OpenID Connect login (AUTH_MODE=oidc)

AUTH_MODE=local keeps the HTTP Basic authentication (unchanged default);
AUTH_MODE=oidc logs in through an OpenID Connect provider with the
authorization code flow and PKCE, standard library only: discovery,
ID token signature (RS/PS/ES) and claims checks, signed session cookie
whose key is kept in DATA_DIR. The UI gets a log out button and reloads
into the login when the session ends.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.env.example

@@ -4,9 +4,21 @@ HTTP_PORT=8080
 TZ=Europe/Paris
 # How long logs are kept (e.g. 7d, 30d, 12w, 1y)
 RETENTION=30d
-# Web UI authentication (empty = disabled)
+# Web UI authentication: local (HTTP Basic below, or none) or oidc (OpenID Connect provider)
+AUTH_MODE=local
+# local mode: user and password (empty = no authentication)
 AUTH_USER=
 AUTH_PASS=
+# oidc mode: issuer URL exactly as the provider announces it
+# (Keycloak: https://sso.example.org/realms/<realm>, Authentik: https://auth.example.org/application/o/<slug>/)
+OIDC_ISSUER=
+OIDC_CLIENT_ID=
+OIDC_CLIENT_SECRET=
+# Callback URL of logstream, to register in the provider (path free, /auth/callback recommended)
+OIDC_REDIRECT_URL=https://logs.example.org/auth/callback
+# Requested scopes (openid is always added) and session lifetime (e.g. 8h, 24h)
+OIDC_SCOPES=openid profile email
+OIDC_SESSION_TTL=12h
 # Reverse DNS: show host names instead of IP addresses (on/off)
 RDNS=on
 # DNS server used for reverse lookups (e.g. your router: 192.168.1.1). Empty = system resolver

README.fr.md

@@ -243,7 +243,44 @@ couleur, est mémorisé par navigateur.
   taper `PURGE` pour confirmer). Les tags et les paramètres sont conservés. VictoriaLogs doit
   être lancé avec `-delete.enable` (déjà présent dans `docker-compose.yml`) ; mettez
   `ALLOW_PURGE=false` pour désactiver la fonction. Toute personne qui peut ouvrir l'interface
-  peut purger : définissez `AUTH_USER` / `AUTH_PASS` si l'interface est accessible à d'autres.
+  peut purger : activez l'[authentification](#authentification) si l'interface est accessible
+  à d'autres.
+
+## Authentification
+
+`AUTH_MODE` choisit comment l'interface et l'API sont protégées (`/healthz` reste toujours ouvert) :
+
+- **`local`** (par défaut) : authentification HTTP Basic avec `AUTH_USER` / `AUTH_PASS` ; laissez-les
+  vides pour n'avoir aucune authentification (par exemple derrière un reverse proxy qui contrôle déjà).
+- **`oidc`** : connexion par un fournisseur OpenID Connect (Keycloak, Authentik, Authelia, Zitadel…),
+  flux « authorization code » avec PKCE.
+
+Pour utiliser OIDC :
+
+1. Dans le fournisseur, créez un client **confidentiel** (avec secret) pour logstream et déclarez
+   l'URL de retour `https://logs.example.org/auth/callback` (votre adresse).
+2. Dans `.env` :
+   ```bash
+   AUTH_MODE=oidc
+   OIDC_ISSUER=https://sso.example.org/realms/maison    # exactement l'« issuer » du fournisseur
+   OIDC_CLIENT_ID=logstream
+   OIDC_CLIENT_SECRET=...
+   OIDC_REDIRECT_URL=https://logs.example.org/auth/callback
+   ```
+3. `docker compose up -d`. Les logs affichent `oidc authentication enabled`, ou la raison pour
+   laquelle le fournisseur n'a pas pu être lu (issuer incorrect, injoignable…).
+
+Ouvrir l'interface renvoie vers la page de connexion du fournisseur, puis revient sur logstream.
+La session dure `OIDC_SESSION_TTL` (12 h par défaut) et survit aux redémarrages (sa clé de
+signature est dans `/data/session.key`) ; à son expiration, la page repasse par la connexion. Le
+bouton de déconnexion (en haut à droite) termine la session logstream, puis ouvre la page de
+déconnexion du fournisseur s'il en a une.
+
+Tout utilisateur accepté par le fournisseur pour ce client peut se connecter : restreignez l'accès
+dans le fournisseur (Keycloak : rôles du client ou realm dédié ; Authentik : liaisons de
+l'application). Les connexions sont écrites dans les logs de logstream (`oidc: alice logged in`).
+Avec une URL de retour en `https`, les cookies ne sont envoyés qu'en HTTPS : logstream doit être
+joint à travers un reverse proxy TLS.
 
 ## Noms d'hôtes (DNS inverse)
 
@@ -265,7 +302,13 @@ résolutions.
 | `SYSLOG_PORT` | `514` | port syslog publié sur l'hôte |
 | `HTTP_PORT` | `8080` | port de l'interface web |
 | `RETENTION` | `30d` | durée de conservation des logs dans VictoriaLogs |
-| `AUTH_USER` / `AUTH_PASS` | vide | authentification HTTP Basic pour l'interface |
+| `AUTH_MODE` | `local` | `local` (HTTP Basic) ou `oidc`, voir [Authentification](#authentification) |
+| `AUTH_USER` / `AUTH_PASS` | vide | authentification HTTP Basic pour l'interface (mode `local`) |
+| `OIDC_ISSUER` | vide | URL de l'issuer du fournisseur OpenID Connect (mode `oidc`) |
+| `OIDC_CLIENT_ID` / `OIDC_CLIENT_SECRET` | vide | client déclaré dans le fournisseur |
+| `OIDC_REDIRECT_URL` | vide | URL de retour de logstream, ex. `https://logs.example.org/auth/callback` |
+| `OIDC_SCOPES` | `openid profile email` | scopes demandés |
+| `OIDC_SESSION_TTL` | `12h` | durée de la session |
 | `RDNS` | `on` | résoudre les hôtes donnés par leur IP en noms DNS |
 | `DNS_SERVER` | vide | serveur DNS pour les résolutions inverses (`ip` ou `ip:port`) |
 | `ALLOW_PURGE` | `true` | autoriser « Supprimer tous les logs » dans les Paramètres |
@@ -322,7 +365,8 @@ Pour mettre à jour l'une d'elles :
 
 | Fichier | Contenu |
 |---|---|
-| `main.go` | configuration, démarrage, authentification |
+| `main.go` | configuration, démarrage |
+| `auth.go` | authentification : HTTP Basic ou OpenID Connect (découverte, PKCE, contrôle de l'ID token, cookie de session) |
 | `syslog.go` | écoute UDP/TCP et analyse RFC 3164 / 5424 |
 | `store.go` | insertions par lots dans VictoriaLogs et requêtes LogsQL |
 | `query.go` | traduit les filtres de l'interface en LogsQL ; filtre du direct |

README.md

@@ -219,8 +219,42 @@ remembered per browser.
 - **Data**: "Delete all logs" permanently erases every stored log (you must type
   `PURGE` to confirm). Tags and settings are kept. VictoriaLogs needs `-delete.enable`
   (already set in `docker-compose.yml`); set `ALLOW_PURGE=false` to disable the feature.
-  Anyone who can open the UI can purge: set `AUTH_USER` / `AUTH_PASS` if the UI is reachable
-  by others.
+  Anyone who can open the UI can purge: turn on [authentication](#authentication) if the UI
+  is reachable by others.
+
+## Authentication
+
+`AUTH_MODE` picks how the UI and the API are protected (`/healthz` always stays open):
+
+- **`local`** (default): HTTP Basic authentication with `AUTH_USER` / `AUTH_PASS`; leave them
+  empty to have no authentication (for instance behind a reverse proxy that already checks).
+- **`oidc`**: login through an OpenID Connect provider (Keycloak, Authentik, Authelia, Zitadel…),
+  authorization code flow with PKCE.
+
+To use OIDC:
+
+1. In the provider, create a **confidential** client (with a secret) for logstream and register
+   the redirect URL `https://logs.example.org/auth/callback` (your address).
+2. In `.env`:
+   ```bash
+   AUTH_MODE=oidc
+   OIDC_ISSUER=https://sso.example.org/realms/home      # exactly the "issuer" of the provider
+   OIDC_CLIENT_ID=logstream
+   OIDC_CLIENT_SECRET=...
+   OIDC_REDIRECT_URL=https://logs.example.org/auth/callback
+   ```
+3. `docker compose up -d`. The logs show `oidc authentication enabled`, or the reason the
+   provider could not be read (wrong issuer, unreachable…).
+
+Opening the UI sends you to the provider's login page, then back to logstream. The session
+lasts `OIDC_SESSION_TTL` (12 h by default) and survives restarts (its signing key is in
+`/data/session.key`); when it ends, the page goes through the login again. The log out button
+(top right) ends the logstream session, then opens the provider's log out page if it has one.
+
+Every user the provider accepts for this client can log in: restrict access in the provider
+(Keycloak: client roles or a dedicated realm; Authentik: application bindings). Logins are written
+in the logstream logs (`oidc: alice logged in`). With an `https` redirect URL, the cookies are
+only sent over HTTPS: logstream must be reached through a TLS reverse proxy.
 
 ## Host names (reverse DNS)
 
@@ -240,7 +274,13 @@ are only known by your router or a local DNS (Pi-hole, AdGuard, Unbound…), set
 | `SYSLOG_PORT` | `514` | syslog port published on the host |
 | `HTTP_PORT` | `8080` | web UI port |
 | `RETENTION` | `30d` | how long VictoriaLogs keeps logs |
-| `AUTH_USER` / `AUTH_PASS` | empty | HTTP Basic authentication for the UI |
+| `AUTH_MODE` | `local` | `local` (HTTP Basic) or `oidc`, see [Authentication](#authentication) |
+| `AUTH_USER` / `AUTH_PASS` | empty | HTTP Basic authentication for the UI (`local` mode) |
+| `OIDC_ISSUER` | empty | issuer URL of the OpenID Connect provider (`oidc` mode) |
+| `OIDC_CLIENT_ID` / `OIDC_CLIENT_SECRET` | empty | client registered in the provider |
+| `OIDC_REDIRECT_URL` | empty | callback URL of logstream, e.g. `https://logs.example.org/auth/callback` |
+| `OIDC_SCOPES` | `openid profile email` | requested scopes |
+| `OIDC_SESSION_TTL` | `12h` | session lifetime |
 | `RDNS` | `on` | resolve IP hosts to DNS names |
 | `DNS_SERVER` | empty | DNS server for reverse lookups (`ip` or `ip:port`) |
 | `ALLOW_PURGE` | `true` | allow "Delete all logs" in Settings |
@@ -294,7 +334,8 @@ To update one of them:
 
 | File | Contents |
 |---|---|
-| `main.go` | configuration, startup, authentication |
+| `main.go` | configuration, startup |
+| `auth.go` | authentication: HTTP Basic or OpenID Connect (discovery, PKCE, ID token checks, session cookie) |
 | `syslog.go` | UDP/TCP listeners and RFC 3164 / 5424 parsing |
 | `store.go` | batched inserts into VictoriaLogs and LogsQL queries |
 | `query.go` | turns UI filters into LogsQL; live-view filter |

auth.go

@@ -0,0 +1,631 @@
+package main
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	_ "crypto/sha512" // SHA-384/512 for RS384, ES384, RS512…
+	"crypto/subtle"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"math/big"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Web UI authentication. AUTH_MODE=local (default) keeps the optional HTTP Basic
+// authentication (AUTH_USER / AUTH_PASS); AUTH_MODE=oidc delegates the login to an
+// OpenID Connect provider (Keycloak, Authentik, Authelia…) with the authorization code
+// flow and PKCE. Only the standard library is used.
+
+const (
+	sessionCookie = "logstream_session"
+	loginCookie   = "logstream_login_" // + state: one cookie per login in progress
+	loginTTL      = 10 * time.Minute
+	clockSkew     = time.Minute
+)
+
+type authConfig struct {
+	mode         string
+	user, pass   string // local mode
+	issuer       string
+	clientID     string
+	clientSecret string
+	redirectURL  string
+	scopes       string
+	sessionTTL   time.Duration
+	dataDir      string
+}
+
+// newAuth returns the middleware that protects the UI and the API (except /healthz).
+func newAuth(c authConfig, next http.Handler) (http.Handler, error) {
+	switch strings.ToLower(c.mode) {
+	case "", "local":
+		return basicAuth(c.user, c.pass, next), nil
+	case "oidc":
+		o, err := newOIDC(c)
+		if err != nil {
+			return nil, err
+		}
+		o.next = next
+		log.Printf("oidc authentication enabled (issuer %s)", c.issuer)
+		return o, nil
+	}
+	return nil, fmt.Errorf("AUTH_MODE=%q: expected local or oidc", c.mode)
+}
+
+// basicAuth protects the UI when AUTH_USER is set (except /healthz).
+func basicAuth(user, pass string, next http.Handler) http.Handler {
+	if user == "" {
+		return next
+	}
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/healthz" {
+			next.ServeHTTP(w, r)
+			return
+		}
+		u, p, ok := r.BasicAuth()
+		if !ok ||
+			subtle.ConstantTimeCompare([]byte(u), []byte(user)) != 1 ||
+			subtle.ConstantTimeCompare([]byte(p), []byte(pass)) != 1 {
+			w.Header().Set("WWW-Authenticate", `Basic realm="logstream"`)
+			http.Error(w, "authentication required", http.StatusUnauthorized)
+			return
+		}
+		next.ServeHTTP(w, r)
+	})
+}
+
+type oidcMeta struct {
+	Issuer           string   `json:"issuer"`
+	AuthEndpoint     string   `json:"authorization_endpoint"`
+	TokenEndpoint    string   `json:"token_endpoint"`
+	JWKSURI          string   `json:"jwks_uri"`
+	EndSession       string   `json:"end_session_endpoint"`
+	TokenAuthMethods []string `json:"token_endpoint_auth_methods_supported"`
+}
+
+type OIDC struct {
+	cfg      authConfig
+	callback string // path of OIDC_REDIRECT_URL
+	secure   bool   // cookies only sent over HTTPS
+	key      []byte // signs the session and login cookies
+	client   *http.Client
+	next     http.Handler
+
+	mu     sync.Mutex
+	meta   *oidcMeta
+	keys   map[string]crypto.PublicKey
+	keysAt time.Time
+}
+
+func newOIDC(c authConfig) (*OIDC, error) {
+	var missing []string
+	for _, v := range [][2]string{
+		{"OIDC_ISSUER", c.issuer}, {"OIDC_CLIENT_ID", c.clientID},
+		{"OIDC_CLIENT_SECRET", c.clientSecret}, {"OIDC_REDIRECT_URL", c.redirectURL},
+	} {
+		if v[1] == "" {
+			missing = append(missing, v[0])
+		}
+	}
+	if len(missing) > 0 {
+		return nil, fmt.Errorf("AUTH_MODE=oidc: missing %s", strings.Join(missing, ", "))
+	}
+	ru, err := url.Parse(c.redirectURL)
+	if err != nil || ru.Host == "" || ru.Path == "" || ru.Path == "/" {
+		return nil, fmt.Errorf("OIDC_REDIRECT_URL=%q: expected a full URL such as https://logs.example.org/auth/callback", c.redirectURL)
+	}
+	if c.scopes == "" {
+		c.scopes = "openid profile email"
+	}
+	if !strings.Contains(" "+c.scopes+" ", " openid ") {
+		c.scopes = "openid " + c.scopes
+	}
+	if c.sessionTTL <= 0 {
+		c.sessionTTL = 12 * time.Hour
+	}
+	return &OIDC{
+		cfg:      c,
+		callback: ru.Path,
+		secure:   ru.Scheme == "https",
+		key:      sessionKey(c.dataDir),
+		client:   &http.Client{Timeout: 10 * time.Second},
+	}, nil
+}
+
+// checkProvider reads the provider configuration at startup so a mistake shows in the logs.
+func (o *OIDC) checkProvider() {
+	if _, err := o.discover(); err != nil {
+		log.Printf("oidc: %v", err)
+	}
+}
+
+// sessionKey is kept in DATA_DIR so sessions survive a restart.
+func sessionKey(dir string) []byte {
+	path := filepath.Join(dir, "session.key")
+	if k, err := os.ReadFile(path); err == nil && len(k) >= 32 {
+		return k
+	}
+	k := make([]byte, 32)
+	if _, err := rand.Read(k); err != nil {
+		log.Fatalf("session key: %v", err)
+	}
+	if err := os.WriteFile(path, k, 0o600); err != nil {
+		log.Printf("oidc: cannot save %s (%v): sessions end when logstream restarts", path, err)
+	}
+	return k
+}
+
+type session struct {
+	User string `json:"u"`
+	Exp  int64  `json:"e"`
+}
+
+type loginState struct {
+	Nonce    string `json:"n"`
+	Verifier string `json:"v"`
+	Return   string `json:"r"`
+	Exp      int64  `json:"e"`
+}
+
+func (o *OIDC) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	switch r.URL.Path {
+	case "/healthz":
+		o.next.ServeHTTP(w, r)
+		return
+	case o.callback:
+		o.handleCallback(w, r)
+		return
+	case "/auth/logout":
+		o.handleLogout(w, r)
+		return
+	}
+	var s session
+	if c, err := r.Cookie(sessionCookie); err == nil && o.verifyCookie(c.Value, &s) && time.Now().Unix() < s.Exp {
+		if r.URL.Path == "/auth/me" {
+			writeJSON(w, http.StatusOK, map[string]string{"mode": "oidc", "user": s.User})
+			return
+		}
+		o.next.ServeHTTP(w, r)
+		return
+	}
+	// Not logged in: pages go to the provider, API calls get a 401 that the UI turns
+	// into a reload (and so into a new login).
+	if r.Method == http.MethodGet && !strings.HasPrefix(r.URL.Path, "/api/") && r.URL.Path != "/auth/me" {
+		o.startLogin(w, r)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusUnauthorized)
+	_, _ = w.Write([]byte(`{"error":"authentication required","code":"auth"}` + "\n"))
+}
+
+func (o *OIDC) startLogin(w http.ResponseWriter, r *http.Request) {
+	meta, err := o.discover()
+	if err != nil {
+		log.Printf("oidc: %v", err)
+		http.Error(w, "identity provider unreachable, try again later", http.StatusBadGateway)
+		return
+	}
+	state, nonce, verifier := randomString(), randomString(), randomString()+randomString()
+	ret := r.URL.RequestURI()
+	if !strings.HasPrefix(ret, "/") || strings.HasPrefix(ret, "//") {
+		ret = "/"
+	}
+	http.SetCookie(w, &http.Cookie{
+		Name:     loginCookie + state,
+		Value:    o.signCookie(loginState{Nonce: nonce, Verifier: verifier, Return: ret, Exp: time.Now().Add(loginTTL).Unix()}),
+		Path:     "/",
+		MaxAge:   int(loginTTL.Seconds()),
+		HttpOnly: true,
+		Secure:   o.secure,
+		SameSite: http.SameSiteLaxMode, // sent back on the redirect from the provider
+	})
+	challenge := sha256.Sum256([]byte(verifier))
+	q := url.Values{
+		"response_type":         {"code"},
+		"client_id":             {o.cfg.clientID},
+		"redirect_uri":          {o.cfg.redirectURL},
+		"scope":                 {o.cfg.scopes},
+		"state":                 {state},
+		"nonce":                 {nonce},
+		"code_challenge":        {base64.RawURLEncoding.EncodeToString(challenge[:])},
+		"code_challenge_method": {"S256"},
+	}
+	http.Redirect(w, r, addQuery(meta.AuthEndpoint, q), http.StatusFound)
+}
+
+func (o *OIDC) handleCallback(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	if e := q.Get("error"); e != "" {
+		log.Printf("oidc: login refused by the provider: %s %s", e, q.Get("error_description"))
+		http.Error(w, "login refused by the identity provider: "+e, http.StatusForbidden)
+		return
+	}
+	state := q.Get("state")
+	var ls loginState
+	c, err := r.Cookie(loginCookie + state)
+	if state == "" || err != nil || !o.verifyCookie(c.Value, &ls) || time.Now().Unix() > ls.Exp {
+		http.Error(w, "login expired or started in another browser: open logstream again", http.StatusBadRequest)
+		return
+	}
+	http.SetCookie(w, &http.Cookie{Name: loginCookie + state, Path: "/", MaxAge: -1, HttpOnly: true, Secure: o.secure})
+
+	user, err := o.exchange(r, q.Get("code"), ls)
+	if err != nil {
+		log.Printf("oidc: login failed: %v", err)
+		http.Error(w, "login failed, see the logstream logs", http.StatusForbidden)
+		return
+	}
+	log.Printf("oidc: %s logged in", user)
+	http.SetCookie(w, &http.Cookie{
+		Name:     sessionCookie,
+		Value:    o.signCookie(session{User: user, Exp: time.Now().Add(o.cfg.sessionTTL).Unix()}),
+		Path:     "/",
+		MaxAge:   int(o.cfg.sessionTTL.Seconds()),
+		HttpOnly: true,
+		Secure:   o.secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+	http.Redirect(w, r, ls.Return, http.StatusFound)
+}
+
+// The session ends here; the provider's own session ends on its logout page if it has one.
+func (o *OIDC) handleLogout(w http.ResponseWriter, r *http.Request) {
+	http.SetCookie(w, &http.Cookie{Name: sessionCookie, Path: "/", MaxAge: -1, HttpOnly: true, Secure: o.secure})
+	if meta, err := o.discover(); err == nil && meta.EndSession != "" {
+		http.Redirect(w, r, addQuery(meta.EndSession, url.Values{"client_id": {o.cfg.clientID}}), http.StatusFound)
+		return
+	}
+	http.Redirect(w, r, "/", http.StatusFound)
+}
+
+// exchange trades the code for tokens and returns the user name from the verified ID token.
+func (o *OIDC) exchange(r *http.Request, code string, ls loginState) (string, error) {
+	if code == "" {
+		return "", errors.New("no code in the callback")
+	}
+	meta, err := o.discover()
+	if err != nil {
+		return "", err
+	}
+	form := url.Values{
+		"grant_type":    {"authorization_code"},
+		"code":          {code},
+		"redirect_uri":  {o.cfg.redirectURL},
+		"code_verifier": {ls.Verifier},
+	}
+	// client_secret_basic is the default; some providers only accept client_secret_post.
+	post := len(meta.TokenAuthMethods) > 0 && !contains(meta.TokenAuthMethods, "client_secret_basic") && contains(meta.TokenAuthMethods, "client_secret_post")
+	if post {
+		form.Set("client_id", o.cfg.clientID)
+		form.Set("client_secret", o.cfg.clientSecret)
+	}
+	req, err := http.NewRequestWithContext(r.Context(), http.MethodPost, meta.TokenEndpoint, strings.NewReader(form.Encode()))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.Header.Set("Accept", "application/json")
+	if !post {
+		req.SetBasicAuth(url.QueryEscape(o.cfg.clientID), url.QueryEscape(o.cfg.clientSecret))
+	}
+	res, err := o.client.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("token endpoint: %w", err)
+	}
+	defer res.Body.Close()
+	body, _ := io.ReadAll(io.LimitReader(res.Body, 1<<20))
+	if res.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("token endpoint: %s: %s", res.Status, bytes.TrimSpace(body))
+	}
+	var tok struct {
+		IDToken string `json:"id_token"`
+	}
+	if err := json.Unmarshal(body, &tok); err != nil || tok.IDToken == "" {
+		return "", errors.New("token endpoint: no id_token in the response")
+	}
+	claims, err := o.verifyIDToken(tok.IDToken, ls.Nonce)
+	if err != nil {
+		return "", err
+	}
+	for _, k := range []string{"preferred_username", "email", "name", "sub"} {
+		if v, _ := claims[k].(string); v != "" {
+			return v, nil
+		}
+	}
+	return "", errors.New("id_token: no sub")
+}
+
+// verifyIDToken checks the signature (keys from jwks_uri) and the claims of an ID token.
+func (o *OIDC) verifyIDToken(raw, nonce string) (map[string]any, error) {
+	parts := strings.Split(raw, ".")
+	if len(parts) != 3 {
+		return nil, errors.New("id_token: not a JWT")
+	}
+	var hdr struct {
+		Alg string `json:"alg"`
+		Kid string `json:"kid"`
+	}
+	if err := decodeSegment(parts[0], &hdr); err != nil {
+		return nil, fmt.Errorf("id_token header: %w", err)
+	}
+	sig, err := base64.RawURLEncoding.DecodeString(parts[2])
+	if err != nil {
+		return nil, errors.New("id_token: bad signature encoding")
+	}
+	key, err := o.keyFor(hdr.Kid)
+	if err != nil {
+		return nil, err
+	}
+	if err := verifySignature(hdr.Alg, key, []byte(parts[0]+"."+parts[1]), sig); err != nil {
+		return nil, fmt.Errorf("id_token: %w", err)
+	}
+	var claims map[string]any
+	if err := decodeSegment(parts[1], &claims); err != nil {
+		return nil, fmt.Errorf("id_token claims: %w", err)
+	}
+	if iss, _ := claims["iss"].(string); iss != o.cfg.issuer {
+		return nil, fmt.Errorf("id_token: issuer %q, expected %q", iss, o.cfg.issuer)
+	}
+	var aud []string
+	switch v := claims["aud"].(type) {
+	case string:
+		aud = []string{v}
+	case []any:
+		for _, a := range v {
+			if s, ok := a.(string); ok {
+				aud = append(aud, s)
+			}
+		}
+	}
+	if !contains(aud, o.cfg.clientID) {
+		return nil, fmt.Errorf("id_token: audience %v does not include %q", aud, o.cfg.clientID)
+	}
+	if azp, ok := claims["azp"].(string); ok && len(aud) > 1 && azp != o.cfg.clientID {
+		return nil, fmt.Errorf("id_token: azp %q", azp)
+	}
+	now := time.Now()
+	exp, _ := claims["exp"].(float64)
+	if exp == 0 || now.After(time.Unix(int64(exp), 0).Add(clockSkew)) {
+		return nil, errors.New("id_token: expired (check the clocks)")
+	}
+	if iat, ok := claims["iat"].(float64); ok && time.Unix(int64(iat), 0).After(now.Add(clockSkew)) {
+		return nil, errors.New("id_token: issued in the future (check the clocks)")
+	}
+	if n, _ := claims["nonce"].(string); subtle.ConstantTimeCompare([]byte(n), []byte(nonce)) != 1 {
+		return nil, errors.New("id_token: wrong nonce")
+	}
+	return claims, nil
+}
+
+func verifySignature(alg string, key crypto.PublicKey, signed, sig []byte) error {
+	if len(alg) != 5 {
+		return fmt.Errorf("unsupported algorithm %q", alg)
+	}
+	var h crypto.Hash
+	switch alg[2:] {
+	case "256":
+		h = crypto.SHA256
+	case "384":
+		h = crypto.SHA384
+	case "512":
+		h = crypto.SHA512
+	}
+	if h == 0 {
+		return fmt.Errorf("unsupported algorithm %q", alg)
+	}
+	hh := h.New()
+	hh.Write(signed)
+	digest := hh.Sum(nil)
+	switch k := key.(type) {
+	case *rsa.PublicKey:
+		switch alg[:2] {
+		case "RS":
+			return rsa.VerifyPKCS1v15(k, h, digest, sig)
+		case "PS":
+			return rsa.VerifyPSS(k, h, digest, sig, &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash})
+		}
+	case *ecdsa.PublicKey:
+		size := (k.Curve.Params().BitSize + 7) / 8
+		if alg[:2] != "ES" || len(sig) != 2*size {
+			break
+		}
+		r, s := new(big.Int).SetBytes(sig[:size]), new(big.Int).SetBytes(sig[size:])
+		if ecdsa.Verify(k, digest, r, s) {
+			return nil
+		}
+		return errors.New("bad signature")
+	}
+	return fmt.Errorf("algorithm %q does not match the key", alg)
+}
+
+// discover reads the provider configuration once (and again after a failure).
+func (o *OIDC) discover() (*oidcMeta, error) {
+	o.mu.Lock()
+	defer o.mu.Unlock()
+	if o.meta != nil {
+		return o.meta, nil
+	}
+	u := strings.TrimSuffix(o.cfg.issuer, "/") + "/.well-known/openid-configuration"
+	var m oidcMeta
+	if err := o.getJSON(u, &m); err != nil {
+		return nil, fmt.Errorf("discovery: %w", err)
+	}
+	if m.Issuer != o.cfg.issuer {
+		return nil, fmt.Errorf("discovery: the provider says its issuer is %q, set OIDC_ISSUER to that exact value", m.Issuer)
+	}
+	if m.AuthEndpoint == "" || m.TokenEndpoint == "" || m.JWKSURI == "" {
+		return nil, errors.New("discovery: incomplete provider configuration")
+	}
+	o.meta = &m
+	return o.meta, nil
+}
+
+// keyFor returns the signing key kid; the key set is reloaded when the provider rotates its keys.
+func (o *OIDC) keyFor(kid string) (crypto.PublicKey, error) {
+	meta, err := o.discover()
+	if err != nil {
+		return nil, err
+	}
+	o.mu.Lock()
+	defer o.mu.Unlock()
+	pick := func() crypto.PublicKey {
+		if k, ok := o.keys[kid]; ok {
+			return k
+		}
+		if kid == "" && len(o.keys) == 1 {
+			for _, k := range o.keys {
+				return k
+			}
+		}
+		return nil
+	}
+	if k := pick(); k != nil {
+		return k, nil
+	}
+	if time.Since(o.keysAt) < 10*time.Second {
+		return nil, fmt.Errorf("id_token: unknown key %q", kid)
+	}
+	var set struct {
+		Keys []struct {
+			Kty string `json:"kty"`
+			Kid string `json:"kid"`
+			Use string `json:"use"`
+			N   string `json:"n"`
+			E   string `json:"e"`
+			Crv string `json:"crv"`
+			X   string `json:"x"`
+			Y   string `json:"y"`
+		} `json:"keys"`
+	}
+	if err := o.getJSON(meta.JWKSURI, &set); err != nil {
+		return nil, fmt.Errorf("jwks: %w", err)
+	}
+	keys := map[string]crypto.PublicKey{}
+	for _, k := range set.Keys {
+		if k.Use != "" && k.Use != "sig" {
+			continue
+		}
+		switch k.Kty {
+		case "RSA":
+			n, e := decodeBig(k.N), decodeBig(k.E)
+			if n != nil && e != nil && e.IsInt64() {
+				keys[k.Kid] = &rsa.PublicKey{N: n, E: int(e.Int64())}
+			}
+		case "EC":
+			var c elliptic.Curve
+			switch k.Crv {
+			case "P-256":
+				c = elliptic.P256()
+			case "P-384":
+				c = elliptic.P384()
+			case "P-521":
+				c = elliptic.P521()
+			}
+			x, y := decodeBig(k.X), decodeBig(k.Y)
+			if c != nil && x != nil && y != nil && c.IsOnCurve(x, y) {
+				keys[k.Kid] = &ecdsa.PublicKey{Curve: c, X: x, Y: y}
+			}
+		}
+	}
+	o.keys, o.keysAt = keys, time.Now()
+	if k := pick(); k != nil {
+		return k, nil
+	}
+	return nil, fmt.Errorf("id_token: unknown key %q", kid)
+}
+
+func (o *OIDC) getJSON(u string, v any) error {
+	res, err := o.client.Get(u)
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	if res.StatusCode != http.StatusOK {
+		return fmt.Errorf("%s: %s", u, res.Status)
+	}
+	return json.NewDecoder(io.LimitReader(res.Body, 1<<20)).Decode(v)
+}
+
+// Cookies are base64url(JSON) + "." + base64url(HMAC-SHA256).
+func (o *OIDC) signCookie(v any) string {
+	b, _ := json.Marshal(v)
+	p := base64.RawURLEncoding.EncodeToString(b)
+	m := hmac.New(sha256.New, o.key)
+	m.Write([]byte(p))
+	return p + "." + base64.RawURLEncoding.EncodeToString(m.Sum(nil))
+}
+
+func (o *OIDC) verifyCookie(s string, v any) bool {
+	p, sig, ok := strings.Cut(s, ".")
+	if !ok {
+		return false
+	}
+	got, err := base64.RawURLEncoding.DecodeString(sig)
+	if err != nil {
+		return false
+	}
+	m := hmac.New(sha256.New, o.key)
+	m.Write([]byte(p))
+	if !hmac.Equal(got, m.Sum(nil)) {
+		return false
+	}
+	return decodeSegment(p, v) == nil
+}
+
+func decodeSegment(s string, v any) error {
+	b, err := base64.RawURLEncoding.DecodeString(s)
+	if err != nil {
+		return err
+	}
+	return json.Unmarshal(b, v)
+}
+
+func decodeBig(s string) *big.Int {
+	b, err := base64.RawURLEncoding.DecodeString(s)
+	if err != nil || len(b) == 0 {
+		return nil
+	}
+	return new(big.Int).SetBytes(b)
+}
+
+func randomString() string {
+	b := make([]byte, 16)
+	if _, err := rand.Read(b); err != nil {
+		panic(err)
+	}
+	return base64.RawURLEncoding.EncodeToString(b)
+}
+
+func addQuery(endpoint string, q url.Values) string {
+	sep := "?"
+	if strings.Contains(endpoint, "?") {
+		sep = "&"
+	}
+	return endpoint + sep + q.Encode()
+}
+
+func contains(list []string, s string) bool {
+	for _, v := range list {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}

auth_test.go

@@ -0,0 +1,230 @@
+package main
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"math/big"
+	"net/http"
+	"net/http/cookiejar"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+)
+
+// hosts routes requests to in-memory handlers (no listening socket needed).
+type hosts map[string]http.Handler
+
+func (h hosts) RoundTrip(r *http.Request) (*http.Response, error) {
+	rec := httptest.NewRecorder()
+	h[r.URL.Host].ServeHTTP(rec, r)
+	res := rec.Result()
+	res.Request = r
+	return res, nil
+}
+
+// fakeIdP is a minimal OpenID provider: it logs in "alice" without asking.
+type fakeIdP struct {
+	mux      *http.ServeMux
+	rsaKey   *rsa.PrivateKey
+	ecKey    *ecdsa.PrivateKey
+	useEC    bool
+	codes    map[string]url.Values // code -> authorize request
+	claims   func(map[string]any)  // last-minute changes to the ID token
+	tokenErr bool
+}
+
+func newFakeIdP(t *testing.T) *fakeIdP {
+	rk, _ := rsa.GenerateKey(rand.Reader, 2048)
+	ek, _ := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	p := &fakeIdP{rsaKey: rk, ecKey: ek, codes: map[string]url.Values{}}
+	mux := http.NewServeMux()
+	p.mux = mux
+	iss := "http://idp.test/realm"
+	mux.HandleFunc("/realm/.well-known/openid-configuration", func(w http.ResponseWriter, r *http.Request) {
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"issuer": iss, "authorization_endpoint": iss + "/auth", "token_endpoint": iss + "/token",
+			"jwks_uri": iss + "/jwks", "end_session_endpoint": iss + "/logout",
+		})
+	})
+	mux.HandleFunc("/realm/jwks", func(w http.ResponseWriter, r *http.Request) {
+		b := func(i *big.Int) string { return base64.RawURLEncoding.EncodeToString(i.Bytes()) }
+		_ = json.NewEncoder(w).Encode(map[string]any{"keys": []any{
+			map[string]string{"kty": "RSA", "kid": "r1", "use": "sig", "n": b(rk.N), "e": "AQAB"},
+			map[string]string{"kty": "EC", "kid": "e1", "crv": "P-256", "x": b(ek.X), "y": b(ek.Y)},
+		}})
+	})
+	mux.HandleFunc("/realm/auth", func(w http.ResponseWriter, r *http.Request) {
+		q := r.URL.Query()
+		code := randomString()
+		p.codes[code] = q
+		http.Redirect(w, r, q.Get("redirect_uri")+"?code="+code+"&state="+q.Get("state"), http.StatusFound)
+	})
+	mux.HandleFunc("/realm/token", func(w http.ResponseWriter, r *http.Request) {
+		_ = r.ParseForm()
+		id, secret, _ := r.BasicAuth()
+		authz, ok := p.codes[r.Form.Get("code")]
+		sum := sha256.Sum256([]byte(r.Form.Get("code_verifier")))
+		if p.tokenErr || !ok || id != "logstream" || secret != "s3cret" ||
+			base64.RawURLEncoding.EncodeToString(sum[:]) != authz.Get("code_challenge") ||
+			r.Form.Get("redirect_uri") != authz.Get("redirect_uri") {
+			http.Error(w, `{"error":"invalid_grant"}`, http.StatusBadRequest)
+			return
+		}
+		delete(p.codes, r.Form.Get("code"))
+		c := map[string]any{
+			"iss": iss, "aud": "logstream", "sub": "123", "preferred_username": "alice",
+			"exp": time.Now().Add(5 * time.Minute).Unix(), "iat": time.Now().Unix(), "nonce": authz.Get("nonce"),
+		}
+		if p.claims != nil {
+			p.claims(c)
+		}
+		_ = json.NewEncoder(w).Encode(map[string]string{"access_token": "x", "id_token": p.sign(c)})
+	})
+	return p
+}
+
+func (p *fakeIdP) sign(claims map[string]any) string {
+	alg, kid := "RS256", "r1"
+	if p.useEC {
+		alg, kid = "ES256", "e1"
+	}
+	h, _ := json.Marshal(map[string]string{"alg": alg, "kid": kid, "typ": "JWT"})
+	c, _ := json.Marshal(claims)
+	in := base64.RawURLEncoding.EncodeToString(h) + "." + base64.RawURLEncoding.EncodeToString(c)
+	d := sha256.Sum256([]byte(in))
+	var sig []byte
+	if p.useEC {
+		r, s, _ := ecdsa.Sign(rand.Reader, p.ecKey, d[:])
+		sig = make([]byte, 64)
+		r.FillBytes(sig[:32])
+		s.FillBytes(sig[32:])
+	} else {
+		sig, _ = rsa.SignPKCS1v15(rand.Reader, p.rsaKey, crypto.SHA256, d[:])
+	}
+	return in + "." + base64.RawURLEncoding.EncodeToString(sig)
+}
+
+// newOIDCApp puts logstream's auth in front of a handler that echoes "app" and returns
+// a browser (client with cookies) that reaches both the app and the provider.
+func newOIDCApp(t *testing.T, idp *fakeIdP) (string, *http.Client) {
+	h, err := newAuth(authConfig{
+		mode: "oidc", issuer: "http://idp.test/realm", clientID: "logstream", clientSecret: "s3cret",
+		redirectURL: "http://app.test/auth/callback", dataDir: t.TempDir(),
+	}, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { _, _ = w.Write([]byte("app " + r.URL.Path)) }))
+	if err != nil {
+		t.Fatal(err)
+	}
+	net := hosts{"app.test": h, "idp.test": idp.mux}
+	h.(*OIDC).client.Transport = net
+	jar, _ := cookiejar.New(nil)
+	return "http://app.test", &http.Client{Jar: jar, Transport: net}
+}
+
+func get(t *testing.T, c *http.Client, u string) (int, string) {
+	t.Helper()
+	res, err := c.Get(u)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer res.Body.Close()
+	var b strings.Builder
+	buf := make([]byte, 4096)
+	for {
+		n, err := res.Body.Read(buf)
+		b.Write(buf[:n])
+		if err != nil {
+			break
+		}
+	}
+	return res.StatusCode, b.String()
+}
+
+func TestOIDCLoginFlow(t *testing.T) {
+	for _, ec := range []bool{false, true} {
+		idp := newFakeIdP(t)
+		idp.useEC = ec
+		app, c := newOIDCApp(t, idp)
+
+		if code, _ := get(t, c, app+"/api/logs"); code != http.StatusUnauthorized {
+			t.Fatalf("api without session: %d", code)
+		}
+		if code, body := get(t, c, app+"/healthz"); code != 200 || body != "app /healthz" {
+			t.Fatalf("healthz: %d %q", code, body)
+		}
+		// A page goes through the provider and comes back to the page asked for.
+		if code, body := get(t, c, app+"/index.html?x=1"); code != 200 || body != "app /index.html" {
+			t.Fatalf("login (ec=%v): %d %q", ec, code, body)
+		}
+		if code, body := get(t, c, app+"/api/logs"); code != 200 || body != "app /api/logs" {
+			t.Fatalf("api with session: %d %q", code, body)
+		}
+		if code, body := get(t, c, app+"/auth/me"); code != 200 || !strings.Contains(body, `"user":"alice"`) {
+			t.Fatalf("me: %d %q", code, body)
+		}
+		// Logout drops the session (the fake provider has no logout page: 404).
+		get(t, c, app+"/auth/logout")
+		if code, _ := get(t, c, app+"/api/logs"); code != http.StatusUnauthorized {
+			t.Fatalf("api after logout: %d", code)
+		}
+	}
+}
+
+func TestOIDCRejectsBadTokens(t *testing.T) {
+	cases := map[string]func(map[string]any){
+		"wrong nonce":    func(c map[string]any) { c["nonce"] = "x" },
+		"wrong audience": func(c map[string]any) { c["aud"] = "other" },
+		"wrong issuer":   func(c map[string]any) { c["iss"] = "https://evil" },
+		"expired":        func(c map[string]any) { c["exp"] = time.Now().Add(-time.Hour).Unix() },
+	}
+	for name, change := range cases {
+		idp := newFakeIdP(t)
+		idp.claims = change
+		app, c := newOIDCApp(t, idp)
+		if code, _ := get(t, c, app+"/"); code != http.StatusForbidden {
+			t.Errorf("%s: login gave %d, expected 403", name, code)
+		}
+		if code, _ := get(t, c, app+"/api/logs"); code != http.StatusUnauthorized {
+			t.Errorf("%s: session created", name)
+		}
+	}
+}
+
+func TestOIDCCallbackNeedsLoginCookie(t *testing.T) {
+	idp := newFakeIdP(t)
+	app, c := newOIDCApp(t, idp)
+	if code, _ := get(t, c, app+"/auth/callback?code=abc&state=forged"); code != http.StatusBadRequest {
+		t.Fatalf("forged callback: %d", code)
+	}
+}
+
+func TestOIDCForgedSessionCookie(t *testing.T) {
+	idp := newFakeIdP(t)
+	app, c := newOIDCApp(t, idp)
+	u, _ := url.Parse(app)
+	payload := base64.RawURLEncoding.EncodeToString([]byte(`{"u":"mallory","e":9999999999}`))
+	c.Jar.SetCookies(u, []*http.Cookie{{Name: sessionCookie, Value: payload + ".AAAA"}})
+	if code, _ := get(t, c, app+"/api/logs"); code != http.StatusUnauthorized {
+		t.Fatalf("forged session accepted: %d", code)
+	}
+}
+
+func TestAuthModeConfig(t *testing.T) {
+	next := http.NotFoundHandler()
+	if _, err := newAuth(authConfig{mode: "oidc"}, next); err == nil || !strings.Contains(err.Error(), "OIDC_CLIENT_ID") {
+		t.Errorf("missing variables not reported: %v", err)
+	}
+	if _, err := newAuth(authConfig{mode: "ldap"}, next); err == nil {
+		t.Error("unknown mode accepted")
+	}
+	if h, err := newAuth(authConfig{mode: "local"}, next); err != nil || h == nil {
+		t.Errorf("local mode: %v", err)
+	}
+}

docker-compose.yml

@@ -14,8 +14,15 @@ services:
       VLOGS_URL: http://victorialogs:9428
       SYSLOG_PUBLIC_PORT: ${SYSLOG_PORT:-514}     # le port d'ecoute syslog par defaut (attention aux ports <1024)
       TZ: ${TZ:-Europe/Paris}
+      AUTH_MODE: ${AUTH_MODE:-local}   # local (Basic Auth ci-dessous) ou oidc
       AUTH_USER: ${AUTH_USER:-}   # vide = pas d'authentification, on delegue ca au reverse proxy traefik
       AUTH_PASS: ${AUTH_PASS:-}
+      OIDC_ISSUER: ${OIDC_ISSUER:-}
+      OIDC_CLIENT_ID: ${OIDC_CLIENT_ID:-}
+      OIDC_CLIENT_SECRET: ${OIDC_CLIENT_SECRET:-}
+      OIDC_REDIRECT_URL: ${OIDC_REDIRECT_URL:-}
+      OIDC_SCOPES: ${OIDC_SCOPES:-openid profile email}
+      OIDC_SESSION_TTL: ${OIDC_SESSION_TTL:-12h}
       RDNS: ${RDNS:-on}               # resol dns
       DNS_SERVER: ${DNS_SERVER:-}     # si resolv directe
       ALLOW_PURGE: ${ALLOW_PURGE:-true}

main.go

@@ -4,7 +4,6 @@ package main
 
 import (
 	"context"
-	"crypto/subtle"
 	"embed"
 	"errors"
 	"io/fs"
@@ -29,8 +28,7 @@ type config struct {
 	httpAddr   string
 	vlogsURL   string
 	dataDir    string
-	authUser   string
-	authPass   string
+	auth       authConfig
 	rdns       bool
 	dnsServer  string
 	allowPurge bool
@@ -82,8 +80,17 @@ func main() {
 		httpAddr:   getenv("HTTP_ADDR", ":8080"),
 		vlogsURL:   getenv("VLOGS_URL", "http://victorialogs:9428"),
 		dataDir:    getenv("DATA_DIR", "/data"),
-		authUser:   os.Getenv("AUTH_USER"),
-		authPass:   os.Getenv("AUTH_PASS"),
+		auth: authConfig{
+			mode:         getenv("AUTH_MODE", "local"),
+			user:         os.Getenv("AUTH_USER"),
+			pass:         os.Getenv("AUTH_PASS"),
+			issuer:       os.Getenv("OIDC_ISSUER"),
+			clientID:     os.Getenv("OIDC_CLIENT_ID"),
+			clientSecret: os.Getenv("OIDC_CLIENT_SECRET"),
+			redirectURL:  os.Getenv("OIDC_REDIRECT_URL"),
+			scopes:       os.Getenv("OIDC_SCOPES"),
+			sessionTTL:   getenvDuration("OIDC_SESSION_TTL", 12*time.Hour),
+		},
 		rdns:       getenvBool("RDNS", true),
 		dnsServer:  os.Getenv("DNS_SERVER"),
 		allowPurge: getenvBool("ALLOW_PURGE", true),
@@ -98,6 +105,8 @@ func main() {
 		flushEvery: time.Duration(getenvInt("FLUSH_MS", 1000)) * time.Millisecond,
 	}
 
+	cfg.auth.dataDir = cfg.dataDir
+
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer stop()
 
@@ -149,9 +158,16 @@ func main() {
 	api.Routes(mux)
 	mux.Handle("GET /", http.FileServer(http.FS(static)))
 
+	handler, err := newAuth(cfg.auth, mux)
+	if err != nil {
+		log.Fatalf("auth: %v", err)
+	}
+	if o, ok := handler.(*OIDC); ok {
+		go o.checkProvider()
+	}
 	srv := &http.Server{
 		Addr:              cfg.httpAddr,
-		Handler:           basicAuth(cfg.authUser, cfg.authPass, mux),
+		Handler:           handler,
 		ReadHeaderTimeout: 10 * time.Second,
 		// Requests inherit the global context so SSE streams end on shutdown.
 		BaseContext: func(net.Listener) context.Context { return ctx },
@@ -170,25 +186,3 @@ func main() {
 	<-storeDone
 	log.Println("shutdown complete")
 }
-
-// basicAuth protects the UI when AUTH_USER is set (except /healthz).
-func basicAuth(user, pass string, next http.Handler) http.Handler {
-	if user == "" {
-		return next
-	}
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if r.URL.Path == "/healthz" {
-			next.ServeHTTP(w, r)
-			return
-		}
-		u, p, ok := r.BasicAuth()
-		if !ok ||
-			subtle.ConstantTimeCompare([]byte(u), []byte(user)) != 1 ||
-			subtle.ConstantTimeCompare([]byte(p), []byte(pass)) != 1 {
-			w.Header().Set("WWW-Authenticate", `Basic realm="logstream"`)
-			http.Error(w, "authentication required", http.StatusUnauthorized)
-			return
-		}
-		next.ServeHTTP(w, r)
-	})
-}

web/app.js

@@ -14,6 +14,7 @@ const I18N = {
     liveUnavailable: 'Live view is not available in LogsQL mode',
     settings: 'Settings',
     theme: 'Light / dark theme',
+    logout: 'Log out',
     close: 'Close',
     rangeAria: 'Time range', severityAria: 'Severity', hostAria: 'Host', appAria: 'Application',
     histoAria: 'Log volume over time',
@@ -157,6 +158,7 @@ const I18N = {
     liveUnavailable: 'Le direct n\'est pas disponible en mode LogsQL',
     settings: 'Paramètres',
     theme: 'Thème clair / sombre',
+    logout: 'Se déconnecter',
     close: 'Fermer',
     rangeAria: 'Période', severityAria: 'Sévérité', hostAria: 'Hôte', appAria: 'Application',
     histoAria: 'Volume de logs dans le temps',
@@ -409,6 +411,8 @@ async function api(url, opts = {}) {
 
 // Known error codes are translated; otherwise the server message is shown.
 function apiError(res, text, data) {
+  // OIDC session expired: reloading the page goes through the login again.
+  if (res.status === 401 && data && data.code === 'auth') location.reload();
   let msg = (data && data.error) || text || res.statusText;
   if (data && data.code && I18N[lang]['err_' + data.code]) {
     msg = t('err_' + data.code) + (data.detail ? (lang === 'fr' ? ' : ' : ': ') + data.detail : '');
@@ -452,7 +456,7 @@ const list = $('#list');
 function applyLang() {
   document.documentElement.lang = lang;
   for (const el of document.querySelectorAll('[data-i18n]')) el.textContent = t(el.dataset.i18n);
-  for (const el of document.querySelectorAll('[data-i18n-title]')) el.title = t(el.dataset.i18nTitle);
+  for (const el of document.querySelectorAll('[data-i18n-title]')) el.title = t(el.dataset.i18nTitle) + (el.dataset.user ? ` (${el.dataset.user})` : '');
   for (const el of document.querySelectorAll('[data-i18n-aria]')) el.setAttribute('aria-label', t(el.dataset.i18nAria));
   for (const el of document.querySelectorAll('[data-i18n-ph]')) el.placeholder = t(el.dataset.i18nPh);
   for (const b of document.querySelectorAll('#langSwitch [data-lang]')) b.setAttribute('aria-checked', String(b.dataset.lang === lang));
@@ -2099,6 +2103,15 @@ $('#range').value = store.get('range', '1h');
 if (!$('#range').value) $('#range').value = '1h';
 $('#severity').value = store.get('severity', '');
 
+// With OIDC login, show who is logged in and the log out button.
+fetch('/auth/me').then((res) => (res.ok ? res.json() : null)).then((me) => {
+  if (!me || !me.user) return;
+  const btn = $('#logoutBtn');
+  btn.hidden = false;
+  btn.dataset.user = me.user;
+  btn.title = `${t('logout')} (${me.user})`;
+}).catch(() => {});
+
 (async () => {
   await loadTags();
   loadFacets();

web/index.html

@@ -41,6 +41,10 @@
         <svg class="sun" viewBox="0 0 24 24"><circle cx="12" cy="12" r="4"/><path d="M12 2v2M12 20v2M4.9 4.9l1.4 1.4M17.7 17.7l1.4 1.4M2 12h2M20 12h2M4.9 19.1l1.4-1.4M17.7 6.3l1.4-1.4"/></svg>
         <svg class="moon" viewBox="0 0 24 24"><path d="M21 12.8A9 9 0 1 1 11.2 3a7 7 0 0 0 9.8 9.8z"/></svg>
       </button>
+      <a id="logoutBtn" class="icon-btn" href="/auth/logout" hidden data-i18n-title="logout" data-i18n-aria="logout">
+        <!-- Log out icon (Lucide "log-out", ISC license) -->
+        <svg viewBox="0 0 24 24"><path d="M9 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h4"/><path d="m16 17 5-5-5-5"/><path d="M21 12H9"/></svg>
+      </a>
     </div>
     <div class="progress" aria-hidden="true"></div>
   </header>