adminui: an admin interface, behind authentication without exception

Replaces the unauthenticated admin mux. Everything but /healthz requires a
session, and that is the point: the previous arrangement relied on binding to
loopback, which worked exactly until the address changed and then failed
silently and publicly. A binding address is a deployment detail, not an access
control, and this package does not treat it as one.

Two ways in. OIDC through the confidential client, with state and PKCE - PKCE
even here, because it costs one hash and closes code interception independently
of the secret. And the break-glass password, throttled, for when the IdP is the
thing that is broken. Signing in without the admin group is refused with the
group named, because "you are not an admin" is a different problem from "your
password is wrong" and the remedy is elsewhere.

Sessions are MAC-checked cookies: HttpOnly, SameSite=Lax, Secure when TLS is on.
CSRF tokens are derived from the session rather than stored, so there is no
server-side table to keep in sync, and they are required on every state-changing
POST - SameSite already blocks cross-site posts in current browsers, but this is
the control that does not depend on the browser being current.

Server-rendered with html/template and no JavaScript: the pages are lists and
forms, and a framework would add a build step, a dependency tree and an update
treadmill to a program that has none of those. The CSP is default-src 'none'
accordingly.

Pages: overview, devices (with revocation and enrolment-link minting), uploaded
runs and a run viewer. Revocations and deletions are logged with who did them.
Runs are shown exactly as uploaded, at the privacy level their uploader chose -
nothing in the UI can un-redact one.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/cmd/echolot-server/main.go

@@ -19,7 +19,6 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
-	"encoding/json"
 	"encoding/pem"
 	"errors"
 	"fmt"
@@ -39,6 +38,7 @@ import (
 
 	"echo-lot.app/server/internal/acmehttp"
 	"echo-lot.app/server/internal/adminauth"
+	"echo-lot.app/server/internal/adminui"
 	"echo-lot.app/server/internal/canarydns"
 	"echo-lot.app/server/internal/certreload"
 	"echo-lot.app/server/internal/compat"
@@ -297,36 +297,34 @@ func serve(cfg *config.Config) error {
 		return best
 	}
 
-	// Admin/health (plain HTTP, localhost by default; spec §7)
-	admin := http.NewServeMux()
-	admin.HandleFunc("GET /healthz", func(w http.ResponseWriter, _ *http.Request) {
-		fmt.Fprintf(w, `{"ok":true,"version":%q}`, Version)
-	})
-	admin.HandleFunc("GET /admin/selftest", func(w http.ResponseWriter, _ *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-		_ = json.NewEncoder(w).Encode(selftestPtr.Load())
-	})
-	// TODO(spec §7): enrollment token management + device list. Until the
-	// admin UI exists, mint tokens with: echolot-admin (or curl on this
-	// listener once the endpoint lands).
-	admin.HandleFunc("POST /admin/enroll-tokens", func(w http.ResponseWriter, r *http.Request) {
-		tok, err := st.NewEnrollToken(24*time.Hour, r.URL.Query().Get("note"))
-		if err != nil {
-			http.Error(w, err.Error(), 500)
-			return
-		}
-		// The whole bootstrap, not just the token: this is what gets pasted or turned into a
-		// QR code, and assembling it here is what keeps an operator from transcribing a pin by
-		// hand — a pin wrong by one character fails as an inscrutable TLS error days later.
-		w.Header().Set("Content-Type", "application/json")
-		enc := json.NewEncoder(w)
-		enc.SetEscapeHTML(false) // the link is full of / and =; escaping them helps nobody
-		_ = enc.Encode(map[string]any{
-			"token":        tok,
-			"expires_in_s": 86400,
-			"enroll_uri":   ctl.EnrollmentLink(tok),
-		})
-	})
+	// The admin interface. Every route except /healthz requires a session — the old arrangement
+	// (no auth, kept safe by binding to loopback) failed the moment the address changed, and a
+	// binding address is a deployment detail rather than an access control.
+	secret, err := st.SessionSecret()
+	if err != nil {
+		return fmt.Errorf("admin session secret: %w", err)
+	}
+	adminSecure := cfg.AdminTLSCert != ""
+	ui := &adminui.Server{
+		Store:        st,
+		Runs:         runStore,
+		OIDC:         adminIdP,
+		Sessions:     adminauth.NewSessions(secret, 12*time.Hour),
+		Throttle:     adminauth.NewThrottle(),
+		AdminUser:    cfg.AdminUser,
+		BaseURL:      cfg.AdminBaseURL,
+		ClientSecret: cfg.OIDCClientSecret,
+		Secure:       adminSecure,
+		EnrollLink:   ctl.EnrollmentLink,
+		SelfTest:     func() any { return selftestPtr.Load() },
+		Version:      Version,
+	}
+	if st.LocalAdmin() == nil && adminIdP == nil {
+		slog.Warn("nobody can sign in to the admin UI: no break-glass password is set " +
+			"(--set-admin-password) and no identity provider is configured")
+	}
+	admin := ui.Handler()
+
 	adminSrv := &http.Server{Addr: cfg.AdminListen, Handler: admin, ReadHeaderTimeout: 10 * time.Second}
 	if cfg.AdminTLSCert != "" {
 		// Terminated here rather than behind a reverse proxy: this binary already serves TLS for

server/internal/adminui/auth.go

@@ -0,0 +1,346 @@
+// SPDX-FileCopyrightText: 2026 Echolot contributors
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+// Package adminui serves the operator's web interface.
+//
+// Everything here is behind authentication, without exception. The previous arrangement — an
+// unauthenticated listener kept safe by binding to loopback — worked exactly until the address
+// changed, and then failed silently and publicly. Binding address is a deployment detail; it is
+// not an access control, and this package does not treat it as one.
+//
+// Rendered server-side with html/template and no JavaScript. The pages are lists and forms; a
+// framework would add a build step, a dependency tree and an update treadmill to a program that
+// currently has none of those.
+package adminui
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"echo-lot.app/server/internal/adminauth"
+	"echo-lot.app/server/internal/oidc"
+	"echo-lot.app/server/internal/runs"
+	"echo-lot.app/server/internal/store"
+)
+
+const (
+	sessionCookie = "echolot_admin"
+	stateCookie   = "echolot_oidc"
+	csrfField     = "csrf"
+)
+
+// Server is the admin interface.
+type Server struct {
+	Store    *store.Store
+	Runs     *runs.Store
+	OIDC     *oidc.Verifier // admin client; nil when no IdP is configured
+	Sessions *adminauth.Sessions
+	Throttle *adminauth.Throttle
+
+	// AdminUser is the break-glass username; the password hash lives in the store.
+	AdminUser string
+	// BaseURL is where this UI is reachable, for building the OIDC redirect. Must match the URI
+	// registered at the IdP exactly.
+	BaseURL string
+	// ClientSecret authenticates the confidential admin client at the token endpoint.
+	ClientSecret string
+	// Secure marks cookies Secure. Off only for loopback HTTP, where there is no network to
+	// intercept and browsers refuse Secure cookies over plaintext anyway.
+	Secure bool
+
+	// EnrollLink builds the §2.1 bootstrap link for a token. Injected rather than rebuilt here,
+	// so the SPKI pin and public URL stay owned by the control server that actually knows them.
+	EnrollLink func(token string) string
+	// SelfTest and Version render on the dashboard.
+	SelfTest func() any
+	Version  string
+}
+
+// Handler builds the routes. Only /healthz is reachable without a session.
+func (s *Server) Handler() http.Handler {
+	mux := http.NewServeMux()
+
+	// Unauthenticated: a health check that required a session would be no use to a monitor, and
+	// it discloses nothing beyond "the process is up".
+	mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		fmt.Fprintf(w, `{"ok":true,"version":%q}`+"\n", s.Version)
+	})
+
+	mux.HandleFunc("GET /login", s.loginForm)
+	mux.HandleFunc("POST /login", s.loginSubmit)
+	mux.HandleFunc("GET /auth/start", s.oidcStart)
+	mux.HandleFunc("GET /admin/callback", s.oidcCallback)
+	mux.HandleFunc("POST /logout", s.logout)
+
+	mux.HandleFunc("GET /", s.guard(s.dashboard))
+	mux.HandleFunc("GET /devices", s.guard(s.devices))
+	mux.HandleFunc("POST /devices/{id}/revoke", s.guard(s.revokeDevice))
+	mux.HandleFunc("POST /enroll-tokens", s.guard(s.mintToken))
+	mux.HandleFunc("GET /runs", s.guard(s.runsList))
+	mux.HandleFunc("GET /runs/{device}/{id}", s.guard(s.runView))
+	mux.HandleFunc("POST /runs/{device}/{id}/delete", s.guard(s.runDelete))
+
+	return mux
+}
+
+// guard requires a valid session, and checks CSRF on anything that changes state.
+func (s *Server) guard(h func(http.ResponseWriter, *http.Request, *adminauth.Session)) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		sess := s.session(r)
+		if sess == nil {
+			http.Redirect(w, r, "/login", http.StatusSeeOther)
+			return
+		}
+		if r.Method != http.MethodGet && r.Method != http.MethodHead {
+			// SameSite=Lax already blocks cross-site form posts in current browsers, but this
+			// is the control that does not depend on the browser being current.
+			if !s.csrfOK(r, sess) {
+				http.Error(w, "stale form — reload the page and try again", http.StatusForbidden)
+				return
+			}
+		}
+		h(w, r, sess)
+	}
+}
+
+func (s *Server) session(r *http.Request) *adminauth.Session {
+	c, err := r.Cookie(sessionCookie)
+	if err != nil {
+		return nil
+	}
+	sess, err := s.Sessions.Parse(c.Value)
+	if err != nil {
+		return nil
+	}
+	return sess
+}
+
+// csrfToken derives a per-session token. Derived rather than stored so it needs no server-side
+// state and cannot drift out of sync with the session it belongs to.
+func (s *Server) csrfToken(sess *adminauth.Session) string {
+	sum := sha256.Sum256([]byte("csrf|" + sess.Subject + "|" + sess.Expires.String()))
+	return base64.RawURLEncoding.EncodeToString(sum[:16])
+}
+
+func (s *Server) csrfOK(r *http.Request, sess *adminauth.Session) bool {
+	if err := r.ParseForm(); err != nil {
+		return false
+	}
+	return r.PostFormValue(csrfField) == s.csrfToken(sess)
+}
+
+func (s *Server) setSession(w http.ResponseWriter, subject, display string) {
+	http.SetCookie(w, &http.Cookie{
+		Name:     sessionCookie,
+		Value:    s.Sessions.Issue(subject, display),
+		Path:     "/",
+		HttpOnly: true, // the cookie is a bearer credential; script has no business reading it
+		Secure:   s.Secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func (s *Server) logout(w http.ResponseWriter, r *http.Request) {
+	http.SetCookie(w, &http.Cookie{
+		Name: sessionCookie, Value: "", Path: "/", MaxAge: -1,
+		HttpOnly: true, Secure: s.Secure, SameSite: http.SameSiteLaxMode,
+	})
+	http.Redirect(w, r, "/login", http.StatusSeeOther)
+}
+
+// ---- local password ---------------------------------------------------------------------
+
+func (s *Server) loginSubmit(w http.ResponseWriter, r *http.Request) {
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "bad form", http.StatusBadRequest)
+		return
+	}
+	// The delay is applied before the answer, so a wrong guess costs time whether or not the
+	// username exists — the timing carries no information either way.
+	if d := s.Throttle.Delay(); d > 0 {
+		time.Sleep(d)
+	}
+	user := r.PostFormValue("username")
+	pass := r.PostFormValue("password")
+
+	cred := s.Store.LocalAdmin()
+	if cred == nil || !cred.Verify(user, pass) {
+		s.Throttle.Failed()
+		slog.Info("admin login failed", "user", user, "from", clientIP(r))
+		s.render(w, r, "login", map[string]any{
+			"Error": "Incorrect username or password.",
+			"OIDC":  s.oidcAvailable(),
+		})
+		return
+	}
+	s.Throttle.Succeeded()
+	slog.Info("admin login", "user", user, "method", "local", "from", clientIP(r))
+	s.setSession(w, "local:"+cred.Username, cred.Username)
+	http.Redirect(w, r, "/", http.StatusSeeOther)
+}
+
+// ---- OIDC -------------------------------------------------------------------------------
+
+func (s *Server) oidcAvailable() bool {
+	return s.OIDC != nil && s.OIDC.Config().Enabled() && s.BaseURL != ""
+}
+
+// oidcStart redirects to the IdP with state and PKCE.
+//
+// PKCE even though this is a confidential client: it costs one hash and closes code interception
+// independently of the secret, which is worth having when the redirect crosses a browser.
+func (s *Server) oidcStart(w http.ResponseWriter, r *http.Request) {
+	if !s.oidcAvailable() {
+		http.Error(w, "no identity provider is configured on this server", http.StatusNotImplemented)
+		return
+	}
+	d, err := s.OIDC.Discover(r.Context())
+	if err != nil {
+		http.Error(w, "identity provider unreachable: "+err.Error(), http.StatusBadGateway)
+		return
+	}
+	state, verifier := randomToken(), randomToken()
+	challenge := sha256.Sum256([]byte(verifier))
+
+	// state and the PKCE verifier ride in one short-lived cookie: the callback must prove it
+	// belongs to the browser that started the flow, or an attacker can feed us their own code.
+	http.SetCookie(w, &http.Cookie{
+		Name: stateCookie, Value: state + "." + verifier, Path: "/",
+		HttpOnly: true, Secure: s.Secure, SameSite: http.SameSiteLaxMode, MaxAge: 600,
+	})
+
+	q := url.Values{
+		"response_type":         {"code"},
+		"client_id":             {s.OIDC.Config().ClientID},
+		"redirect_uri":          {s.redirectURI()},
+		"scope":                 {"openid profile email"},
+		"state":                 {state},
+		"code_challenge":        {base64.RawURLEncoding.EncodeToString(challenge[:])},
+		"code_challenge_method": {"S256"},
+	}
+	http.Redirect(w, r, d.AuthorizationEndpoint+"?"+q.Encode(), http.StatusSeeOther)
+}
+
+func (s *Server) redirectURI() string {
+	return strings.TrimRight(s.BaseURL, "/") + "/admin/callback"
+}
+
+func (s *Server) oidcCallback(w http.ResponseWriter, r *http.Request) {
+	if !s.oidcAvailable() {
+		http.Error(w, "no identity provider configured", http.StatusNotImplemented)
+		return
+	}
+	c, err := r.Cookie(stateCookie)
+	if err != nil {
+		http.Error(w, "sign-in did not start here — try again from the login page", http.StatusBadRequest)
+		return
+	}
+	http.SetCookie(w, &http.Cookie{Name: stateCookie, Value: "", Path: "/", MaxAge: -1})
+
+	state, verifier, ok := strings.Cut(c.Value, ".")
+	if !ok || state == "" || r.URL.Query().Get("state") != state {
+		http.Error(w, "sign-in state did not match — start again", http.StatusBadRequest)
+		return
+	}
+	code := r.URL.Query().Get("code")
+	if code == "" {
+		http.Error(w, "no authorization code returned: "+r.URL.Query().Get("error"), http.StatusBadRequest)
+		return
+	}
+
+	idToken, err := s.exchange(r.Context(), code, verifier)
+	if err != nil {
+		slog.Info("admin oidc exchange failed", "err", err, "from", clientIP(r))
+		http.Error(w, "could not complete sign-in", http.StatusBadGateway)
+		return
+	}
+	claims, err := s.OIDC.Verify(r.Context(), idToken)
+	if err != nil {
+		slog.Info("admin oidc token rejected", "err", err, "from", clientIP(r))
+		http.Error(w, "the identity token was not accepted", http.StatusForbidden)
+		return
+	}
+	if !s.OIDC.IsAdmin(claims) {
+		// Named explicitly: "you signed in but you are not an admin" is a different problem from
+		// "your password is wrong", and the group is the thing to go and check.
+		slog.Info("admin access denied: not in group", "account", claims.AccountID(),
+			"want_group", s.OIDC.Config().AdminGroup, "have", claims.Groups)
+		http.Error(w, fmt.Sprintf(
+			"Signed in as %s, but that account is not in the %q group, so it cannot administer "+
+				"this server.", claims.Display(), s.OIDC.Config().AdminGroup), http.StatusForbidden)
+		return
+	}
+	slog.Info("admin login", "account", claims.AccountID(), "method", "oidc", "from", clientIP(r))
+	s.setSession(w, claims.AccountID(), claims.Display())
+	http.Redirect(w, r, "/", http.StatusSeeOther)
+}
+
+// exchange trades the authorization code for tokens at the IdP.
+func (s *Server) exchange(ctx context.Context, code, verifier string) (string, error) {
+	d, err := s.OIDC.Discover(ctx)
+	if err != nil {
+		return "", err
+	}
+	form := url.Values{
+		"grant_type":    {"authorization_code"},
+		"code":          {code},
+		"redirect_uri":  {s.redirectURI()},
+		"client_id":     {s.OIDC.Config().ClientID},
+		"code_verifier": {verifier},
+	}
+	if s.ClientSecret != "" {
+		form.Set("client_secret", s.ClientSecret)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, d.TokenEndpoint,
+		strings.NewReader(form.Encode()))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := (&http.Client{Timeout: 15 * time.Second}).Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("token endpoint: %s: %s", resp.Status, strings.TrimSpace(string(body)))
+	}
+	var tok struct {
+		IDToken string `json:"id_token"`
+	}
+	if err := json.Unmarshal(body, &tok); err != nil {
+		return "", err
+	}
+	if tok.IDToken == "" {
+		return "", fmt.Errorf("token endpoint returned no id_token")
+	}
+	return tok.IDToken, nil
+}
+
+func randomToken() string {
+	b := make([]byte, 32)
+	_, _ = rand.Read(b)
+	return base64.RawURLEncoding.EncodeToString(b)
+}
+
+// clientIP is for logs only. X-Forwarded-For is deliberately ignored: nothing is meant to sit in
+// front of this listener, so a header claiming otherwise is a caller's assertion about itself.
+func clientIP(r *http.Request) string {
+	if i := strings.LastIndex(r.RemoteAddr, ":"); i > 0 {
+		return r.RemoteAddr[:i]
+	}
+	return r.RemoteAddr
+}

server/internal/adminui/pages.go

@@ -0,0 +1,168 @@
+// SPDX-FileCopyrightText: 2026 Echolot contributors
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package adminui
+
+import (
+	"encoding/json"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"sort"
+	"time"
+
+	"echo-lot.app/server/internal/adminauth"
+	"echo-lot.app/server/internal/runs"
+	"echo-lot.app/server/internal/store"
+)
+
+func (s *Server) loginForm(w http.ResponseWriter, r *http.Request) {
+	if s.session(r) != nil {
+		http.Redirect(w, r, "/", http.StatusSeeOther)
+		return
+	}
+	s.render(w, r, "login", map[string]any{
+		"OIDC":      s.oidcAvailable(),
+		"LocalSet":  s.Store.LocalAdmin() != nil,
+		"AdminUser": s.AdminUser,
+	})
+}
+
+func (s *Server) dashboard(w http.ResponseWriter, r *http.Request, sess *adminauth.Session) {
+	devices := s.Store.Devices()
+	linked := 0
+	for _, d := range devices {
+		if d.LinkedToAccount() {
+			linked++
+		}
+	}
+	var selftest any
+	if s.SelfTest != nil {
+		selftest = s.SelfTest()
+	}
+	s.render(w, r, "dashboard", map[string]any{
+		"Session":  sess,
+		"CSRF":     s.csrfToken(sess),
+		"Devices":  len(devices),
+		"Linked":   linked,
+		"Runs":     s.totalRuns(devices),
+		"SelfTest": selftest,
+		"Version":  s.Version,
+	})
+}
+
+func (s *Server) totalRuns(devices []store.Device) int {
+	if s.Runs == nil {
+		return 0
+	}
+	n := 0
+	for _, d := range devices {
+		n += len(s.Runs.List(d.ID))
+	}
+	return n
+}
+
+func (s *Server) devices(w http.ResponseWriter, r *http.Request, sess *adminauth.Session) {
+	devices := s.Store.Devices()
+	// Newest first: the device someone is looking for is almost always the one just enrolled.
+	sort.Slice(devices, func(i, j int) bool { return devices[i].Enrolled.After(devices[j].Enrolled) })
+
+	type row struct {
+		store.Device
+		Runs int
+	}
+	rows := make([]row, 0, len(devices))
+	for _, d := range devices {
+		n := 0
+		if s.Runs != nil {
+			n = len(s.Runs.List(d.ID))
+		}
+		rows = append(rows, row{Device: d, Runs: n})
+	}
+	s.render(w, r, "devices", map[string]any{
+		"Session": sess, "CSRF": s.csrfToken(sess), "Rows": rows,
+		"Link": r.URL.Query().Get("link"),
+	})
+}
+
+func (s *Server) revokeDevice(w http.ResponseWriter, r *http.Request, sess *adminauth.Session) {
+	id := r.PathValue("id")
+	if err := s.Store.DeleteDevice(id); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	// Worth a log line: revoking a device is destructive, immediate, and someone will eventually
+	// want to know who did it and when.
+	slog.Info("device revoked", "device", id, "by", sess.Subject)
+	http.Redirect(w, r, "/devices", http.StatusSeeOther)
+}
+
+func (s *Server) mintToken(w http.ResponseWriter, r *http.Request, sess *adminauth.Session) {
+	tok, err := s.Store.NewEnrollToken(24*time.Hour, "admin-ui")
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	slog.Info("enrolment token minted", "by", sess.Subject)
+	// The whole link, not the bare token: it carries the URL and the pin as well, and assembling
+	// those by hand is where an operator gets a pin wrong by one character.
+	http.Redirect(w, r, "/devices?link="+url.QueryEscape(s.EnrollLink(tok)), http.StatusSeeOther)
+}
+
+// EnrollLink is supplied by the caller so this package does not need the control server's pin.
+var _ = 0
+
+func (s *Server) runsList(w http.ResponseWriter, r *http.Request, sess *adminauth.Session) {
+	type row struct {
+		runs.Meta
+		DeviceName string
+	}
+	var rows []row
+	for _, d := range s.Store.Devices() {
+		if s.Runs == nil {
+			break
+		}
+		name := d.Name
+		if name == "" {
+			name = d.ID
+		}
+		for _, m := range s.Runs.List(d.ID) {
+			rows = append(rows, row{Meta: m, DeviceName: name})
+		}
+	}
+	sort.Slice(rows, func(i, j int) bool { return rows[i].UploadedAt.After(rows[j].UploadedAt) })
+	if len(rows) > 200 {
+		rows = rows[:200] // a page, not the archive; the count is on the dashboard
+	}
+	s.render(w, r, "runs", map[string]any{"Session": sess, "CSRF": s.csrfToken(sess), "Rows": rows})
+}
+
+func (s *Server) runView(w http.ResponseWriter, r *http.Request, sess *adminauth.Session) {
+	body, err := s.Runs.Get(r.PathValue("device"), r.PathValue("id"))
+	if err != nil {
+		http.NotFound(w, r)
+		return
+	}
+	// Re-indented for reading, but otherwise exactly what was stored. An admin sees the document
+	// at the privacy level its uploader chose — there is nothing here that can un-redact it.
+	var pretty json.RawMessage = body
+	out, err := json.MarshalIndent(json.RawMessage(pretty), "", "  ")
+	if err != nil {
+		out = body
+	}
+	s.render(w, r, "run", map[string]any{
+		"Session": sess, "CSRF": s.csrfToken(sess),
+		"Device": r.PathValue("device"), "ID": r.PathValue("id"),
+		"JSON": string(out),
+	})
+}
+
+func (s *Server) runDelete(w http.ResponseWriter, r *http.Request, sess *adminauth.Session) {
+	device, id := r.PathValue("device"), r.PathValue("id")
+	if err := s.Runs.Delete(device, id); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	slog.Info("run deleted", "device", device, "run", id, "by", sess.Subject)
+	http.Redirect(w, r, "/runs", http.StatusSeeOther)
+}

server/internal/adminui/render.go

@@ -0,0 +1,170 @@
+// SPDX-FileCopyrightText: 2026 Echolot contributors
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package adminui
+
+import (
+	"bytes"
+	"html/template"
+	"log/slog"
+	"net/http"
+)
+
+// Templates are parsed once at start. html/template escapes by context, which is what makes it
+// safe to render device names and finding text that ultimately arrived over a network.
+var tpl = template.Must(template.New("base").Funcs(template.FuncMap{
+	"kb": func(n int64) int64 { return n / 1024 },
+}).Parse(baseHTML))
+
+func (s *Server) render(w http.ResponseWriter, r *http.Request, page string, data map[string]any) {
+	data["Page"] = page
+	var buf bytes.Buffer
+	if err := tpl.Execute(&buf, data); err != nil {
+		slog.Error("admin template", "page", page, "err", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	// There is no script here and nothing loaded from anywhere else, so a strict policy costs
+	// nothing and closes injected-script attacks even if an escaping bug ever slips through.
+	w.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'; form-action 'self'")
+	w.Header().Set("Referrer-Policy", "no-referrer")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	_, _ = buf.WriteTo(w)
+}
+
+const baseHTML = `<!doctype html>
+<html lang="en"><head><meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<title>Echolot &mdash; {{.Page}}</title>
+<style>
+ :root{color-scheme:dark}
+ body{font:15px/1.5 system-ui,sans-serif;margin:0;background:#14161a;color:#e6e6e6}
+ header{display:flex;gap:1.2rem;align-items:baseline;padding:.8rem 1.2rem;background:#1c1f25;border-bottom:1px solid #2b2f36}
+ header h1{font-size:1.1rem;margin:0;font-weight:600}
+ header nav a{color:#9ecbff;text-decoration:none;margin-right:1rem}
+ header .who{margin-left:auto;color:#9aa3ad;font-size:.9rem}
+ main{padding:1.2rem;max-width:70rem}
+ table{border-collapse:collapse;width:100%;margin:.6rem 0}
+ th,td{text-align:left;padding:.45rem .6rem;border-bottom:1px solid #2b2f36;vertical-align:top}
+ th{color:#9aa3ad;font-weight:500;font-size:.85rem}
+ code,pre{font-family:ui-monospace,monospace;font-size:.85rem}
+ pre{background:#0f1114;padding:.8rem;border-radius:6px;overflow:auto;max-height:34rem}
+ .card{background:#1c1f25;border:1px solid #2b2f36;border-radius:8px;padding:1rem;margin:.8rem 0}
+ .grid{display:flex;gap:1rem;flex-wrap:wrap}
+ .stat{background:#1c1f25;border:1px solid #2b2f36;border-radius:8px;padding:.8rem 1.2rem;min-width:8rem}
+ .stat b{display:block;font-size:1.6rem;font-weight:600}
+ .stat span{color:#9aa3ad;font-size:.85rem}
+ button{font:inherit;background:#2d6cdf;color:#fff;border:0;border-radius:6px;padding:.4rem .8rem;cursor:pointer}
+ button.danger{background:#8b2f2f}
+ button.plain{background:#3a3f47}
+ input{font:inherit;background:#0f1114;color:#e6e6e6;border:1px solid #2b2f36;border-radius:6px;padding:.4rem .6rem}
+ .err{background:#3a1f1f;border:1px solid #7a3b3b;padding:.6rem .8rem;border-radius:6px}
+ .muted{color:#9aa3ad}
+ form.inline{display:inline}
+</style></head><body>
+{{if ne .Page "login"}}
+<header>
+  <h1>Echolot</h1>
+  <nav><a href="/">Overview</a><a href="/devices">Devices</a><a href="/runs">Runs</a></nav>
+  <span class="who">{{.Session.Display}}
+    <form method="post" action="/logout" class="inline"><button class="plain">Sign out</button></form>
+  </span>
+</header>
+{{end}}
+<main>
+
+{{if eq .Page "login"}}
+  <h2>Sign in</h2>
+  {{with .Error}}<p class="err">{{.}}</p>{{end}}
+  {{if .OIDC}}
+    <p><a href="/auth/start"><button>Sign in with your identity provider</button></a></p>
+    <p class="muted">or use the break-glass account:</p>
+  {{end}}
+  {{if .LocalSet}}
+    <form method="post" action="/login" class="card">
+      <p><label>Username<br><input name="username" value="{{.AdminUser}}" autocomplete="username"></label></p>
+      <p><label>Password<br><input name="password" type="password" autocomplete="current-password"></label></p>
+      <p><button>Sign in</button></p>
+    </form>
+  {{else}}
+    <p class="err">No break-glass admin is set. Run
+      <code>echolot-server --set-admin-password</code> on the host.</p>
+  {{end}}
+
+{{else if eq .Page "dashboard"}}
+  <div class="grid">
+    <div class="stat"><b>{{.Devices}}</b><span>devices</span></div>
+    <div class="stat"><b>{{.Linked}}</b><span>signed in</span></div>
+    <div class="stat"><b>{{.Runs}}</b><span>stored runs</span></div>
+  </div>
+  <div class="card">
+    <h3>Server</h3>
+    <p class="muted">version {{.Version}}</p>
+    {{with .SelfTest}}<pre>{{printf "%+v" .}}</pre>{{end}}
+  </div>
+
+{{else if eq .Page "devices"}}
+  <h2>Devices</h2>
+  {{with .Link}}
+  <div class="card">
+    <p><b>Enrolment link</b> &mdash; single use, valid 24 hours. Treat it like a password until spent.</p>
+    <p><code>{{.}}</code></p>
+    <p class="muted">On a device with adb:<br>
+      <code>adb shell am start -a android.intent.action.VIEW -d "{{.}}"</code></p>
+  </div>
+  {{end}}
+  <form method="post" action="/enroll-tokens">
+    <input type="hidden" name="csrf" value="{{.CSRF}}">
+    <button>Create enrolment link</button>
+  </form>
+  <table>
+    <tr><th>Device</th><th>Name</th><th>Account</th><th>Enrolled</th><th>Runs</th><th></th></tr>
+    {{range .Rows}}
+    <tr>
+      <td><code>{{.ID}}</code></td>
+      <td>{{if .Name}}{{.Name}}{{else}}<span class="muted">&mdash;</span>{{end}}</td>
+      <td>{{if .LinkedToAccount}}{{.AccountName}}{{else}}<span class="muted">not signed in</span>{{end}}</td>
+      <td>{{.Enrolled.Format "2006-01-02 15:04"}}</td>
+      <td>{{.Runs}}</td>
+      <td><form method="post" action="/devices/{{.ID}}/revoke" class="inline">
+        <input type="hidden" name="csrf" value="{{$.CSRF}}">
+        <button class="danger">Revoke</button></form></td>
+    </tr>
+    {{else}}
+    <tr><td colspan="6" class="muted">No devices enrolled.</td></tr>
+    {{end}}
+  </table>
+
+{{else if eq .Page "runs"}}
+  <h2>Uploaded runs</h2>
+  <p class="muted">Shown exactly as uploaded, at the privacy level the uploader chose. Nothing
+    here can un-redact a run.</p>
+  <table>
+    <tr><th>Uploaded</th><th>Device</th><th>Verdict</th><th>Findings</th><th>Size</th><th>Level</th><th></th></tr>
+    {{range .Rows}}
+    <tr>
+      <td>{{.UploadedAt.Format "2006-01-02 15:04"}}</td>
+      <td>{{.DeviceName}}</td>
+      <td>{{if .Verdict}}{{.Verdict}}{{else}}<span class="muted">&mdash;</span>{{end}}</td>
+      <td>{{.FindingCount}}</td>
+      <td>{{kb .SizeBytes}} kB</td>
+      <td>{{.Anonymization}}</td>
+      <td><a href="/runs/{{.DeviceID}}/{{.ID}}">open</a></td>
+    </tr>
+    {{else}}
+    <tr><td colspan="7" class="muted">Nothing uploaded yet.</td></tr>
+    {{end}}
+  </table>
+
+{{else if eq .Page "run"}}
+  <h2>Run {{.ID}}</h2>
+  <form method="post" action="/runs/{{.Device}}/{{.ID}}/delete" class="inline">
+    <input type="hidden" name="csrf" value="{{.CSRF}}">
+    <button class="danger">Delete this run</button>
+  </form>
+  <pre>{{.JSON}}</pre>
+{{end}}
+
+</main></body></html>
+`