certificates/authority/provisioner/ssh_test.go

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2019-08-01 00:46:28 +00:00
package provisioner
import (
"crypto"
"crypto/rand"
"fmt"
"reflect"
"time"
"golang.org/x/crypto/ssh"
)
func validateSSHCertificate(cert *ssh.Certificate, opts *SSHOptions) error {
switch {
case cert == nil:
return fmt.Errorf("certificate is nil")
case cert.Signature == nil:
return fmt.Errorf("certificate signature is nil")
case cert.SignatureKey == nil:
return fmt.Errorf("certificate signature is nil")
case !reflect.DeepEqual(cert.ValidPrincipals, opts.Principals):
return fmt.Errorf("certificate principals are not equal, want %v, got %v", opts.Principals, cert.ValidPrincipals)
case cert.CertType != ssh.UserCert && cert.CertType != ssh.HostCert:
return fmt.Errorf("certificate type %v is not valid", cert.CertType)
case opts.CertType == "user" && cert.CertType != ssh.UserCert:
return fmt.Errorf("certificate type is not valid, want %v, got %v", ssh.UserCert, cert.CertType)
case opts.CertType == "host" && cert.CertType != ssh.HostCert:
return fmt.Errorf("certificate type is not valid, want %v, got %v", ssh.HostCert, cert.CertType)
case cert.ValidAfter != uint64(opts.ValidAfter.Unix()):
return fmt.Errorf("certificate valid after is not valid, want %v, got %v", opts.ValidAfter.Unix(), time.Unix(int64(cert.ValidAfter), 0))
case cert.ValidBefore != uint64(opts.ValidBefore.Unix()):
return fmt.Errorf("certificate valid after is not valid, want %v, got %v", opts.ValidAfter.Unix(), time.Unix(int64(cert.ValidAfter), 0))
case opts.CertType == "user" && len(cert.Extensions) != 5:
return fmt.Errorf("certificate extensions number is invalid, want 5, got %d", len(cert.Extensions))
case opts.CertType == "host" && len(cert.Extensions) != 0:
return fmt.Errorf("certificate extensions number is invalid, want 0, got %d", len(cert.Extensions))
default:
return nil
}
}
func signSSHCertificate(key crypto.PublicKey, opts SSHOptions, signOpts []SignOption, signKey crypto.Signer) (*ssh.Certificate, error) {
pub, err := ssh.NewPublicKey(key)
if err != nil {
return nil, err
}
var mods []SSHCertificateModifier
var validators []SSHCertificateValidator
for _, op := range signOpts {
switch o := op.(type) {
// modify the ssh.Certificate
case SSHCertificateModifier:
mods = append(mods, o)
// modify the ssh.Certificate given the SSHOptions
case SSHCertificateOptionModifier:
mods = append(mods, o.Option(opts))
// validate the ssh.Certificate
case SSHCertificateValidator:
validators = append(validators, o)
// validate the given SSHOptions
case SSHCertificateOptionsValidator:
if err := o.Valid(opts); err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("signSSH: invalid extra option type %T", o)
}
}
// Build base certificate with the key and some random values
cert := &ssh.Certificate{
Nonce: []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 0},
Key: pub,
Serial: 1234567890,
}
// Use opts to modify the certificate
if err := opts.Modify(cert); err != nil {
return nil, err
}
// Use provisioner modifiers
for _, m := range mods {
if err := m.Modify(cert); err != nil {
return nil, err
}
}
// Get signer from authority keys
var signer ssh.Signer
switch cert.CertType {
case ssh.UserCert:
signer, err = ssh.NewSignerFromSigner(signKey)
case ssh.HostCert:
signer, err = ssh.NewSignerFromSigner(signKey)
default:
return nil, fmt.Errorf("unexpected ssh certificate type: %d", cert.CertType)
}
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if err != nil {
return nil, err
}
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cert.SignatureKey = signer.PublicKey()
// Get bytes for signing trailing the signature length.
data := cert.Marshal()
data = data[:len(data)-4]
// Sign the certificate
sig, err := signer.Sign(rand.Reader, data)
if err != nil {
return nil, err
}
cert.Signature = sig
// User provisioners validators
for _, v := range validators {
if err := v.Valid(cert); err != nil {
return nil, err
}
}
return cert, nil
}