Files
diskless-workstation/serving/enrol-broker/admin.go
T
2026-06-28 10:33:14 +00:00

202 lines
7.1 KiB
Go

// admin.go — the mTLS admin plane: the pending-queue web UI + approve/deny.
//
// This listener is the AUTHENTICATED half of the broker and must live on the
// management network / loopback only — NEVER the boot LAN (docs invariant: the
// management plane is recon-valuable). Admins authenticate with a client cert
// issued by the fleet CA; the cert CN is recorded as who approved each enrolment.
// The fingerprint shown here is what the admin cross-checks against the device's
// Plymouth splash before approving (the human OOB gate).
package main
import (
"crypto/tls"
"crypto/x509"
"html/template"
"log"
"net/http"
"os"
"time"
)
func (b *broker) serveAdmin() {
mux := http.NewServeMux()
mux.HandleFunc("GET /", b.handleAdminIndex)
mux.HandleFunc("GET /pending", b.handleAdminPending)
mux.HandleFunc("POST /approve/{id}", b.handleApprove)
mux.HandleFunc("POST /deny/{id}", b.handleDeny)
srv := &http.Server{
Addr: b.cfg.adminAddr,
Handler: mux,
ReadHeaderTimeout: 5 * time.Second,
ReadTimeout: 10 * time.Second,
WriteTimeout: 40 * time.Second, // approve blocks on step-ca
IdleTimeout: 60 * time.Second,
}
if b.cfg.adminInsecure {
log.Printf("WARNING: BROKER_ADMIN_INSECURE=true — admin UI is PLAINTEXT with NO client-cert auth. DEV ONLY. Bind to loopback and never expose it.")
log.Fatalf("admin listener: %v", srv.ListenAndServe())
return
}
if b.cfg.adminCert == "" || b.cfg.adminKey == "" || b.cfg.adminClientCA == "" {
log.Fatalf("admin mTLS requires BROKER_ADMIN_CERT, BROKER_ADMIN_KEY and BROKER_ADMIN_CLIENT_CA (or set BROKER_ADMIN_INSECURE=true for dev)")
}
cert, err := tls.LoadX509KeyPair(b.cfg.adminCert, b.cfg.adminKey)
if err != nil {
log.Fatalf("admin server cert: %v", err)
}
caPEM, err := os.ReadFile(b.cfg.adminClientCA)
if err != nil {
log.Fatalf("admin client CA: %v", err)
}
pool := x509.NewCertPool()
if !pool.AppendCertsFromPEM(caPEM) {
log.Fatalf("admin client CA %s contains no certificates", b.cfg.adminClientCA)
}
srv.TLSConfig = &tls.Config{
Certificates: []tls.Certificate{cert},
ClientAuth: tls.RequireAndVerifyClientCert,
ClientCAs: pool,
MinVersion: tls.VersionTLS12,
}
log.Fatalf("admin listener: %v", srv.ListenAndServeTLS("", ""))
}
func adminCN(r *http.Request) string {
if r.TLS != nil && len(r.TLS.PeerCertificates) > 0 {
if cn := r.TLS.PeerCertificates[0].Subject.CommonName; cn != "" {
return cn
}
return "unknown-admin"
}
return "dev-insecure"
}
func (b *broker) handleAdminPending(w http.ResponseWriter, _ *http.Request) {
writeJSON(w, http.StatusOK, b.store.Pending())
}
func (b *broker) handleApprove(w http.ResponseWriter, r *http.Request) {
id := r.PathValue("id")
admin := adminCN(r)
csrPEM, ok := b.store.csrFor(id)
if !ok {
http.Error(w, "enrol-id not pending (expired/decided/unknown)", http.StatusConflict)
return
}
csr, err := parseCSR(csrPEM)
if err != nil {
http.Error(w, "stored CSR unparsable: "+err.Error(), http.StatusInternalServerError)
return
}
ctx, cancel := ctxWithTimeout(35 * time.Second)
defer cancel()
certPEM, serial, err := b.signer.Sign(ctx, csrPEM, csr.Subject.CommonName)
if err != nil {
log.Printf("audit approve-FAILED id=%s admin=%q err=%v", id, admin, err)
http.Error(w, "signing failed: "+err.Error(), http.StatusBadGateway)
return
}
e, err := b.store.Approve(id, certPEM, serial, admin)
if err != nil {
http.Error(w, err.Error(), http.StatusConflict)
return
}
log.Printf("audit APPROVE id=%s cn=%q serial=%s hostnqn=%s admin=%q", e.ID, e.CN, e.CertSerial, e.Hostnqn, admin)
redirectOrJSON(w, r)
}
func (b *broker) handleDeny(w http.ResponseWriter, r *http.Request) {
id := r.PathValue("id")
admin := adminCN(r)
e, err := b.store.Deny(id, admin)
if err != nil {
http.Error(w, err.Error(), http.StatusConflict)
return
}
log.Printf("audit DENY id=%s cn=%q admin=%q", e.ID, e.CN, admin)
redirectOrJSON(w, r)
}
// redirectOrJSON sends a browser form back to the queue, or a 204 for API callers.
func redirectOrJSON(w http.ResponseWriter, r *http.Request) {
if isBrowser(r) {
http.Redirect(w, r, "/", http.StatusSeeOther)
return
}
w.WriteHeader(http.StatusNoContent)
}
func isBrowser(r *http.Request) bool {
a := r.Header.Get("Accept")
return len(a) >= 9 && a[:9] == "text/html" || // explicit
r.Header.Get("Sec-Fetch-Mode") == "navigate"
}
func (b *broker) handleAdminIndex(w http.ResponseWriter, r *http.Request) {
data := struct {
Admin string
Pending []*Enrolment
Now time.Time
}{
Admin: adminCN(r),
Pending: b.store.Pending(),
Now: time.Now(),
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
if err := adminTmpl.Execute(w, data); err != nil {
log.Printf("admin template: %v", err)
}
}
var adminTmpl = template.Must(template.New("admin").Funcs(template.FuncMap{
"age": func(t time.Time) string { return time.Since(t).Round(time.Second).String() },
}).Parse(adminHTML))
const adminHTML = `<!doctype html>
<html lang="en"><head><meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>fleet enrolment — pending</title>
<style>
:root{color-scheme:dark}
body{background:#0b0f14;color:#cfe3ee;font:14px/1.5 ui-monospace,Menlo,Consolas,monospace;margin:0;padding:1.5rem}
h1{font-size:1.1rem;color:#7fd1ff;margin:0 0 .25rem}
.sub{color:#6b8294;margin:0 0 1.25rem}
.empty{color:#6b8294;padding:2rem 0}
.card{background:#111923;border:1px solid #1f2d3a;border-radius:8px;padding:1rem 1.1rem;margin:0 0 1rem}
.fp{font-size:1.25rem;color:#aef9b0;letter-spacing:.5px;word-break:break-word}
.meta{display:grid;grid-template-columns:max-content 1fr;gap:.1rem .8rem;margin:.6rem 0;color:#9fb6c4}
.meta b{color:#6b8294;font-weight:400}
.actions{margin-top:.7rem}
button{font:inherit;border:0;border-radius:6px;padding:.45rem .9rem;cursor:pointer}
.approve{background:#15602f;color:#d6ffe0}
.deny{background:#5e1b1b;color:#ffd9d9;margin-left:.5rem}
form{display:inline}
code{color:#cfe3ee}
</style></head><body>
<h1>fleet enrolment — pending approvals</h1>
<p class="sub">admin: <code>{{.Admin}}</code> · {{len .Pending}} pending · cross-check each fingerprint against the device's splash before approving</p>
{{if not .Pending}}<div class="empty">no pending enrolments.</div>{{end}}
{{range .Pending}}
<div class="card">
<div class="fp">{{.Fingerprint}}</div>
<div class="meta">
<b>enrol-id</b><code>{{.ID}}</code>
<b>CN</b><code>{{.CN}}</code>
{{if .Context.MAC}}<b>MAC</b><code>{{.Context.MAC}}</code>{{end}}
{{if .Context.DMISerial}}<b>DMI serial</b><code>{{.Context.DMISerial}}</code>{{end}}
{{if .Context.DMIUUID}}<b>DMI uuid</b><code>{{.Context.DMIUUID}}</code>{{end}}
{{if .Context.EKHash}}<b>TPM EK</b><code>{{.Context.EKHash}}</code>{{end}}
<b>pubkey</b><code>{{.PubKeyHash}}</code>
<b>age</b><code>{{age .CreatedAt}}</code>
</div>
<div class="actions">
<form method="post" action="/approve/{{.ID}}"><button class="approve" type="submit">approve</button></form>
<form method="post" action="/deny/{{.ID}}"><button class="deny" type="submit">deny</button></form>
</div>
</div>
{{end}}
</body></html>`