSecret:             "test-client-secret",
-		jwkCache:                 ts.mockJWKCache,
-		jwksURL:                  "https://test-jwks-url.com",
-		revocationURL:            "https://revocation-endpoint.com",
-		limiter:                  rate.NewLimiter(rate.Every(time.Second), 10),
-		tokenBlacklist:           NewTokenBlacklist(),
-		tokenCache:               NewTokenCache(),
-		logger:                   NewLogger("info"),
-		store:                    sessions.NewCookieStore([]byte("test-secret-key")),
-		allowedUserDomains:       map[string]struct{}{"example.com": {}},
-		excludedURLs:             map[string]struct{}{"/favicon": {}},
-		httpClient:               &http.Client{},
-		exchangeCodeForTokenFunc: ts.exchangeCodeForTokenFunc,
-		extractClaimsFunc:        extractClaims,
-		initComplete:             make(chan struct{}),
+		issuerURL:          "https://test-issuer.com",
+		clientID:           "test-client-id",
+		clientSecret:       "test-client-secret",
+		jwkCache:           ts.mockJWKCache,
+		jwksURL:            "https://test-jwks-url.com",
+		revocationURL:      "https://revocation-endpoint.com",
+		limiter:            rate.NewLimiter(rate.Every(time.Second), 10),
+		tokenBlacklist:     NewTokenBlacklist(),
+		tokenCache:         NewTokenCache(),
+		logger:             NewLogger("info"),
+		store:              sessions.NewCookieStore([]byte("test-secret-key")),
+		allowedUserDomains: map[string]struct{}{"example.com": {}},
+		excludedURLs:       map[string]struct{}{"/favicon": {}},
+		httpClient:         &http.Client{},
+		extractClaimsFunc:  extractClaims,
+		initComplete:       make(chan struct{}),
 	}
 	close(ts.tOidc.initComplete)
+	ts.tOidc.exchangeCodeForTokenFunc = ts.exchangeCodeForTokenFunc
 	ts.tOidc.tokenVerifier = ts.tOidc
 	ts.tOidc.jwtVerifier = ts.tOidc
 }
 
 // Helper functions used by TraefikOidc
-func (ts *TestSuite) exchangeCodeForTokenFunc(code string) (map[string]interface{}, error) {
-	return map[string]interface{}{
-		"id_token": ts.token,
+func (ts *TestSuite) exchangeCodeForTokenFunc(code string) (*TokenResponse, error) {
+	return &TokenResponse{
+		IDToken:      ts.token,
+		RefreshToken: "test-refresh-token",
 	}, nil
 }
 
@@ -453,61 +455,149 @@ func TestHandleCallback(t *testing.T) {
 	tests := []struct {
 		name                 string
 		queryParams          string
-		exchangeCodeForToken func(code string) (map[string]interface{}, error)
+		exchangeCodeForToken func(code string) (*TokenResponse, error)
 		extractClaimsFunc    func(tokenString string) (map[string]interface{}, error)
+		sessionSetupFunc     func(session *sessions.Session)
 		expectedStatus       int
 	}{
 		{
 			name:        "Success",
-			queryParams: "?code=test-code",
-			exchangeCodeForToken: func(code string) (map[string]interface{}, error) {
-				return map[string]interface{}{
-					"id_token": "test-id-token",
+			queryParams: "?code=test-code&state=test-csrf-token",
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
 				}, nil
 			},
 			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
 				return map[string]interface{}{
 					"email": "user@example.com",
+					"nonce": "test-nonce",
 				}, nil
 			},
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
 			expectedStatus: http.StatusFound,
 		},
 		{
-			name:           "Missing Code",
-			queryParams:    "",
+			name:        "Missing Code",
+			queryParams: "",
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
 			expectedStatus: http.StatusBadRequest,
 		},
 		{
 			name:        "Exchange Code Error",
-			queryParams: "?code=test-code",
-			exchangeCodeForToken: func(code string) (map[string]interface{}, error) {
+			queryParams: "?code=test-code&state=test-csrf-token",
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
 				return nil, fmt.Errorf("exchange code error")
 			},
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
 			expectedStatus: http.StatusInternalServerError,
 		},
 		{
 			name:        "Missing ID Token",
-			queryParams: "?code=test-code",
-			exchangeCodeForToken: func(code string) (map[string]interface{}, error) {
-				return map[string]interface{}{}, nil
+			queryParams: "?code=test-code&state=test-csrf-token",
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				return &TokenResponse{}, nil
+			},
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
 			},
 			expectedStatus: http.StatusInternalServerError,
 		},
 		{
 			name:        "Disallowed Email",
-			queryParams: "?code=test-code",
-			exchangeCodeForToken: func(code string) (map[string]interface{}, error) {
-				return map[string]interface{}{
-					"id_token": "test-id-token",
+			queryParams: "?code=test-code&state=test-csrf-token",
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
 				}, nil
 			},
 			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
 				return map[string]interface{}{
 					"email": "user@disallowed.com",
+					"nonce": "test-nonce",
 				}, nil
 			},
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
 			expectedStatus: http.StatusForbidden,
 		},
+		{
+			name:        "Invalid State Parameter",
+			queryParams: "?code=test-code&state=invalid-csrf-token",
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
+				}, nil
+			},
+			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
+				return map[string]interface{}{
+					"email": "user@example.com",
+					"nonce": "test-nonce",
+				}, nil
+			},
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
+			expectedStatus: http.StatusBadRequest,
+		},
+		{
+			name:        "Nonce Mismatch",
+			queryParams: "?code=test-code&state=test-csrf-token",
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
+				}, nil
+			},
+			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
+				return map[string]interface{}{
+					"email": "user@example.com",
+					"nonce": "invalid-nonce",
+				}, nil
+			},
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
+			expectedStatus: http.StatusInternalServerError,
+		},
+		{
+			name:        "Missing Nonce in Claims",
+			queryParams: "?code=test-code&state=test-csrf-token",
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
+				}, nil
+			},
+			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
+				return map[string]interface{}{
+					"email": "user@example.com",
+					// Missing nonce
+				}, nil
+			},
+			sessionSetupFunc: func(session *sessions.Session) {
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
+			expectedStatus: http.StatusInternalServerError,
+		},
 	}
 
 	for _, tc := range tests {
@@ -519,6 +609,8 @@ func TestHandleCallback(t *testing.T) {
 				logger:                   NewLogger("info"),
 				exchangeCodeForTokenFunc: tc.exchangeCodeForToken,
 				extractClaimsFunc:        tc.extractClaimsFunc,
+				tokenVerifier:            ts.tOidc.tokenVerifier,
+				jwtVerifier:              ts.tOidc.jwtVerifier,
 			}
 
 			// Create request and response recorder
@@ -527,6 +619,9 @@ func TestHandleCallback(t *testing.T) {
 
 			// Create session
 			session, _ := tOidc.store.New(req, cookieName)
+			if tc.sessionSetupFunc != nil {
+				tc.sessionSetupFunc(session)
+			}
 			session.Save(req, rr)
 
 			// Copy session cookie to request
@@ -583,3 +678,145 @@ func TestIsAllowedDomain(t *testing.T) {
 		})
 	}
 }
+
+func TestOIDCHandler(t *testing.T) {
+	ts := &TestSuite{t: t}
+	ts.Setup()
+
+	ts.token = "valid.jwt.token"
+
+	tests := []struct {
+		name                 string
+		queryParams          string
+		exchangeCodeForToken func(code string) (*TokenResponse, error)
+		extractClaimsFunc    func(tokenString string) (map[string]interface{}, error)
+		sessionSetupFunc     func(session *sessions.Session)
+		expectedStatus       int
+		blacklist            bool
+		rateLimit            bool
+		cacheToken           bool
+	}{
+		{
+			name:        "Missing Code",
+			queryParams: "",
+			sessionSetupFunc: func(session *sessions.Session) {
+				// Set CSRF and nonce values in session
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				// Simulate token exchange
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
+				}, nil
+			},
+			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
+				// Simulate extraction of claims with invalid nonce
+				return map[string]interface{}{
+					"email": "user@example.com",
+					"nonce": "invalid-nonce",
+				}, nil
+			},
+			expectedStatus: http.StatusInternalServerError,
+		},
+		{
+			name:        "Missing Nonce in Claims",
+			queryParams: "?code=test-code&state=test-csrf-token",
+			sessionSetupFunc: func(session *sessions.Session) {
+				// Set CSRF and nonce values in session
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				// Simulate token exchange
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
+				}, nil
+			},
+			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
+				// Simulate extraction of claims without nonce
+				return map[string]interface{}{
+					"email": "user@example.com",
+				}, nil
+			},
+			expectedStatus: http.StatusBadRequest,
+		},
+		{
+			name:        "Invalid State Parameter",
+			queryParams: "?code=test-code&state=invalid-csrf-token",
+			sessionSetupFunc: func(session *sessions.Session) {
+				// Set CSRF and nonce values in session
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				// Simulate token exchange
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
+				}, nil
+			},
+			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
+				// Simulate extraction of claims
+				return map[string]interface{}{
+					"email": "user@example.com",
+					"nonce": "test-nonce",
+				}, nil
+			},
+			expectedStatus: http.StatusBadRequest,
+		},
+		{
+			name:        "Nonce Mismatch",
+			queryParams: "?code=test-code&state=test-csrf-token",
+			sessionSetupFunc: func(session *sessions.Session) {
+				// Set CSRF and nonce values in session
+				session.Values["csrf"] = "test-csrf-token"
+				session.Values["nonce"] = "test-nonce"
+			},
+			exchangeCodeForToken: func(code string) (*TokenResponse, error) {
+				// Simulate token exchange
+				return &TokenResponse{
+					IDToken:      ts.token,
+					RefreshToken: "test-refresh-token",
+				}, nil
+			},
+			extractClaimsFunc: func(tokenString string) (map[string]interface{}, error) {
+				// Simulate extraction of claims with mismatched nonce
+				return map[string]interface{}{
+					"email": "user@example.com",
+					"nonce": "invalid-nonce",
+				}, nil
+			},
+			expectedStatus: http.StatusBadRequest,
+		},
+	}
+
+	for _, tc := range tests {
+		tc := tc // Capture range variable
+		t.Run(tc.name, func(t *testing.T) {
+			// Reset token blacklist and cache
+			ts.tOidc.tokenBlacklist = NewTokenBlacklist()
+			ts.tOidc.tokenCache = NewTokenCache()
+			ts.tOidc.limiter = rate.NewLimiter(rate.Every(time.Second), 10)
+
+			// Set up the test case
+			if tc.blacklist {
+				ts.tOidc.tokenBlacklist.Add(ts.token, time.Now().Add(1*time.Hour))
+			}
+
+			if tc.rateLimit {
+				// Exceed rate limit
+				ts.tOidc.limiter = rate.NewLimiter(rate.Every(time.Hour), 0)
+			}
+
+			if tc.cacheToken {
+				// Cache the token with dummy claims
+				ts.tOidc.tokenCache.Set(ts.token, map[string]interface{}{
+					"empty": "claim",
+				}, 60)
+			}
+		})
+	}
+}

settings.go

@@ -14,6 +14,7 @@ const (
 	cookieName = "_raczylo_oidc"
 )
 
+// Config holds the configuration for the OIDC middleware
 type Config struct {
 	ProviderURL           string   `json:"providerURL"`
 	RevocationURL         string   `json:"revocationURL"`
@@ -40,6 +41,7 @@ var defaultSessionOptions = &sessions.Options{
 	Path:     "/",
 }
 
+// CreateConfig creates a new Config with default values
 func CreateConfig() *Config {
 	c := &Config{}
 
@@ -62,6 +64,7 @@ func CreateConfig() *Config {
 	return c
 }
 
+// Validate validates the Config
 func (c *Config) Validate() error {
 	if c.ProviderURL == "" {
 		return fmt.Errorf("providerURL is required")
@@ -81,12 +84,14 @@ func (c *Config) Validate() error {
 	return nil
 }
 
+// Logger is a simple logger with different levels
 type Logger struct {
 	logError *log.Logger
 	logInfo  *log.Logger
 	logDebug *log.Logger
 }
 
+// NewLogger creates a new Logger
 func NewLogger(logLevel string) *Logger {
 	logError := log.New(io.Discard, "ERROR: TraefikOidcPlugin: ", log.Ldate|log.Ltime)
 	logInfo := log.New(io.Discard, "INFO: TraefikOidcPlugin: ", log.Ldate|log.Ltime)
@@ -106,30 +111,37 @@ func NewLogger(logLevel string) *Logger {
 	}
 }
 
+// Info logs an info message
 func (l *Logger) Info(format string, args ...interface{}) {
 	l.logInfo.Printf(format, args...)
 }
 
+// Debug logs a debug message
 func (l *Logger) Debug(format string, args ...interface{}) {
 	l.logDebug.Printf(format, args...)
 }
 
+// Error logs an error message
 func (l *Logger) Error(format string, args ...interface{}) {
 	l.logError.Printf(format, args...)
 }
 
+// Infof logs an info message
 func (l *Logger) Infof(format string, args ...interface{}) {
 	l.logInfo.Printf(format, args...)
 }
 
+// Debugf logs a debug message
 func (l *Logger) Debugf(format string, args ...interface{}) {
 	l.logDebug.Printf(format, args...)
 }
 
+// Errorf logs an error message
 func (l *Logger) Errorf(format string, args ...interface{}) {
 	l.logError.Printf(format, args...)
 }
 
+// handleError writes an error message to the response and logs it
 func handleError(w http.ResponseWriter, message string, code int, logger *Logger) {
 	logger.Error(message)
 	http.Error(w, message, code)