cmd/derper: add GCP Certificate Manager support (#18161)

Add --certmode=gcp for using Google Cloud Certificate Manager's
public CA instead of Let's Encrypt. GCP requires External Account
Binding (EAB) credentials for ACME registration, so this adds
--acme-eab-kid and --acme-eab-key flags.

The EAB key accepts both base64url and standard base64 encoding
to support both ACME spec format and gcloud output.

Fixes tailscale/corp#34881

Signed-off-by: Raj Singh <raj@tailscale.com>
Co-authored-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Raj Singh
2025-12-10 04:51:53 +05:30
committed by GitHub
parent 1dfdee8521
commit 8eda947530
4 changed files with 76 additions and 8 deletions
+6 -4
View File
@@ -60,9 +60,11 @@ var (
httpPort = flag.Int("http-port", 80, "The port on which to serve HTTP. Set to -1 to disable. The listener is bound to the same IP (if any) as specified in the -a flag.")
stunPort = flag.Int("stun-port", 3478, "The UDP port on which to serve STUN. The listener is bound to the same IP (if any) as specified in the -a flag.")
configPath = flag.String("c", "", "config file path")
certMode = flag.String("certmode", "letsencrypt", "mode for getting a cert. possible options: manual, letsencrypt")
certDir = flag.String("certdir", tsweb.DefaultCertDir("derper-certs"), "directory to store LetsEncrypt certs, if addr's port is :443")
hostname = flag.String("hostname", "derp.tailscale.com", "LetsEncrypt host name, if addr's port is :443. When --certmode=manual, this can be an IP address to avoid SNI checks")
certMode = flag.String("certmode", "letsencrypt", "mode for getting a cert. possible options: manual, letsencrypt, gcp")
certDir = flag.String("certdir", tsweb.DefaultCertDir("derper-certs"), "directory to store ACME (e.g. LetsEncrypt) certs, if addr's port is :443")
hostname = flag.String("hostname", "derp.tailscale.com", "TLS host name for certs, if addr's port is :443. When --certmode=manual, this can be an IP address to avoid SNI checks")
acmeEABKid = flag.String("acme-eab-kid", "", "ACME External Account Binding (EAB) Key ID (required for --certmode=gcp)")
acmeEABKey = flag.String("acme-eab-key", "", "ACME External Account Binding (EAB) HMAC key, base64-encoded (required for --certmode=gcp)")
runSTUN = flag.Bool("stun", true, "whether to run a STUN server. It will bind to the same IP (if any) as the --addr flag value.")
runDERP = flag.Bool("derp", true, "whether to run a DERP server. The only reason to set this false is if you're decommissioning a server but want to keep its bootstrap DNS functionality still running.")
flagHome = flag.String("home", "", "what to serve at the root path. It may be left empty (the default, for a default homepage), \"blank\" for a blank page, or a URL to redirect to")
@@ -343,7 +345,7 @@ func main() {
if serveTLS {
log.Printf("derper: serving on %s with TLS", *addr)
var certManager certProvider
certManager, err = certProviderByCertMode(*certMode, *certDir, *hostname)
certManager, err = certProviderByCertMode(*certMode, *certDir, *hostname, *acmeEABKid, *acmeEABKey)
if err != nil {
log.Fatalf("derper: can not start cert provider: %v", err)
}