nebula/cmd/nebula-cert/ca.go

125 lines
3.1 KiB
Go

package main
import (
"crypto/rand"
"flag"
"fmt"
"io"
"io/ioutil"
"os"
"strings"
"time"
"github.com/slackhq/nebula/cert"
"golang.org/x/crypto/ed25519"
)
type caFlags struct {
set *flag.FlagSet
name *string
duration *time.Duration
outKeyPath *string
outCertPath *string
groups *string
}
func newCaFlags() *caFlags {
cf := caFlags{set: flag.NewFlagSet("ca", flag.ContinueOnError)}
cf.set.Usage = func() {}
cf.name = cf.set.String("name", "", "Required: name of the certificate authority")
cf.duration = cf.set.Duration("duration", time.Duration(time.Hour*8760), "Optional: amount of time the certificate should be valid for. Valid time units are seconds: \"s\", minutes: \"m\", hours: \"h\"")
cf.outKeyPath = cf.set.String("out-key", "ca.key", "Optional: path to write the private key to")
cf.outCertPath = cf.set.String("out-crt", "ca.crt", "Optional: path to write the certificate to")
cf.groups = cf.set.String("groups", "", "Optional: comma separated list of groups. This will limit which groups subordinate certs can use")
return &cf
}
func ca(args []string, out io.Writer, errOut io.Writer) error {
cf := newCaFlags()
err := cf.set.Parse(args)
if err != nil {
return err
}
if err := mustFlagString("name", cf.name); err != nil {
return err
}
if err := mustFlagString("out-key", cf.outKeyPath); err != nil {
return err
}
if err := mustFlagString("out-crt", cf.outCertPath); err != nil {
return err
}
if *cf.duration <= 0 {
return &helpError{"-duration must be greater than 0"}
}
groups := []string{}
if *cf.groups != "" {
for _, rg := range strings.Split(*cf.groups, ",") {
g := strings.TrimSpace(rg)
if g != "" {
groups = append(groups, g)
}
}
}
pub, rawPriv, err := ed25519.GenerateKey(rand.Reader)
if err != nil {
return fmt.Errorf("error while generating ed25519 keys: %s", err)
}
nc := cert.NebulaCertificate{
Details: cert.NebulaCertificateDetails{
Name: *cf.name,
Groups: groups,
NotBefore: time.Now(),
NotAfter: time.Now().Add(*cf.duration),
PublicKey: pub,
IsCA: true,
},
}
if _, err := os.Stat(*cf.outKeyPath); err == nil {
return fmt.Errorf("refusing to overwrite existing CA key: %s", *cf.outKeyPath)
}
if _, err := os.Stat(*cf.outCertPath); err == nil {
return fmt.Errorf("refusing to overwrite existing CA cert: %s", *cf.outCertPath)
}
err = nc.Sign(rawPriv)
if err != nil {
return fmt.Errorf("error while signing: %s", err)
}
err = ioutil.WriteFile(*cf.outKeyPath, cert.MarshalEd25519PrivateKey(rawPriv), 0600)
if err != nil {
return fmt.Errorf("error while writing out-key: %s", err)
}
b, err := nc.MarshalToPEM()
if err != nil {
return fmt.Errorf("error while marshalling certificate: %s", err)
}
err = ioutil.WriteFile(*cf.outCertPath, b, 0600)
if err != nil {
return fmt.Errorf("error while writing out-crt: %s", err)
}
return nil
}
func caSummary() string {
return "ca <flags>: create a self signed certificate authority"
}
func caHelp(out io.Writer) {
cf := newCaFlags()
out.Write([]byte("Usage of " + os.Args[0] + " " + caSummary() + "\n"))
cf.set.SetOutput(out)
cf.set.PrintDefaults()
}