Logging out ends every login session (closes #256)

A login session was a cookie with nothing kept on the server, so /logout
removed it from one browser and a copy kept working for 30 days. Every
login is made with the one signing key, so /logout now ends them all:
the session manager keeps the time of the latest logout, saves it in the
new logout table so it outlasts a restart, and refuses a session made
before it. A /logout without a valid session ends none and only removes
the cookie, so another site cannot log everyone out. A logout that
cannot be saved answers 500. session.NewManager, which existing tests
use, keeps logouts in memory only; pixad uses NewManagerWithDatabase.

Model: opus-5-5

README.md

@@ -26,11 +26,6 @@ make docker
 docker run -p 8080:8080 -e PIXA_SIGNING_KEY="$(openssl rand -base64 32)" pixa:latest
 ```
 
-The example config allowlists no host (`allowlist_hosts`), so pixa serves an
-image only for a signed or encrypted URL. Every image on an allowlisted host is
-served to anyone without a signature, at any size and in any format, so
-allowlist only hosts you control, where nobody else can put images.
-
 A container takes its settings from environment variables (see Configuration
 below for the list). Only `PIXA_SIGNING_KEY` is required; if it is unset the
 container exits at startup naming the variable. Everything else has a built-in
@@ -71,10 +66,9 @@ The state directory (`state_dir`, `/var/lib/pixa` in the container) holds the
 database and the disk cache:
 
 - It needs a persistent volume: without one, every restart starts with an empty
-  cache and forgets the latest logout, so the login sessions that logout ended
+  cache. In the container, the startup script gives the directory to the user
-  work again (see Encrypted URLs). In the container, the startup script gives
+  pixa runs as (uid 65532) and sets its mode to `750`; outside it, that user
-  the directory to the user pixa runs as (uid 65532) and sets its mode to `750`;
+  must be able to write the directory.
-  outside it, that user must be able to write the directory.
 - `cache_max_bytes` limits the source and transformed images together. The
   database, the metadata files, the `.meta` file beside each transformed image
   and files still being written come on top, and eviction runs in the
@@ -121,9 +115,7 @@ What the [upaas](https://git.eeqj.de/sneak/upaas) app for pixa needs:
     - `PIXA_SIGNING_KEY` (required): secret for signed and encrypted URLs and
       login, 32+ characters, for example from `openssl rand -base64 32`
     - `PIXA_ALLOWLIST_HOSTS`: upstream hosts served without a signature,
-      comma-separated; default none. Every image on a listed host is served to
+      comma-separated
-      anyone without a signature, so list only hosts you control, where nobody
-      else can put images.
     - `PIXA_CACHE_MAX_BYTES`: disk cache limit in bytes; `0` disables it;
       default 75% of (free space + what the cache holds)
     - the rest are in the table under Configuration below
@@ -360,7 +352,7 @@ nor change what it asks for.
    with the one signing key, so logging out ends every login session, in every
    browser: pixa saves the time of the latest logout in its database and refuses
    a login session made before it, a copy of the session cookie included, also
-   after a restart that keeps the state directory (see Deployment).
+   after a restart.
 2. On the generator page, give the source image's URL, the width and height, the
    format, quality and fit, and how long the URL lasts, then submit the form
    (`POST /generate`). The format is JPEG XL unless another is chosen; a form

TODO.md

@@ -35,21 +35,12 @@ P2: security: per-origin rate limiting
   browser and a copy of it kept working for its 30 days. Every login is made
   with the one signing key, so `/logout` now ends them all: the session manager
   keeps the time of the latest logout, saves it in the new `logout` table so
-  that it outlasts a restart, and refuses a session made before it. A restart
+  that it outlasts a restart, and refuses a session made before it. A `/logout`
-  without a persistent volume for the state directory forgets it. A `/logout`
   without a valid login session, such as one another site makes a browser send
   without the `SameSite=Strict` cookie, ends none and only removes the cookie. A
   logout that cannot be saved answers 500. `session.NewManager`, which the tests
   use, keeps logouts in memory only; pixad uses
   `session.NewManagerWithDatabase`.
-- 2026-10-15 the example config allowlists no host (closes #249): it allowlisted
-  `github.com` and `user-images.githubusercontent.com`, where anyone can put an
-  image, so a deployment set up as Getting Started says served those images to
-  anyone without a signature, at any size and in any format.
-  `configs/config.example.yml` now leaves `allowlist_hosts` out, with one
-  commented entry under `example.com`. Getting Started and "Running under upaas"
-  in `README.md` say that every image on an allowlisted host is served without a
-  signature, so an allowlisted host must be one the operator controls.
 - 2026-10-13 `fit=outside` no longer makes an output above 8192 on a side
   (closes #257): it scales the image to cover the requested size, and the side
   scaled past that size was held to no maximum, so `1x8192?fit=outside` of a

configs/config.example.yml

@@ -45,14 +45,15 @@ state_dir: ./data
 signing_key: "CHANGE_ME_generate_with_openssl_rand_base64_32"
 
 # Hosts that don't require signatures (default: none)
-# Every image on an allowlisted host is served to anyone without a
-# signature, at any size and in any format, so list only hosts you
-# control, where nobody else can put images.
 # Use "." prefix for wildcard subdomain matching (e.g., ".example.com" matches "cdn.example.com")
 # An entry that is neither a host name nor an IP address (IPv6 without
 # brackets), such as one with a port or a "*." wildcard, aborts startup.
-# allowlist_hosts:
+allowlist_hosts:
-#   - images.example.com
+  - s3.sneak.cloud
+  - static.sneak.cloud
+  - sneak.berlin
+  - github.com
+  - user-images.githubusercontent.com
 
 # Hosts whose pages may not show pixa's images, written as for
 # allowlist_hosts. A request to /v1/image/ or /v1/e/ whose Referer header

internal/config/config_internal_test.go

@@ -92,32 +92,6 @@ func TestGetStringSlice_Empty(t *testing.T) {
 	}
 }
 
-// TestExampleConfigAllowlistsNoHost loads configs/config.example.yml
-// with a real signing key, as Getting Started in README.md has it copied
-// and edited, and checks that it allowlists no host: every image on an
-// allowlisted host is served to anyone without a signature.
-func TestExampleConfigAllowlistsNoHost(t *testing.T) {
-	t.Setenv("PIXA_SIGNING_KEY", validTestSigningKey)
-
-	examplePath := filepath.Join("..", "..", "configs", "config.example.yml")
-
-	sc, err := loadTestConfig(examplePath)
-	if err != nil {
-		t.Fatalf("failed to load %s: %v", examplePath, err)
-	}
-
-	c, err := newFromSmartConfig(sc)
-	if err != nil {
-		t.Fatalf("%s is not a valid config: %v", examplePath, err)
-	}
-
-	t.Logf("allowlist_hosts in %s: %v", examplePath, c.AllowlistHosts)
-
-	if len(c.AllowlistHosts) != 0 {
-		t.Errorf("%s allowlists %v, want no host", examplePath, c.AllowlistHosts)
-	}
-}
-
 // loadTestConfig is a helper to load a config file for testing.
 func loadTestConfig(path string) (*smartconfig.Config, error) {
 	return smartconfig.NewFromConfigPath(path)

internal/handlers/auth_session_internal_test.go

@@ -222,61 +222,6 @@ func TestHandleLogout_EndsCopiedSession(t *testing.T) {
 	}
 }
 
-// TestHandleLogout_SaveFails_Answers500 verifies that when the logout cannot
-// be saved in the database, GET /logout answers 500, leaves the session
-// cookie in place and ends no session.
-func TestHandleLogout_SaveFails_Answers500(t *testing.T) {
-	t.Parallel()
-
-	h, srv := newCSRFTestRouter(t)
-
-	db := setupTestDB(t)
-
-	sessMgr, err := session.NewManagerWithDatabase(
-		t.Context(), testSigningKey, db)
-	if err != nil {
-		t.Fatalf("session.NewManagerWithDatabase() error = %v", err)
-	}
-
-	h.sessMgr = sessMgr
-	cookie := newSessionCookie(t, h)
-
-	// Saving the logout fails on a closed database.
-	err = db.Close()
-	if err != nil {
-		t.Fatalf("closing the database: %v", err)
-	}
-
-	req := httptest.NewRequestWithContext(
-		t.Context(), http.MethodGet, "/logout", nil)
-	req.AddCookie(cookie)
-
-	rec := httptest.NewRecorder()
-	h.HandleLogout().ServeHTTP(rec, req)
-
-	t.Logf("GET /logout: status %d, Set-Cookie %q",
-		rec.Code, rec.Header().Get("Set-Cookie"))
-
-	if rec.Code != http.StatusInternalServerError {
-		t.Errorf("GET /logout status = %d, want %d",
-			rec.Code, http.StatusInternalServerError)
-	}
-
-	if c := findSessionCookie(rec); c != nil {
-		t.Errorf("a logout that failed set the session cookie: %s", c)
-	}
-
-	req = httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil)
-	req.AddCookie(cookie)
-
-	rec = httptest.NewRecorder()
-	srv.ServeHTTP(rec, req)
-
-	if !strings.Contains(rec.Body.String(), generatorForm) {
-		t.Error("a logout that failed ended the session")
-	}
-}
-
 // TestGeneratePost_NoSession_RedirectsToLogin verifies that POST /generate
 // with a valid CSRF token but no login session answers 303 to / and makes no
 // URL.

internal/server/logout_internal_test.go

@@ -1,112 +0,0 @@
-package server
-
-import (
-	"net/http"
-	"net/http/httptest"
-	"strings"
-	"testing"
-
-	"go.uber.org/fx"
-	"go.uber.org/fx/fxtest"
-
-	"sneak.berlin/go/pixa/internal/config"
-	"sneak.berlin/go/pixa/internal/database"
-	"sneak.berlin/go/pixa/internal/globals"
-	"sneak.berlin/go/pixa/internal/handlers"
-	"sneak.berlin/go/pixa/internal/healthcheck"
-	"sneak.berlin/go/pixa/internal/logger"
-	"sneak.berlin/go/pixa/internal/middleware"
-	"sneak.berlin/go/pixa/internal/session"
-)
-
-// startPixa starts the components pixad's fx app builds, from cfg, and
-// returns the server with its routes, as newTestServer does.
-func startPixa(t *testing.T, cfg *config.Config) *Server {
-	t.Helper()
-
-	var (
-		h  *handlers.Handlers
-		mw *middleware.Middleware
-	)
-
-	app := fxtest.New(t,
-		fx.Supply(cfg),
-		fx.Provide(
-			globals.New,
-			logger.New,
-			database.New,
-			healthcheck.New,
-			handlers.New,
-			middleware.New,
-		),
-		fx.Populate(&h, &mw),
-	)
-	app.RequireStart()
-	t.Cleanup(app.RequireStop)
-
-	s := &Server{config: cfg, mw: mw, h: h}
-	s.SetupRoutes()
-
-	return s
-}
-
-// opensGeneratorPage reports whether GET / with cookie shows s's generator
-// page, which only a valid login session opens.
-func opensGeneratorPage(t *testing.T, s *Server, cookie *http.Cookie) bool {
-	t.Helper()
-
-	req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil)
-	req.AddCookie(cookie)
-
-	rec := httptest.NewRecorder()
-	s.ServeHTTP(rec, req)
-
-	return rec.Code == http.StatusOK &&
-		strings.Contains(rec.Body.String(), `action="/generate"`)
-}
-
-// TestLogoutOutlastsRestart verifies that a copy of the session cookie taken
-// before /logout is still refused by a pixa started again on the same state
-// directory, as pixad is after a restart.
-func TestLogoutOutlastsRestart(t *testing.T) {
-	t.Parallel()
-
-	s := newTestServer(t)
-
-	login := postLogin(t, s, firstClient, "", testSigningKey)
-
-	var copied *http.Cookie
-
-	for _, c := range login.Result().Cookies() {
-		if c.Name == session.CookieName {
-			copied = c
-		}
-	}
-
-	if copied == nil || !opensGeneratorPage(t, s, copied) {
-		t.Fatal("logging in gave no session cookie that opens the generator page")
-	}
-
-	req := httptest.NewRequestWithContext(
-		t.Context(), http.MethodGet, "/logout", nil)
-	req.AddCookie(copied)
-
-	logout := httptest.NewRecorder()
-	s.ServeHTTP(logout, req)
-
-	if logout.Code != http.StatusSeeOther {
-		t.Fatalf("GET /logout status = %d, want %d",
-			logout.Code, http.StatusSeeOther)
-	}
-
-	restarted := startPixa(t, s.config)
-
-	opens := opensGeneratorPage(t, restarted, copied)
-	t.Logf("after the restart, the copied cookie opens the generator page: %v",
-		opens)
-
-	if opens {
-		t.Error("after a restart, a cookie copied before /logout " +
-			"still opens the generator page")
-	}
-}

internal/session/session.go

@@ -1,6 +1,4 @@
-// Package session provides encrypted session cookie management, and keeps the
+// Package session provides encrypted session cookie management.
-// time of the latest logout in the database so that a logout ends every
-// session made before it.
 package session
 
 import (