key_expiry.go

package main

import (
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/rsa"
	"fmt"
	"net"
	"os"

	"golang.org/x/crypto/ssh"
	"golang.org/x/crypto/ssh/agent"
)

func main() {
	// rsa key + cert
	pr, _ := rsa.GenerateKey(rand.Reader, 2048)
	r, _ := ssh.NewPublicKey(&pr.PublicKey)
	cr := &ssh.Certificate{
		Key:         r,
		CertType:    ssh.UserCert,
		ValidBefore: ssh.CertTimeInfinity,
	}
	signer, _ := ssh.NewSignerFromKey(pr)
	cr.SignCert(rand.Reader, signer)

	// ecdsa key + cert
	pe, _ := ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
	e, _ := ssh.NewPublicKey(&pe.PublicKey)
	ce := &ssh.Certificate{
		Key:         e,
		CertType:    ssh.UserCert,
		ValidBefore: ssh.CertTimeInfinity,
	}

	ce.SignCert(rand.Reader, signer)
	soc, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
	if err != nil {
		fmt.Printf("Error connecting to agent: %v\n", err)
		os.Exit(1)
	}

	local := agent.NewClient(soc)
	local.Add(agent.AddedKey{
		Certificate:  cr,
		PrivateKey:   pr,
		LifetimeSecs: 1,
	})
	local.Add(agent.AddedKey{
		Certificate:  ce,
		PrivateKey:   pe,
		LifetimeSecs: 1,
	})
}