1
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forked from wrenn/wrenn

Enforce mandatory mTLS for CP↔agent communication

Both the control plane and host agent now refuse to start without valid
mTLS configuration, closing the unauthenticated proxy/RPC attack surface
that existed when running in plain HTTP fallback mode.
This commit is contained in:
2026-04-08 02:25:43 +06:00
parent 2737288a2b
commit c8615466be
2 changed files with 59 additions and 80 deletions

View File

@ -69,52 +69,44 @@ func main() {
}
slog.Info("connected to redis")
// mTLS: parse internal CA and build a TLS-capable host client pool.
// When CA env vars are absent the pool falls back to plain HTTP (dev mode).
var ca *auth.CA
if cfg.CACert != "" && cfg.CAKey != "" {
var err error
ca, err = auth.ParseCA(cfg.CACert, cfg.CAKey)
if err != nil {
slog.Error("failed to parse mTLS CA from environment", "error", err)
os.Exit(1)
}
slog.Info("mTLS enabled: CA loaded")
} else {
slog.Warn("mTLS disabled: WRENN_CA_CERT/WRENN_CA_KEY not set — host agent connections are unencrypted")
// mTLS is mandatory — parse internal CA for CP↔agent communication.
if cfg.CACert == "" || cfg.CAKey == "" {
slog.Error("WRENN_CA_CERT and WRENN_CA_KEY are required — mTLS is mandatory for CP↔agent communication")
os.Exit(1)
}
ca, err := auth.ParseCA(cfg.CACert, cfg.CAKey)
if err != nil {
slog.Error("failed to parse mTLS CA from environment", "error", err)
os.Exit(1)
}
slog.Info("mTLS enabled: CA loaded")
// Host client pool — manages Connect RPC clients to host agents.
var hostPool *lifecycle.HostClientPool
if ca != nil {
cpCertStore, err := auth.NewCPCertStore(ca)
if err != nil {
slog.Error("failed to issue CP client certificate", "error", err)
os.Exit(1)
}
// Renew the CP client certificate periodically so it never expires
// while the control plane is running (TTL = 24h, renewal = every 12h).
go func() {
ticker := time.NewTicker(auth.CPCertRenewInterval)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
return
case <-ticker.C:
if err := cpCertStore.Refresh(); err != nil {
slog.Error("failed to renew CP client certificate", "error", err)
} else {
slog.Info("CP client certificate renewed")
}
cpCertStore, err := auth.NewCPCertStore(ca)
if err != nil {
slog.Error("failed to issue CP client certificate", "error", err)
os.Exit(1)
}
// Renew the CP client certificate periodically so it never expires
// while the control plane is running (TTL = 24h, renewal = every 12h).
go func() {
ticker := time.NewTicker(auth.CPCertRenewInterval)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
return
case <-ticker.C:
if err := cpCertStore.Refresh(); err != nil {
slog.Error("failed to renew CP client certificate", "error", err)
} else {
slog.Info("CP client certificate renewed")
}
}
}()
hostPool = lifecycle.NewHostClientPoolTLS(auth.CPClientTLSConfig(ca, cpCertStore))
slog.Info("host client pool: mTLS enabled")
} else {
hostPool = lifecycle.NewHostClientPool()
}
}
}()
hostPool := lifecycle.NewHostClientPoolTLS(auth.CPClientTLSConfig(ca, cpCertStore))
slog.Info("host client pool: mTLS enabled")
// Scheduler — picks a host for each new sandbox (round-robin for now).
hostScheduler := scheduler.NewRoundRobinScheduler(queries)

View File

@ -5,7 +5,6 @@ import (
"crypto/tls"
"flag"
"log/slog"
"net"
"net/http"
"os"
"os/signal"
@ -99,23 +98,23 @@ func main() {
// httpServer is declared here so the shutdown func can reference it.
httpServer := &http.Server{Addr: listenAddr}
// Set up mTLS if the CP issued a certificate during registration.
// mTLS is mandatory — refuse to start without a valid certificate.
var certStore hostagent.CertStore
if creds.CertPEM != "" && creds.KeyPEM != "" && creds.CACertPEM != "" {
if err := certStore.ParseAndStore(creds.CertPEM, creds.KeyPEM); err != nil {
slog.Error("failed to load host TLS certificate", "error", err)
os.Exit(1)
}
tlsCfg := auth.AgentTLSConfigFromPEM(creds.CACertPEM, certStore.GetCert)
if tlsCfg == nil {
slog.Error("failed to build agent TLS config: invalid CA certificate PEM")
os.Exit(1)
}
httpServer.TLSConfig = tlsCfg
slog.Info("mTLS enabled on agent server")
} else {
slog.Warn("mTLS disabled: no certificate received from CP — agent serving plain HTTP")
if creds.CertPEM == "" || creds.KeyPEM == "" || creds.CACertPEM == "" {
slog.Error("mTLS certificate not received from CP — ensure WRENN_CA_CERT and WRENN_CA_KEY are configured on the control plane")
os.Exit(1)
}
if err := certStore.ParseAndStore(creds.CertPEM, creds.KeyPEM); err != nil {
slog.Error("failed to load host TLS certificate", "error", err)
os.Exit(1)
}
tlsCfg := auth.AgentTLSConfigFromPEM(creds.CACertPEM, certStore.GetCert)
if tlsCfg == nil {
slog.Error("failed to build agent TLS config: invalid CA certificate PEM")
os.Exit(1)
}
httpServer.TLSConfig = tlsCfg
slog.Info("mTLS enabled on agent server")
// doShutdown is the single shutdown path. sync.Once ensures mgr.Shutdown
// and httpServer.Shutdown are each called exactly once regardless of
@ -182,29 +181,17 @@ func main() {
}()
slog.Info("host agent starting", "addr", listenAddr, "host_id", creds.HostID)
if httpServer.TLSConfig != nil {
// When TLSConfig is pre-populated (cert via GetCertificate callback),
// ListenAndServeTLS does not work because it requires on-disk cert/key paths.
// Instead, create the TLS listener manually and call Serve.
ln, err := tls.Listen("tcp", listenAddr, httpServer.TLSConfig)
if err != nil {
slog.Error("failed to start TLS listener", "error", err)
os.Exit(1)
}
if err := httpServer.Serve(ln); err != nil && err != http.ErrServerClosed {
slog.Error("https server error", "error", err)
os.Exit(1)
}
} else {
ln, err := net.Listen("tcp", listenAddr)
if err != nil {
slog.Error("failed to start listener", "error", err)
os.Exit(1)
}
if err := httpServer.Serve(ln); err != nil && err != http.ErrServerClosed {
slog.Error("http server error", "error", err)
os.Exit(1)
}
// TLSConfig is always set (mTLS is mandatory). Create the TLS listener
// manually because ListenAndServeTLS requires on-disk cert/key paths
// but we use GetCertificate callback for hot-swap support.
ln, err := tls.Listen("tcp", listenAddr, httpServer.TLSConfig)
if err != nil {
slog.Error("failed to start TLS listener", "error", err)
os.Exit(1)
}
if err := httpServer.Serve(ln); err != nil && err != http.ErrServerClosed {
slog.Error("https server error", "error", err)
os.Exit(1)
}
slog.Info("host agent stopped")